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Straightening Warped Parts

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  • Member since
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  • 297 posts
Straightening Warped Parts
Posted by markie97 on Saturday, March 23, 2019 1:51 PM

Hello;

I have built the Walthers elevated suburban station. However, the roofs are warped and I am wondering how to straighten them. I suspect I can do it in the oven but am concernewd about too much heat ruining them. Any suggestions?

Thank you

Mark

  • Member since
    December 2014
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Posted by Wolf359 on Saturday, March 23, 2019 2:01 PM

Try soaking the roofs in hot water for several minutes. It might soften them just enough for you to straighten them out.

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Posted by mbinsewi on Saturday, March 23, 2019 2:43 PM

The hot water is probably worth a try.  The oven might work, also, but becareful with heat.  I think at some point and time, just about everyone in here has dealt with this, with roofs, flat cars, etc.

The key might be to try and get it to it's original position, and hold it that way, so as it heats, it straightens itself out.

I had a couple of trailer bottoms I needed to flatten out.  I tried everything, but I was too impatient, so I got out the heat gun.  I was making progress, being ever so careful, and poof!  just like that, the trailer bottom crinkled up into a mess right before my eyes.

Another member in here had trouble with a flat car, and I don't think he's posted yet if he ever got something work.

Whatever method you try, and it works, tell the rest of us, please!

Mike.

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Posted by j. c. on Saturday, March 23, 2019 3:07 PM

oven is too hard to control, what i have used on flat stuff is clamp it between two 1/4 steel plates , then heat up plates wih heat gun/hair drier to around 100 deg. then let cool overnight.

ps DON'T excede 100 deg.

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Posted by dknelson on Saturday, March 23, 2019 3:33 PM

Sometimes a warp is so bad there is no reason not to "shoot for the moon" in trying out extreme suggestions, and to me the oven idea (oven thermostats are VERY approximate) is an extreme idea. 

But if the warp is not a bad one, I would not start with the oven idea.

One thing to remember is that styrene plastic holds heat and can get painfully hot to the touch.  Any method of straightening that involves heat has to take this into account.

Hot water is one idea that some guys report having success with.  Another idea that has been tried by others is to put the warped part between panes of glass and have an ordinary light bulb nearby as the heat source - but you have to keep an eye on it.  The idea is that the panes of glass will tend to straighten the part as its gets soft.  Of course we have reached the point where ordinary light bulbs are rare!

One well known modeler, after finding parts badly warped because he left them near a photo flood lamp too long while distracted, got pretty good at using his photo floods to "de-warp" plastic parts.  But you have to find a way to make the softened plastic straight, or should I say straightER, without burning your fingers.  

Here are three ideas that have worked for me.  In one case the warp was bad and I actually cut the piece in half to try to minimize just how much of the warp I had to deal with.  I used heat to straighten the ends.  The end result was not perfect flatness but in context it looked OK (easier to accept some modest warp in a structure than on rolling stock).

Somewhat related, I scored the back of the part with knife cuts so that it became just a bit bendable.  Careful because the next step would be score and snap and you don't want to go that far.  I then applied a very liberal dose of styrene cement to that scored back side so the plastic was softened by the cement, NOT by heat.  I then cemented a rather rigid piece of styrene in place as a brace.  I used those Coffman braces to hold it perfectly straight while the cement softened the styrene and then hardened and set.  Coffman is known for the right angle clamps but they also make a splice clamp that holds things straight.  One can work; two are better.  They aren't cheap but fortunately have many uses in structure building.

https://www.coffmaneng.com/shop

I have also used a heat gun used by rubber stamp hobbyists (less heat than the paint stripping kind of heat gun but be careful as it is still plenty hot).  Holding the part in my hands I would move the warped portion of the part back and forth in the hot air and was able to find the "magic moment" when the plastic softened, straighted it by hand, and then quickly immersed it in a pan of cold water to "freeze" the part in its straightened condition.  This might need repetition.  This takes practice and you might want to rehearse this with plastic bits from the junk box.

Dave Nelson

 

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    January 2008
  • From: Tampa, Florida
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Posted by cedarwoodron on Saturday, March 23, 2019 5:47 PM

Years ago I read an article in Fine Scale Modeler where a car model chassis was warped as it came out of a sealed box. The writers solution was to use a heat lamp- buy an infra red bulb- and elevate the diagonal opposite corner of the part, allowing the heat to slowly relax the warp. I'm sure that one would want to put this on a piece of wood to help dissappate heat of the working surface and monitor the part as the heat works on it.

Cedarwoodron

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    February 2008
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Posted by maxman on Saturday, March 23, 2019 5:52 PM

mbinsewi
Another member in here had trouble with a flat car

Yes, that was me.  Have not posted because I haven't tried anything yet.  I haven't convinced myself that anything I might try would not result in anything more than a pile of deformed plastic.

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Posted by hon30critter on Saturday, March 23, 2019 5:57 PM

Would a hair dryer work?

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by BigDaddy on Saturday, March 23, 2019 5:58 PM

I bought a F&C gondola at Timonium that was already assembled.  I just added decals and couplers.  A month or two later I noticed it was warped inward along the long ends.

A hair dryer completely fixed it, until the next time I looked at it.  It is now much worse.  Is this a resin car thing?

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by MisterBeasley on Saturday, March 23, 2019 5:58 PM

E-mail Walthers and ask for replacements.

It takes an iron man to play with a toy iron horse. 

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    January 2015
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Posted by Lone Wolf and Santa Fe on Sunday, March 24, 2019 1:13 PM

I have used hot water in a sink. I have also used a hairdryer. The hairdryer worked better because I could lay the warped plastic on a flat surface.

I would never attempt to use the oven because a certain person would throw a fit.

Modeling a fictional version of California set in the 1990s Lone Wolf and Santa Fe Railroad
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  • From: Heart of Georgia
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Posted by Doughless on Sunday, March 24, 2019 6:17 PM

Two pieces of glass and sunshine.

Also, a hair dryer would work, but the product needs to be laid flat first.

- Douglas

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