Applying Weldon 40 to a DIY Kreisel (Picture Heavy)

[wednesday13]

I did have something interesting happen today. Last week, I used the #40 to cement together this tank. After 72 hours, I tested it, and it held water quite well. The seams appeared to be very strong. I was able to apply a tremendous amount of pressure and the acrylic would barely flex - fairly optimistic at that point! After this, I decided to clean up the seams a little, as there were small globs of excess in the tank. I drained it, and used a small orbital palm sander to wet sand off the excess cement. I was able to get it about as clean as I could ask, and it was looking fairly nice. However, when I was polishing it, I noticed some water stared to work it's way into the seam. I pulled on the pane, and it popped off with almost no real effort, haha. Obviously, this is concerning, and I'm glad that I didn't have the opportunity to fill it a second time.

I've used high grit sandpaper and an orbital sander to and to polish acrylic many times before without issue, but this time, it almost seemed like the vibrations simply shook the seam apart - more specifically, the seam appeared to separate from the front panel, as opposed to from the curved acrylic. After separating, the front pane barely had any cement on it at all. Do you have any suspicions as to why this may have happened?

Id suspect the glue just didn’t bite into the front panel enough. Sanding prep goes a long way with 40. Pretty hard in this case with the curved shape tho. Good news is u can sand prep all ur surfaces and glue again for another round … IMO sanding/buffing is the worst part of any acrylic work and if ur already comfortable with that ull get the glue work down in no time. Can always try the router channels also. I bet just regular sanding on the front/back panels will be enough tho.

I went back and zoomed into the seams from the pics where its full. Lots of bubbles and white spots. Looks spot on with setting the piece more than once/ bad adhesion from the rip. Ive done the same thing before on a frag tank i built with all 40. 4’x2’x8”… even at just 8” height in 1” material my 1 seam that i re set and looked like this popped after about a year. Im not sure how 40 is 30x stronger than solvent, but a solvent bond, even a terrible one covered in bubbles is pretty hard to break off clean. Bad solvent bonds will leak but really dont just let loose. Always something to learn. Don’t give up lol… pretty impressive 1st attempt in my book esp with ur “baking” skills … the jig and oven work has never even been attempted on this forum.