Attaching Acrylic to Acrylic

[Itchy Trigger]

My 330g acrylic tank is currently empty. It has a clear back, but I recently decided I'd like black better, so I bought some 1/4" acrylic sheets in black and then siliconed them to the back of the tank. I know that Weld-On is the best thing to use for this, but I tried using that and couldn't get it to hold.

The silicone held it really tight and seemed to be doing the job, but after a day or two, the acrylic sheets started warping and coming off the back wall of the tank. The tank is still empty and dry, so I'm guessing it was humidity in the air that caused the acrylic to warp and pull away from the wall? If I reattach it with silicone, would putting a fan in the tank to keep humidity down help? Or is there some other method I should use to attach the acrylic?

 

[asudavew]

Some people use black window tint.

 

[dattack]

how come you dont want to paint the back?

 

[Itchy Trigger]

That would go on the outside of the tank though right? This tank is flat against the wall and there's no way to get to the back.

 

[Itchy Trigger]

how come you dont want to paint the back?

Tank is flat against wall and built in to a cabinet. Not possible to access the back.

 

[asudavew]

I use a generic brand of Weldon 16.
It's cheaper than Weldon 16.
It's also thicker than Weldon 4 (just like Weldon 16 is), and works great for building overflows.

I use: SCIGRIP 16 10315 Acrylic Cement, Low-VOC, Medium bodied, 5 Ounce Tube, Clear

Amazon has it for around 8 bucks.

 

[Itchy Trigger]

I use a generic brand of Weldon 16.
It's cheaper than Weldon 16.
It's also thicker than Weldon 4 (just like Weldon 16 is), and works great for building overflows.

I use: SCIGRIP 16 10315 Acrylic Cement, Low-VOC, Medium bodied, 5 Ounce Tube, Clear

Amazon has it for around 8 bucks.

Oooh, I like the sound of that. The Weld-on 4 was so watery it wouldn't hold at all. So this stuff sounds like the ticket. I'll order some now - thanks! I may also try to get some thinner acrylic sheets. When 1/4" starts to warp it will pull harder than a thinner more flexible sheet. May try 1/8".

Thanks again!

 

[mcgyvr]

Oooh, I like the sound of that. The Weld-on 4 was so watery it wouldn't hold at all. So this stuff sounds like the ticket. I'll order some now - thanks! I may also try to get some thinner acrylic sheets. When 1/4" starts to warp it will pull harder than a thinner more flexible sheet. May try 1/8".

Thanks again!

If you can't get weldon 4 to work you are doing something really wrong..

 

[Itchy Trigger]

If you can't get weldon 4 to work you are doing something really wrong..

I must have gotten a bad can of it then. It was so thin and watery and didn't hold at all.

 

[todddye]

Weldon 4 is like water but it won't bond unless there is direct contact/pressure.

 

[mcgyvr]

yes its supposed to be like water.. You put the 2 pieces in direct contact and let the weldon wick into the joint while you apply pressure.
3 and 4 is like water thin.. 16 is "basically" just 3/4 with bits of acrylic melted in it to thicken it up..

 

[Itchy Trigger]

Yes, I understand how it's supposed to work.

I think for an application like this - adhering large sheets of acrylic to the tank back (while vertical - I can't lay this tank on its back) - a thicker, more syrupy adhesive will work better. At least I hope so! Anyhow, ordered the generic 16 that asudavew mentioned.

 

[Itchy Trigger]

I use a generic brand of Weldon 16.
It's cheaper than Weldon 16.
It's also thicker than Weldon 4 (just like Weldon 16 is), and works great for building overflows.

I use: SCIGRIP 16 10315 Acrylic Cement, Low-VOC, Medium bodied, 5 Ounce Tube, Clear

Amazon has it for around 8 bucks.

This stuff worked great! Thanks again for the tip!