Hi,
I see from the basking area thread that a lot of people use acrylic for their ATBAs.
I worked with acrylic a lot when I built shelf liners for my pet rats, so I thought I'd just post some tips that might be useful.
There are two ways to attach acrylic. One is cement like aquarium-safe silicon. The other is a solvent.
While cement can be used to attach acrylic to other things, solvent can only be used to attach acrylic to acrylic. That's because the solvent actually melts the plastic and fuses it together. This is also known as welding.
Weld-On is the name of a line of products, designated by the number. For example, Weld-On 16 is a traditional cement. Weld-On 3 and Weld-On 4 are solvents.
The chemical name for this solvent is methylene chloride. As far as I know, Weld-On is the only solvent you can buy, but some plastic companies make up their own batches.
When I built my boxes, the only place you could buy Weld-On 3 or 4 was Tap Plastics on the west coast, but now I see them sold all over including Amazon and Ebay. Keep in mind that it is a hazardous substance, so it can only be sent by ground shipping.
The different between Weld-On 3 and 4 is how fast it dries. Weld-On 4 is a fast set and sets up in minutes. (Although I think you are supposed to wait 24 hours until you put strain on it; I'm not sure). Weld-On 3 is still plenty fast, and that's what I used.
In order for the solvent to work, the two pieces have to be totally flush. What you do is put the pieces together so that the joint is horizontal (not vertical) and then apply the solvent to where they join. Here's the key: capillary action draws the solvent in (it is the consistency of water) and fuses the pieces together.
If they two pieces are not totally flush, the solvent will just puddle and will not weld properly. I used a table saw to try to get a totally plumb edge, but even then I had problems with the pieces not fitting exact. If you can push a business card or the corner of an envelope between the pieces, the solvent will not work.
Here's the best instruction I found on using solvent. It really gives you a good idea of the capillary action needed:
http://youtu.be/hT6Ow_cBTps
Here's also a helpful video on making a box:
http://youtu.be/FNPNiIeAi5g
Most of the Weld-On solvents you buy also come with an applicator, but I used a hobby syringe available at any hobby store. It worked fine.
So, I hope this was helpful.
