Found something neat

[Stumpjumper]

I've been making MDF speaker boxes for years, and found a how-to on the net for making plexiglass boxes. I know it's gonna be harder, but it seems interesting to try. For those interested, here's the write up, and I don't know the name of the source or I'd give them total credit:

Open a yellow pages and find a plastics supplier near you. Industrial plastics suppliers will sell you cut-offs at substantially reduced prices. I used to get all my plexiglass that way when I was doing custom car work back in the stone age (early to mid 90's). Most of the suppliers will be curious enough about what you are doing to give you some hints as well. Go with 3/4" for entire boxes, you can get away with 1/2" for windows or panels. I've used up to 1", which is pretty steep in price.

Screws do work fine to hold the sides together, but you must predrill the holes. Use a drill bit with a stop collar to get everything the same depth, and try to get the alignment straight up and down so it doesn't look like some gimp the box. You see EVERY flaw with clear edges. Countersink the screw heads on the flat panels so the screws don't stick out. Get youself a carbide-tipped veining router bit with a 1/4" shank ($8-$9) and chuck it into your drill to make the countersinks - cuts the plexi like butter,

You'll also need a fairly ballsy table saw with a carbide tipped blade to make your panel cuts worth a damn. The more teeth on the blade the better, 40 is minimum and 80+ is better for a 10" saw. Don't be afrid to raise the blade in steps to make multiple cuts. Put masking tape on top of the line of cut to prevent chipout (if you've peeled the paper off the plexiglass already - bad, bad, bad). PS, don't stand behind the line of cut, the plastic shrapnel hurts. Be careful, the blade will try to push the material up as it cuts, much more so than with wood. It also melts the plastic as it cuts, gumming up the blade.

Break sharp outside corners with a router and carbide-tipped rounding over bit, then burnish the edges with a sanding block. Start out with 120-150 grit silicon carbide paper and water (the correct sandpaper is black, get it in the auto body section of your favorite store) and work up to 600-100 grit. Don't go to a finer grit until the saw marks disappear with the 120-150, then work your way up to 600-1000. I'd go 150, 220, 320, 400, 600, 1000.

Finish up by buffing the edges with a plastics polish (the goop they make to restore dull convertible rear windows) and burnishing them with a soft cloth. Presto, you now have smooth and nearly clear edges, as well as a very tired arm and elbow. If you want transparent edges, you have to flame-polish them with a propane torch. This is something of an art and you'll probably want to get plenty good at it on scraps before melting your shiny new $4 a square foot subwoofer enclosure.

I always just used clear silicone for sealant in the corners after the sides were assembled.

Good Luck, the more cash you invest into decent tools, the better your result will be when working with plastics/acrylics.

[Barknard]

Thanks for the info man, really helpful!

[vballer22]

If I remember, wasnt this on a boating diy site or something? I remember seeingthis a while back.