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Why haven't the model companies addressed the problem with tire melt ?


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4 hours ago, Peter Jenssen said:

This is still happening with newer kits.

My Takom Meillerwagen/V2/Hanomag combo is already showing rim melt after a couple of years.

 

Peter

Vinyl (PVC) is a relatively stiff plastic material.  Adding plasticizer compounds to PVC to make it softer (more rubber-like).  I suppose there are several types of PVC and plasticizes and the companies to which model companies outsource the manufacturing likely use cheapest raw materials without really considering how that will affect the polystyrene parts. When the plasticizer in PVC leaches out, it gets absorbed by the polystyrene parts in contact with the tire and softens those too.

Edited by peteski
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4 hours ago, Peter Jenssen said:

This is still happening with newer kits.

My Takom Meillerwagen/V2/Hanomag combo is already showing rim melt after a couple of years.

 

Peter

Might want to check on a Military Model Board to see if anyone else is having this issue. Given the origin of the company, who knows what they are using for materials. 

The Modelling News: Picture n' Video Build: Takom's Hanomag SS100 w/ Meillerwagen & V-2 Rocket by David Damek

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2 hours ago, The Junkman said:

Why do vinyl tires in any case?  Offering tires in the same styrene as the rest of the kit would completely eliminate the problem along with being painted/trimmed with the same techniques.

I can think of few reasons:
1.  because it has almost always been done that way
2. Because those tires do require any painting to look fairly realistic.  This is probably the main reason.
3. Because if tires were made of styrene, they would have to be painted, and manufacturers assume that the average modeler will not be happy with the way their painted tires look like, or with the additional painting step required.

What you propose has been used in urethane resin and plastic military and aircraft kits all along.

There is also another option (which happens to be used by most Japanese kit manufacturers): real rubber tires.  Japanese automotive kits use rubber tires and those do not cause the "tire melt".  They also look more realistic (because it is real rubber, and they also usually have finer sidewall and tread detail than vinyl tires). But I suspect that they are much more expensive to manufacture.  Instead of just injection-molding (like vinyl), rubber tires likely have more complex manufacturing process, which likely also uses the vulcanizing process to harden the rubber.  And we all know that maximizing the profits is the main goal of any company, so many go with vinyl tires.  That is just my personal view of this - there might be other factors involved in deciding whether to use rubber or vinyl tires.

But I have also noticed that the tires in some of the more recent Japanese kits, while still appearing to be rubbery, are not as realistic looking as the older tires.  They looks shinier, not nice flat rubber look of the rubber tires in the older kits.  They might be using some different material which does not require the complicated manufacturing process for real rubber tires.

Either way, we are stuck with what we get. Even Fireball Model Works tires are made from some sort of soft (polyurethane?) rubber, and have a warning not to place them model on a varnished wood surface (because they could leave marks).  Fireball did make hard resin versions of some tires (to be painted by the modeler) but I guess due to the low sales volume they discontinued them.

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Tire melt and even stains on painted display shelves. These have been a problem for as long as I can remember. Model companies have adjusted the compounds from which the kits tires are made thru the years. While there have been improvements the problem still exists. I don't know if I have an answer and it would seem no one else does either. I would offer a suggestion that may work and would be interested in anyone else's opinion as well. I recall years ago when AMT offered wrinkle wall style drag slicks as an option in some kits. These were done in the same white plastic as the kit. The builder would paint them whatever shade of flat black that looked correct to them and you could even scrape the paint off of the raised lettering on the tire if you wanted. My thought is why couldn't that be done for all tires in todays kits ? This may or may not even cost less to the manufacture than the tire formulas used today. They could be cast in a manor to reflect a small flat spot on the bottom of the tire where it makes contact with the shelf or ground or whatever. We see plastic inserts for white wall tires now, we could have redlines for an option or paint them black. Does this make sense to anyone else ? 

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Consider the big picture.

It's unfortunate, but in the real-world, most manufactured items aren't made with any kind of "archival" quality in mind.

REAL car tires hardly last for decades, even in dry storage off the car. They dry-rot, crack, treads separate, etc.

Dash panels and car interiors in general dry out, shrink, and crack. Plastic knobs get brittle, plastic lenses cloud up, and anything plastic under-hood deteriorates with time.

Many household items, commercial products and even tools disintegrate while in storage as well, particularly plastic stuff from "offshore" manufacturers.

We live in a society that considers just about everything to be disposable...even personal relationships...and where short-term-gain is king.

Is it really hard to grasp why manufacturers of "toys" rarely go the extra mile to make their products last indefinitely?

Unless a specific manufacturer is actively pursuing quality at (possibly) the expense of a little profit, you get what you get.

 

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Except for an AMT  '40 Willys( that was built in the last 25 years) I've never had a tire melt problem. I have original  60s and 70s vintage MPC, JoHan, and AMT kits and there's no tire melt. Was this more of a problem with Revell or Monogram kits?

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11 minutes ago, ZTony8 said:

Except for an AMT  '40 Willys( that was built in the last 25 years) I've never had a tire melt problem. I have original  60s and 70s vintage MPC, JoHan, and AMT kits and there's no tire melt. Was this more of a problem with Revell or Monogram kits?

It depends on the issue of each kit and exactly what tire compound they used at the time, and storage conditions.

I've seen just as bad tire-melt with AMT, MPC, and JoHan as Revellogram...and there really seems to be no easily identifiable common denominator...short of a full-blown chemical analysis.

I've also seen model tires that shrink, or get a dry powdery surface, or become sticky where the black gets all over everything, or crumble to powder.

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15 minutes ago, Oldcarfan27 said:

Why can't they use a similar formula like Johan used on their whitewall tires? They were hard, but they never melted plastic.

It's not a matter of "can't".

It's a matter of caring enough about long term quality to DO it...even if it takes a little extra effort and shaves a few bucks off the profit margin.

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  • 2 weeks later...
On 12/30/2021 at 6:01 AM, ZTony8 said:

Except for an AMT  '40 Willys( that was built in the last 25 years) I've never had a tire melt problem. I have original  60s and 70s vintage MPC, JoHan, and AMT kits and there's no tire melt. Was this more of a problem with Revell or Monogram kits?

I have several old kits I built in the 70s, Monogram classic cars. They are all good, no sign of any melt in all these years. I have one classic car kit from the 70s from Airfix, Chrysler Imperial. This one has always had a bit of tire melt..

That's the only other kit I have that has the problem, which is why I was really surprised to see it on the newly issued Takom kit. I thought this was bad manufacturing from the 70s and not something that still happens..

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On 12/30/2021 at 12:07 PM, Ace-Garageguy said:

It's not a matter of "can't".

It's a matter of caring enough about long term quality to DO it...even if it takes a little extra effort and shaves a few bucks off the profit margin.

Another issue of having the kits produced by a third party in China.  No face to face oversight.  Things like the mix in the plastic... we've all noticed varying degrees of workability with the different model issues.  Tires would fall into that same crevice!  

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  • 2 years later...

I recently discovered tire melt on a model that I used some aftermarket soft resin tires that I installed when I built an AMT F350 about two years ago.  A different version of the F350 built at the same time with resin wheels, but same tires, has shown no signs of melting or other damage.

Replaced the plastic wheels, cleaned the inside of the tires, lined the new plastic wheels with Bare Metal foil before reinstalling the tires. First time this has happened since some of my original builds back in the '60's.  Now I don't take chances anymore and routinely line the plastic wheels before installing soft resin tires.

 

A.J.

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Recurring problem. All one can do is check out all your stash and ensure that tyres are wrapped in tissue or bagged separately from the polystyrene kit parts.

When building make sure there is a barrier all around the wheels where the tyres will fit on them. Bare metal foil or kitchen foil would work being metal.

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