Repair Help with Weird Mottling

It looks like some MSC/sealant remnants to me. I've had some really stubborn spots over the years, and usually I resort to light sanding (very light if you're dying!) to get it off. I found some 12,000 grit sandpaper used for modeling kits at a local craft store and used that to very gently sand it off. It took time and patience, but we got there Some sealants take forever to get off, no matter how well you scrub with Winsor and Newton or acetone.

 

I agree its the sealant. You still have some sealants on it. There’s a chance it gotten into the pores of the resin and it would be difficult to clean, and again, I agree that you will need to lightly sand the surface to get it completely cleaned.

 

I am not entirely sure those are sealant residues. Can you scratch it off? Then yes, it's residue. Keep using a magic eraser, a non-aggressive solvent (like isopropyl 90%+ strength) and scrub. Make sure to regularly rinse with water so the loosened residues are washed off while it's still wet. If you let it dry it will just bake on again. Do not let it soak.

However, I think the resin probably got damaged by you using acetone. Acetone is way too aggressive for resin and can cause it to soften or show other unpleasant changes. Don't use it anymore in future because you never know how resin will react to it.

Adding: someone mentioned below that sanding spots can get more pronounced, that is true. I've especially seen this in darker skinned dolls once they got cleaned for the first time. Spraying on sealant often helps to make it even out again.

 

The acetone seems to have "bleached" some of the pigment. I had that happen to an old NS Souldoll head of mine, albeit a bit more subtle (probably because it was NS), and a Bluefairy doll. It's very unfortunate. I've been trying to avoid acetone ever since that experience, but isopropyl alcohol isn't enough sometimes.

 

What they all said, yes. But all you will need to do to fix it is some wet-sanding- it is very repairable and probably only surface deep.

 

When I've seen this on my own dolls, it was areas of sanding (seam lines etc.) on older dolls that became more pronounced after a thorough deep-clean.

 

I’ve had that happen multiple times when I’m cleaning old heads and all it’s ever required for me is extra rounds of cleaning- I’ve never had to resort to sanding. I use 90% isopropyl alcohol, and I lightly scrub the area with that > rinse > dry with a soft towel > see where residue is left > repeat until clean. When I’m done I usually do a light wash with dish soap, rinse well, and dry to make sure any of the cleaning agents I was using were gone. I've never had it do permanent damage, even when it initially showed up after using acetone. I panicked so much when it first happened!

 

I personally don’t use acetone I had it melt a doll head before. I use 90% alcohol but I don’t soak long and use a toothbrush to get the eyes, ears, and mouth clean. It does look like the sealant isn’t all off, I’ve had that before. I also personally wouldn’t sand the doll unless you know how and if you do, I’d recommend researching wet sanding. I’d try getting that off, it does look like the spray didn’t all come off.

 

Acetone dissolves resin and all liquid softens it temporarily. You should never use acetone and you should never leave resin soaking. Sanding is always the best option to remove stains. For removing face ups always use 99% isopropyl alcohol.

There's lot of contradicting information about this stuff, however my partner is a scientist who works a lot with resin and what I wrote above is his professional/scientific opinion lol. No data on dyeing though.

 

Under most normal circumstances you never want to soak a painted BJD part in any kind of solvent and here is why:

1.Polyurethane is very resistant to solvents comaperd to many other kinds of plastic, but prolonged exposure will weaken it and eventually damge it.
When you wipe a faceup, the idea is to dissolve only the sealant and the paints, without damaging the doll. Most sealants will dissolve quite easily and long before any harm is done to the polyurethane. The strength of the solvent is a trade off. A stonger solvent like acetone will wipe the sealent and paint off quickly and as long as a good technique is used (fresh part of the rag for each wipe, quick and controlled work flow etc.) and the fact that highly concentrated acetone evaporates quickly and doesn't leave any residue of it's own, the exposure to the doll can be very short in deed. We are talking seconds on any given part of the surface, rather than minutes. A less agressive solvent like isopropanol will take a lot longer to dissolve the face up materials, but also a lot longer to cause any damage to the doll underneath.
If you go too weak or dilute the solvent at the wrong time all you do is increasing the exposure time and give the solvent time to cause potential harm. If you go too stong you shorten the time you have to do the job before you risk damage.

2. Polyurethane is slightly porous. This is one of the reasons that we protect the surface with a sealant before adding any kind of pigments. If we don't, the pigments can potentially get trapped within the plastic and settle there causing permanent staining.
When you start wiping a faceup, you dissolve the paint and the protective layer at the same time. If you soak, you have no control over where these pigments end up and they will be suspended in the solvent. Even worse, as the sealent layer is breaking down the solvent will penetrate into the polyurethane and can potentially carry those pigments into the doll part, essentially dying it.

3. While the polyurethane is quite resistant, it is not indestructable.
Solvents will sort of soften/weaken the material before it fully breaks down. If the solvent is allowed to fully evaporate at this stage, the polyurethane will harden again and no real harm is done. However, during this stage, the material is much more fragile than usual and much more sensitive to abrasuions and dents. If you do any kind of agressive scrubbing (stiff bristled brush, harsh cloth etc.) or any kind of abrasion (melamine sponge) during this stage, you risk taking the surface layer off completely.
Keep this in mind when hitting a tough spot and have to resort to agitating the surface. Solvents are ment to dissolve the paints so that you can wipe them off. If they dont's do the job, a stronger solvent and less force may actually cause alot less harm to the doll undeneath than a weaker solvent and prolonged exposure and scrubbing.
Solvents usually evaporate very quickly, ranging from seconds for a thin surface spread of acetone to minutes for weaker solvents. Typically, when you are done you want to make sure the solvent used evaporates completely, before doing any kind of harsh handeling. Naturally, any solvent that has penetrated into the plastic will take longer to evaporate than solvent on the surface. If you have a piece that has been subjected to long exposure to a strong solvent, leave it in an airy place and allow it to rest while the last of the solvent evaporates.
Soaking or rinsing in water at this stage will only prolong the process. The water will not penetrate as deeply or quickly as the solvent so it may not avutally dilute the solvent trapped withing the plastic, but it will prevent evaporation.

If you use a slovent with hand moistureisers in it, is such as W&N Brush cleaner and restorer or a nail polish remover, you need to wash the piece in soapy water afterwards, but wait until after the solvents are completely gone before doing that and there is no reason for soaking in water, it's not going to do a thing to the oils. Rather, use a high concentraton dish soap (preferably one without dye or perfume, to dissolve the oil and then use the water to dissolve and rinse off the soap. It's much faster and much more eficient than soaking in diluted soap and is going to cause less work for you and less wear on the doll.

Finally: No solvent is completely "safe" for the doll. But just about all of the ones commonly used are safe when used properly. You do have to adapt your technique and work flow to suit the materials you are working with.

 

Chinese companies' resins tend to have much smoother finishes than Korean ones, which are often more... grainy? in texture. Some sealants that come off chinese resin (like AE) easily might be a nightmare to remove from korean ones (like Souldoll) because they get really stuck in the texture and leave a residue more easily. Likewise, the solvent might seep into the grain and do some damage as it's harder to wipe off completely. So I think you're not far off with different companies' resins reacting differently to what you use! Unfortunately, there's never a way of knowing 100%, though. Souldoll's tan and special colours are also known for not being the most stable (at least to light) so maybe it was also an unfortunate mix with that... In any case, I'm glad that the sanding worked!

 

To help keep the dye from accumulating when you remove the pieces from the pot, you should rinse off the pieces. I set up a large dish with cool water next to the dye pot and swish pieces around in that when i remove them from the dye bath, then do a fuller rinse with dish soap to make sure any excess dye is removed when all the pieces are out and cooled down.

 

If you're doing it right after you take your pieces out of the pot I don't think it would, but if you take them out and set them down to work on other pieces, then the dye is going to accumulate and end up sitting longer, which could explain the uneveness. But if you're doing that, then your dye is still boiling, and as you lose some to steam, your dye bath will become more concentrated as well. So i found the dye bath--- big punch bowl full of water---> final rinse with soapy water to kind of balance out the timing and rinsing things worked pretty well.