acrylic advice needed

[ou812pezz]

I need to build a acrylic tank 14.5"LX7"WX9"H. What thickness should I use and where to get the material cheap? Also, what type of glue to use?

[LoneStar]

I would go 1/4" on the thickness. I buy my material at Regal Plastics in San Antonio. Weld On #3 and #16 (#3 for creating the joints and #16 for sealing them water tight).

[ou812pezz]

Where would I find the weld on at home depot? Does it come in a tube? Thanks lonestar.

[Ram_Puppy]

they don't sell weldon at home depot or lowes, you need to go to the store lonestar mentioned, or to a similar one in your area.

[Ram_Puppy]

btw, I doubt the acrylic they sell at home depot is suitable for your needs either. if you are building a show tank you probably want to get cell cast acrylic.

[matt]

I'm afraid I disagree with Lonestar a little, I'd forget about the weldon #16. For something this small, 1/4" will work fine, but try to get cyro FF, which is extruded, but it has pretty good welding properties. If you want to make it stronger you can get cast acrylic, but I wouldn't get anything other than cyro GP or spartech polycast. Cheap cast is worse for welding than cyro FF.

You don't glue acrylic, you actually weld the joints with solvent, that's the weldon #3. Might be better to use #4, it's a little slower acting and the joints might come out a little better. All you do is cut your pieces so the edges are really clean and everything fits together perfectly. Usually building a box you'd weld the sides to the ends, then the whole thing to the bottom. You have to take care and make sure the edges of the sides/ends line up just right so the whole thing will fit to the bottom well. It's not that hard, it just takes some patience. There's a monster thread on reefcentral, something 100 pages long, about acrylic fabrication, with lots of pictures and advice. You might want to read some of that. You get the weldon #4 (or #3) at the acrylic place; regal is fine. They'll even cut your pieces for you and finish the edges on a router which makes everything fit better, but you'll have to pay them for that.

If, when you finish, there are leaks or lots of bubbles in the seams, a last resort fix is to shoot a bead of weldon#16, which is basically the solvent in #3 thickened with acrylic resin, along the seam. It never looks good if you ask me, and it's not very strong. This is a small tank so probably it won't matter. Much better than weldon #16 is weldon #40, which is a 2 part polimerizing cement for acrylic and will really fix any leaks. It's hard to find locally, though, and it really stinks when you're mixing and applying it.

Oh yeah, you need a needle/squeeze bottle applicator to apply the solvent; you just line up your joint and run the needle along the seam. The solvent will wick into the joint, melt the acrylic at the joint, then evaporate quickly, which makes the acrylic dry into a nice watertight joint. It just won't fill any gaps at all. When I'm lining up joints I use a slip of paper as a feeler guage to check for gaps. If I can get the paper in the joint anywhere, I redo the edge until there are no gaps.

Have fun!

[LoneStar]

I would make a pass with weldon #16 anyway after you glue with either #3 or #4. Its like running a bead of caulk or silicone. If your not sure if its water tight, just run a pass along the edges. It won't take much and if you do a thin bead, its hardly noticeable.

[ou812pezz]

This is going to be a 4 gallon top off tank hidden above my tank in the hood. As long as it holds water that's all that matters to me. So I go to Regal,ask for weldon #4, a squeeze bottle applicator and enough cyro FF acrylic to do the job. I plan to cut a wooden jig to keep the insides square and spot tape the the outer walls to hold it togther. Anything missing? If I have leaks then run a bead of the#16. On bonding, do I put solvent on both edges before putting them together or just let the solvet flow into the joint by capillary action?

[Ram_Puppy]

curious, why are you making a container, are you unable to find one that is adequte for your needs elsewhere? Off the top of my head you can by two gallon fish tanks at petsmar that are dirt cheap, and I bet you could find a dirt cheap 4 or 5 gallon plastic aquarium for a good deal as well.

[LoneStar]

You clamp the pieces together fairly snug. Then with the needle applicator, run the weld on (which is water consitancy) along the joints. It will seap into the space between the acrylic pieces and weld them together chemically. You can have then tighten down the clamps right after you make a pass with the weldon. I like #3 cause I work quick, but since its your first project, I would say get the #4 Weld On.

Depending on if you have the tools to cut acrylic, they have a scrap bin at Regal Plastics where they sell nice sheets of scrap for cheap. Good sizes to build a small aquarium sometimes. If you are going to have them cut out the pieces for you, I would call them up before you go there and talk to them. You might not be able to walk in one day and have them cut it out that same day. For my sump and refugium, I had to email them the prints, go and pay, then wait 2 days before they had it all cut out.