mpt meets fpt stuck

[emissary]

I've got a sch80 1.5" bulkhead FPT meeting up with a sch80 mpt 90 degree elbow. Perhaps half way into insertion it got stuck. Okay, pulled out some long pliers for leverage and held once side and stuck the pliers in the elbow on the other side and turned. Good, it went father. Now I'm down to the last 3-4 threads ... there's still some distance it can go... but it's totally stuck. How am I supposed to get these guys together? Is there a lubricant I'm supposed to use?

[craby]

You are not supposed to get these fittings to cover full thread. These fittings are tapered & you are likely to break them if you screw them all the way until no treads are showing.

On another note, you can use teflon to help seal/lube it.

[Guest Keyoke]

You are not supposed to get these fittings to cover full thread. These fittings are tapered & you are likely to break them if you screw them all the way until no treads are showing.

On another note, you can use teflon to help seal/lube it.

33516[/snapback]

 

 

There's something dirty there, I know there is..

[emissary]

You are not supposed to get these fittings to cover full thread. These fittings are tapered & you are likely to break them if you screw them all the way until no treads are showing.

On another note, you can use teflon to help seal/lube it.

 

What if I *really really* want to make it short? Can I use a saw to saw off the bottom-most threads or ... since it's tapered, I'll have the exact same problem, just sooner?

[dchild]

First off, back it off smoothly and inspect for cracks

 

I'm thinking you'll have to cut off part of the female end (still won't cover full thread). I'm not sure whether the male or female (or both) portion is tapered, but I'd think either way you will have to cut off part of the female and potentially part of the male. As that is not the way the fittings are typically screwed together, I'd use lots of teflon tape and watch carefully for leaks. I also wonder if there is an alternative to a threaded bulkhead if space is such an issue.

[emissary]

First off, back it off smoothly and inspect for cracks

 

I'm thinking you'll have to cut off part of the female end (still won't cover full thread).  I'm not sure whether the male or female (or both) portion is tapered, but I'd think either way you will have to cut off part of the female and potentially part of the male.  As that is not the way the fittings are typically screwed together, I'd use lots of teflon tape and watch carefully for leaks.  I also wonder if there is an alternative to a threaded bulkhead if space is such an issue.

 

Well... if the elbow's cracked it doesn't matter. If the bulkhead's cracked... well there may be problems. But I don't think anything's cracked yet. As for sawing off the female end -- that's inside the bulkhead so I'm not going to be able to do that.

 

As for space ... it's not really a huge issue, I was just hoping to minimize how far the elbows came into the tank.

 

Finally... I got the bulkheads from glasscages... I didn't know beforehand whether they were going to be threaded or what.

[craby]

Well, since it's in the tank & all you're really concerned about is it draining to the bottom of the elbow when power goes off,you just need to make sure it doesn't leak (very much that is). In your case, you should be able to cut off about half the MPT side of the Ell. Just as long as it screws in a few good turns & teflon goes between the treads, you should be in good shape. If you have a dremel, use it to clean up the threads on the cut. If not, spurs may snag the teflon & break your seal.