Help! Sticky rubber from alclad painted wheels.

[Stray]

Hey guys and girls. So I used alclad on my wheels and parts, I gave them almost 3 days to cure and put a couple of the wheels into their rubber. They have been like that for a couple days now and I have started making up the backs for the wheels and brakes etc.

When i removed the rims from the tires they are extremely tacky. Do I have a chemical reaction here or something??? I don't want anything to melt!!!

Here is a pic showing the tacky areas:

[Art Anderson]

Most tires in model car kits, save for those from Japan (where Neoprene rubber seems to be the norm) are made from PVC--vinyl. With PVC, in order to make that plastic (which chemical formula goes all the way back to the 1890's) soft, a plasticizer is added to it. Trouble is, that plasticizer also will soften most any enamel, even lacquer based paints. Years ago, before model companies found that minimal plasticizer would greatly reduce, if not eliminate altogether, that softening effect, model car kit tires would actually soften the surfaces of styrene wheels (or any other styrene part they came in contact with for any length of time)--the once-dreaded "Revell Tire Disease".

Art

[Stray]

Yeah Art. I remember reading about that back in old SAE magazines. I believe some kits came with the tyres and bodies in the same bags and the rubber had melted into the roofs!

But what does this mean to me right now? IS there a way I can stop this? The tyres are relatively new ones, I believe they were the big'n'littles from a 34 ford kit. Can I paint the outside of the rims using tamiya acrylic to seal them? Should I just spill thinners on my desk and set fire to it all now???

[Guest]

Is it possible that the paint on the wheels still isn't fully dry? Not long ago, I had an episode with Model Masters Clear lacquer. It should have been dry. But, almost a month later, it was still soft and the body would "stick" to my cutting mat if left for any length of time.

[Art Anderson]

Yeah Art. I remember reading about that back in old SAE magazines. I believe some kits came with the tyres and bodies in the same bags and the rubber had melted into the roofs!

But what does this mean to me right now? IS there a way I can stop this? The tyres are relatively new ones, I believe they were the big'n'littles from a 34 ford kit. Can I paint the outside of the rims using tamiya acrylic to seal them? Should I just spill thinners on my desk and set fire to it all now??

Perhaps the only way to stop this would be to lay a "band" of BMF around the circumference of the rim itself--any plasticizer that might leach out of the tires won't penetrate that. Or, wipe a very thin layer of epoxy around the circumference/mating surface of the wheels before mounting the tires. Both of those techniques have been used for a long time on plated wheel rims, which can suffer from the same problem.

Art

[Fat Brian]

A layer of water based paint where the rim contacts the tire should do it, you just need a barrier coat in there.

[Stray]

Perhaps the only way to stop this would be to lay a "band" of BMF around the circumference of the rim itself--any plasticizer that might leach out of the tires won't penetrate that. Or, wipe a very thin layer of epoxy around the circumference/mating surface of the wheels before mounting the tires. Both of those techniques have been used for a long time on plated wheel rims, which can suffer from the same problem.

Art

A layer of water based paint where the rim contacts the tire should do it, you just need a barrier coat in there.

Awesome! Thanks for the suggestion guys. I just couldn't think of a way to rectify this that wouldn't ruin the finish on the rims.

I will try the bmf first, but thanks for the info Brian too, so waterbased acrylic is ok to use over the lacquer? Or is that just because it wont be visible once the tyres are mounted?

[Ben]

Dip or spray the wheels with Future Floor polish to put a clear acrylic barrier on them, then after they dry, reinstall them into the tires.

[Fat Brian]

The waterbased paint will work fine over the Alclad to protect it from the tire, I can't speak to how it would affect the finish on the face of the rim because everything seems to affect Alclad differently. Ben is correct that Future will do the same thing, you just need anything that the softeners in the tire can't penetrate.