Need help with leaks around standpipe in acrylic

[dough12boy]

I got a used tank with dual corner overflows. The one hole for the water return on one of the overflows has a bunch of spider web looking cracks around the hole on the inside of the tank. For the life of me I cannot get it to stop leaking when I set up the standpipe and hook it all up and I assum no matter how good the gasket is, it just leads through the tiny stress cracks around the hold. I've seen others suggest silicone. Any suggestions? The gasket is new by the way.

 

[dnjan]

Just making sure - nut is on the outside (underside of tank) and flange is on inside? and gasket is between flange and the bottom of the tank?

Is the bulkhead for the standpipe new? Check it to make sure the flange itself is smooth and flat (and not distorted).

 

[dough12boy]

Just making sure - nut is on the outside (underside of tank) and flange is on inside? and gasket is between flange and the bottom of the tank?

Is the bulkhead for the standpipe new? Check it to make sure the flange itself is smooth and flat (and not distorted).

Yeah, the gasket is on the inside and nut on the outside. The bulkhead is old and I found the cracking when I pulled it apart to clean the tank. I tried to test out the system but it leaks around the bulkhead which I think is related to the hairline cracks all around the drilled hole in the acrylic that wasn't noticeable until you pull the bulkhead out.

 

[DonW]

Is it crazed or cracked? Have any pictures.

Don

 

[dough12boy]

Here's a picture that actually turned out pretty good.

 

[DonW]

Here's a picture that actually turned out pretty good.

That is crazing from a way overheated hole. Probable a dull holesaw. Crazing usually does not go all the way through. Try a sched 80 bulkhead fitting they are bulkier and seal better than those black ones.

Don