View Full Version : flame polishing acrylic

greg lindsey
06-16-2010, 4:35 PM
Hopefully I'm in the correct forum for this. I have a customer who needs me to cut them out 400 pcs 14" x 14" of 3/16" acrylic, normally I would laser cut these, but in the interest of saving machine time, I thought I would saw cut and flame polish these. Now for the question. I've never done any flame polishing, never needed too untill now. What kind of equipment will I require and is it a long process.

Joe Chritz
06-16-2010, 9:11 PM
A fine tip propane torch and a little practice.


Christopher Saar
06-16-2010, 11:19 PM
Did flame polishing a long time ago. Can't remember but i think we used oxygen and hydrogen mix from welding tanks. DOUBLE CHECK THIS!!!!!!!! mapp gas works to. Used to make a stack of plexi, even up sides and flame polish all around. Your cuts have to be pretty good or you will see saw cuts or trim on jointer or router a bunch at a time. Paper or plastic coverings give different problems. Paper scorches a little and plastic melts. Sometimes removed covering but then you have to be extra careful in handling after polishing. Experiment Flame needs to be hot to get good finish small tip. The smoother the plexi before polishing the better the result. Depends on what your customer is looking for. Good Luck Chris

james mcgrew
06-17-2010, 6:23 AM
i gice it a little rub with 180gr and the flame, test test test, develop a feel for heat and distance


Christopher Saar
06-17-2010, 8:34 AM
Another thought cut your pieces oversize on table saw. Joint one edge and make a jig. Take 3/4 plywood cut it to the size you need allowing extra material to attach a stop block. Put the jointed side against stop block that has hold down clamps attached and trim the remaining sides on shaper or router in table using a bearing as a guide. Make pieces about 1/8" oversize to trim 1/16 off each side. If plexi slipping in jig put some sand paper on it. You can do a couple of pieces at a time depending on power of machine and holding power of clamps. This leaves a series of up and down lines not the curve of table saw blade. Then light torch and run it over surface. Fast enough to polish but not burn.
Sanding then flaming probably best but to do 400 pcs and keep square I see headaches. ALL DEPENDS ON WHAT CUSTOMER IS EXPECTING!! MAKE SAMPLES AND GET THEIR OK. Chris

Rodne Gold
06-17-2010, 9:22 AM
You will have to finish the sides before flame polishing to remove the worst of the saw marks , the flame polishing wont be that effective without doing so
Apart from that acrylic reacts badly to heat , it stresses it , especially the cheaper extruded form. The flame heats up the pex a lot more than a laser would and this makes stress cracking a far higher possibility doing things this way - the flame polishing will also blunt the sharp edges of the pieces (this may or may not be a bad thing)
You will also have to buy a special blade for the table saw - one specifically for plastics , negative rake , TC tipped and lots of teeth
I would laser cut these pieces- it must be far more cost effective than the DIY method.