Acrylic Fabrication Q & A

cromag27 · Jul 12, 2023

TaylorPilot said:
Dying of heat stroke baby sitting this CNC in my garage in Houston Tx heat and 75% humidity...I need an air conditioned shop...LOL

TaylorPilot · Jul 12, 2023

cromag27 said:

yea, we aren't as hot as that, but at 75% humidity, we get "feels like" in that range. The other night it was 2am and we still had a feels like of 96f. It is pretty brutal with the dust collector and vacuum pumps dumping a ton of extra heat. I have a big 4' shop fan, but it just kind of stirs the hot air around...I have also just built 100' of wooden fence in my back yard over the past few weeks...I started with a post hole digger and got the first one done and told my wife that i was going to go rent an auger...she said I needed the exercise and should do them by hand, I said ok, if she dug the next one, I would dig the rest. She got about 6" down then hit that clay gumbo dirt we have and she gave up...people need to buy more overflows so that I can get a summer home in Colorado!

Koleswrath · Jul 17, 2023

My first try at some welding. Was a great test since it didn't need to be watertight. Not sure it's the best comparison though since it's polycarbonate.
I tried the capillary method first. Lot's of bubbles. The pins method went much better. Pins with clamps even better than that. It was hot and humid and it seemed like the #3 solvent was evaporating very quick. I'll be practicing more before I try my hand at a sump. Not sure if it was my applicator bottles or just me but I dripped solvent EVERYWHERE!

Turbo's Aquatics · Jul 17, 2023

Weld-on 3/4/40/42 are not the proper solvents for polycarbonate. At best you will have a very weak bond that will fail easily. So this might work for the rollermat you built, but it might fail under weight/pressure and over time. Definitely don't use it to build anything that has to hold water.

For poly, SciGrip/WeldOn #55 or #58.

Then again, I'm not an expert in welding Polycarbonate

cromag27 · Jul 17, 2023

3/4 can be used for pc to pc, 4 giving you a little more working time. i bring my work indoors when the temps get too high. i’d also suggest just using acrylic for something like that as acrylic is much much easier to cut.

Koleswrath · Jul 17, 2023

cromag27 said:
3/4 can be used for pc to pc, 4 giving you a little more working time. i bring my work indoors when the temps get too high. i’d also suggest just using acrylic for something like that as acrylic is much much easier to cut.

Thanks, it seems to glue up fine. Good squeeze out and seemingly very strong joints. I tested one of the acrylic rods glued to some scrap polycarbonate and when I tried to break it the acrylic broke instead of the joint.
I've heard the polycarbonate is tough to cut but it went smooth for me. Then again I'm only using 1/4". Lots of hot little chips though.

Koleswrath · Jul 17, 2023

Turbo's Aquatics said:
Weld-on 3/4/40/42 are not the proper solvents for polycarbonate. At best you will have a very weak bond that will fail easily. So this might work for the rollermat you built, but it might fail under weight/pressure and over time. Definitely don't use it to build anything that has to hold water.

For poly, SciGrip/WeldOn #55 or #58.

Then again, I'm not an expert in welding Polycarbonate

Thanks, definitely not going to be using it for any vessels but it seems plenty strong. Can't go wrong when you get a bunch for free. I'll keep an eye on it.

cromag27 · Jul 17, 2023

Koleswrath said:
Thanks, it seems to glue up fine. Good squeeze out and seemingly very strong joints. I tested one of the acrylic rods glued to some scrap polycarbonate and when I tried to break it the acrylic broke instead of the joint.
I've heard the polycarbonate is tough to cut but it went smooth for me. Then again I'm only using 1/4". Lots of hot little chips though.

and keep in mind not all pc is bpa free.

Turbo's Aquatics · Jul 17, 2023

Koleswrath said:
I've heard the polycarbonate is tough to cut but it went smooth for me. Then again I'm only using 1/4". Lots of hot little chips though.

Poly is softer, so it tends to "grab" very easily. Generally, I've heard that you want to use a template & double-stick tape whenever routing poly (or sheet PVC). For saw-cutting, that's not quite as dangerous but the blade can still bite, and when it does, you don't want to be anywhere near it.

I had a friend who was routing PVC with a flush trim bit and it grabbed on him, the bit exploded and the part got thrown. He found a small piece of the bit embedded in the drywall but the rest of it he never did find, even when he moved out of his house and cleaned out the garage....and that was a 1/2" diameter 2" long Amana bit, so a lot of metal that ended up somewhere, just lucky it wasn't in his body.

cromag27 · Jul 17, 2023

Turbo's Aquatics said:
Poly is softer, so it tends to "grab" very easily. Generally, I've heard that you want to use a template & double-stick tape whenever routing poly (or sheet PVC). For saw-cutting, that's not quite as dangerous but the blade can still bite, and when it does, you don't want to be anywhere near it.

I had a friend who was routing PVC with a flush trim bit and it grabbed on him, the bit exploded and the part got thrown. He found a small piece of the bit embedded in the drywall but the rest of it he never did find, even when he moved out of his house and cleaned out the garage....and that was a 1/2" diameter 2" long Amana bit, so a lot of metal that ended up somewhere, just lucky it wasn't in his body.

i work with pc every day. it is absolutely more dangerous saw cutting it!

Troylee · Jul 17, 2023

cromag27 said:
i work with pc every day. it is absolutely more dangerous saw cutting it!

I’ve had my fair share of a table saw throwing it lol..

Turbo's Aquatics · Jul 17, 2023

cromag27 said:
i work with pc every day. it is absolutely more dangerous saw cutting it!

More dangerous to saw cut PC vs route PC, or more dangerous to saw cut PC vs saw cut acrylic? Or, both? I think both

cromag27 · Jul 17, 2023

Turbo's Aquatics said:
More dangerous to saw cut PC vs route PC, or more dangerous to saw cut PC vs saw cut acrylic? Or, both? I think both

saw cutting pc is more dangerous than all the above.

Troylee · Jul 17, 2023

cromag27 said:
saw cutting pc is more dangerous than all the above.

Lexan is super grabby.. it’s a toss up really in my opinion between poly and pvc. Styrofoam is the worst off all on a table saw haha!

@Turbo's Aquatics as for gluing poly with Weldon 3/4 it actually works much better these days then It did 15 years ago.. I’m thinking over the years the formulas have changed and it’s cross linked with acrylic because it does glue up pretty well now vs back then! It’s no where strong enough to make a pressure vessel to hold water but it works decent now.

cromag27 · Jul 17, 2023

Troylee said:
Lexan is super grabby.. it’s a toss up really in my opinion between poly and pvc. Styrofoam is the worst off all on a table saw haha!

@Turbo's Aquatics as for gluing poly with Weldon 3/4 it actually works much better these days then It did 15 years ago.. I’m thinking over the years the formulas have changed and it’s cross linked with acrylic because it does glue up pretty well now vs back then! It’s no where strong enough to make a pressure vessel to hold water but it works decent now.

it’s not supposed to cross, but i have made it work.

Troylee · Jul 17, 2023

cromag27 said:
it’s not supposed to cross, but i have made it work.

It does cross and there’s glues for it.. Weldon 58 or lords 7550/ac. I build letters out of it all the time and we use lexan faces and acrylic returns or trim cap.

cromag27 · Jul 17, 2023

Troylee said:
It does cross and there’s glues for it.. Weldon 58 or lords 7550/ac. I build letters out of it all the time and we use lexan faces and acrylic returns or trim cap.

no i’m referring to weldon 3/4 that you mentioned.

Koleswrath · Jul 17, 2023

You guys are a priceless resource, thank you!

Lowell Lemon · Jul 17, 2023

Saw cutting PC is best with a fine tooth plywood blade. Does not grab like a triple chip for acrylic. Try to avoid routing it unless I use my CNC machine.

TaylorPilot · Aug 4, 2023

cromag27 said:
i work with pc every day. it is absolutely more dangerous saw cutting it!

I hate hate hate cutting PC. The only thing I use it for is the lids on my rear boxes. It always seems to chatter and really tries to lift if I don't use really shallow DOC. I am using an uncoated Spetool (cheap) 1/4" O-Flute at 18k and 145 IMP. I have used the coated Amana bits, but never seemed to see much of a difference in cut. I see you cut some pretty intricate stuff and I am blown away that you can hold it down. I made a custom fixture with cover gasket to get max sq-in and am holding almost 14" of vacuum, and I still have to baby it...I can rip through acrylic at those same settings. Any recommendations on different tooling or S&F.