plexiglass

[David Starks]

One of the guys that works for me wants me to try turning plexiglass:eek:. He claims you can 'glue' it together with light coats of acetone. One of the questions is would it stay together at the seams and is it dangerous?

Has anyone ever tried it or would you?

[curtis rosche]

a sheet of 1 inch plexi is over $300 if a ready another thread right. it would be way to costly to do anything but pens

[Andrew Kertesz]

Laminated may work but I would only laminate a couple pieces at a time. You would want to make sure there are no voids in the glue lines. Even laminated I would not go to big. Finishing would be the hardest part depending on the complexity of the turning. The sharper the tool the better.

[Richard Allen]

Plexi is very brittle. You will have plastic everywhere and static will cause it to cling to everything. Plexi is also prone to crazing into a spiderweb of cracks.

Lexan on the other hand is much softer and turns with long ribbons of plastic. That is pretty cool until you try to untangle it from all the stuff it wraps itself around.

If it is plexi I would suggest staying well out of the line of fire and wear personal protection.

[Donny Lawson]

You would probally be better to cast some clear PR and turn it down. It's almost the same but not as brittle.

[Jim Burr]

Steve S does finials with it, or a similar material

[David Epperson]

Methylene chloride is a pretty strong bonding agent for acrylic (Plexiglas) and will also work with polycarbonate (Lexan) and can in fact bond them together from what I've read. But as has been mentioned, Plexi is a bit brittle and impact sensitive, where as I've actually used polycarbonate as part of a bullet back stop with out having it crack.

[Steve Schlumpf]

David - I've turned both plexiglass and polycarbonate and find the poly much easier to work with. I have not tried to glue sheets together yet but have considered it every once in a while and figured you could turn it much like a segmented form - one ring at a time. Just not sure exactly how to securely bond the materials together.

Also, Richard is correct in that either type of material makes one heck of a mess! I found that very sharp tools, slower speeds and patience works well. One other thing is that either type of material will get tear-out just like wood if you do not take your time. You can hog off material in a hurry - just like wood - but then you get a pattern of chip-out and flying pieces of sharp plastic you have to deal with. Also, use light pressure when rubbing the bevel in order to reduce any heat that you may build through friction. Believe me, you don't want melted plastic sticking to the tool edge!

Oh, and be sure to wear some form of breathing and eye protection! This stuff gets everywhere!!

[Greg Ketell]

Having had plexiglas shatter into dozens of sharp knives just trying to cut it on the table saw... And having it crack like a spider web from the pressure of a screw going through a slightly too small hole... I think the chances of a successful turn are low and the chance of being seriously hurt is high.

Add to that the extreme difficulty of getting clear laminations without a huge press (we've tried it for our fish tanks)... I think Donnie's idea of casting your rough shape from alumilite or epoxy resin and the turning that softer material would have a much better chance of success.

Good luck in whatever you attempt and please do go overboard with safety precautions!

[David Starks]

I really questioned his reasoning and wasnt to sure about it myself, hence the post.

I told him about the epoxy resins that are made to use pens but he said something about wanting something clear. I think ill let him get his own equipment and try it...

Thanks for all the imput!

[Nathan Hawkes]

Greg, PM me if you want to talk about plexiglas fabrication. I've made quite a few filters and protein skimmers over the years. I'm out of the aquarium hobby at the moment.

As for laminating sheets of cast acrylic, unless you already have the thick stock, it is NOT worth it to buy any--it is WAAAAY expensive, as Curtis already pointed out. That $300 figure is pretty low, unless you're talking about a small piece. Its more like $600-700 for a 4x8 sheet. Making a seam more than 1/2-1" wide with methylene chloride solvent is difficult for someone without a bit of experience. There are other, better products. Weldon 3 or weldon 4 is good for up to about 1/2-3/4" seams, then 2-part Weldon 40 or 42 resin for wider seams. DO NOT use Weldon 16!! This shrinks as it cures, leaving lots of bubbles and a weak seam. As Steve S. said, wear eye and lung protection.

[M Toupin]

Nope, can't be done & if you do try, you'll die...

218872

Ok, maybe you'll get away with it once.

Mike

[Harry Robinette]

When I talked to Bonnie Klein a couple years ago she said that gluing Plexiglas is very dangerous. She said she uses solid acrylic bar stock to do her boxes.She said glued up Plexiglas has a very low tolerance for shear forces which makes it bad for the lathe.
Just what info I got about it.

[Nathan Hawkes]

When I talked to Bonnie Klein a couple years ago she said that gluing Plexiglas is very dangerous. She said she uses solid acrylic bar stock to do her boxes.She said glued up Plexiglas has a very low tolerance for shear forces which makes it bad for the lathe.
Just what info I got about it.


Harry, I've done a fair bit of fabrication and repair of large aquarium filters, using 1/2" or 3/4" sheet stock. I have my own 1.25" sheet that I was going to build a tank with, but abandoned the project. In regard to glue joints being dangerous, this is very true of many glue joints, but if done properly, with enough time for the solvent to react, the pieces will break in another spot before they break along the glue line. That said, a joint that looks perfect with no bubbles that was done with (capillary action) solvent cement can be very weak if the joint was formed by capillary action alone. A "proper" joint should have something in the joint like a sewing pin or very small gauge wire acting as a "spacer" to keep the surfaces off one another while the solvent has a chance to react with the plexiglas. It's a little difficult to explain without a visual aid; alas I can't provide that at the moment. The tough part comes in the form of keeping the parts square when you remove the spacers and apply clamping pressure, then dealing with squeeze-out that occurs as the material in the joint, which has been chemically melted to fuse together, flows out of the seam. I don't know what the solvent company gives as a cure time for the maximum strength, but experience says it takes several days to weeks to achieve a full cure, regardless of whether or not you use a methylene chloride based solvent or a 2-part acrylic monomer resin glue.

PS: do NOT take what I say here as a tutorial on acrylic fabrication--this is purely meant as information. You need to do your own reading and trial and error before attempting to glue pieces up for turning or any other purpose that would put major stresses on your glue joints. You absolutely can have disastrous results with any glue seam if it is not performed properly.

[Lee Koepke]

additional consideration for a clear pen, is how you are going to do the components. Typical pens use brass tubes (that get sanded a bit for adhesion), so when doing normal acrylic pours, you can back paint the tubes to match the color pattern. With completely clear, you would need to decide what that tube should look like.