Working with plexi/acrylic

[Playdope]

Im thinking about modifying my sump, and I wanted to ask what kind of stuff I should use to do it. I have a truvu acrylic sump, and I want to put some walls in here and there. I have some "aquarium silicone I got from home depot, but I wasn't sure whether this was the stuff I should be using to bind the pieces of plexi (I doubt it b/c the stuff is tacky).

I have also heard there are products out that let one work with water in the tank. Should these be trusted?

Thanks,
Jon

 

[danmhippo]

To get a secure bond, you will have to work with your acrylic tank dried. Underwater epoxy is OK to use for porous rocks, but I don't think they works with smooth surfaces.

 

[Anonymous]

If these "walls" are just baffles then silicone would work fine since leaking really isn't an issue. You are just trying to hold them in place, right?

Louey

 

[Anonymous]

Silicone is not the best material to use to glue/cement acrylic. You should get the solvent cement (also available in home depot in brown glass bottle) instead. WeldOn is an other popular plastic cement for this purpose.

 

[ChrisRD]

While I agree that Weld-On is a good choice for permanent acrylic bonds, as Louey said, for baffles in a sump silicone will work.

 

[Anonymous]

... if you go a bit further, you may feel that baffles held in place by mere friction (cut the baffles slightly wider...) maybe acceptible in sump...

Also use a drill to cut a slight depression/crater on the sump wall (not drill all the way thru), and use those underwater epoxy to make a stub to hold the baffle in place....

I am sure there are other wilder ideas, albeit not very professional.

 

[ChrisRD]

... if you go a bit further, you may feel that baffles held in place by mere friction (cut the baffles slightly wider...) maybe acceptible in sump...

Also use a drill to cut a slight depression/crater on the sump wall (not drill all the way thru), and use those underwater epoxy to make a stub to hold the baffle in place....

I am sure there are other wilder ideas, albeit not very professional.

...and I'm sure there are less sarcastic, more tactful ways of expressing your opinion as well... :roll:

 

[Anonymous]

Sorry about that, Chris.

I guess I was a bit carried away on that when I see Louey made the suggestion of using silicon on acrylic. There are certainly many ways to do thing, and many of them will work well.

 

[ChrisRD]

Ah, no harm done.

Don't get me wrong, I agree with you. The solvent cement is the stuff to use for a professional bond.

I was just agreeing with Louey that for something that is "non-structural" like a baffle, overflow, etc., silicone will work (I've done it myself).

OTOH, I sure wouldn't recommend that someone assemble structural panels of an acrylic sump or tank with silicone!

 

[dwall174]

I've used Marine Goop to bond acrylic to glass! It bonds better to the acrylic than silscone. It does need to cure for 24 hours tho. I haven't heard that much about the under water type of products.

 

[hdtran]

Solvent cement for acrylic is wonderful, but is not gap-filling. You need a good fit between the surfaces. Not something that's readily done by most DIYers. An easy way to prevent needing a good fit is to use a square bar of acrylic as a fillet or gusset, e.g. join bar to wall, join baffle to bar. If I can try ascii drawing (too lazy to fire up paint & draw for you), here goes:


_______________
[ ]|
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This would give you a real nice joint (on clean, dry acrylic surfaces, of course!)

Aquarium silicone on clean dry acrylic also sticks nicely. For baffles, where there's no need to maintain watertight integrity, that's probably more than enough.