Polishing Acrylic / General Science and Electronics / Forums

Forums

4hv.org :: Forums :: General Science and Electronics

« Previous topic | Next topic »

Polishing Acrylic

1 2 next

Move Thread

LAN_403

Voltwad

Sat Dec 12 2009, 03:00PM

Registered Member #1829 Joined: Sun Nov 30 2008, 01:06AM
Location: Raleigh N.C.
Posts: 74

Hey everyone. I've got a bit of a problem. I'm making some Whimshurst discs. I cut them from scrap pieces of Plaskolite Optix acrylic (the stuff available in Lowes). The backing was already peeled off so the disks got some scratches in. Now I've tried several methods on some scrap pieces: acetone, ether, mineral spirits, a nasty combination of xylene, toluene and benzine, and I've tried sanding and flame polishing but the point between the scratches melting and the plastic bubbling is thin or non existent. Most of what I've found about finishing this stuff deals with the edges, not an entire surface. I'm wondering if anyone has a good method for de-scratching this stuff. At the moment I'm considering either putting it in the oven on top of a piece of fiberglass so the top surface will flow just a bit while the bottom remains solid. I just need to know what temps to use. Or building a turntable and doing a lot of tedious sanding and polishing (something I'm not looking forward to). Any help is appreciated.

lpfthings

Sat Dec 12 2009, 03:12PM

Registered Member #1361 Joined: Thu Feb 28 2008, 10:57AM
Location: Cairns, Australia
Posts: 305

I dont think sticking it in the oven will help, as the stuff doesn't really melt before it starts burning, just becomes flexible.

Hope you find a fix :)

Dennis Rogers

Sat Dec 12 2009, 08:10PM

Registered Member #1837 Joined: Tue Dec 02 2008, 02:20PM
Location: NYC
Posts: 65

I had an old Jeep with the clear plastic soft windows a while back. They would get scratches often and i found using automotive compound worked great. First a coarse compound, then a light compound, finally a polish/wax. Came out looking like new with not too much effort. I imagine acrylic would polish up similarly, maybe a little more labor since it's harder. Know anyone with a buffing wheel?

Nik

Sat Dec 12 2009, 08:14PM

Registered Member #53 Joined: Thu Feb 09 2006, 04:31AM
Location: Ontario, Canada
Posts: 638

I was wondering how to clear up my jeep windows! Ill try that on the spare set i have.

Hazmatt_(The Underdog)

Sat Dec 12 2009, 08:31PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

I use Propane-Oxy to polish and I don't have that much trouble with it. If that's not working you may need to use one of those huge blast burner handles that Harbor Freight has for Propane and do multiple passes over the entire surface as if you were spray painting it. That's how I would approach it.

If that doesn't work out, you're putting way too much effort in for what is going to be a poor end product, and you should consider getting some fresh plastic and start over. I know that sounds like an easy answer, but I have delt with plastic and it never quite looks right after you fix it.

Just consider how much time and effort you're putting into this.

MinorityCarrier

Sat Dec 12 2009, 09:28PM

Registered Member #2123 Joined: Sat May 16 2009, 03:10AM
Location: Bend, Oregon
Posts: 312

Cerium Oxide works well for polishing acrylic. Mildly toxic so wear gloves.

I think there may be some buffer wheel polishing compounds for plastic that you can buy. You'd probably need to dress up a new buffing wheel with it and only use this wheel for plastic (don't dress with aluminum polish, etc)

Hon1nbo

Sun Dec 13 2009, 05:32PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

I had a big problem like this with my Bullet Resistant Panels when I was getting them framed for an art piece!
what I did was use a brand of Polish called "Novus" - it is available in three steps, in small bottles or big buckets - you likely do not need all of the three steps, as they are for different levels of scratches

I also had some mild success with Meguiar's Plastx, which is made to restore car headlights... might be worth a shot

but do it by hand no matter what with the novus, and as for the other stuff you can if you are good with a buffer

Proud Mary

Sun Dec 13 2009, 10:19PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Toothpaste is very good abrasive for final finishing, but very slow, as you'd expect.

Voltwad

Fri Dec 18 2009, 05:37PM

Registered Member #1829 Joined: Sun Nov 30 2008, 01:06AM
Location: Raleigh N.C.
Posts: 74

Well, I built a turntable and wet sanded them both down to 600 grit. After that I've just decided to leave them frosty as further polishing is just going to take too much time. The next one I build I'll use fresh plastic with the backing still on. I don't think the frostiness will adversely affect the performance because I've seen discs with matte finishes before. Anyway, here's what I've got so far.

IntraWinding

Fri Dec 18 2009, 07:15PM

Registered Member #2261 Joined: Mon Aug 03 2009, 01:19AM
Location: London, UK
Posts: 581

Micro Mesh cushioned abrasives are worth knowing about

People use this stuff for things like polishing the scratches out of aircraft windows.
It's a lot more expensive than Wet'n'Dry and the grit numbers don't relate directly to convention papers either.
Always use wet.

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob