Well I have bad news, the acrylic sump seams are a disaster. I dont know why I was allowed to buy weld on 4, there should be a waiting period when buying a can. It could have saved an acrylic atrocity. The seams are bad, and by that I mean, I'm not sure I trust them to support weight. I am already planning to silicone, but I actually fear a full on blowout. To maybe help one person out there, here are a few things that went wrong.
Make sure the first panel you weld is PERFECT. perfectly square, and aligned the way you want it, before you put solvent anywhere near it. Especially do NOT attempt to adjust it after the solvent has started its work. That will suck in air and probably destroy your will to put in effort on the rest of the seams. Also apply pressure onto the seam to keep it together. I think that would have helped a bit with my first joint.
Secondly, Make sure any panels that need to be the same width, and appear to be so, are DARN close to identical. This was an issue for me, because I began by welding the baffles onto one side of the sump first, then welding on the opposite side. this means that any difference in the width of the internal baffles, resulted in a gap on the second side. I saw that one coming and sanded all of the baffles as they were assembled, with a large 3/4" sheet of glass and some adhesive backed sandpaper. I sanded until I had 1 flat plane to weld on the final side. That took the entirety of "Pans Labyrinth" with me stopping fairly often to read subtitles. Would have been much easier to match the panels before assembly.
DONT MAKE THE FIRST SEAM YOU WELD THE MOST VISIBLE ON YOUR SUMP. should be pretty obvious that the most visible seam should be done when you have the most experience. Well starting off I thought "I can take all the time I want with this first one and get it right, and at least the most obvious will be prefect." that was great until I realized I had welded it at an angle and had to break the seam mid cure to adjust it.
All in all I think I will probably be doing this again, after a bit more panning. I plan to do some testing on this to see if it has any structural issues. I would have very little concern if my sump was staying in one spot for 8 years. The issue is the impacts of sliding in and out the sump. There is a slight bump when you close it, and the same exists when you open it. Not that big of a deal, but this can contain as much as 20 gallons or 170lbs of water that will then slosh against these possibly unstable seams. I made this out of 9mm acrylic to be more than strong enough to embrace this, but I may only be getting 1/8" of welded support at some points in some seams.
Once the plastic wrap is off and I have been able to investigate the seams hopefully things aren't as bad as I think they are. If you read this far, take your time and make a PVC sump. Welding acrylic sucks. If anyone knows a really good person that knows their acrylic, please send them here, because I will definitely be looking for some expert guidance on whether or not I should just plan to throw this thing out.
