Re: Warped Plastic Gondola


al_brown03
 

I've straightened out a scratchbuilt styrene boxcar roof, which had warped (due to too much glue on one side), by putting it in a pan of water and bringing it to the boil. I kept it at the boil maybe a minute before turning off the heat. Then I put the roof between paper towels on a flat surface (as if the roof were a strip of bacon), and flattened it with a weight. The roof didn't straighten out completely, but close enough that I could attach it to the car with cement and a few pins.

A gondola is a different shape, of course, which you'd need to enforce somehow. I wouldn't expect it to spontaneously re-assume its original shape. I'm tempted by the thought of removing the car from the hot water, inserting a wood block of the desired dimensions, clamping as necessary, and letting the assembly cool; but that's speculation.

-- fwiw --

-- Al Brown, Melbourne, Fla.

--- In STMFC@yahoogroups.com, PennsyNut <pennsynut@...> wrote:

On 18,10 2011 17:14 PM, soolinehistory wrote:

--- In STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com>,
"behillman" <chris_hillman@> wrote:
I think I remember it mentioned on this list about how to heat-up a
plastic car like this and re-flatten it out, like in an oven at 100
deg.? maybe?
Any suggestions about how to do this correctly? I don't want to wind
up with a melted experimentation on my own.
Thanks, Paul Hillman
from Dennis Storzek

The danger isn't melting the kit... injection molded styrene needs to
go north of 420* F before it will actually liquefy. The danger is it
will warp worse.....snip....Injection molded parts are a whole 'nother
animal. They were molded under extreme pressure (up to 30,000psi) and
then frozen in place to the shape of the mold. Heating an injection
molded part is just asking to have it turn into something resembling
either a banana, or a strip of bacon. LOCALIZED heating can be used to
bend a part... the theory behind deforming gon panels and the like.
But overall heating can yield some really unpredictable results. The
best bet is to grasp the ends of the part, and play the center ober
the hot air from a hair drier... when it yields, STOP, and see if it
will stay when it cools. Then quit. Overall heating will not yield
good results.
Dennis
So, let me interject a thought: Is there anyone who has done this sort
of thing? I did try a hair drier once and failed. But that was a
different material. There are so many different kinds of plastics. Look
at all the trouble removing paint.
And I'll bet there are many with ECW kits with warped roofs. Will those
straighten out with your technique? So, again I ask for specific results
from someone who has actually fixed a plastic kit? Details are nice. And
are always helpful for beginners as well as old timers.
Morgan Bilbo, Ferroequinologist and Pennsy Fan!



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