hot wire bending clear plastic

[popeye74]

Hi all, just joined and I have several questions regarding bending clear plastic sheet for the purposes of making several display cases, I have been researching it a bit on google and watched several U tube vids, on one "google hit" they state hot wire bending has problems over 24"- 36" lengths and above,(like "waving" or "bowing") going to make a bending machine similar to the ones shown but I would like to be able to bend up to 1.5 metre lengths, all the vids I saw were short lengths, I indent to make clamps to hold the material to the base and the moving part of the bender along with other angles etc, Also i don't know the difference between Perspex, Acrylic and Polycarbonate, so my questions are, what's the best material to use?, what Nichrome wire gauge will I need for 1500mm bend length?, and can anyone recommend a decent variable transformer/power source that's not going to require me to re-mortgage?
Going to try and make a real professional job of this bender and i'm sure a can make it a bit better than some of the ones I've seen on U tube, what I want to do is be able to bend "U" shapes for the display cases and just cut panels for each end or in one case join three together for an extremely long model truck and trailers model I made, ( Aussie road train) the other two large ones are for 1/200th scale ship models at just over 1200mm long each (battleship Yamato and carrier Shinano), thanks in advance for any ideas you guys can supply, regard's, Ian

[Bob225]

there is an art to bending. i fear you will be buying extra sheets and this stuff isn't cheap, Your best bet is some proper Lexan (polycarbonate) as its more durable and is UV stable unlike acrylic what goes brittle

Lexan is the brand name for Polycarbonate

Perspex is the brand name for Acrylic


I have used - The plastic shop and a company called Display developments https://www.displaydevelopments.co.uk/ in the past without issue

[popeye74]

Thanks Bob, appreciate your reply, Yes mate it isn't cheap I know, several year ago I got two panels cut to size for a display front they were about £90 as I remember, they were about 1000mm square with polished edges, many of the cases I made in the past were done with that "secondary double glazing" stuff B&Q used to sell, cutting it was a nightmare, and fixing together was difficult, I used silicon mastic and many of em came apart after a while, didn't do the model ships inside a lot of good
Just fancied having a go at bending, they make it look easy in the U tube vids, anyway I will take your advice and try some Lexan on some smaller scale cases gain a little experience before tackling bigger ones, thanks again, Ian
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[Someone-Else]

Just saying.............there is/was a "fly on the wall" programme on TV about a company that made all sorts of fish tanks, they didn't go into that great detail of how it was done (Not enough entertainment value I guess) but on the odd occasion you would see them put a huge sheet of "plastic" into an oven then bend it into a perfect cylinder. They didn't show how they joined it though.

My point being if its small, you may want to try putting it in an old oven to warm it up? just a thought.

[popeye74]

Thanks someone-else that sort of programme has entertainment value for me, better than the reality tripe that seems to appeal to morons these days, love that "how stuff's made" that on quest or yesterday now and then, doubt i'd get a decent size of sheet in our oven though, I did see a bend being done many years ago when me and a pal who was a blacksmith/metal fabricator had to deliver to a plastics place that did signs, big machine and a hot wire coil must have been well over a mt long, made a lovely bend tho, Wont be trying any time soon with my efforts as still busy redecorating the room the models are going in and I got to make the bending table yet, just getting as much info and tips together for now, cheer's, Ian

[kjones1829]

Have you tried forging? This technique was used to make efficient swords or knife. Maybe this will work on bending clear plastic sheet as well. What do you think?