Backyard Aquaponics
A place to discuss aquaponics

My bulkhead fittings are leaking. A family friend who operates some aquariums at a sushi place recommended #16 solvent cement for joining acrylic, would this be safe to use? I am rather doubtful. Does anyone know what would be a strong, food safe adhesive? Thanks!

I would look at replacing the rubber seal (and make sure it's on the flange side of the bulkhead). You can use a fish safe silicone but that doesnt usually last very long. Never heard of using #16 solvent. Good luck!

Which side would the flange side be? The bulkhead fittings are brand new and the rubber doesn't have any cracks in it or anything. I think it might be because the IBC is slightly curved? Anyway, thanks for the advice.

Flange side is the wider end (head of the bolt). If you put the gasket on the wrong side, it can get distorted as you tighten down the nut. A new bulkhead should definately not be leaking and I don't think there is enough curvature on an IBC to give it any problem(I have some installed in 35gal trash cans which have a lot more of a radius). Good luck bud.

The tank manufacturer in my building makes tanks out of HDPE. Everything they produce has bulkhead fittings or fittings that are welded. You can't glue to HDPE.

Make sure you didn't overtighten your fittings and crack the rubber gasket. (The gasket should be on the inside of the tank)

Hey there, NM!

When I have watertight connections with a slight leak I often use silicone grease. The stuff is like thicker vaseline and works well on threads and gaskets.

Another option, if the PE is thick enough, is to simply use uniseals rather than bulkhead fittings. I've never had one of those leak.

You might change your personal data to reflect your city or town or county, just so folks can help out if you are close enough.

Good luck!

Hmm this is very strange, I can't seem to figure out why it's leaking!

Ryan: Thanks for the info, I've tried putting the rubber gasket on both the inside and the outside of the tank to no avail.

Web: The bulkhead fitting and rubber gasket are both new and the rubber is still flexible with no cracks. Am I tightening it too much? The rubber gasket is pretty thick...

Hydro: I looked up what a uniseal was and I think I am gonna have to try this out. Maybe if I have a gasket on one side with a uniseal on the other it can seal up the leaks. And thanks for the advice, my info has been updated.

Thanks everyone for your input! Will report back with results.

If I were installing the bulkhead fitting, I would apply sealant to the fixed flange, then slide the gasket against it, then apply sealant to that so that it seals against the container. Once you do this it SHOULD seal better and better as it gets tighter, but there is a chance that the gasket could slip out under pressure....

I bought some uniseal fittings, they finally came in this week and I had a chance to install one today. (Just to make sure it works before I put them on the other 2.) The holes I had drilled were a bit too big (3 1/4 inches when the uniseal requires a hole that is 3 inches) but I wrapped the fittings with teflon tape until it was difficult to punch through. Hopefully this works! Will get back to you with results, thanks again for the suggestion hydro!