reseal an acrylic sump? It doesn't look good !

[lapin]

Just to give you an idea; Sheets of 3/8 cell cast here in Austin were about $250 with tax, before the tariff stuff. Some places will do a limited number of cuts for free others charge per cut.

 

[cracker]

@lapin , I could make some calls & price again . A supply here in Jax Fl will throw in some free cuts also. How ever the guy told me the edges weren't finished ? I 'd feel much better if I could supply the material to someone & have them fabricate it.

 

[cromag27 Verified Sponsor]

edges need to be properly prepped for welding. can’t use them straight from a saw. you would need to use a router.

 

[MARK M. DAVIS]

Acylic will bow with water pressure. You can dry and strengthen. I have a 100 g sump. It had sprung a leak around 2 years ago after initial manufacture. I repaired and strengthened all seams. I also put a rim to stop bowing. The sump hasn't leaked again. If the sump wasn't built strong enough at first, you can strengthen to withstand water pressure. And, flexing due to uneven surfaces.

 

[lapin]

@lapin , I could make some calls & price again . A supply here in Jax Fl will throw in some free cuts also. How ever the guy told me the edges weren't finished ? I 'd feel much better if I could supply the material to someone & have them fabricate it.

As mentioned above the edges need to be smoothed out if the panels are cut with a saw. You can ask if they have a cnc machine. They can cut/route the panels with it and the edges should be ready for bonding.
If you route them yourself, it can be a challenge. Opposite sides need to be mated and routed at the same time to insure they match. The way I route acrylic is is to run the panels between the bit and a fence, using a router table mounted flush to my table saw bench. (disclaimer) This is a no no as far as safety is concerned. You take off a very small amount of material it takes me 2 passes and I dont move the fence between passes. You need to be very smooth with your feeding of the material. An auto feeder is nice for this but they cost a bunch of money. You might all ready know this since you built it yourself once.

 

[cracker]

I have a hand held held router but is well beyond my skill level . Three things hurt me . The material was too thin, I didn't brace properly & the edges weren't smooth enough.
I knew these things but blew them off. I figured the real thick weldon would fill the gaps as small as they seemed to me.

 

[BornHandy]

If I were in your position, I would take the sump apart and see if the silicone one peels off. I have a feeling most of it will. Just to be sure, you can scrape the cut edges with a flat blade, that will clean and prep edges at the same time, the you can use weld-on #3 if the edges mate up nicely, thickend if you need to fill a gap or two.

As for the acrylic expanding with water, that is true, but there are a lot of diy acrylic sumps out there that have stood the test of time, so I wouldn't worry too much about that (so long as you get a clean weld).

As for welding right off of the saw blade, it really depends on the blade. If you had it cut reasonably clean, then hand scraping with a metal scraper will do the rest. The king of diy has a video on it...

I am convinced that your acrylic is still viable, and you can pick up a new skill to boot if you want to give it a try. You really don't have much to lose, so I just can't see a reason not to go for it.

 

[BornHandy]

And one more thing, plastic shops are not always the best place to buy acrylic. I cut it on my cnc at least once a month, and it has never been for a plastics dealer. I cut it regularly for sign shops. There is almost always a good bit left over, and the cost has usually been covered by whoever bought the sign, so the sign shop may be willing to sell the leftovers for cheap. My sump was built from scraps left over from 3 sign jobs, and I only had to pay about a hundred bucks for all of the material, and still have a bit left.