Bulkhead Hole Size

[Grant]

I'm having a hard time determining exactly what size bulkhead I need to get for the holes drilled in my tank. I know that sounds backwards, and ideally I'd pick the return size and THEN drill the hole for that size bulkhead, but I had the tank built and requested holes drilled for two 1/2" return lines. I've had the tank in my possession for a while and recently went to put on the two 1/2" bulkheads I had and found that the hole is just too big. They fit, but just barely and I don't think there's any way they wouldn't leak. It's way too late for me to go back and ask them to change it, and honestly I'm so close to actually getting water in this thing finally that I don't want to risk anything happening to it. I'd rather just buy two new bulkheads.

The two holes are exactly 1.5" across, so what size bulkhead would I use for this? I looked at BRS and they have the sch40 listed as 1.33" for the 3/4" and 1.65" for the 1". Sch80 is 1.61" for the 3/4". I'm thinking that the sch40 3/4" is the way to go, since it looks like the others would be slightly too big, but I was hoping someone could confirm that?

Thanks!

 

[RAMTEX]

I just purchased a tank that was drill for 3/4 inch return and 1 inch drain. I purchased the bulkhead and they supplied me a 3/4 schedule 40 for the return. I didn't check the size of the hole or the bulkhead. It worked fine no leaks. If you had them drill 1/2 inch return then I would think you need 1/2 inch bulkhead.

 

[Grant]

I would have thought so, since I told them I was planning to use 1/2" returns, but I confirmed yesterday that the 1/2" sch40 bulkhead is just too small. The 3/4" sch40 works fine. Looks like they drilled the wrong size hole. Luckily it's not a big issue since I haven't bought the return pumps or plumbing yet.

 

[jccaclimber]

While it seems they should be standardized (per BRS) I've actually found a bulkhead here and there that doesn't fit the BRS hole size, but isn't a schedule 80 bulkhead. It may have something to do with threaded vs. slip, but I've always just matched to the closest size in my hole saw set. I would be inclined to use the larger pipe (1/2" is really small and restricting), although you could always get some adapter bushings for $1 at the hardware store if you really want the smaller pipe.

 

[Grant]

@jccaclimber wrote:

I was just going with the 1/2" because it was big enough to flow the amount of water I needed, especially with two returns. But there's no reason the 3/4" won't work just fine, too. The only negative is that now I have two 1/2" bulkheads sitting on my parts shelf that I don't need and knowing me I'll manage to somehow turn two extra bulkheads into another tank project. [smilie=itwasntme.gif]