How to Oven Bend Styrene

[Glenderg]

Evening lads. Been using this method for the last few months to form roofs for wagons, and I think I have the process and the pitfalls licked. This can be useful for recovering goods wagons where the roof is cracked, or forming curved panels in general.

 

 

 

First thing you will need is a former to create the curve. I made one up from balsa wood and mounting board, with regular sections to keep it's shape. Superglued the whole lot, and it hasn't buckled in over 50 oven forming operations.

 

 

But since the general curvature of goods/brake wagons is 123mm/5 inches approx diameter, any similar non-combustible cylinder will do. That's my flat piece on the right hand side which is made from 0.25mm styrene sheet.

 

 

Place it in the middle, and starting at one end wrap the entire shape in masking tape, ensuring its pulled tight. Now, the fun bit. Take everything out of the oven including racks, and give the bottom tray a bit of a sweep if there are bits of food there. Pre-heat the oven to 115 degrees centigrade (this is for fan assisted ovens) and place the wrapped former on the bottom of the oven, the long side perpendicular to the fan.

 

For 60 seconds only. Remove the former, inspect masking, pull taught if necessary and replace it in the oven for a further 60 seconds, this time with the other face now perpendicular to the fan. After this period, remove and set aside, allowing it to cool naturally for about 2 minutes. Remove the masking tape and this is the result.

 

 

This is how it looks loose laid on a wagon, and several pieces laminated together produce very strong wagon roofs.

 

 

This method also works for longer coach roofs, and sides, but is trickier generally. Things to avoid.

 

Never let the fan of the oven wash directly against the plastic face, or you will have ripples in the styrene which can't be removed.

Never put the former on any upper rack of the oven, or you will get rippling.

Don't skimp on masking tape, cos if it comes loose during the "cook" you'll have a sculptural piece of styrene, and no roof.

Don't leave it in for more than 60 seconds at a go. Ever.

Wine bottles with boiling water doesn't work.

And doesn't create fumes or a smell so it keeps domestic authorities calm. Sort of....

 

Have fun "cooking"

Heisenderg

[Garfield]

Nice one, Rich... Gordon Ramsey eat your heart out!

[Dave]

I like it Heisenderg!

[BosKonay]

Genius!

[heirflick]

i knew there was more to you than your good looks Richie - well done! now im off to specsavers:rolleyes:

[Kirley]

"First thing you will need is a former to create the curve. I made one up from balsa wood and mounting board, with regular sections to keep it's shape. "

 

Trying to figure out how you did this Richie, did you use strips of balsa to make the roof former and then sand it down?

 

"This method also works for longer coach roofs, but is trickier generally"

 

What difficulties did you encounter with the longer roof lengths?

[scahalane]

So that's where I went wrong, tried this a few years back and ended up with a brancusian type sculpture! Nice tutorial, thanks.

[Glenderg]

"First thing you will need is a former to create the curve. I made one up from balsa wood and mounting board, with regular sections to keep it's shape. "

 

Trying to figure out how you did this Richie, did you use strips of balsa to make the roof former and then sand it down?

 

Sorry for the delay in responding Kieran, been looking to see if I had photos of the process. This is for a Park Royal/Bredin MKII type roof

 

 

I treated it a bit like ship building, cutting regular sections out of 220gsm white card and laminating three together to give me a thickness of 0.75mm. The outer pieces are just pieces of mounting board strip set at about an inch depth. They were just glued on at about 40mm centres over a length of 300mm.

 

 

I sourced the thinnest balsa I could find, about 1mm and cut it to fit *almost* all of the curve, leaving the severe corner angle of the tumblehome for the minute. Started by superglueing little blobs along each section and using the mat rolling the shape so it grabbed the card sections internally.

 

 

You'll see two thin strips inserted either side to finish the tumblehome, and sanded with wet and dry 600 (dry) to get a smooth transition.

 

 

Test run

 

 

Test piece sitting on donor prior to adding filler. I hope that explains the process a bit better. If you need drawings of roof sections for a particular coach, shout and I'll do up a template.

 

 

"This method also works for longer coach roofs, but is trickier generally"

 

What difficulties did you encounter with the longer roof lengths?

 

With longer coaches you will be missing adhesion between the former and the material in the middle since the masking tape isn't near it, and usually the one area that ripples. To get over this I give both former and styrene a liberal blast of spray mount (readjustable) so that they part-bond for the two minutes that you need. This can be removed from the styrene with a wipe of white spirits on kitchen towel once "cooked"

 

You also have so much more masking to do, so it's easy to do a couple of strips and realize the styrene has gone out of alignment. Hope that helps.

 

Richie.

[Kirley]

Thanks for taking the time to explain that in detail, I got a grasp of it now.

[Weshty]

Now that's damn tasty.