Help With Weldon 4 & 16 on ATO

Smiz · Sep 23, 2015

Ok R2R,

I am having some major issues putting together a ATO tank. I am not getting a strong bond and am having leaks spring after several days of bonding time. Here are some details:

All of my pieces have been laser cut and have a fire polished edge.
Everything was securely clamped down while using weldon
All seams were hit with weldon 4 followed by weldon 16 to fill the seams.
tank was left to bond for 4 days.

After my first go at sealing, the tank held water. I then had to add two divider walls as it is a ATO and dosing chamber unit. When I added the inner dividers I heard some cracking when I was clamping them into place. I sealed the inner walls and then re sealed the outer seams. Water tested 3 days later and had leaks everywhere.

Now I'm guessing I need to break apart the tank, sand all the edges and then give it another go?

Also I was under the impression the smother the piece the better. Is this true or do you want to hit it with like 600 grit sandpaper for best bond?

Here are some pics of it. Please help!

Smiz · Sep 23, 2015

No acrylic masters out there?

Pepcrylic · Sep 23, 2015

Laser cutting acrylic will change the molecular structure of the acrylic. (its the heat) You could retemper it. I dont know what temp and for how long it would take to do that.
I prep my edges (after they are rough cut on a table saw) with a down cut patter making router bit.
Yes smooth is better, but if you doing by sanding you run the risk of not keeping the edge 90 deg. to the face.
It is not good to use weldon 16 over a seam that has been welded with weldon 3 or 4. It will cause the seam to craz.
The container looks awsome.
I also never clamp my seams. I use weight. I is very easy to over tighten the cdlamps a push all the melted acrylic out of the seam.
Sorry to say you should start over. Do some more research. Reef Central has a thread devoted to acrylic Questions in the DIY fourm. Its all there.

mannyhernz · Sep 24, 2015

Send it to me ill fix it..lol
I have made various sumps and ato containers for friends..never have i used anything other than weldon 4..i cut with tablesaw then hit it couple of times with 600gr on edges..works for me everytime.

Pepcrylic · Sep 24, 2015

Was the fire polished edge done before or after assembly ?

Smiz · Sep 24, 2015

Pepcrylic said:
Laser cutting acrylic will change the molecular structure of the acrylic. (its the heat) You could retemper it. I dont know what temp and for how long it would take to do that.
I prep my edges (after they are rough cut on a table saw) with a down cut patter making router bit.
Yes smooth is better, but if you doing by sanding you run the risk of not keeping the edge 90 deg. to the face.
It is not good to use weldon 16 over a seam that has been welded with weldon 3 or 4. It will cause the seam to craz.
The container looks awsome.
I also never clamp my seams. I use weight. I is very easy to over tighten the cdlamps a push all the melted acrylic out of the seam.
Sorry to say you should start over. Do some more research. Reef Central has a thread devoted to acrylic Questions in the DIY fourm. Its all there.

Lot of great tips, thanks for the input!

mannyhernz said:
Send it to me ill fix it..lol
I have made various sumps and ato containers for friends..never have i used anything other than weldon 4..i cut with tablesaw then hit it couple of times with 600gr on edges..works for me everytime.

I'm just about at that point lol. I think im having these issues due to the fire polish.

Pepcrylic said:
Was the fire polished edge done before or after assembly ?

The fire polish happens during the cutting process because I am using a laser.

Smiz · Sep 24, 2015

So seems the best bet is to redo this and use a router not a laser

mannyhernz · Oct 8, 2015

Dont destroy it..just use some weldon 16 to seal it tight! If not send it my way like said before ill fix it

Jlobes · Oct 8, 2015

laser cutting is not recommended for pieces that will be joined, for those you want to use a router. the cleaner the edge the better. you want it to be straight, square and clean for best bonding.

Smiz · Oct 8, 2015

mannyhernz said:
Dont destroy it..just use some weldon 16 to seal it tight! If not send it my way like said before ill fix it

To late lol....

Jlobes said:
laser cutting is not recommended for pieces that will be joined, for those you want to use a router. the cleaner the edge the better. you want it to be straight, square and clean for best bonding.

Thanks Jlobes. Will be routing tonight, hope it goes smooth!