Duplicolour and resin

[stitchdup]

Has anyone had problems with duplicolour on resin. I'm currently in the paint process on a c1 porsche and at first it pooled in a way similar to oil on water, and just didn't want to flow nice, just to pool. I assumed I'd forgotten to scrub it so I gave it a good scrub with cif household cleaner and hot water, rinsed that off and gave it a scrub with dish soap and hot water with a new toothbrush followed by a rinse and scrub with clean hot water and another new toothbrush. This time some sections crazed a little (seems to be fixed now). I've used duplicolour on resin from the partsbox and it went fine so where have i gone wrong this time. I'm using spray cans in a booth with extractor running and I'm sure its something I'm doing wrong so some advice would be appreciated. Its only the body and not the whole part that has the crazing, the rest seems ok. I'll be using tamiya paints over this and its duplicolour clear plastic primer followed by white primer. I am only noticing the problem when the white goes on, but since the other is clear Its hard to see but it looks to be laying ok

Edited January 16, 2020 by stitchdup

[gotnitro?]

Yep..didn't matter whether I scrubbed w comet, westleys over night soak, washed w dawn dish soap etc..I sometimes have issues w it . Even spraying mist coats sometimes still had spots that didn't cover . This was their sandable gray primer. 

I ended up using tamiya fine white for problem areas 

 

[Ace-Garageguy]

Trash resin can sometimes be porous, and no matter what you do, you'll never get all the release agent out of it. Couple that with some folks using silicone-based release agents, or bizarre cheapo "just as good" release agents like Pam, olive oil, Vaseline, talcum powder, or dog knows what...well, you can get some really oddball problems.

The only thing I've found that will reliably remove silicone contamination, by the way, is isopropyl alcohol. And if the substrate is porous, fuggedaboutit..

 

[stitchdup]

Thanks gents, appreciate the advice. I'm not even sure if i can buy the isopropyl alchohol over here with our stupic alchohol laws but I'm sure i can get it through work if not direct

[Ace-Garageguy]

1 hour ago, stitchdup said:

Thanks gents, appreciate the advice. I'm not even sure if i can buy the isopropyl alchohol over here with our stupic alchohol laws but I'm sure i can get it through work if not direct

It's available here as "rubbing" alcohol, or as a disinfectant, in drug stores. It's not drinkable, but is flammable. It's used as lamp fuel too.

70% is a great cleaner. 90% or higher will strip some lacquer paints, so it's good to have around.

[SfanGoch]

Depending, as you have pointed out, on the quality of the resin, 91% rubbing alcohol can have an effect on said resin. I needed to strip acrylic paint from MIG Productions Scale Thickness Hull Plates.

I brushed on 91% IPA, waited until the paint started lifting and noticed that the resin became a rubbery mess and stayed that way. A lesson that cost me $100. Test first.

[Ace-Garageguy]

18 minutes ago, SfanGoch said:

Depending, as you have pointed out, on the quality of the resin, 91% rubbing alcohol can have an effect on said resin. I needed to strip acrylic paint from MIG Productions Scale Thickness Hull Plates.

I brushed on 91% IPA, waited until the paint started lifting and noticed that the resin became a rubbery mess and stayed that way. A lesson that cost me $100. Test first.

HEED THIS WARNING

[Dave G.]

By the way you can turn 91% ipa into 70% by adding in 21% distilled water. And it will never be 91 again since alcohol evaporates faster than water.

[espo]

I have built a few resin cast bodies, but what I have found was that using a Automotive grade primer helps to seal the resin and helps any color coats of paint adhere better. In the past I tried Tamiya primer and didn't get the adhesion I was looking for and the paint would come off with the use of masking tap in some cases.   

[stitchdup]

I think on my next resin, I'll skip the plastic primer and see if it works any better. It will be grey primer anyway so should be easier to see any problems