Cutting plexi

[Brendan Plavis]

Does anyone else have this issue?

I was cutting some lexan/polycarb, and that was fine, then I cut a piece of home depot borne plexi, and it began to reak of superglue, not to mention it cracked like a SOB.

I was getting ready to ask pops for his SRT gas mask, since I began to get light headed. Not to mention it burns the eyes like hell(I just went down to clean, about 12 hours after doing the cuts, and my eyes are burning like hell now...


The cracking I think I can fix by sandwiching it between two sheets of wood, but I am not sure about the odor.... I am on crunch time(I will be burning the mid night fuel) so any quick answers would be appreciated. And I cannot lug the saw outside, since it weighs 200lbs....

-BTP

[Dave Gaul]

The odor must be coming from heating the plexi during the cut. I have cut plexi on the TS many times... I use a sharp blade, but not my best blade... maybe your blade is dull and causing excessive heat...?

[Brendan Plavis]

The blade is new... just got it three days ago(hell, just bought the saw three days ago...) Its a high tpi(14) and after shutting down the saw, I can touch the blade without a burn(little warm, but not too bad..)

[Dave Gaul]

hmmm.... well the blade probably wouldn't get too hot, but the plexi probably is... somehow.

You say you just got the saw 3 days ago... have you tuned the saw? Blade parallel to the miter slots? Fence parallel to the blade/miter slots? If not, the plexi may be binding between the blade & fence, causing the plexi to heat => the odor...

[Steve knight]

well you buy crap from the borg you never know. cheap lexan really sucks rocks. it is very hard to machine

[Brendan Plavis]

I have it tuned okay, I can cut a rather straight line(still trying to tune it, going to probably print off a guide.) I am not using a fence or mitre guage, since I am cutting it freehand.. Its quicker and these pieces dont need to be pretty(they are being taped over(school project.)

[Brendan Plavis]

well you buy crap from the borg you never know. cheap lexan really sucks rocks. it is very hard to machine

The yea... but hey... I got the blade for $5... I had already spent$320... so that could be why too... still getting over the mild wallet shock...

But I guess you are right, it could damn well have super glue in it... I had only gotten it from the borg, because I wanted a test piece before I dipped into my good stash of lexan and poly carb...

[Ben Hatcher]

I have it tuned okay, I can cut a rather straight line(still trying to tune it, going to probably print off a guide.) I am not using a fence or mitre guage, since I am cutting it freehand.. Its quicker and these pieces dont need to be pretty(they are being taped over(school project.)

I presume that you're using a bandsaw. I assume you know never to freehand a piece on a tablesaw. I think that your blade is too fine. Try a more course blade, like 4 or 5 tpi. What's happening is that the blade isn't taking off large enough chips and that's allowing the material to heat up in front of the blade.

[Brendan Plavis]

I presume that you're using a bandsaw. I assume you know never to freehand a piece on a tablesaw. I think that your blade is too fine. Try a more course blade, like 4 or 5 tpi. What's happening is that the blade isn't taking off large enough chips and that's allowing the material to heat up in front of the blade.

You are correct on that.... I dont use TS, so I dont have to worry about that one....

Too course, and it will just chip.... Odd, because, as I said, the lexan is fine, the BORG stuff... well thats a different story...

I made felt the side of the piece after I cut, and it was cool, not even warm.

[Matt Meiser]

Lexan is GE's brand name for polycarbonate. The stuff you got from the BORG is most likely acrylic. Totally different material. And yes, acrylic melts like crazy when you try to cut it with a jigsaw. I'm not surprised a bandsaw is any different.

Super glue is cyanoacrylate. I'm assuming they have some common chemistry?

[Brendan Plavis]

Yea, sorry if that wasnt clear... The stuff that reaks is acrylic/plexi the stuff thats fine is polycarbonate(lexan and Makarov)

[Rick Markham]

Matt, if my memory serves me (been a few years) the acrylic's has a solvent that is used in manufacture that is a relative (if not THE solvent) used in CA glue. Neither one of which is probably terribly healthy to breathe.

As for cutting it Brendan, do you have access to a hacksaw (would be my first choice to try) or any other handsaw? I know that isn't what you want to hear since you got your new bandsaw. Chances are you will get the least amount of chipping/ cracking with the hacksaw blade. Sandwiching the material between two boards and trying to cut it, might be your next best option if you don't have a handsaw. Though the fumes will still be there.

What saw did you end up getting Brendan?

[Don Jarvie]

Sandwiching it between 2 boards sounds like a pretty good idea. Make the baords a little oversized and screw them together. You still may get a little smell but probably less chip out.

[Clarence Miller]

Try using a manual coping saw.

[Brendan Plavis]

Matt, if my memory serves me (been a few years) the acrylic's has a solvent that is used in manufacture that is a relative (if not THE solvent) used in CA glue. Neither one of which is probably terribly healthy to breathe.

As for cutting it Brendan, do you have access to a hacksaw (would be my first choice to try) or any other handsaw? I know that isn't what you want to hear since you got your new bandsaw. Chances are you will get the least amount of chipping/ cracking with the hacksaw blade. Sandwiching the material between two boards and trying to cut it, might be your next best option if you don't have a handsaw. Though the fumes will still be there.

What saw did you end up getting Brendan?

DELTA single speed model. 14". I finished the cut, just bore the odor of the fumes........

We have a hacksaw..... but it doesnt hack it for quick cutting.... :)

well.. I gotta go clean the egg of my fathers car....(since project's tape let go, and the payload(egg) landed on the windscreen.... opps...)

[Jerome Stanek]

we cut a lot of plexi first off we use a dedicated blade that we only cut plexi. It is an 80 tooth ABT blade and it has to be sharp.

[David Christopher]

I just use masking tape over the cut line and dont feed too fast, the slower the feed the more debris it will remove.....all the lexon that I have cut smells like CA

[Kevin Groenke]

Let's see if I've got this right Brendan,

You bought a new tool which you hoped would be the magic bullet but it doesn't have the functionality you expected. Anybody surprised?

Acrylic is a touchy material, the window is pretty narrow (especially cheap BORG acrylic). We've found that the best way to cut it is with a laser (which doesn't work on polycarbonate at all) or a CNC router. The next best method is with a tablesaw using a negative rake, TCG blade. (it's important to know tooling terminology and to understand HOW tooling works-at a cellular lever-to get the best results). I agree that the 14tpi bandsaw blade you tried to cut it with has too many teeth, the chips are melting before they clear the stock which is why you're smelling the aromatics. I haven't ever seen acrylic cut on a bandsaw without significant chipping.

Are you cutting the acrylic in straight lines?? If so, you can score and snap it in the same manner that glass is cut. You can just use a utility knife but they also make a hook knife designed specifically to score acrylic. The score should be a single cut and it should be as deep as you can make it in a single pass.

http://www.tapplastics.com/uploads/products/images/fullsize/standard/442_acrylicknife.jpg

The polycarbonate is a different matter.

-kg

[Brendan Plavis]

Let's see if I've got this right Brendan,

You bought a new tool which you hoped would be the magic bullet but it doesn't have the functionality you expected. Anybody surprised?

Acrylic is a touchy material, the window is pretty narrow (especially cheap BORG acrylic). We've found that the best way to cut it is with a laser (which doesn't work on polycarbonate at all) or a CNC router. The next best method is with a tablesaw using a negative rake, TCG blade. (it's important to know tooling terminology and to understand HOW tooling works-at a cellular lever-to get the best results). I agree that the 14tpi bandsaw blade you tried to cut it with has too many teeth, the chips are melting before they clear the stock which is why you're smelling the aromatics. I haven't ever seen acrylic cut on a bandsaw without significant chipping.

Are you cutting the acrylic in straight lines?? If so, you can score and snap it in the same manner that glass is cut. You can just use a utility knife but they also make a hook knife designed specifically to score acrylic. The score should be a single cut and it should be as deep as you can make it in a single pass.

http://www.tapplastics.com/uploads/products/images/fullsize/standard/442_acrylicknife.jpg

The polycarbonate is a different matter.

-kg

You have it wrong... I never expected it to be a magic bullet.... I bought it because I needed something that could rip, resaw, crosscut to an extent, as well as cut curves decently...

Please dont speak down about me"anyone else surprised." I know how to work with scoring and snapping, I did it for my first batch, but I sure wasnt scoring and snapping 1/4inch poly...

I have already done what I asked for, so mods, could you perhaps close the thread. Thanks

-Brendan

[Kyle Iwamoto]

Did you try an actual plexi cutter? They VERY cheap, essentially a glass cutter. Score the plexi and break it off much like glass. I typicall score it 3 or 4 times. Risk is that the first few times, you'll get the scorer off track and you got this nice score line in your plexi.

[Mark Woodmark]

Plexiglas just doesnt cut well with a saw, too brittle. Should have stuck with the polycarb