advice on cutting plexie glass

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fritz64

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May 3, 2006
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207
Location
grand rapids, mich., USA.
i am making a pen display ( or 2 or 3 ) for me.should i use a many tooth blade ,should i make one cut, or 2 or 3,(3/16thick ) would like as clean a cut as i can get.would i need tape on top of film already on the plexy.thank you in advance. ps i dont do pictures,sorry bout. that.fritz64
 
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I would use as fine a tooth as possible, on a bandsaw. and yes use tape on both sides even though there is film on it. the cut will still be white and rough. you can turn it clear by passing a torch by it but you can also melt the plexi easily this way. I use a bandsaw to cut plexi all the time and it makes a very clean cut compared to anything else I have tried.
 
I was going to say the same thing Daniel said about clearing up the edge of the plexi. If you hold the heat/flame too close it can start to bubble and deform. You could always just sand the edges with sand paper, which could also round the edges some as well. You may also try lexan, and doesn't break as easily but I believe its prone to cracking like plexi. Though I haven't had much experiance with either lately.
 
I run an electric sign shop and cut plex every day. The cleanest way (without a panel saw), is to rough cut it to within about 1/8" with a circular saw and a hollow ground plywood blade. Go slow and let the saw come up to speed BEFORE starting the cut. NEVER start the saw in the middle of a cut. Then use a straightedge and a flush cut router bit. You CAN eliminate the router but cleaning up the edges will be harder. Then, since you're making a display, clean up the edges with a scraper. Then heat the edges LIGHTLY with a propane torch until all the roughness disappears and they become clear. This will make the glued edges almost invisible. Another trick is to turn the saw blade backwards but if you get a new plywood blade you won't have to. Look for a plywood blade that's thicker in the middle than on the outside. Try to avoid the blades that are all one thickness.
Use masking tape to temporarily hold it together and then apply a water thin plex glue using a needle tip on the bottle. Squeeze the air out of the bottle and hold it there BEFORE you turn it over. This will prevent drips. The thin glue will wick into the joint and it will become almost invisible.:wink:
 
rherrell said:
I run an electric sign shop and cut plex every day. ... apply a water thin plex glue using a needle tip on the bottle. ...thin glue will wick into the joint and it will become almost invisible.
Click to expand...
Rick,

A guy who works with plastics for a living told me that acrylic (plexiglass) glue is just MEK (methyl-ethyl-ketone, not to be confused with MEKP - methyl-ethyl-ketone-peroxide which is used as a hardener for polyester resin). Do you know if that's true? MEK (sold by the quart or gallon at Home Depot) is much less expensive than the little bottle of acrylic glue I got from LaserBits.

Regards,
Eric
 
Your friend is right Eric. MEK or Methylene Chloride are two solvents that will melt Acrylic Plex. MEK evaporates faster so it's not quite as strong as MC but for display cases it's fine. Another thing to consider is MEK is flammable and MC is not. As always, use in a WELL ventilated area.
Years ago we used straight MEK but now there are formulations that are better. Keep in mind that the stuff I build has to stand up to high winds and ultraviolet rays so I need something stronger. We use a product called Weld-on #3. It's a water thin solvent that is mostly MC. Weld-on #16 is the thick version. We get it from a sign supply outfit but you should be able to find it in small quantities on the internet. TAP Plastics would be a good place to start looking. Don't forget the little bottles with the needle tips. IMO that's the best way to apply it and not make a mess.:wink::biggrin:
 
Plex

Rick is completly correct!!. Just make sure you are using Plexiglass and not a polycarb sheet. I just retired from the sign business and have done quit a lot of plex work. when I do it I would leave the masking on the plex when flame polishing to guage the amount of heat I was putting on the plex edge. It will singe the edge of the masking then move on.
Best of luck with your project.
Nick
 
Heck this is a bunch of info-------all I did was cut my 1/4 inch plexi on a bandsaw.
Take a sander and smooth the edges off--a little two part epoxy and I was done.
Now I see there are better ways of doing it guess I should of asked first.
 
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