Bending Acrylic That's Bonded

[crn005]

I know how to bend or mold acrylic in an oven but does bending a piece that has already been bonded to another piece with Weld - On effect the integrity of the bond?

 

[mcgyvr]

Yes

 

[sleepydoc]

It will also likely cause crazing

 

[crn005]

Is this typically something that is a huge blow to the strength of the bond or has just a little effect?

 

[mcgyvr]

Is this typically something that is a huge blow to the strength of the bond or has just a little effect?

sounds like you really want to find out don't you..
I would not recommend it for anything you expect to rely on structurally.

 

[crn005]

sounds like you really want to find out don't you..
I would not recommend it for anything you expect to rely on structurally.

Haha maybe.....

It's not going to be a bond that bears much pressure though. It will be a box about 3"x3" that extends a couple of inches into the water. I just need it to be water-tight.

 

[mng777777]

For such a small box, why not just cut fresh pieces and start fresh? I'm not sure exactly what you're cooking up but if you're putting anything sensitive in it that cannot get wet, you're better off to try a different approach. What are you working on? Electronics? Do you have any pics?

 

[crn005]

Well, long story short, I need to make a topless box, that has a bottom that forms a point down. Here are some concept pictures:

The thing is, I'd like to find a way to pull this off without having to cut the arylic at an angle. Also, it doesnt have to be triangular on the bottom. It can be cone-shaped or a pyramid. A triangle seems easier though.

 

[mng777777]

Looks like you could make that pretty easy. Cut 6 pieces and start gluing. I have to admit, I'm super curious what you're up to!

 

[Gorgok]

I think i understand the title differently now. As i had read it, you were going to bend a bond, like a T piece that you would bend along the spine. Instead you seem to want to bend the T piece somewhere down in the post of the tee, not necessarily touching the bond at all.

If this is the case then i'd say you are fine to bend a piece thats bonded, just bend it away from any of the seams. Focused heat would probably be better here than an overall heating, like bending strip...

I do agree, though, those cuts don't seem complicated assuming you have a table saw. But you could also use one long piece for the bottom/front/back faces with 3 bends in it, then square up the sides (bends will get wider) and add the sides and route off any excess with a flush cut. A bullet shape for the bottom/front/back would probably be easier to square up after bending.

 

[crn005]

I think i understand the title differently now. As i had read it, you were going to bend a bond, like a T piece that you would bend along the spine. Instead you seem to want to bend the T piece somewhere down in the post of the tee, not necessarily touching the bond at all.

If this is the case then i'd say you are fine to bend a piece thats bonded, just bend it away from any of the seams. Focused heat would probably be better here than an overall heating, like bending strip...

I do agree, though, those cuts don't seem complicated assuming you have a table saw. But you could also use one long piece for the bottom/front/back faces with 3 bends in it, then square up the sides (bends will get wider) and add the sides and route off any excess with a flush cut. A bullet shape for the bottom/front/back would probably be easier to square up after bending.

Yeah the cuts aren't too complicated but I don't have a table saw. That tends to get in the way of things. I've built plenty of acrylic projects with just a skill saw, but I'd like something a little cleaner looking this time. And yes, you're right about where I'm wanting to bend it. The seem itself wouldn't be bent. I guess I could get the rounded edge from bending a piece itself then squaring it up with the sides being one solid piece each. That would fix the recoil by bracing the bent piece.

As far as WHAT I'm building, I won't say that yet. I have an idea that I've never seen before, but I want to prove it works before I show it :rollface:

 

[crn005]

It doesn't necessarily have to be that shape though. I just need a sort of box with a point that goes down. I'm trying to think of the easiest and most time efficient way to make it.

 

[mng777777]

How about as crn005 said, one long piece, bend it 3 times then measure and cut your two sides, bond it then you could take some sand paper or a dremel and clean it up...now get to building please. I don't handle anticipation very well!

 

[crn005]

How about as crn005 said, one long piece, bend it 3 times then measure and cut your two sides, bond it then you could take some sand paper or a dremel and clean it up...now get to building please. I don't handle anticipation very well!

Haha believe me, I would be done already if work didn't keep getting in the way! I think I should prob get rid of work, then everything would be perfect! :dance:

 

[leveldrummer]

do you have a router? you can clamp a guide in place and make very clean cuts this way.

 

[crn005]

Yeah I have a router, but to be honest, I haven't had much success using it. I watched a few videos but it still seems pretty difficult.

 

[mng777777]

The key to the router is to use the guide. Tape your cut before you run it. Use a proper bit at a high enough speed that it cuts without chipping, but not so fast that it melts your acrylic.