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Old Jo-Han promo plastic question


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#1 Craig Irwin

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Posted 03 March 2013 - 12:43 PM

I've aquired an old 1960 Jo Han Chrysler promo that has a lot of damage. Is this some kind of strange plastic that can't be repaired or am I OK to start working on it?


Edited by Craig Irwin, 03 March 2013 - 12:44 PM.


#2 Ace-Garageguy

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Posted 03 March 2013 - 01:20 PM

If it's the same as some of mine, it IS much more solvent-resistant than the current crop of 'styrene' model cars. I started re-building this '61 a while back...

 

DSCN5053.jpg

 

I had to use hot liquid cements like Tenax to get any adhesion. Finally ended up using a slow-cure epoxy and fine glass colth inside the body to keep it from re-cracking...

 

DSCN5966.jpg

 

But it's fine now, and on the way to a full recovery...

 

DSCN7592.jpg



#3 george 53

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Posted 03 March 2013 - 01:21 PM

Those old JoHan Promos WERE molded in some weird won't glue plastic. That and the fact that the model KITS were molded in regular styrene makes the hard to find unwarped.



#4 Craig Irwin

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Posted 03 March 2013 - 01:25 PM

Looks great! I've got part of the hood and right fender missing, nothing like you started with! It's not warped so I don't think it's that acetate (spelling?) stuff. I think It's a New Yorker but will be a 300 F.



#5 Ace-Garageguy

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Posted 03 March 2013 - 01:42 PM

You're right...it's definitely NOT acetate, which would most likely be pretty badly warped by now. I honestly haven't tried CA on the old Johan stuff, but it's a possibility.



#6 Art Anderson

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Posted 04 March 2013 - 12:25 PM

You're right...it's definitely NOT acetate, which would most likely be pretty badly warped by now. I honestly haven't tried CA on the old Johan stuff, but it's a possibility.

Those older JoHan promo's prior to 1963 (and AMT promo's through 1961)  were most certainly molded in acetate plastic (trade name TEnite), and for a very good reason:  Safety.  Styrene plastic in its early years was very brittle, and a styrene plastic toy, when dropped, could shatter very much like glass.  Acetate plastic doesn't have that hazard as it is a lot tougher, more resilient.  However,  acetate plastic has a tendency to shrink after being molded, as well as being affected by humidity, which leads to warping of complex hollow shapes, such as a promotional model car body.  For 1962 promo's, AMT switched to a then-new type of plastic: Cycolac, which was the early trade name for ABS plastic.  JoHan made this switch for their promo's for 1963  (MPC came along a couple of years after the introduction of ABS.

 

Art

 

Acetate plastic can be glued though, just not with the cements we are used to using on styrene plastic.  Revell and Monogram both produced their first plastic model kits in acetate, Revell marketing what they called  "Revell Type A Cement", which was acetone based.  In fact, acetone is the solvent for acetate plastic.  However,while acetone will also dissolve styrene,  it's the dissimilar molecular structures that prevent acetate and styrene from bonding with any strength  with the use of solvent-based cements.



#7 Art Anderson

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Posted 04 March 2013 - 12:29 PM

You're right...it's definitely NOT acetate, which would most likely be pretty badly warped by now. I honestly haven't tried CA on the old Johan stuff, but it's a possibility.

Bill, not all acetate models warped--I've seen some, and have a couple that are still straight as a die   It's been said that humidity has a part to play in that, which makes some sense, given that  the straightest acetate promo's I've seen seem to have come from the desert southwest.

 

Art



#8 Austin T

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Posted 04 March 2013 - 01:01 PM

I have a buddy who has an old Chevy pick up promo that has warped down in the middle, providing a fairly realistic representation of what old Chevy work horses look like today.



#9 Ace-Garageguy

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Posted 04 March 2013 - 02:31 PM

Bill, not all acetate models warped--I've seen some, and have a couple that are still straight as a die   It's been said that humidity has a part to play in that, which makes some sense, given that  the straightest acetate promo's I've seen seem to have come from the desert southwest.

 

Art

Thanks Art. That's very interesting. I should have been more clear. What I meant is that MINE is not acetate, at least not like any other acetate I've seen. I have some other acetate models and they don't behave or look like the plastic my '61 Dodge is made of. Based on your information, I did some more research on what I have and APPARENTLY both AMT and Johan kitted the '61 Dart. This one IS extremely brittle, as evidenced by the multiple pieces it had shattered into. Maybe it's an early styrene kit. Liquid glue for styrene WILL work on this old model.

 

I had assumed it was a Johan issue, as the molds I made from a resin-repop that was made from a Johan promo original (supposedly) fit my body perfectly. There was no chassis plate with the broken body-shell I got, so no identifying trademarks.

 

Do you happen to recognize the light-green mine is molded in as being either kit or promo ? I've seen these described as both on the internet.


Edited by Ace-Garageguy, 04 March 2013 - 02:53 PM.


#10 gtx6970

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Posted 04 March 2013 - 03:48 PM

Weird part is, Promos were molded in Acetate but a kit version the same car was molded in stryene

 

Its not unusual to find a warped promo but a perfectly mint unwarped kit of the exact same car / kit / time period  ( Johan 1963 Dodge Polara as an example )



#11 Craig Irwin

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Posted 04 March 2013 - 05:28 PM

So hummmmmm...... Do I try to repair it or look for a 60 Desoto body to start with? 



#12 Ace-Garageguy

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Posted 04 March 2013 - 05:32 PM

If it's not warped, it's repairable with CA or epoxy.



#13 Craig Irwin

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Posted 04 March 2013 - 05:42 PM

If it's not warped, it's repairable with CA or epoxy.

True, but I wonder if it will warp in a few years. I've got it so I might as well go for it and hope for the best. Thanks for the help guys!



#14 Edsel-Dan

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Posted 04 March 2013 - 08:03 PM

I have a 62 Studebaker Lark  convertible Promo that needs a new windshield frame.

Not sure I want to try that work.

 

I though one reason for the Acetate was the High-Gloss the bodies/parts had without the need of paint

 

Also, isn't thickness a factor in warping??

I have a PMC 59 Ford Country Sedan wagon the though it has Shrunk, is still fairly Straight.

The interior has twisted though.

 

Both Hubley 60 Ford wagons I have, have the typical "Smile" effect of warping

 

I have done the Windshield replacement on a 63 Ford convertible promo. I had to add pins to get it to bond well though.

Might have to try a better adhesive.



#15 gtx6970

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Posted 05 March 2013 - 04:35 AM

my gutt says if it's not warped by now, it's not going to .

 

If you want to find one of the original Johan 1960 thru 1962 Chrysler New Yorker kit's . open the wallet they get pricey and fast.

 

I occasionaly try to get a 1961 but would consider a 1960. but I'm not paying nearly a C note for a builder. Unbuilt ? is really gonna hurt

 

True, but I wonder if it will warp in a few years. I've got it so I might as well go for it and hope for the best. Thanks for the help guys!



#16 Casey

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Posted 05 March 2013 - 07:30 AM

However,  acetate plastic has a tendency to shrink after being molded, as well as being affected by humidity, which leads to warping of complex hollow shapes, such as a promotional model car body.  

 

The proof:

 

warp1.jpg

 

warp2.jpg



#17 Art Anderson

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Posted 05 March 2013 - 02:47 PM

Thanks Art. That's very interesting. I should have been more clear. What I meant is that MINE is not acetate, at least not like any other acetate I've seen. I have some other acetate models and they don't behave or look like the plastic my '61 Dodge is made of. Based on your information, I did some more research on what I have and APPARENTLY both AMT and Johan kitted the '61 Dart. This one IS extremely brittle, as evidenced by the multiple pieces it had shattered into. Maybe it's an early styrene kit. Liquid glue for styrene WILL work on this old model.

 

I had assumed it was a Johan issue, as the molds I made from a resin-repop that was made from a Johan promo original (supposedly) fit my body perfectly. There was no chassis plate with the broken body-shell I got, so no identifying trademarks.

 

Do you happen to recognize the light-green mine is molded in as being either kit or promo ? I've seen these described as both on the internet.

Well, if the plastic that body is made from broke or shattered easily, chances are it's the styrene kit, not the promo.  Also,acetate plastic gives off a bit of an odor when it's cut with a razor saw, unlike styrene.

 

Art



#18 Ace-Garageguy

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Posted 07 March 2013 - 09:32 AM

Well, if the plastic that body is made from broke or shattered easily, chances are it's the styrene kit, not the promo.  Also,acetate plastic gives off a bit of an odor when it's cut with a razor saw, unlike styrene.

 

Art

Thanks for the smell reminder, Art. I'd forgotten that.

 

And Casey, what a shame about that wagon. Looks pretty much beyond help.



#19 Casey

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Posted 07 March 2013 - 01:59 PM

Thanks for the smell reminder, Art. I'd forgotten that.

 

And Casey, what a shame about that wagon. Looks pretty much beyond help.

 

I saw it on eBay, but have looked at many similar '60 and '61 Studebaker Lark promos.  :(

 

One of the vintage Car Model mags I recently bought has an ad mentioning Cycolac, so I'll have to scan and post it.



#20 Ace-Garageguy

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Posted 07 March 2013 - 02:22 PM

When I as a kid, I had one of the AMT Turnpike slot-car sets. I seem to recall those bodies were also Cycolac (ABS) and were tougher than the styrene kit bodies. The tooling was the same as the kits, as I swapped several styrene screw-bottoms that were the right length on to the slot chassis.

 

At the time, I didn't realize promos were even still made.