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Bud Carlson
Bud Carlson • Oct 30, 2013

Aquarium Engineering

Hello all!

Found this site via Xenforo and a conversation with Kaustubh over there

I searched this site for "aquarium" and got zero hits. Also not much for acrylic and/or solvent welding, so now there will be one for both!

I'm an Electrical Engineer by education and employment, and I got my PE a few years ago, but my passion outside of that is building aquariums and filtration systems out of acrylic.

I got into the saltwater reef keeping hobby a few years back, but have been in the (freshwater) aquarium hobby since I was a teenager. That means 25 years. Anyways, I got into acrylic fabrication through my Dad, also an EE, but he was doing it for his antique business - building display cases and product holders. We built a filtration system (called an Algae Scrubber) for use on one of my tanks and I liked it so much, I wanted to start building them.

This morphed into me learning as much as I could about acrylic fabrication. My Dad did not make water vessels, so I researched for while, then built a 4' x 8' router table and started building sumps and coral grow-out tanks (called Frag Tanks) for local club members.

Not to get too detailed into the intricacies of acrylic fabrication, but there are ways to do it and ways to do it correctly. I learn the latter and let me tell you, you would be amazed at the stunning shortcuts that the "big" aquarium makers take. For me, as an Engineer, I can't accept manufacturing and selling a low grade product.

There is a lot of engineering thought that goes into building aquariums, more so when it comes to a sump-based filtration system. Things like flow rates through a notched overflow vs a weir, standpipe capacity for drainage to the sump, taking into account draw-down water volume on power outage (worst case scenarios)...I find myself engineering a design for everyone who comes to me saying "can you build this for me"

Anyways, this is my opening post so I'll leave it at that. I would be curious to see if there if there are any others on CE that might do what I do.

Thanks for reading!

Bud
As part of some electro chemical projects we did build a few acrylic tanks Using solvent based acrylic pastes/gels. We used active compression of the joints as leaks of the highly corrosive chemicals cannot be permitted. As part of the process we got a lot of gel like precipitates. We designed a weir type settling cum overflow arrangement so that bulk of the precipitates were settled by gravity prior to filtration.
Bud Carlson
Bud Carlson • Oct 30, 2013
Yeah, leaks are not permitted in aquariums either 😁

Not sure what you mean by active compression, maybe that is just technical for putting heavy weights on top of the joint after applying the solvent?

Edge prep has a lot to do with joint quality. I use a router table and a 3/4" diameter 2-flute straight cutter or mortising bit to get truly straight and square edges on all welding surfaces, then I use the "pins" method for the welding process. Basically you set up the joint on top of a piece of 3/4" MDF that has sticky-backed insulation foam on both sides (camper shell mount foam) and this acts as a cushion and takes some of the irregularities out of the equation. Then you attach a right angle bracket to the vertical piece such that it is held in what will be the 'final' position. Then you insert 28 gauge steel pins (picture hanger wire or garbage bag twist ties, stripped) into the joint to force a separation, then run the solvent in (Weld-on 3, 4, or your own mixture), let it sit for 15 seconds, then pull the pins and align the joint,then don't touch it for 8 hours.

I also do things like cleaning the weld area with denatured alcohol, blowing off with compressed and canned air, and leaving a lip to be trimmed off afterward (to allow a fillet to form on both sides of the joint after pulling the pins - which prevents air intrusion as the solvent dries)

I hadn't thought of the importance of these fabrication techniques with respect to corrosive environments, but the procedures are the same. If you wish more detail I can certainly provide it. Squaring the panels that are bonded on all 4 sides is probably the biggest pain. Secondary edge prep is important too (when bonding the assembly of all 4 sides to the bottom or top panel)

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