[[Template core/front/global/utilitiesMenu does not exist. This theme may be out of date. Run the support tool in the AdminCP to restore the default theme.]]
  • Announcements

    • Dave Ambrose

      Board Status   07/20/2018

      Maintenance completed, but there is still more come.
ranma

Model rubber tire rot, has it happened to you.

Recommended Posts

I had a tamiya ford mustang which the tyres seem to have dried out and split around the edges, and also the imax caddy I just built the tyres seemed to be covered in a mould, I washed it off in dish soap and dried them and within a day they were mouldy again. Bit annoying cos I wanted to use them on the rear of a hot rod

I doubt it is mold. Most likely some plasticizer leaching out.  You could try to scrub them using 91% isopropyl alcohol or even naphtha (Ronsonol lighter fluid).  That might take care of the problem.

Share this post


Link to post
Share on other sites

I doubt it is mold. Most likely some plasticizer leaching out.  You could try to scrub them using 91% isopropyl alcohol or even naphtha (Ronsonol lighter fluid).  That might take care of the problem.

thanks, I'll try that

Share this post


Link to post
Share on other sites

Seen it on several Revell-Germany trucks and fire vehicles.  Once found their Schlingmann Unimog at a swap meet, missing some parts so very cheap. I just wanted the chainsaw and rescue tools so that didn't matter.  But the big tires had sort of melted/collapsed - that's the best way I can describe it.  They were also leaching that weird fluid onto other parts, so I just threw them away.

When buying any vintage kit from Heller, Revell-Germany, Protar and some Asian companies, first I always check where the tires are.  In the Bad Old Days, they were often sealed into a plastic bag (good) along with the clear parts (VERY bad).   That just happened with an old Protar Alfa Giulietta.  Windshield was nicely bagged, with the tires sitting right on top of it.  Luckily no tire burn had happened.

Hobby Lobby/Michaels sells cheap Ziploc bags in various sizes.  I always keep some of those around.  When I open a vintage kit like the Alfa, I immediately bag the tires to keep them separated, and the clear parts to keep them from getting scratched or damaged.

Share this post


Link to post
Share on other sites

I have four Revell BMW Nazcas, and all four had "melted" P-Zeroes. ...

Great, so I better check on mine.
Tamiya tires tend to dry and crack.  I have an Italeri military model that I built decades ago, chemical reaction with the wheel.

Edited by 89AKurt

Share this post


Link to post
Share on other sites

I have a built '57 Chevy model on which I used some old AMT redline Firestone Supreme tires. It has been sitting in a JoHan display case in my basement (along with about a dozen other models so cased) for a couple decades. The redline tires are getting whiter and whiter and are looking more and more like powdered donuts. I'd assumed this had something to do with the humidity in my basement but I now realize that none of the other tires under the same conditions have that. I'll have to get that thing out and take a closer look at it sometime. :wacko:

Fellas,

 Here's an example of the "powdered donut" look on the AMT Firestone Supremes on the left front of the car...the build is from the mid 1980's. The Supremes from the eighties and earlier. 

IMG_9331-vi.jpg

Edited by Pete L.

Share this post


Link to post
Share on other sites

Fellas,

 Here's an example of the "powdered donut" look on the AMT Firestone Supremes on the left front of the car...the build is from the mid 1980's. The Supremes from the eighties and earlier. 

 

That stuff will probably come of using some Naphtha (lighter fluid) or 99% Isopropyl Alcohol. Just try not to get any of those solvents in contact with paint for more than few seconds.

Share this post


Link to post
Share on other sites

I really wonder if there's a better material to make tires out of?

Silicone, perhaps?

Charlie Larkin

Share this post


Link to post
Share on other sites

Every time I suggest it people go into spasms over it, but why not mold them in polystyrene like the rest of the kit. With the paints and weathering product available now there shouldn't be any problem with getting them to look right. In my opinion usually better then most of the vinyl tires with their unrealistic sheen. And as a historical note, Don Emmons was suggesting this over 50 years ago.

Share this post


Link to post
Share on other sites

Every time I suggest it people go into spasms over it, but why not mold them in polystyrene like the rest of the kit. With the paints and weathering product available now there shouldn't be any problem with getting them to look right. In my opinion usually better then most of the vinyl tires with their unrealistic sheen. And as a historical note, Don Emmons was suggesting this over 50 years ago.

While I wont go into histrionics over it, it has two major problems:

1. They can be difficult to mold so they look right.

2. The molds to make them would probably be more expensive.

3. Painting them would be difficult, unless you mold the wheels separately, which could make assembly difficult.

Charlie Larkin

Share this post


Link to post
Share on other sites

Not being a tooling designer not sure how difficult and expensive it would be versus the PVC molds. The military kits seem to have pretty good results.

Don't see why there would be assembly problems as long as tolerances are accurate. But even if they were molded together, don't see were there would be much problem painting except having to do a bit of masking.

Not completely finished with these, but they're (wheels and tires) made out of matt board and card stock. 

2012-08-04 rear tires x.JPG

2015-01-18 002x.JPG

Share this post


Link to post
Share on other sites

Every time I suggest it people go into spasms over it, but why not mold them in polystyrene like the rest of the kit. With the paints and weathering product available now there shouldn't be any problem with getting them to look right. In my opinion usually better then most of the vinyl tires with their unrealistic sheen. And as a historical note, Don Emmons was suggesting this over 50 years ago.

Sliks can, and have been done in the past, but tires with a tread are complicated, cuz you'd have to do the tread in several sections to make it work, see tasca Zundapp KS750 Motorcycle.

http://www.missing-lynx.com/reviews/german/tasca24004reviewbg_1.html

tasca24004reviewbg_3.jpg

Share this post


Link to post
Share on other sites

Not being a tooling designer not sure how difficult and expensive it would be versus the PVC molds. The military kits seem to have pretty good results.

Don't see why there would be assembly problems as long as tolerances are accurate. But even if they were molded together, don't see were there would be much problem painting except having to do a bit of masking.

Not completely finished with these, but they're (wheels and tires) made out of matt board and card stock. 

 

Comparing multi-piece cardboard tires made from several hand-assembled pieces of cardboard to 1-piece molded vinyl tires is like comparing apples to oranges.

I guess because vinyl (and rubber) are flexible (unlike polystyrene which is a hard plastic) it can be molded with complex tread pattern while using a fairly simple mold. At least that is what I gather reading this thread.  But to get the same level of detail in a hard plastic tire would take a complex multi-part mold (which is much more expensive to make).  There also are many  tires out there molded out of resin with very high level of detail but those are molded in rubber molds which makes the process workable. Unfortunately this molding process doesn't work for high-volume production of plastic model kits.

Edited by peteski

Share this post


Link to post
Share on other sites

I'm not comparing the cardstock tires to 1-piece molded vinyl tires except to present a solution to the chemical reactions that seem to take place between the vinyl or rubber and polystyrene. I've had old kits with parts burned through by the tires, tires melt into the shelf, or eat the wheel rims off. It seems that chemically there doesn't seem to be a completely positive, workable solution for the problem. If so at that point the other solution is to use a non-reactive compound to make the tires out of. If styrene then for most would require a multi-piece tire like the example that Luc showed or a very intricate, multi-slide tool that would still produce at best a 2 piece tire. Maybe not the most desirable solution, but would solve the problem. If resin, then you're talking about a labor-intensive process. There are military kits that have resin parts in them so it is doable at a price Any of the methods would add to the cost of the kits. So it sort of comes down to pick your poison.

Share this post


Link to post
Share on other sites

Sliks can, and have been done in the past, but tires with a tread are complicated, cuz you'd have to do the tread in several sections to make it work, see tasca Zundapp KS750 Motorcycle.

http://www.missing-lynx.com/reviews/german/tasca24004reviewbg_1.html

tasca24004reviewbg_3.jpg

The above looks like it could be a little tough to build. Multi-piece tires? Getting things lined up and round? No thanks.

Scott

 

Share this post


Link to post
Share on other sites

That stuff will probably come of using some Naphtha (lighter fluid) or 99% Isopropyl Alcohol. Just try not to get any of those solvents in contact with paint for more than few seconds.

Peter,

 Thanks for the info, I'll give it a try !!!!

Share this post


Link to post
Share on other sites

I discovered a kit that had loose tires that were on the decal, and messed the decal up.  Should put tires in a paper envelope for storage.

Edited by 89AKurt

Share this post


Link to post
Share on other sites
On 2017-05-25 at 10:28 AM, Pete L. said:

Fellas,

 Here's an example of the "powdered donut" look on the AMT Firestone Supremes on the left front of the car...the build is from the mid 1980's. The Supremes from the eighties and earlier. 

IMG_9331-vi.jpg

I had a multiple set of tires that were powdered right or of the box.

356F4118-3FFD-40C1-9848-A34D1CA1D5CF.jpeg

Share this post


Link to post
Share on other sites

The problem stems from the raw material used to make "soft" flexible model car and truck tires, "Polyvinyl Chloride" also simply called PVC.  "Pure" vinyl is a hard plastic (bear in mind this is what phonograph records have been made from for well over a century).  To soften the compound, making PVC flexible, a chemical known as PVC-Monomer is added.  This is just as true of industrial components (at one time, virtually every electrical plug in an automobile wiring harness was molded in place, on the wires themselves, in a fairly soft PVC blend (saw that being done when in Human Resources at a fairly large Essex Wire automobile wiring harness here in Lafayette, back in the mid-1970's).

In 1975-76, however, OSHA determined the "plasticizer" used to soften PVC to be a cause of cancer in humans, and various measures were taken to mitigate that, which included greatly reducing, and controlling the amount of PVC Monomer used (it out-gassed noticeably when melted for injection molding).  That situation forced AMT (for example) to discontinue molding tires in PVC,  hence those horrid 2-piece polyethylene tires.  Revell tires, perhaps the most noticeable wheel-rotters on the model car scene, once the amount of PVC Monomer was greatly reduced, pretty much lost their ability to damage a polystyrene wheel. for the most part.  Even today, it's nowhere nearly as common as it once was.  By late 1976, feedstock manufacturers of PVC discovered that they could greatly reduce the portion of the Monomer in their blends, and manufacturers were able to come up with very acceptable exhaust hoods above the molding machines used to mold PVC into useful items.

Even "back in the day", this sort of "tire rot" was NOT universal, if it had been, there would be virtually no workable model car kits existing that were manufactured in the 1960's to late 1970's. Like many here, I have dozens, if not hundreds of old MIB model car kits that date back to the 60's and early 70's. almost none of them showing any PVC deterioration whatsoever.   But, why all the discussion, when an ounce of prevention means a pound of cure?  Simply, if I have any concern that a PVC tire might attack the styrene wheel that it's to be mounted on, a simple strip of Bare Metal Foil around the circumference of the wheel has worked every time I've felt the need to do it.  Others have used a thin "swipe" of 5-minute epoxy around the circumference of the wheel rim with very much the same result.

Art

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now