Paint not drying on resin parts

[NOBLNG]

This paint was put into an aerosol can many years ago for me by an auto paint supplier. I sprayed this dash weeks ago, and it has been sitting in the dehydrator since. There is a raised portion of the dash that I filed down...and on that spot, the paint is still liquid. How long after casting does resin need to cure before painting? I must have painted this just after the filing that exposed fresher resin?

[Mark]

Probably a bad mix...sanding exposed uncured resin.

[NOBLNG]

Can resin be stripped in Super Clean, same as styrene can?

[Mark]

Some resins can be stripped, others can't.  I used to cast parts to sell, some of them got sent out for plating.  The resin I used got rubbery when soaked in anything I tried.  It ended up being more trouble than it was worth, I just tossed the ones with bad plating and cast new ones.  

 

[NOBLNG]

Thanks! It’s in the pond now. I cast it myself and have extras, so we’ll see what happens.

[Rick L]

Have you tried painting something other than a resin casting. 

[NOBLNG]

1 hour ago, Rick L said:

Have you tried painting something other than a resin casting. 

The paint is fine everywhere else except that one tiny spot.??

[yh70]

3 hours ago, NOBLNG said:

Can resin be stripped in Super Clean, same as styrene can?

i dont know about Super Clean as i dont like it. takes to long to remove paint . i use a lot of resin parts and when i started out i did have to remove paint on a hood. i have always used Easy Off brand name in a yellow can..spray it on in vented area leave on 4 hrs scrub under warm water with old tooth brush repete if needed... wash in soppy water, dry, prime, paint ..i would toss that paint being it be so old...

[stitchdup]

Someone told me the best method for stripping resin is to wipe it down with thinners, not the quickest method but it works if you take your time. Just use the appropriate thinners for the paint used. I've used it on a qtip to strip some resin wheels, and I've used la's totally awesome cleaner for stuff that needs a soak. agin not the fastest but it works mostly, just very slow on mettalics

[Rick L]

13 hours ago, NOBLNG said:

The paint is fine everywhere else except that one tiny spot.??

Unfortunately, this may be a flaw in the resin casting. Some polyurethane resins are quick curing parts A and B and one of those parts are not mixed correctly before they are mixed for casting. This results in a web of uncured  plastic inside and protruding to the outside of the part. You may have to dig it out a little or the web will keep bleeding out under the paint. You can use any stripper suggested for the paint used. It shouldn’t effect the plastic but look carefully at the area that inhibited the paint to see if there is a dark hairline web. That’s the critter you have to dig out before repainting or it will happen again.

Edited May 18, 2021 by Rick L

[John1955]

I work with lots of resin parts and resin kits and I've found that Westley's is great for cleaning resin and that despite instructions from some resin makers, soaking resin in it isn't really needed. I use a small scrub brush to wash the resin parts, then rinse thoroughly and allow to air dry. yh70 is right about Easy Off to strip paint, Westley's won't strip paint off. But I have found that after cleaning with Westley's, even though it didn't strip the paint off, I can repaint over the existing paint with no problems. 

I also use Westley's to clean polystyrene plastic as well, it removes mold release agents used in manufacturing. 

[NOBLNG]

Well it came pretty clean. I think I must have filed off that raised area and then primed and painted it right away. I’ll let it dry real well in the dehydrator and then give it one more try with this old paint.?

[peteski]

4 hours ago, John1955 said:

I work with lots of resin parts and resin kits and I've found that Westley's is great for cleaning resin and that despite instructions from some resin makers, soaking resin in it isn't really needed. I use a small scrub brush to wash the resin parts, then rinse thoroughly and allow to air dry. yh70 is right about Easy Off to strip paint, Westley's won't strip paint off. But I have found that after cleaning with Westley's, even though it didn't strip the paint off, I can repaint over the existing paint with no problems. 

I also use Westley's to clean polystyrene plastic as well, it removes mold release agents used in manufacturing. 

 

While I don't use this stuff for stripping paint, or for cleaning resin and plastic model parts, I am sure I read it (probably most likely on this forum) that Westley's has changed formula several years ago and the "new" formula sucks (less potent than the original).  Of course there is probably no way to tell which one you use (original or new).

http://www.modelcarsmag.com/forums/topic/94554-westleys-bleche-white/?do=findComment&comment=1281491

http://www.modelcarsmag.com/forums/topic/143818-preparing-resin-parts-soak-in-simple-green/?do=findComment&comment=2110063

Edited May 18, 2021 by peteski

[John1955]

On 5/18/2021 at 3:40 PM, peteski said:

While I don't use this stuff for stripping paint, or for cleaning resin and plastic model parts, I am sure I read it (probably most likely on this forum) that Westley's has changed formula several years ago and the "new" formula sucks (less potent than the original).  Of course there is probably no way to tell which one you use (original or new).

I haven't noticed any difference at all over the years in Westley's, and I use it not only for cleaning resin and plastic, but for cleaning the white letter tires on my pickup trucks so I will continue to use it. 

[DRIPTROIT 71]

The only time that I experienced this was on a truck cab that the resin wasn’t completely mixed. The cab had cured for years. It was completely dry to the touch, but the resin had swirl marks in it. The paint wouldn’t dry at all in a couple of spots on the cab and the resin began to soften again. I suppose that the paint re-activated the resin. I’m guessing that resin that wasn’t completely cured could have the same reaction. 

Edited May 22, 2021 by DRIPTROIT 71

[Mark]

One other thing...shake that can the day before you intend to use it.  When you think you are done shaking, the agitator ball/marble should roll freely around the base of the can.  Once it does, give the can another good shake.  On spray day, give it the normal shake, nothing more.  This should be done with sprays that have been sitting a while, especially primers.

[NOBLNG]

The dash was kind of spongy at that spot so I tossed it. Likely not mixed well enough, or because it was from an old batch of resin.?‍♂️