Casting why not smooth-cast 310 or 322? (20 minute pot life)

good questions!
???????

 

Raising hand! I had used the 310 for a while. It worked good for me. I set up my original molds in the dumbest way possible, so I decided to degass the resin quickly before pouring. To do that I needed the long pot life. I use 305 now, but if i want to cram a bunch of molds in the pressure chamber, I think I'll need to go back to the 310. I think it's all sixes in the end. Lots of molds at one time that takes longer, or a few molds at a time that are finished sooner. I could get all the molds poured for my tinies using the 305, and they all fit in the pot. I think if your pour gates aren't too small, you should be able to pour quickly.

How big is Bug again (that's who's being molded now, right?)?

 

good questions!!!
And where (getting way ahead of myself here) can one find and buy the proper pots and the like for removing air???
a what all do you need? and cost is a factor---but so is size and safty

 

I keep readingthis stuff on mold making/resin casting and sometimes I feel like I'm listening to a discussion in another language! The pressure pot thing is really throwing me off. I suppose I should just back up and get a couple of BJDs sculpted before I really even need to worry about all this. At least I will know where to come looking when I'm ready for the info.

I really can't wait to hear about the retreat here in Ohio.

 

Pat, I did very few molds at a time when I used the 3 minute stuff, and the 5 minute stuff was a little better, but I still had to rush and get sweaty. Then I had a break after the first pour while the resin set up, and then I de-potted the first batch, mixed, poured and potted the second batch and then demolded, trimmed and cleaned the first batch... then de-potted the second batch, mixed poured and potted the third batch and cleaned up the second batch.

I find now (in colder weather) than 7 minutes is enough for me. If it were hotter I might need the 310? But I don't like to have to wait so long to demold.. I'd usually only pour the same mold once per day, unless I was trying to do two dolls in one day, but for a resin that takes 2-4 hrs to set up, how long do I need to leave it pressurised.. That's what's bugging me a bit about the 24 hr set silicone.. I don't want to risk bubbles so I'm leaving it in for 24 hrs, but maybe I could take it out after 12 and use the pot for something else.. I still need to wait 24 hrs before demolding though.

 

I'd get the 310, if that's like 305 in colour I think; white not cream. (I just ordered 305 today.)

You shouldn't need a lot of resin as a reservoir.. usually I just fill the mold and spout right up and it's about the same level when I demold, but maybe a little less, hardly noticeable. I guess the idea is to have enough space between the top of the part and the surface of the mold that the spout is long enough for air to rise and resin to sink in to fill any gaps. The bubbles that you remove by using a pressurepot are usually very small, but visible to the eye.

Which pressurepot did you end up getting?

 

Twigling????? What sixe pot do you use????
I really want (some day ) to do large dolls---so I would like to know what type and sixe I should be saving for--lol

I really like the white look --but also a really soft cream---I love how soft and lovely that can be

of course I always love pink--lol---

so have you already taken orders on your doll?
do you have a web site---
I know all these questions--

 

question to Twigling. are you leaving the mold in the pressur pot for 24 hours?

 

that was size--oops

 

Awakened Dreams.. mine is 10 liters ~ I'm not taking any orders yet

Nancy, I leave the molds made from Polytek Platsil 71-40 in for 24 hours because that is the time that particular silicone takes to cure. I may be able to take it out earlier, but don't want to risk it.

 

Thank --
I would love to be amoung the firsts to know when you do begin taking preorders
please

 

Laurie, they will be sold via an online retailer (enchantmentdoll.com) and they won't be taking preorders, just making dolls and then selling what they have in stock. I will be casting more occasional dolls, one-offs and bespoke etc. I'm sure there will be an announcement when sales are open.

 

thanks--good for you!!!!

 

Twigling...I have never used polytex products. do you also need to vacuum the silicone too?

 

I don't have a vacuum chamber, so I pressurise the molds instead. I think even if I did vacuum the silicone I would still want to pressurise the molds incase air got introduced into the mix when I pour them.

I think SmoothOn and Polytek are both based in Easton PA.. wonder if one is an offshoot of the other? I like Polytek's addition cured silicones, but their resins don't have enough potlife for me.

 

Hi Twigling,
If you leave a little of the silicon on a cup or whatever after you pour the molds you can test it to see when it's set (even just the residue in the container you mixed the silicon in would do) .I would not take the pressure off until it is fully set because it can introduce bubbles again and spoil your mold.

Kaye

 

Hi Kaye

Yes there is usually silicone left in the mixing container and I do check it. The 24 hr set was hard after 12 hours, and I still opted to leave it in.

 

there is draw back to the longer demold time they tend to sit longer in a mold before being removed but this is true of any resin. the longer it sits the worse it is for the mold. and the more often in a row you cast out of your mold the faster it will degrade by process of transmigration of resin into silicone. in other words if you vast once a day out of your mold you will have a longer life and more good casts than if you do a lot every day. due to transmigration, heat speeds it up, so more casts more heat. shorter mold life.I have tried more materials and releases to stop than you can imagine but nothing will prevent it but you can slow it by limiting you casts per session