Installing Bulkhead Tips
- Thread starter AZDesertRat
- Start date
- Tagged users None
That is fantastic advice. Very clearly worded. Read through the rest of the thread to confirm that the bulkhead direction that I'm using will work, which - thanks to your many repeats of "The gasket ALWAYS goes on the flange side, regardless on whether or not the flange is on the dry side or the wet side of the tank [emphasis added]". Due to space limitations on my new sump, the drains from the DT will be entering the sump from the side (about 3" above the bottom of the sump) with the flange on the dry side (outside) of the sump with a slip fit 90 degree into a barb for the flexible hose from the DT overflows.Bulkhead tips:
1. Always install bulkheads clean and dry, no silicone, teflon or thread lubricants. Silicone and lubricants cause the gasket to scoot out or not seal properly. Have you ever removed an old automobile windshield or other gasketed glass? The rubber vulcanizes to the glass with time and creates a perfect seal without any help.
2. Before installing the bulkhead take a few minutes using a jewelers file, nail file or pocket knife and clean any excess flashing off both the male and female threads and from the flat gasket mating surfaces of the flange and nut. This is a common source of leaks.
3. Always install the gasket on the flange side of the bulkhead, never on the nut side, regardless if its inside or outside the tank. Installing the gasket next to the nut will lead to leaks as water travels along the threads around the gasket. Hand tighten only with maybe 1/4 to 1/2 turn additional, no more.
4. When using threaded bulkheads, again clean the excess flashing from the threads and valleys and use a stick or crayon type of thread lubricant designed specifically for PVC treads. These can be found at Lowes, HD, Ace and all hardware stores under names like Laco, Permatex and others.
I use this one and have since the 1980's with great success.
LA-CO: Product Detail - PLASTO-JOINT STIK® - Plastic Thread Sealant
It stays pliable forever and does not tear or roll out of the threads like teflon tape. My swimming pool plumbing up to 2" was all installed with this in 1983, outside in Phoenix AZ and its still pliable to this day!
Teflon tape was never designed to be used with PVC. Read this article by LASCO, one of the largest PVC fitting manufacturers in the world:
Assembling Threaded Plastic Fittings
5. Never support any pumps or piping from a bulkhead, always use supports so weight is not on a bulkhead and gasket causing differential stresses on the mating surfaces and leaks.
6. Never screw anything to the external threads of a bulkhead, these are not standard tapered pipe threads (NPT) and will leak. They are there to screw the nut on is all and are not normally even a standard diameter like 1" etc.
Hope you get some use out of this.
ThePickeledReef
Community Member
Hey so I am having some bulkheads fit pipe super tight and others super loose. This seems very odd is there something I should be looking for that I missed.
njudson
New Member
Big thank you for tip #2 !!!
Rusticman
Community Member
Good to know. Came across this tread after searching. After two failed attempts at stopping the return bulkhead leaking, I realized I shouldn't have used teflon tape. I added more teflon tape the second time hoping it would stop the leak. Nope, ended up cracking the bulkhead because I screwed it to tight. Waiting on another set of bulkhead and I won't use teflon tape this time. Lesson learned!
SteveMM62Reef
Valuable Member
If you don’t use Teflon Tape on your PVC Threaded Fitting, you can Friction Weld them together. True that it wasn’t designed for PVC, but actually for Stainless and Monel Threaded Oxygen and Gas Fittings. Rector Seal 5, is best for threaded PVC, but it is toxic to fish. I use Teflon Tape on my Aquarium PVC Threaded Fitting, the PVC Union threads, and where the threads where the Bulk head nut threads on. Silicone Lube, can stop you skimmer from working. BTW, I don’t like using it on Brass, and Copper threads, as it can stretch the fittings.
OK so my application is slightly different - there is no flange involved in holding the gasket.
The gasket goes between the back of the tank/glass and the external overflow box/acrylic.
Would it be a bad idea to lightly coat the seals with the following product (which I already have on hand)
The gaskets appear to have what I would describe as micro-scratches. Pictures to follow.
The gasket goes between the back of the tank/glass and the external overflow box/acrylic.
Would it be a bad idea to lightly coat the seals with the following product (which I already have on hand)
Amazon.com: Dupont Molykote High Vacuum Grease (Formerly Dow Corning) 5.3oz - USAlab : Industrial & Scientific
Buy Dupont Molykote High Vacuum Grease (Formerly Dow Corning) 5.3oz - USAlab: Industrial Lubricants - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
amzn.to
The gaskets appear to have what I would describe as micro-scratches. Pictures to follow.
redfishbluefish
Stay Positive, Stay Productive
Staff member
Super Moderator
Reef Squad
Excellence Award
Article Contributor
NJRC Member
Hospitality Award
Since you already have it, a very light coat would be OK....it is a silicon based grease. If you didn't already have it, there are other options at a much better price point. I use Leslie's Pool Lube.
I got an email response from Modular Marine, they too confirmed a light coat of silicone grease on the rubber seals.
More questions to follow tomorrow re original seals vs replacement seals sold by BRS.
Just found this thread and am in need of some bulkhead advice. I bought an Eshopps Eclipse L overflow box to use with my tank. This is an acrylic overflow box that goes inside the tank and a separate acrylic box on the outside of the tank. There are two 1.5" bulkheads through the glass with the flange built into the interior acrylic box (i.e. you cannot remove the 1.5" bulkheads as the opening is too narrow to remove them). I tried installing this once before and had terrible leaks from both of the bulkheads.
I am unable to remove the flange and thread end of the bulkhead from the box to clean the flange. Also, there are two gaskets included and, per the instructions, are supposed to go next to the glass on the inside and outside.
I've cleaned as much as I'm able and on a second try am still getting leaks. At this point my next step is to put on unholy amounts of silicone and call it done. What's the right way to deal with this sort of thing?
I am unable to remove the flange and thread end of the bulkhead from the box to clean the flange. Also, there are two gaskets included and, per the instructions, are supposed to go next to the glass on the inside and outside.
I've cleaned as much as I'm able and on a second try am still getting leaks. At this point my next step is to put on unholy amounts of silicone and call it done. What's the right way to deal with this sort of thing?
redfishbluefish
Stay Positive, Stay Productive
Staff member
Super Moderator
Reef Squad
Excellence Award
Article Contributor
NJRC Member
Hospitality Award
No gaskets on the inside, wetside. Just slip it through the holes....and don't intall the drill guide with the overflow. I say that because I've seen it before. 
Now on the outside a rubber gasket on each bulkhead...and I've also seen it were two gaskets are installed on each bulkhead. Now slip the dryside over the bulkhead and screw on the nuts.
Now on the outside a rubber gasket on each bulkhead...and I've also seen it were two gaskets are installed on each bulkhead. Now slip the dryside over the bulkhead and screw on the nuts.
No gaskets on the inside, wetside. Just slip it through the holes....and don't intall the drill guide with the overflow. I say that because I've seen it before.
LOL... the drill guide would certainly cause a problem
So just ignore the instructions that come with the thing, install the gaskets on the side with the nut (outside box) and go from there. I'm going to clean it down with some 4-0 steel wool and some windex first just to make sure there is a clean location to bind to. Just to be clear, there are 3 layers the bulkhead passes through. Inner acrylic (inside box), glass, and outside acrylic (outside box). Should I have: inner acrylic, glass, gasket, acrylic, bulkhead nut? The bulkhead goes through all of it and is the only support to hang the outer box from.
Edit: Just had another though that might make more sense. Should it be flange, inner acrylic, gasket, glass, gasket, outer acrylic, nut?
Last edited:
TaylorPilot
Valuable Member
- Joined
- Aug 8, 2015
- Messages
- 1,455
- Reaction score
- 1,267
Yea, it should be inner box, gasket, tank, gasket, outer box, nut. The gasket between the tank and the outer box is the one that keeps the system from leaking, but the one on the inside provides a tiny bit of space between the overflow and the tank, so you do not get pressure points if the overflow isn't perfectly flat. Also, if you do not put one on the inside between the overflow and the tank, water can flow along the bulkhead threads into the rear box. It is very slow, but if the return pump was off for an extended time, it could cause the tank to leak down below the bottom of the weir teeth. Do you have any big chips in the glass? I am thinking I may start producing some oversized EPDM gaskets for people who have chips in their glass, and can't get them to not leak.LOL... the drill guide would certainly cause a problem
Just to be clear, there are 3 layers the bulkhead passes through. Inner acrylic (inside box), glass, and outside acrylic (outside box). Should I have: inner acrylic, glass, gasket, acrylic, bulkhead nut? The bulkhead goes through all of it and is the only support to hang the outer box from.
Edit: Just had another though that might make more sense. Should it be flange, inner acrylic, gasket, glass, gasket, outer acrylic, nut?
There are some tiny chips, but they're less than 1/16" inch which is quite a bit smaller than the gasket. I've since learned that I can't actually buy the 1" bulkheads that Eshopps used to make this overflow, so I'm just going to remove the entire outside box, cement 1.5" pvc to the bulkheads, and go. It'll make more noise, but better chance of me getting the thing to work.
Similar threads
