I would like to build plastic sign blanks with bend to hold it upright- like a custom car showcard kind of thing. Probably bend PVC and acrylic. Anybody do this or have any thoughts? Thanks Gene
Posted by jimmy chatham (Member # 525) on :
if you use lexan you can bend it with a sheet metal break.
Posted by Joe Rees (Member # 211) on :
Yeah Gene, I HAVE done it. It's long gone now, sold when I sold my former shop back in '92, but it was cheap and worked really well! The heating element was from a plastics supplier, a flexible cloth-wrapped strip (about 18" as I recall) with an electric cord on one end. It had a fixed operating temp so you could plug it in an let it warm up. We had routed a slot into a piece of MDO for it to fit flush into, following the directions that came with the unit. Just lay your plex over it where you wanted the bend, wait 3 minutes of so and that sucker would flow nicely into position. We found that leaving the plastic on it for too long could cause some tiny bubbles in the heated area, so you might want to set a timer or something. Basically a ultra simple affair.
On a side note, we much preferred using Lexan and not heating it at all, but cold bending it in a sheetmetal break. It won't crack, and we have bent up to 1/4" with no problems.
Posted by Tony McDonald (Member # 1158) on :
Hi Gene, I've got a plastic bender from Grimco. It's just a piece of heavy sheet metal about 3' long and 8" wide with a deep groove down the middle of it. In the groove lays a heat element. You lay the plexi over the groove and it heats in a straight line evenly. I usually bend it over a dowell rod. Would be really easy to make one it you could find a long single tube element. A piece of sheet metal, heat element, and an on & off switch. Maybe put it on a dimmer so you could adjust the heat.
Posted by Gene Uselman (Member # 2508) on :
Thanks All. Now that I look at the blanks (made by a plastic co.) that prompted this thread- I think that they were bent cold. It would be nice to bend other plastics tho- I will probably get the heater in grimco altho it seems a little short. Probably a limit to how much plastic you can handle when hot anyway. Gene Posted by Monte Jumper (Member # 1106) on :
Not sure I understand what you are trying to do here.
Whenever I have Plex (acrylic) to bend I make up a form jig (the shape I'm wanting to bend to.Usually out of redwood or sugar pine (they sand the best and cut easily)
I then lay my cut material on the bench with the plex hanging over the edge(at the point you want to bend it)then heat it with a propane torch (moving it rapidly side to side) when the plex is ready to bend it will drape over the edge of the bench at which point I lay it over the form jig and shape it to the form, when I have it where I want it I cool the plex with a damp rag.
Werks fer me it'll werk fer you...
Posted by EPatzer (Member # 135) on :
I used the propane torch method to make a custom fitted plexi cover for a box (rounded corners and all). BUT! I used a piece of scrap oak for the 'buck' and ended up with a piece of plexi that had a really nice wood grain debossed surface! Just make sure your mold is smooth and free of dirt! Ahh lessons...
![[Big Grin]](biggrin.gif)