curving styrene

Hi all
I need to curve styrene for a set of OO carriages I am finishing. Is there a
tried and true permanent method for curving it along its length?
Any tips gratefully appreciated
thanks
Steve
Reply to
mindesign
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Frequently used trick is to wrap the styrene over a former of required shape, holding the styrene in place with suitable bandages, and place in very hot water for a few minutes. Remove, allow to cool, and the styrene takes on the new shape. It may take an impression of the bandaging, so pick something which won't leave a pattern.
Another method is to score the inside of the material, and it will usually set in a curve. Particularly if given a bit of solvent on that side.
Final method; don't curve it, instead build up layers and cut down to shape (sanding/milling). Possibly works better with ABS than styrene.
Must be other ways....
- Nigel
Reply to
Nigel Cliffe
how timely!
I just got done racing around looking for a former - believe it or not the perfect diameter former for 4 wheel coach rooves is a 250ml spray can
:)
I managed to successfully curve the styrene initially by rubbing it over the edge of the table..... now I am going to wrap rubber bands around the can and then apply a hair dryer to the pieces - once that's done I will leave them til they cool off and see how well they retain their shape
Thanks
Steve
Reply to
mindesign
Warm water is the accepted "standard" method if you're forming the styrene over a mould/former. Takes a bit of practice to get the temperature right, practice on scrap first.
If you're stretching it to make (say) aerials then heat over a candle flame and pull.
Reply to
Chris Wilson
I've used a variation on this theme in 7mm scale. I use some 30 thou sheet for a base and cut deep grooves in it using a skrawker type tool. I make the grooves very deep - almost right through to teh other side.
I then stick the 30 thou onto formers which give the curved shape required and with the grooves on the outside of the curve - especially if the curve is quite a small radius. When everything has set hard, I sand down the 30 thou to get it as smooth as possible and fill in the grooves with putty if they have opened up a bit with a sharp curve. I then stick 10 thou sheet over the 30 thou to cover up the grooves. You have to be careful with this method if you are using sheet formers at intervals to give the shape since the 30 thou sheet might dip or hammock between the formers if you are not careful. I put in horizontal strips between the formers and flush with their edges to support the 30 thou between formers and avoid any sagging problems.
Another method I have read about is to make a solid former for your shape and then apply layers of thin sheet (5 thou or 10 thou) to build up a curved sheet. Obviously the former will have to be X thou smaller overall depending on how many sheets you are using and of what thickness. I think you would have to be careful with this method and not use too much MEKPAK when sticking sheets together - especially if you are trying to use the 5 thou sheet. You could finish up with a sticky mess which will take years to harden off.
Jim.
Reply to
Jim Guthrie
Chris
you really took me back to my childhood then - I used to make aerials, fencing, handrails, etc from kit sprues (if that's the right term)
flame + stretch to varying lengths and presto!
Thanks
Steve
Reply to
mindesign
I put the piece of polystyrene away, and replace it with a piece of venetian blind slat. This is a very useful material, light, strong and cheap. An old venetian blind will cost around $5 at a garage sale.
You can cut the aluminium material with scissors, or score and snap. Form tighter curves around any smaller diameter tube. Glue with superglue - I use the gel.
Reply to
Allan Lees
As a variation on Jim's sugegstions I have tried a similar system of scoring the plastic sheet - I bought mine in large sheets many years ago from the local plastics supplier (yellow pages) so it's not Plastikard, which is Slater's trademark - but instead of covering it with a thin layer of plastic sheet after sanding, I draped some toilet tissue over it and flooded it with MEK. I have tried both the luxury Andrex type as well as the Izal type. You get different effects, so it's worth experimenting to see what suits your modelling 'tastes' best.
You could also try the aircraft technique of planking with individual strips of plastic sheet over formers instead of scoring the sheet.
In my youth I used to use the Izal toilet paper as tracing paper - all my tracings implored you to 'now wash your hands' o:))
Jim Guthrie wrote:
Reply to
Dick Ganderton
you know, ever since I was a little tacker I have thought an old Venetian blind would be perfect for such a thing ..... so, I have asked around since I bought these 4 wheel coaches 6 months ago and do you think I can find anyone with one of the buggers?????? It was definitely my first choice!
Thanks
Steve
Reply to
mindesign
Hi Guys,
I've found that it is important to cool the hot paltic quickly. I plunge it into cold water as soon as it comes out of the hot water. I found that if one lets the polystyrene cool slowly it tends to unravel when removed fom the former.
Cheers, Roger Gillard
Reply to
Roger Gillard

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