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Casting What is a realistic result for home casting...

Jul 15, 2019

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    1. ...without a pressure pot or vacuum chamber?

      I have tried twice so far to cast my head, and the results are pretty bad. I had really high hopes because the mold-making process was so straightforward, but I don't know what I did wrong this time. Both heads did cure, but the first one was so full of bubbles that parts of her looked like they were made of foam, and the second one isn't much better (though I avoided large air pockets at least).

      Supples: Smooth Cast 326, 9 minute pot life
      UVO pigments
      Sun Devil anti-UV additive
      2 two-part silicone molds (one for the head, one for the cap)
      talc baby powder

      I measured parts A and B properly into graduated plastic mixing cups, then thoroughly mixed the pigments and Sun Devil into part B. I let it sit for a while for bubbles to pop themselves, then poured enough part B for just one of the molds into a new plastic cup, and mixed in a corresponding amount of part A. I mixed with the handle of a plastic fork, scraping the sides and bottom of the cup. There were a few surface bubbles at this point, which I flicked the cup to get rid of. I then poured the resin into the mold in a thin stream down the handle of the fork. A few times the stream broke, so I wonder if the resin splashing back in would have produced more bubbles.

      Anyway, by the time I had one of the molds poured, the remainder of the resin still in the cup had heated up. I tapped all over the mold with my hands and flicked it to try to encourage the bubbles to escape. I repeated the process for the second mold.

      Here is the result :...(

      [​IMG]Second casting. Look at all the bubbles :'( by AndreaJEP, on Flickr

      [​IMG]Second casting. Look at all the bubbles :'( by AndreaJEP, on Flickr

      [​IMG]Second casting. Look at all the bubbles :'( by AndreaJEP, on Flickr

      [​IMG]Second casting. Look at all the bubbles :'( by AndreaJEP, on Flickr

      [​IMG]Second casting. Look at all the bubbles :'( by AndreaJEP, on Flickr

      [​IMG]Second casting. Look at all the bubbles :'( by AndreaJEP, on Flickr

      Seams partially cleaned up
      [​IMG]Second casting. Look at all the bubbles :'( by AndreaJEP, on Flickr

      [​IMG]Second casting. Look at all the bubbles :'( by AndreaJEP, on Flickr

      I feel like I should be able to do better than this. Smooth-on claims that their 325 series doesn't require degassing, and they have a tutorial video that shows them getting a lovely casting from this series of resin, and they say nothing about using a pressure pot.

      I don't know if my expectations are unrealistic, or if I'm just doing something wrong (and in that case, I don't know what I'm doing wrong). What kind of results have you achieved with home casting without machinery? And what can I do to improve my result?
       
      #1 Zardi, Jul 15, 2019
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    2. first time home castings usually have some faults in them. . Sometimes it's a problem with materials. Try a "Junk cast" of just the resin without the colorants.
       
      #2 Elysion gear, Jul 17, 2019
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    3. I probably should have tried a junk cast from the beginning. Still, I don't know what I'm doing wrong or how good of a result is even reasonable to expect. That's what I was hoping to find out.

      I'll try a junk cast tomorrow and see what happens, though.
       
      #3 Zardi, Jul 17, 2019
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    4. Was the mould wet or moist? That’s extreme bubbling and water can cause polyurethane to foam slightly.
       
      #4 Spuggey, Jul 18, 2019
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    5. Don't forget to keep us updated on your ventures
       
      #5 TheJokerAnachronism, Jul 18, 2019
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    6. Did you mix up the compounds immediately after shaking them? Try shaking and letting the bottles rest for a couple of minutes before mixing them up.
       
      #6 LilaAIP, Jul 18, 2019
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    7. @Zardi
      You should be able to produce a piece without bubbles in the most visible places.
      Here a couple pictures of the doll I cast without vacuum chamber and pressure pot.
      Mauri junk cast
      mauri4
      I used Alumilite Amazing Casting Resin instead of Smooth-On. I tried putting baby powder in my mold too and that actually caused my pieces not curing on the surface, they remained sticky. I ended up just pouring resin into clean molds if I remember correctly. So maybe try pouring resin into clean molds and use resin without dye like @Elysion gear suggested or a different resin? Alumilite kit that I used is $17 on Amazon.
       
      #7 CrazyAnna, Jul 18, 2019
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    8. The mold was completely dry and dusted with talcum powder. The humidity inside my house was less than 50% according to my thermostat, but I don't remember the exact number. I did let the bottles rest before pouring.

      I did another tinted cast yesterday before seeing the post about the junk cast, and I noticed that the orange UVO pigment was basically a water consistency, and the brown wasn't much better, so I tinted the resin just with yellow, red, green, and white. I hoped that is where the moisture was coming from, but now I know that isn't it either. I unmolded it earlier. The bubbling is about the same (better in some places, worse in others), but the difference is that I let the extra resin cure inside the mixing cup. The cured excess resin is almost perfectly bubble-free. I think I noticed two bubbles that were barely visible.

      So, it seems to me that the bubbles are occurring during pouring or due to the mold configuration. I can't imagine mold configuration being a problem for the cap, since it's such a simple shape. The pouring spouts on both molds, however, are really rough. I tried sticking straws into them to pour into, but some resin still flows around the straws and into the mold just because I have a hard time keeping the stream of resin steady.

      Could the roughness of the pouring spouts be what is generating the bubbles? If so, how do I cut the silicone smoothly? Most of my cutting tools just push it around. Or, I could put a straw in the spout again and use a plastic stick of some kind during pouring to direct the resin directly into the straw.

      Those pictures are really informative, thank you! My next attempt will be a junk cast with no baby powder. If I get through this whole resin kit without a successful cast, I will try Alumilite instead. Or maybe even before that. I know I can get decent eye blanks out of the Smooth On resin, at least.
       
      #8 Zardi, Jul 18, 2019
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    9. Are you using wooden or plastic to stir? Wooden mixing utensils can sometimes absorb moisture from the air. Even that can make a difference.
      @CrazyAnna is right, even junk casts shouldn’t have that many bubbles. Mine generally have a couple and some on their ears, but nothing like as bad as your pictures. It may be worth buying a new resin batch to test.

      It probably isn’t the pour spout. I’ve created some terrible ones, cut out roughly with a scalpel. They always work about the same. In some cases, baby powder has additional chemicals and perfumes, any of which might react with the resin. Talc release agent is pure talc. I use Macwax now as a release. Similar sprays might be better when creating a two part mould. With actual casting of polyurethane in silicone, you shouldn’t need any release agent. Silicone will release anything but silicone!
       
      #9 Spuggey, Jul 18, 2019
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    10. I'm using plastic to stir. I even used plastic coffee stirrers to mix the UVO pigments together and transfer it to the part B cup.

      I checked the baby powder and it does have a fragrance :doh I'll clean out the molds with alcohol swabs (assuming that's ok?? I'm doubting everything now) before I try again.
       
      #10 Zardi, Jul 18, 2019
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    11. Oh my goodness, I think it really is the baby powder. I just started an experiment. What I intended to do was this:

      1. Mix a small amount of resin in a clean cup.
      2. Pour some into a plastic mixing cup dusted with baby powder.
      3. Pour some into a small silicone mold dusted with baby powder. I have used the mold before for bubble-free UV resin castings, without baby powder. Downside is that the shape of the mold is very simple so it doesn't compare to a doll head.
      4. Leave the rest of the mixed resin in the original cup to cure, without touching any baby powder, as a control.

      What actually happened is that the mixing cup I grabbed to initially combine A and B had had the brush resting in it that I'd used to dust my head molds with baby powder :doh It was contaminated from the beginning, ruining my "control" completely. The interesting part? Part B was completely bubble free in my dedicated "part B" cup...but as soon as I poured it into the contaminated mixing cup, it created bubbles that I couldn't get rid of.

      I went ahead and mixed part A in anyway, and poured the mixture into the purposely-powdered cup and mold. I can't see inside the mold very well, but the bubbling in the cup continued to get worse and worse until the resin got fairly firm. It's still really hot at the moment, but is hard and no longer sticky, and it's got so many little bubbles that it looks like a cup of soda :aeyepop:

      So...no more baby powder! Lesson learned.

      Do you think wiping the molds with alcohol swabs be sufficient? Or should I soak them in soapy water and then let them dry out really well? I want to make sure I get rid of all the baby powder before I try again.
       
      #11 Zardi, Jul 19, 2019
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    12. I’d give them a good wash! If using polyurethane in silicone, no release agent is necessary. The release is only really needed when you pour the second half of the two part mould. Glad you found the issue! The number and consistency of the bubbles in your picture didn’t look like mixing or pouring mishaps, they looked clearly like a chemical reaction to me so that’s why I thought it was that!
       
      #12 Spuggey, Jul 20, 2019
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    13. @Zardi I ran just quicky through your posts and I'd like to add I have had the same outcome with my first home casting. The material was Smooth Cast as well, except that was 322. I repeated the casting without colorant with the same result. I've consulted this with an experienced caster and the supplier and their verdict was: the moisture. Strange enough, the supplier tested my package of resin himself with the same result. So this means that the moisture was in the material in the package itself. He sent me a new package for free. I didn't try it since. Btw, your sculpt looks very good. Check my photos of the cast below. I'm looking forward to sharing experience!
      [​IMG]Untitled by Sillion, on Flickr
       
      #13 Sillion, Jul 20, 2019
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    14. Yep, polyurethane hates water!
       
      #14 Spuggey, Jul 21, 2019
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    15. Here are my latest results. This was done with NO mold release of any kind, after washing the molds and mixing cups, and allowing them to dry thoroughly. There were plastic straws/coffee stirrers placed into the pouring spouts and air vents in order to make demolding easier.

      The head is lighter in color this time on purpose to better match the body. Also, please disregard the mess where the top magnet hole should be. I accidentally cut the mold while unmolding one of my earlier attempts, so that's what you're seeing.

      Here is the head. The mold is oriented so that the chin is at the bottom. The bubbles look more like the type @Sillion got. There are fewer on the outside, but still a lot on the inside.
      [​IMG]Another casting attempt, no baby powder. by AndreaJEP, on Flickr

      [​IMG]Another casting attempt, no baby powder. by AndreaJEP, on Flickr

      [​IMG]Another casting attempt, no baby powder. by AndreaJEP, on Flickr

      [​IMG]

      [​IMG]Headcap, no release agent. by AndreaJEP, on Flickr

      [​IMG]Headcap, no release agent. by AndreaJEP, on Flickr

      [​IMG]Headcap, no release agent. by AndreaJEP, on Flickr

      Here is a photo of the inside of the previous casting on the left, and the newer one on the right. There are still so many bubbles, the difference being that they look...softer? Kind of? And some of them broke the surface. The "insides" of the head and cap are at the top of both molds. @Spuggey Do these still look like chemical reaction bubbles?
      [​IMG]Head on left used baby powder as a release agent, head on right and head cap did not. by AndreaJEP, on Flickr


      Here are various tips I've found online for reducing bubbles in casting, some of which contradict each other.
      • Dust the mold with baby powder -- clearly a bad idea!! But the ears actually came out better/fully-formed on the baby powder cast. Maybe it's worth trying to find pure talcum powder? I don't know. Tip comes from Alumilite, not Smooth-on.
      • Pour the resin gently down the side of the mold (or pour spout), with the mold tilted so that the resin doesn't splash.
      • Pour the resin in a thin stream from high up so the bubbles have a chance to burst. However, this is what I've been doing, and it doesn't seem to have helped.
      • Fill the mold about halfway, then roll it around to push air out of the undercuts. Squeeze it a few times. When you see the air come up, fill the rest of the mold.
      • Fill the mold completely, then place a sheet of acrylic over the pour spout/vents and roll the mold around. Turn it right side up to finish curing and remove the acrylic. I actually did this with the head in the first post, but I forgot to wash the acrylic sheet afterward, so I didn't do that with this casting.
      • Pre-heat the molds in a warm oven or in the microwave.
      For now, I'm going to accept the cap as-is, but I want to try again with the head either until I get one I'm happy with, or I run out of resin. Anyone have other ideas about what I can try?
       
      #15 Zardi, Jul 22, 2019
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    16. I think there is improvement! The headcup has some spots, but it is actually almost bubble free on the outer surface.
      I just remembered now that I had to remake the head mold myself because I realized that when the face surface is at the bottom of the mold (head facing down) then the bubbles theoretically should move up and away from the surface and further into resin. I am not sure if this will work for you, depends on where the pouring channels are. You could try to orient the head mold in such way that the face is pointing down, pour resin and let it cure in that position. Does this make sense?
      From the earlier pictures it looks like the head is in upright position in the mold, is there less bubbles under the chin and around the neck hole area?
       
      #16 CrazyAnna, Jul 22, 2019
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    17. No, the face is in a diagonal position within the mold, with the chin at the very bottom of the mold. The "inside" surface of the head faces up. I figure this is why there are actually fewer bubbles on the face than on the inside. The chin itself has a few white-ish spots on it, but it and the lower lip don't have any bubbles at all. The highest concentration of bubbles on the face itself is on the upper lip, which might be a bit of an undercut...or at least horizontal in the mold, so the I guess the bubbles had a hard time escaping.

      I also realized that I forgot to check the humidity yesterday before casting. I really need to be more careful about that.
       
      #17 Zardi, Jul 22, 2019
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    18. This is certainly odd. I’ve never used smoothcast at home, but I’m tempted to give it a try just to see if I get the same issues as you. I’ve used pigments, talc and other fillers and not had this problem. The only time I’ve seen foaming & bubbling like your headcap is when there was water in the mould, but that’s not the case here. I use a generic brand ‘cheap’ polyurethanes and they all perform way better than this, but I know smoothon are a leading brand & I know others have no problems with them.

      Humidity can be an issue, especially in slow cure resins. I use a fast-cast, which is set hard in 10 minutes (this means a lot of practice in a quick mix and pour - you get about two minutes from combining the two parts to finishing the pour). That said, I’m in the U.K. where everything is soggy for 70% of the year, and I’ve still not had the issue. I’ve poured resin in a damp shed in the rain with no problems.

      It’s possible you got a bad batch, that’s contaminated or water damaged. I know it’s costly, but would you consider trying a different resin? You could also experiment without uv additive & without pigments. Unfortunately, this may be a learning curve until you find the cause. You may just get a second batch and find it solves the problem.

      For the trapped face bubbles, try to let the resin rest a minute before pouring, and stir it slowly to avoid introducing air. You can also tap the mould. I just bump it on the table a few times (yes, resin will splash out a bit so be warned) and tilt & tap it. This can dislodge some trapped air.

      Nice sculpt, btw!
       
      #18 Spuggey, Jul 23, 2019
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    19. I thought I'd share pictures of my junk cast. I let the mixed resin rest a bit to eliminate bubbles. There were only a few, but they were stubbornly sticking around this time. I used my mixing stick (a plastic spoon handle) to pop them before pouring.

      I tried pouring slowly and carefully directly into the spout with the mold tilted so the resin wouldn't splash in. I also squeezed the mold a few times to try forcing air out, and then once it was full, I placed an acrylic sheet over the pouring spout and rotated the mold around a few times (like in Smooth-On's tutorial). I've been tapping the mold every time after pouring, and made sure to do it this time as well.

      I had fewer bubbles that actually broke the surface, but otherwise the result is pretty similar.
      [​IMG]Junk cast. Bubbling is still about the same. by AndreaJEP, on Flickr

      [​IMG]Junk cast. Bubbling is still about the same. by AndreaJEP, on Flickr

      [​IMG]Junk cast. Bubbling is still about the same. by AndreaJEP, on Flickr

      This ear helix consistently doesn't get cast once I stopped using baby powder, and I don't know why.
      [​IMG]Junk cast. Bubbling is still about the same. by AndreaJEP, on Flickr

      [​IMG]Junk cast. Bubbling is still about the same. by AndreaJEP, on Flickr

      [​IMG]Junk cast. Bubbling is still about the same. by AndreaJEP, on Flickr

      [​IMG]Junk cast. Bubbling is still about the same. by AndreaJEP, on Flickr

      [​IMG]Junk cast. Bubbling is still about the same. by AndreaJEP, on Flickr

      [​IMG]Junk cast. Bubbling is still about the same. by AndreaJEP, on Flickr

      I really don't know what to do at this point. I think I'll send some of these pictures to Smooth-On and see if they have any feedback. Their customer service page forces you to agree not to ask them for any sort of guarantee, but that's not even what I want. Hopefully they won't see it that way and refuse to help.
       
      #19 Zardi, Jul 25, 2019
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    20. Here is what Smooth-On had to say.

      Me:
      Smooth-On:
      Me:
      Smooth-On:
      The only new suggestion in that list is to bake the baby powder. I searched online and someone suggests 200 F for an hour, fluffing the baby powder every 15 minutes so it dries evenly. I guess it's worth a shot. I'll bake/dry some baby powder, mix a small amount of resin, and dust a plastic cup with the dried baby powder so I can watch it while it cures. If I don't get resin soda again, then I'll try baked baby powder in my mold.
       
      #20 Zardi, Jul 26, 2019
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    21. This is a curious one! I’m still following the thread but am at a loss with advice... hopefully the baking will work.
       
      #21 Spuggey, Jul 26, 2019
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    22. Well, I baked some baby powder for 2.5 hours, then dusted it in a cup and poured in mixed resin.

      It seemed really promising at first. There was no instant bubble formation, and I watched it for a minute or two afterward. All seemed well, so I walked away for a few minutes.

      I got back to a very hot, nearly cured, cup of resin soda :doh It isn't as bubbly as the first baby powder test, but it's still pretty bubbly. I've sent these pictures to Smooth-On. Let's see what they say.

      [​IMG]Test with baked baby powder dusting the cup. Bubbles still formed during curing. by AndreaJEP, on Flickr

      [​IMG]Test with baked baby powder dusting the cup. Bubbles still formed during curing. by AndreaJEP, on Flickr

      [​IMG]Test with baked baby powder dusting the cup. Bubbles still formed during curing. by AndreaJEP, on Flickr



      In the mean time...
      My Smooth-On kit is almost empty and I have yet to solve my problem, so...which Alumilite kit did you use? What did you use to color your resin? I'm hoping I can still use the UVO pigments I got, or something else I already own :)
       
      #22 Zardi, Jul 26, 2019
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    23. I'll give Smooth-On one thing: they respond fast. Here is the condescending blow-off response I just got:
      I can't believe this dude tried to explain the definitions of clear and opaque. Seriously.

      If he wanted to tell me that my casts were going to have bubbles no matter what, then that's fine. Whether the amount of bubbling was normal was my initial question anyway. But he should have said that in the beginning, not gone round and round with all these suggestions, only to end with, "but you can see through clear stuff!!!"

      Sorry. I'm kinda pissed off right now. :vein
       
      #23 Zardi, Jul 26, 2019
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    24. Hey,
      I did some reading. It may... *might* be the 326 resin, which a lot of people seem to have issues with if not using a degassing chamber and pressure pot. It occurred to me that I’ve never used clear polyurethane, and that many clear ones are advertised as pro-only (although not 326). It’s possible that the semi clear resin has different properties to the white or cream coloured ones often used by home casters. Slow setting though it is, if I want clear casts I usually resort to epoxies.

      Obviously the issue with opaque resin is getting the colour you want, if you’re not going for pale. It’s possible, I’ve done it, but it’s not as easy. This may be why doll companies ask for extra for tan skin - pale cream (or NS) is close to the original resin colour and easier to obtain without issue.

      You’re in the U.S so I don’t know if this is available but I mostly use Polycraft Easyflo or fastcast. There’s also ‘Amazing casting resin’ (yep actually called that), but that is opaque white. It did give me a bunch of very quick, very bubble free casts though. I’ve not tried tinting amazing resin, but I have coloured Polycraft resin (and mixed powder, pigments, glitter, filler etc in it). Smooth-on don’t seem helpful at all, which is irritating. It’s also not true that you wouldn’t see bubbles if they’re that bad so I’m not sure what he’s on about. (I did one pour of Amazing with water in the mould - yes it bubbles, and yes, you could see them.)

      If I can get flickr sorted I’ll try to upload some examples of my tests for comparison. I’ve spent years playing with resins and I’m curious about this...
       
      #24 Spuggey, Jul 27, 2019
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    25. I just wanted to say I really appreciate the help that you and others in this thread are willing to give! Not only that, but the solidarity in knowing I'm not completely crazy to expect better results.

      I'm impressed by your Google skills. When I searched, I found a decent amount of info on 325, but pretty much nothing about 326. Pot life is theoretically the only difference between them. It makes me wonder if the longer pot time is part of the problem, considering the bubbles didn't form right away in my last cup test.

      I found some of the Polycraft resin on Amazon, but it looks like only larger and more expensive kits are available to me. Amazing Casting Resin is made my Alumilite, so I wonder if that's the same one @CrazyAnna used. If so, that's at least two people who have had decent results with that resin. I think I have seen it available locally, just need to make sure it's the same one.

      Alumilite has some...interesting dye names for their resins. The various browns are called "Caucasian," "African American," and "Native American." :aeyepop: But uh, maybe it'll be easier to get the color I want that way, and it suggests that Alumilite expects people to be making dolls and figurines with their resin. It also says the flesh tone dyes are formulated for their white resin.

      That would be an awesome resource if you are able to!
       
      #25 Zardi, Jul 27, 2019
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    26. @Zardi I used Alumilite Amazing Casting Resin too and their dyes. I also injected the liquid resin into my molds with a plastic measuring syringe (you can get them for free at pharmacies). The reason for syringe is that the pot life of that resin was very short and I was casting parts for 1/8 size doll, so there were some tight spots where I needed to get the resin in quickly as it was already thickening.
       
      #26 CrazyAnna, Jul 28, 2019
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    27. I got some Amazing Casting Resin at Michael's yesterday for $15 with a coupon. I did a junk cast of the head just in white and the result is actually really promising. I did nothing special to try reducing bubbles or anything...just poured it as fast as I could. Both ear helixes didn't quite cast and I noticed two large air bubbles on the inside surface, but I don't see any on the face at all. If I'd turned the mold around and done more squeezing, shaking, etc. I bet I could have gotten an even better result.

      Today, I mixed a small amount of ACR with black UVO pigment from my Smooth-On kit to make some black sclera eye blanks. I think I may have used too much dye because the eyes are still a bit flexible, but it's possible they will continue to harden overnight. (I poured less than an hour ago.) Anyway, there are some small bubbles on the back surface of the eye blanks, but very few on the actual front surfaces. Again, I did nothing whatsoever to try reducing bubbles and was just trying to get everything poured.

      I think this is very promising, considering I didn't really take any anti-bubble measures. :) Tomorrow, if the eye blanks are completely cured and rigid, I will go ahead and try casting a color-matched head and get some pictures.
       
      #27 Zardi, Jul 29, 2019
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    28. I've found one of my older head molds, it has a detail that may help you with your ear-bubble problem.
      [​IMG]Detalhe do molde by Lilian Pereira, no Flickr

      You'll need to cut a small opening on each ear to help the air bubbles escape, just wide enough for the air to go out once you pour your resin.
       
      #28 LilaAIP, Jul 30, 2019
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    29. I thought I'd share some pictures of the cast I got with Amazing Casting Resin. This is the third head I cast, the first being plain white and the second being a failed attempt at color matching the body :sweat It's not completely bubble-free, but it is SO much better than what I got with Smooth-Cast 326!

      There is no way I will be able to get this same color again, so my next step will be to cast the head and headcap together so they will at least match each other. Also, when I was cleaning up this head, I accidentally cut too much extra resin out of one of the eyes. I seriously need to be more careful.

      I took @LilaAIP's advice and cut a few of those slits above the ears, as well as in a few other places that the first two casts had air pockets. That pretty much took care of it :)

      There are a few tiny air bubbles visible on the face. If the head were blushed I don't think they would be visible at all. Ignore the nick that looks like an air bubble on the eyelid...it isn't. That's me not being careful in cleaning up the extra resin.
      [​IMG]Head cast using Amazing Casting Resin. by AndreaJEP, on Flickr

      [​IMG]Head cast using Amazing Casting Resin. by AndreaJEP, on Flickr


      Ignore the mess near the top, which is where I accidentally cut my mold. I'll have to resculpt that magnet hole on the final head no matter what. Otherwise, you can see a few bubbles where the air vents had been. It is NOT full of tiny bubbles like the Smooth-On heads.
      [​IMG]Head cast using Amazing Casting Resin. by AndreaJEP, on Flickr

      There are a few bubbles in one ear. But both helixes actually cast this time.
      [​IMG]Head cast using Amazing Casting Resin. by AndreaJEP, on Flickr

      Bubbles still accumulate here for some reason, but still not as bad as the Smooth-On cast.
      [​IMG]Head cast using Amazing Casting Resin. by AndreaJEP, on Flickr

      Comparison pictures!
      Amazing Casting Resin (top and left)
      The "best" Smooth-On cast I got (bottom and right)
      [​IMG]Amazing Casting Resin (top and left) vs. Smooth-Cast 326 (bottom and right) by AndreaJEP, on Flickr

      [​IMG]Amazing Casting Resin (top and left) vs. Smooth-Cast 326 (bottom and right) by AndreaJEP, on Flickr
       
      #29 Zardi, Jul 31, 2019
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    30. >_> I'm not nearly there yet, but I had been planning to get Smooth-On resin if I ever cast my own head... But just based on that CS rep, I think I would go with Alumilite now. :XD:
       
      #30 AirimirOfGondor, Sep 1, 2019
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    31. I scrolled through this thread and read most of it hopefully I didn't miss anything but I may have a suggestion! First off that Smooth On rep is bogus, try calling a Reynolds Advanced Materials rep! They are amazing and will happily answer your questions at length. I only buy my materials from them and I'm constantly calling them asking questions.

      What I am going to suggest is possibly trying a resin called Smooth-Cast 65D. It's not clear though so if you had your heart on a clear resin this won't be the thing for you. It's a resin that's designed to be used for slush casting, where you pour a bit of resin in then slosh it around the mold getting in all the nooks and crannies putting down a nice even layer of resin. This helps to eliminate bubbles! After doing a slush casted layer then you can pour in the resin like normal. And to be extra sure you are getting the bubbles out, try vibrating the mold by slapping the sides consistently to release any stuck bubbles. And best part is since it's a urethane resin if you are using a silicone mold there is no need for mold release.

      I haven't finished sculpting my first doll just yet but I work with molds every day figured I'd put in my two cents! Good luck with figuring out your problem!
       
      #31 Ashes, Sep 27, 2019
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    32. I have to add my very bad experience with Smooth Cast resin. I've already reported it here but the sad story was going on. I received a new package of the resin from my supplier after I had claimed the first package of material was defect. I requested Smooth-Cast 321 instead - the same series but with shorter pot life and cure time. My hope was at high level that this would work this time. But - nope. The results were exactly the same. I pursued all the instructions, I was super careful to avoid any even small risk of moisture etc. The temperature and humidity in the room were on ideal levels. And again, the resin started foaming once the curing process was initiated. I made several control castings into different OPEN small moulds from two different kinds of silicone and the result was the same - terrible. I will add photos later on. The only part of resin that stayed bubble free was the remnant in the PP cup. My resume was that Smooth-Cast (at least that from 320 series) hates silicone! Wait, isn't it supposed to be cast in silicone moulds?? The only answer that comes to my mind is, that Smooth-Cast hates resin from OTHER makers than Smooth-Cast. Mine was from other maker asi I wanted a translucent one to be able to produce one-piece mould which opens with cutting.
      So I really don't know what to think about it.
       
      #32 Sillion, Sep 28, 2019
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    33. Hi Zardi..I too am having issues with bubbles..which I have never had with the products I use..I've been considering any and all possible causes..two different colors and brands doing the same thing..I have read your entire thread and like you I'm very careful..so I am at a loss as to what it could be..I thought maybe the woodstove in the front part of the house but from what I have been ready it's a dry heat will lower humidy..so I'm stumped and perplexed..I dont want to waste resin casting over and over but at the same time I want to cast my body..but if it did the same thing I would literally cry..so Im waiting maybe someone will help me figure it out in my post :(
       
      #33 Fattoe, Dec 9, 2019
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    34. I’ve got some smooth cast. I’ll report back with my findings!
       
      #34 Spuggey, Dec 10, 2019
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    35. I'm excited to hear about your results
       
      #35 Fattoe, Dec 10, 2019
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    36. I also look forward to seeing your results!
       
      #36 Zardi, Dec 10, 2019
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    37. Thanks guys. Might be after Christmas now because.... Christmas.
       
      #37 Spuggey, Dec 10, 2019
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    38. Hi Zardi
      I was wondering how your casting is going and if you solved your bubble problem..I have a friend that's getting me environmental resin..she does miniatures and showed me a piece..I was actually shocked at the quality of the resin it has a very luminous quality..she said she uses it because it works so well even with deep under cuts and it is virtually bubble free each time she uses it..I did get a new batch of my normal resin..the results were better but still had too many bubbles on the back of the head and the neck hole to be happy with..I dont get it I have used it for the last couple of years with no issues..and boom all of a sudden it bubbles every time
       
      #38 Fattoe, Jan 4, 2020
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    39. I did several more casts with Amazing Casting Resin to try to get the color right (to match the existing body), and eventually settled on one and did a face-up, but the results are still pretty much what you see above. Where did your friend get environmental resin? I'd be open to buying some and giving it another go.

      I have some 2-part epoxy resin from Sophie & Toffee that I may try, but it takes over a day to cure so I haven't had the patience yet.
       
      #39 Zardi, Jan 5, 2020
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    40. Well after talking to her I'm nill on the resin she uses..it too had a long cure time and she has to put silica or silicates in it to get that lovely soft look it has.. I would have to add pigment to it also..too much work for this old gal..lol..so I guess I will look for another resin to try :(
       
      #40 Fattoe, Jan 7, 2020
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    41. Thanks for checking anyway. I'll give the S&T resin a try one of these days and at least see how the headcap turns out.
       
      #41 Zardi, Jan 7, 2020
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    42. I'm excited to see how it turns out..let me know when you do :) ❤
       
      #42 Fattoe, Jan 7, 2020
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    43. I ended up pouring some S&T epoxy resin into the head mold last night. The leftover in the mixing cup is still gooey, so I may wait until tomorrow evening to demold it, just to be safe. I'll post pictures here once that's done.
       
      #43 Zardi, Jan 12, 2020
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    44. I have my fingers crossed for you..it'll turn out great..(positivity) :)
       
      #44 Fattoe, Jan 12, 2020
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    45. I hope so! I'm a little worried that the resin is still so squishy because it's supposed to have a 24 hour cure time. It's been probably 20 hours now, and it's got a taffy-like consistency. I hope I mixed it thoroughly enough.
       
      #45 Zardi, Jan 12, 2020
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    46. Humm I've had resin cure kinda slow..you could try warming your mold..I had to once..it actually worked fairly well
       
      #46 Fattoe, Jan 12, 2020
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    47. Yeah, I should have done that. I didn't even think about it. But can I warm it now that the resin is already inside? My only options are to stick it in a low-temp oven (which seems like a bad idea for the resin), or to take a hair dryer to it.
       
      #47 Zardi, Jan 12, 2020
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    48. Absolutely..I warmed mine after the resin was in it..like you it stayed kind of rubbery not stiff in the mixing cup..I heated the oven turned it off then put it in since I was afraid it would damage my mold..after it warmed up good it sat for a couple hours I used a toothpick to poke in the pour hole to see if it was harder or still softer
       
      #48 Fattoe, Jan 12, 2020
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    49. Well, here we are on Wednesday night, and the head never cured. It's a putty consistency now, and has been for at least 24 hours, so I think that's as far as it's going to go. I don't know if I got a bad batch of resin, if I measured it wrong, or if I didn't mix it well enough. I suspect insufficient mixing is the problem, though.

      I do wonder, though...this particular resin is labelled as being for "larger parts," so maybe the head wasn't big enough to generate sufficient heat?

      The putty head has roughly the same amount of bubbling as the Amazing Casting Resin ones, maybe a little less.

      I have some 1:1 epoxy from S&T that I want to try on the head, since I've got it lying around. I used it for a few smaller molds and it cured nicely, though it still takes a day or two.
       
      #49 Zardi, Jan 15, 2020
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    50. :( I'm sorry it didn't cure..I think it tis the season for doll making woes in general..I know you will get it to where you want it to be..I'm still hangin out waiting to see your head in all of its glory..hugs.. :)
       
      #50 Fattoe, Jan 15, 2020
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    51. This is shockingly strange as I have never experienced bubbling like that with epoxy. Maybe it’s the weather/humidity where you live?
       
      #51 Spuggey, Jan 16, 2020
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    52. Maybe they've sold you the wrong stuff? There is a type of epoxy resin that cures into a soft-rubber-ish state, used mainly in laminated surfaces and small stuff, like keychains.
       
      #52 LilaAIP, Jan 16, 2020
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    53. I don't know why I can't get 2-part resin to work when everyone else seems to be able to :...( It was a humid day, but my indoor humidity (according to my thermostat) was under 45%. Unless that's considered high?

      This isn't their soft resin. It came in a subscription box, so if there were an issue with it or people were sent the wrong resin, I would have expected to see something on Instagram about it :(

      This is the one: Clear AB Epoxy Resin Hard (Ratio 3:1) - 120g (for larger molds)
       
      #53 Zardi, Jan 16, 2020
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    54. Maybe I’m a little late and I hope I’m not repeating something that didn’t work, but for the first type of resin you tried you could try warming up the resin before you mix it, place the bottles in a container of warm water for ten minutes (of course make sure they are sealed well and keep the tops above the water) disclaimer though I have not used smooth-on brand before but this worked for another 2 part resin! good luck c:
       
      #54 Karabee, Jan 16, 2020
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    55. I've long since given up on Smooth-On resin. Every resin I've tried since has been less bubbly. Thanks anyway.

      ------------------------

      You know, I think I'm going to start fresh and make a new mold, at least for the head itself. I had to carve the pouring and air escape holes after the fact, so they've always been messy looking and made the casting look rough even without the bubbles. And maybe orienting the head differently in the mold will help air escape.
       
      #55 Zardi, Jan 16, 2020
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    56. So, sorry for the delay, but due to home renovations I’ve been unable to do any casting for ages.

      I did a test with smooth cast 325 and used smooth on ‘sorta-clear 37’ silicone. The silicone was a bubbly nightmare but turned out okay. It had a few bubbles that damaged the cast but not many.

      I used my pressure pot at 30psi. The resin left in the cup had some bubbles. But the cast had none. None at all.

      [​IMG]
      Here’s a super close up of it. The whole cast is like that: perfect.

      It’s strange... even the 325 that cured in the cup, with a steamer on in the room, didn’t bubble like yours has. I am baffled by this. But I would say the only, only way to guarantee a bubble free cast is with a pressure pot. Smooth on are a company that provide materials to pros (I’ve been in a film SFX department & can confirm they use the same supplies) so I wouldn’t say the products are bad at all. I am utterly baffled now.
       
      #56 Spuggey, Jan 17, 2020
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    57. Oi :doh That makes me think that I probably had a bad batch and the rep I emailed with just didn't want to admit the possibility (especially since the Alumilite resin did noticeably better).
       
      #57 Zardi, Jan 17, 2020
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    58. I may just bite the bullet and get a pressure pot and...compressor? Which one do you use, @Spuggey ?
       
      #58 Zardi, Jan 17, 2020
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    59. Mine came from a U.K. based company, but I think amazon have similar ones.This is the one I have. With compressors, pretty much any one will do. I used the one from my airbrush, which is a tiny 3 bar one (hence I only got 30psi) but the tank can work at 4 or 5 bar.

      Be careful with spray paint tanks: they’re not the same, but the resin tank is no more expensive so just get the right one. Also, theres a lot of tutorials on making one at home, and I can only warn against it. They are potentially dangerous so please just buy one from a proper company with safety valves etc.
       
      #59 Spuggey, Jan 17, 2020
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    60. Thanks :) I'll keep looking around for one. I'm not finding very many resin tanks (most are paint tanks), and the cheapest one is $250, which is over twice the price of the cheapest paint tanks. I definitely wouldn't make my own, though :sweat That sounds terrifying.
       
      #60 Zardi, Jan 18, 2020
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