Degreasing a resin body prior to paint

[MrAdept]

I have a couple of resin bodies that I can't seem to remove something greasy from as I am getting patches in the paint.
I have tried alcohol and dish soap that you use to wash dishes by hand, but so far no success.
Any other thoughts?


Mark

[Dangermouse]

Have you tried sanding the body? That may work.

I thought maybe something like a citrus cleaner may work as well, not sure if it would leave an oily residue

David

[Ember]

The citrus cleaners do leave some oiliness.

Do you guys get Selley's Sugar Soap? Great for cleaning greasy kitchen walls prior to painting. Also works a treat cleaning mold release from resin.

[racer6583]

Go to a auto parts store and get some Wesley tire cleaner pour some in a little container that your resin fits in use a soft toothbrush to wash it and let it soak for about 15 min or so then scrub it with the toothbrush then rinse off then you should have an oily free resin to paint.

[RichD]

I have run into this problem myself, it happens when a mould release agent is used. If you are unlucky some of the release agent is trapped in the resin, rather than just coating the surface and that can be more difficult to deal with. If the release agent is stuck in the resin it will probably take repeated treatments to remove it no matter what you use.

[waaytoomuchintothis]

The whitewall tire cleaner is a "never fail" for me. I have never heard of mold release trapped in the resin. That would make it incredibly fragile.

[MrAdept]

Thanks guys - plenty to try there.

I tried sanding and it improved the area but didn't fix it on the one shell, and had very little effect on the other shell, but then that one seems to be covered from 'A' pillars back!

I don't think sugar soap is available in the USA - I remember my Mom using it in the UK though.

Looks like I am off to get some tire cleaner.

Mark

[dreinecke]

Mark, one of mine? Either way, Wesley's is the way to go. Let it soak for about 10 minutes, hit it with a toothbrush and then wash the body with dish soap.

[MrAdept]

Hi David,

not one of yours :)
The least affected one is an Ocar, and the really bad one is Highway 32. These are the first 2 that I have had issues with from either company, usually I can get away with cleaning up the flash, filling any pinholes and then a coat of paint.

I have one of your Firebirds that I really should put on a chassis! It's been sitting around that long!

Mark

[FootScoot]

Yep, Wesely's Bleche White will do the job, then the dish soap. Never use alcohol on resin! Don't ask me how I know. It will make the resin swell and crumble. Not good. :(

[MrAdept]

Seems there might have been a name change to Black Magic Bleche Wite.

I will avoid the alcohol. I did notice a thin section became soft. Fortunately for me it would seem that was the only section to succumb.

Mark

[Datto]

A stubborn greasiness that causes paint failure more often happens when a release agent IS NOT used. Silicone oils from the mold contaminate the resin surface and cause fish-eyes, etc. This kind of contamination is very difficult to get rid of. A release agent actually acts as a barrier between the silicone and the resin, and more often than not prevents paint failure. Another good cleaner is Barkeeper's friend. It's a powdered cleaner with a mild abrasive containing oxalic acid. clean your resin part by dipping a wet toothbrush into a little pile of the cleanser and scrubbing. Rinse, repeat, and to get rid of residual cleansing powder. clean it with dish-washing liquid. I imagine a bleach based cleanser like Comet would work too. A side benefit is the mild abrasive leaves a 'tooth' in the resin that helps with adhesion.

Depending on the batch, some resins just ooze oils, sometimes for years (looking at you, Alumilite) Not much you can do in a case like that.

[MrAdept]

I tried the Bleche Wite and that did for most of the spots. There were a couple of dots that I couldn't fix with anything, but I am now assuming it was something to do with the Tamiya spray paint as I could paint over the spot with some acrylic clear coat as well as being able to take a brush and apply the Tamiya spray paint to the spot. Flatting it back smooth and applying another coat when dry all was well...
Learning a lot in all of this...

Mark

[interst8er]

Uh oh. It's possible that the resin your model is made of is "leeching". People who sell or use urethane resins alot know about this. This problem can come up when #the 2 part resin hasn't been mixed thotoughly, #the 2 parts weren't shaken up (like paint) prior to mixing, #the mixing ratios were off, #or the resin materials are too old. Any of these things or a combination of these things can make the resin leech. Ive had problems using Alumilite resin but I haven't used their stuff for over 15 years now.

I've made resin casts that have done this. Usually if it happens to me it was because I was too eager to pour the resin and didn't spend enough time stirring the resin. The residue never washes away because its continually leaking this stuff to the surface of the model. Sometimes if the model is thin enough might be little translucent. Hold the model up to a strong light and see if you can see swirling in the model. I you see swirling it can mean it wasnt mixed enough. Also, just because you see swirling in a model dosn't mean it will leech and can be fine with a some swirling too. If I see wet patches in my primer coat (I know I screwd up) I dont bother fixing it ...I"ll just pour a new one properly.

When it comes to washing mold release away wich is typically used with urethane molds and not often with silicone molds. Washing and sanding(resurfacing) always handles cleaning the release away in my experience. I personally never use mold release in silicone molds when casting urethane resins. On rare ocasions I use mold release when I cast with epoxy resins or polyester resins. The best part of working with silicone molds is the fact you dont have to use mold release when using 2 part urethane for casting. Also unless you using it to seperate silicone form silicone.

I wouldnt be 100% sure that your model is leeching without looking at it. Personally I would contact the suplier of the model and talk to him about the problem. Also maybe hooking you up with a replacement.

Hope this helps

[MoparGreg]

Im a little late to the party but scrub the bodies in warm water with dishwashing liquid. Then I use some prepsol (Or prepwash, comes under different names, just a wax & grease remover that you would use for 1:1 painting). Then I wash it again in warm water with dishwashing liquid. This works for me. Apparently the Westleys tire bleach is an awesome product but we cant get it over here.

I have had 2 bodies over the years that the resins have continued to leach oils from the resins. 1 of them I undercoated, color coated, basically finished the whole car. A few weeks later the paint went sticky, that is after the paint had dried. That was 4 years ago & the paint is still sticky. It was a Jalopy so it added to the realism. :)