You can do a lot with acrylic and few tools. If you’re just starting out we’d suggest taking a look at [Michael Colombo’s] guide to heating, bending, and gluing to create custom acrylic enclosures. Chances are you already have most of what you need. The one tool you might be lacking is a heat gun.
The process starts with math. Before cutting the acrylic down to size you need to calculate how much you need. Next [Michael] demonstrates his cutting technique using a Dremel and a cut-off wheel. We prefer to clamp along the cut line, score many times with a razor knife, and snap the stuff. But you can also send it through a table saw if you have the right blade.
The bending technique he uses starts by clamping boards on either side of the bend. The acrylic left sticking out is pushed with a scrap board while the bend is heated with the heat gun. Once all of the corners were made in one piece the sides were glued in place. This last step can be tricky. The acrylic glue is made to work with perfect seams, so make sure your cuts are clean and the bent pieces line up.
The process was documented in the clip found after the jump. If you’re looking for a more targeted heat source check out this dedicated acrylic bender.
17 thoughts on “Heating, Bending, And Gluing To Make Acrylic Enclosures”
the video seems to be broken
Just as a general tip. There’s a quite a few helpful videos over at Tap Plastics. I have no connection with them at all, in fact it would be a bit silly for me to order from them as I’d have to ship it across the Atlantic. Still though, they give lots of nice pointers:
http://www.tapplastics.com/product_info/videos (just look through the list to find those specific to bending/cutting/gluing plastics)
Did he make a case for his Zoid? All nerdiness aside, it actually looks pretty good.
Pretty sure that’s part of Voltron.
Oh, I know I am not supposed to be negative here, but his techniques are terrible and his finished product is awful.
Go down to Tap or whoever is your local plastic supplier is and buy a scoring blade for your utility knife. They work great and make a nice clean score on only one or two passes.
If you must do bends get a strip heater element and build your own heater strip. They make a nice narrow softened zone and make bends nice, clean, even and most importantly, straight. Otherwise just make it out of flat panels.
You can also use a torch to flame polish the edges. They will need to be sanded first to get the best finish. It takes practice, you need to melt the edges and let surface tension pull it clean and smooth while making sure you keep the temp low enough to avoid causing bubbles to appear in the plastic.
Last, and I know this is nitpicking. Pick appropriate hardware for the job. Cheap zinc plated hardware store hinges with over-long screws really look like crap. At the plastic shops they sell some nice little acrylic glue on hinges that would look so much better. If you need to attach to something other than plastic you can drill and countersink for screws.
Speaking of drills, if you do a lot of work with plastic invest in some for-plastic drills, they make life less frustrating. Standard drills have a positive clearance angle, this causes them to force their way through like a screw leaving chips and broken pieces. Plastic drills have a neutral clearance so they dont pull in. You can modify existing twist drills too: http://www.bertram31.com/proj/tips/drill_acrylic.htm These drills are also good for drilling soft metals like brass.
I would also highly recommend step-drills for thinner stuff. They still have a tendency to grab but it won’t pull the entire bit through the hole (if you’ve had this happen with regular bits, then you know what I’m talking about). I’ve had fewer ‘blow-outs’ when using step drills (well, none at all now that I think about it).
Methylene-chloride works extremely well for gluing, but (in some reports) is considered quite nasty stuff. Must be applied with a syringe since it has a very low viscosity. This takes practice, but if done well, the results can be really good. I seem to remember it works better on polycarbonate than other ‘clear’ plastics, but it’s been awhile so I may have it wrong. You can do the same with acetone, though I’ve never tried this method.
Nope. I was wrong. Works better on acrylic, not so much on polycarbonate. It will still ‘glue’, but the joint isn’t anywhere near as strong and will often fail (at least in my experience).
you can increase the viscosity of these solvents by first dissolving scrap plastic in the solvent until you get the desired viscosity.
Hrm. Never tried that. My experience with acrylic has been that the plastic “goo” that gets scraped off the joint during application tends to clog the needle (grind the tip flat, so no sharp point). You can get away with plastic syringes, but they don’t last too long. ;)
I was a bit confused why he’d go through so much trouble to make a nice clear case and then stick it all on a piece of rough lumber too
As for cutting acrylic, I achieve my best results by using a melamine blade (-10 degree tooth angle) on a table saw. That blade leaves very light tool markings even in 1/2 inch material.Then finish the edge by removing the tool marks with a cabinet scraper and sanding with 400 grit paper and grade 0000 steel wool. That process leaves a very clean brushed look, which is what I prefer. if you want a shiny clear edge, flame polish at the end with a quickly moving torch.
just recently repurposed a hot wire bag sealer into a plexi bender, http://www.flickr.com/photos/quelabnm/8422052077
Most of what works for acrylic also works for polycarbonate, so if you want a tougher plastic than acrylic, that’s an option.
Preheating the plastic at a relatively low temperature will dry it out and prevent bubbles. Bubbles are caused by steam from water in the plastic – most plastics like acrylic will absorb a bit of water. Instructions for what temperate and for how long to heat are available at several plastic supplier web sites – I haven’t checked the Tap site, but they probably have this info there.
Before you pinch it in the vise to do the bending, round the corner of the wood so you are bending across a less brutal edge. This will help distribute the force of the bend more evenly and uniformly. The sharp edge causes focal points of stress across the bend, and they show up as whiteness in the crazing of the material.
If you want an acrylic, glass, or metal base you can create strong flexible joints with silicon sealant. You can get a cleaner look.
The joints really makes it look bad, get a vacuum mold and make the clear case top out of one solid piece.
Video isn’t working for me, either. :( Too bad, I could really use it for an upcoming project this weekend.
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