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Doubt how to paint/protect vinyl rubber tires


Lazy Modeller

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I haven't done it for many years, and the ones I have were painted with Tamyia's paint and they're in perfect condition, but I've read somewhere that sometimes they soften and become defective. My question is: isn't it better to paint with a Oneshot type primer that has a vinyl base and as such will be better suited for the effect?

Cheers

LM

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I've never heard this about painting vinyl tires, but I do know about vinyl tires reacting to/with unpainted styrene.

Back in the early 80's, I started the Tamiya 1/35 British LRDG truck. The it got put back into the box because I moved out of my apartment. After a few years another couple moves, marriage and house purchase, I opened it up to restart. The vinyl tires had been put onto the unpainted rims but now they had kinda melted and split It was quite a mess! I found out later that the rims should have been fully painted first before mounting onto the rims.

 

 

 

Chris

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12 minutes ago, dogsbody said:

I've never heard this about painting vinyl tires, but I do know about vinyl tires reacting to/with unpainted styrene.

Back in the early 80's, I started the Tamiya 1/35 British LRDG truck. The it got put back into the box because I moved out of my apartment. After a few years another couple moves, marriage and house purchase, I opened it up to restart. The vinyl tires had been put onto the unpainted rims but now they had kinda melted and split It was quite a mess! I found out later that the rims should have been fully painted first before mounting onto the rims.

 

 

 

Chris

Thanks for your view. But I'm still in doubt. Tamyia or Oneshot (vinyl). I used to paint it with Tamiya but now I'm Thinking maybe a vinyl paint type should be better?

Cheers

LM

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Any acrylic polymer based primer should be more than adequate. Avoid the solvent based stuff.

 

In my opinion, bin them and get resin replacements. I have an old Tamiya Flak 36/37 as well as an Italeri RSO with PAK 40 and both have been sitting entombed in the stash for over a decade, all the bags are still sealed. The vinyl tyres/tracks in both kits have crumbled into cous cous sized pieces from age. They will give you nothing but grief. But that's just my opinion.

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2 hours ago, Crayons said:

Any acrylic polymer based primer should be more than adequate. Avoid the solvent based stuff.

 

In my opinion, bin them and get resin replacements. I have an old Tamiya Flak 36/37 as well as an Italeri RSO with PAK 40 and both have been sitting entombed in the stash for over a decade, all the bags are still sealed. The vinyl tyres/tracks in both kits have crumbled into cous cous sized pieces from age. They will give you nothing but grief. But that's just my opinion.

 

 

Thanks for the comment.

It's not that so far I've personally had any problems with the tires. I have some build for about 30 years and they are perfect. I also have several in the stash that have the same age and they are also in perfect condition.

I just remembered to ask this question to see if anyone has any concrete reason why this happens, and the best way to solve it, as I've read a lot of complaints about this anomaly.

Replacement with resin equivalents will be a solution, for some, but not for me, since I build practically what comes in the box and my add-ons are quite residual, because what I really like is the construction phase, and the painting not really, in addition to the fact that all these add-ons would double or sometimes triple the price of construction, and this is only useful, in my opinion, for those who want to make museum-like models.

 

Anyway, I am really intrigued by the situation and would like to know if anyone has any ideas or scientific knowledge about this situation. Will a vinyl based primer have more advantage to protect the tires than an acrylic based Tamiya?

 

Cheers

LM

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The only scientific knowledge which I can give you is to be wary of the term "acrylic". It is really just an adjective for a paint in a polymeric binder of some kind, so it covers a huge range of types, including water-based polyurethane and resin paints, but doesn't tell us very much at all about its chemical make-up, compatibility, or behaviour.

 

As I make quite a few civilian automotive kits, I just have blind faith that modern kits (last decade or so) from Tamiya, Aoshima, et al. have a "rubber" material which is durable enough for display and has no reaction with bare polystyrene. Of course, I am far too young to have experienced such horrors... 😉

 

But I can't really address your main question. It's rare for me to even buy a military kit with squidgy black tyres or tracks; when I have, it was with the certainty that I would not be using them... Ordinarily, my solution is to test whatever it is and discover for myself whether it works (a policy which has saved several kits and a lot of effort from being wasted) but I appreciate that this is easier said than done when you probably have no spare tyre, nor indeed enough time to sit around waiting for nothing bad to happen.

 

I think that you will have to go with your gut about this one and paint them or not as you think best.

 

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The only idea I have is to why this potentially happens comes down to the materials used in manufacture. Polystyrene contains vinyl benzene and those awful tyres/tracks are made from vinyl esters which are far more tolerant to stretching (thus kit tyres and tracks). I can only assume, that the two vinyls used are either incompatible thus causing a negative contact chemical reaction (think galvanic but in plastics) or are similar in chemical behaviour to silicone and chemically try to bond to another through the exchange of molecules.

 

Vinyl esters also use peroxides as hardeners (the one I immediately recall is methyl ethyl ketone peroxide MEKP which inhalation of is akin to washing your brain in battery acid). This could also cause an issue in so far as making materials chemically brittle and more susceptible to decomposition.

 

Just my thoughts on the possible cause. I could be way off the mark.

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22 hours ago, Ade H said:

The only scientific knowledge which I can give you is to be wary of the term "acrylic". It is really just an adjective for a paint in a polymeric binder of some kind, so it covers a huge range of types, including water-based polyurethane and resin paints, but doesn't tell us very much at all about its chemical make-up, compatibility, or behaviour.

 

As I make quite a few civilian automotive kits, I just have blind faith that modern kits (last decade or so) from Tamiya, Aoshima, et al. have a "rubber" material which is durable enough for display and has no reaction with bare polystyrene. Of course, I am far too young to have experienced such horrors... 😉

 

But I can't really address your main question. It's rare for me to even buy a military kit with squidgy black tyres or tracks; when I have, it was with the certainty that I would not be using them... Ordinarily, my solution is to test whatever it is and discover for myself whether it works (a policy which has saved several kits and a lot of effort from being wasted) but I appreciate that this is easier said than done when you probably have no spare tyre, nor indeed enough time to sit around waiting for nothing bad to happen.

 

I think that you will have to go with your gut about this one and paint them or not as you think best.

 

Thanks for your contribution, but I would like to know the explanation from the scientific side. It's not that I had any problems, but I would really like to know the reason for the situation, because I'm building one that has 12 tires...

Cheers

LM

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4 hours ago, Crayons said:

The only idea I have is to why this potentially happens comes down to the materials used in manufacture. Polystyrene contains vinyl benzene and those awful tyres/tracks are made from vinyl esters which are far more tolerant to stretching (thus kit tyres and tracks). I can only assume, that the two vinyls used are either incompatible thus causing a negative contact chemical reaction (think galvanic but in plastics) or are similar in chemical behaviour to silicone and chemically try to bond to another through the exchange of molecules.

 

Vinyl esters also use peroxides as hardeners (the one I immediately recall is methyl ethyl ketone peroxide MEKP which inhalation of is akin to washing your brain in battery acid). This could also cause an issue in so far as making materials chemically brittle and more susceptible to decomposition.

 

Just my thoughts on the possible cause. I could be way off the mark.

 

 

 

Thanks for your contribution.

Really what you mention must be the main cause for this to happen, that must be why I never had any problems with mine, since I paint them all the time. And it's not just a problem with the tires, as I've seen pictures where it wasn't just the tire that was affected, but the rim also melted. This can maybe different from brand to brand and they say 60 and 70 kits were even more affected...

Apparently the solution will be to completely seal the tire, so that this doesn't happen, so I think in the future I'm gonna  do two coats of Oneshot primer to seal them completely, because maybe I think the vinyl coat its better.

It's good to know what's going on so you don't step into the puddle, because I'm also starting to build one with twelve wheels...

Thank you very much for your enlightening comment. I suppose the topic can also serve as a warning to the staff...

Cheers

LM

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  • Lazy Modeller changed the title to Doubt how to paint/protect vinyl rubber tires
On 15/01/2022 at 07:39, zigster said:

Maybe I'm late "for the party", but all I do is spray the tyres using Tamiya can of grey primer.

Zig

Thanks Zig. Its never to late to give some help or comment. That's what the forum is for.

But As our mates said before the most important is to seal them. It seems paint type is not important but I'm gonna seal them with Oneshot primer just to be sure.

Cheers

LM

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