USDTwin manifold overhaul questions

[ScubaLawyer]

See previous post on first page. This is a continuation of that post.

Ok, here are the pics of my defective tank neck. Let's play spot the problem!

Any quick fixes or do I have a new pot for long-stemmed flowers? Mark

[antique diver]

The corrosion spot could be the trouble, but in the second photo it looks like there could be a crack across the neck. Those tanks are the old alloy that is susceptible to neck cracks. Use a magnifying glass to closely look for a crack.

The first crack I ever noticed in an aluminum cyl of that type leaked air just like you reported.

If you can be absolutely certain that there is no crack, you might try a Quad-ring or X-ring of the 214 size. There are more sealing surfaces to those, and we found they would sometimes work when there was a lightly corroded spot. Check your local seal store or try Grainger. I'll look to see if I have any left.

[captain]

Find a shop that has one of these.

http://www.oceanenterprises.com/scuba-g ... -tool.html

[antique diver]

X Rings.jpg

Here's a look at X-Rings / Quad-Rings. I have found them useful in hard to seal applications, and always used them on camera control seals on my housings for added protections against wear and leaking.

[antique diver]

ScubaLawyer, check you PM's.
I found my stash of X-rings in the right size (214). Hopefully you don't have a crack in the cylinder neck, and maybe one of these will work.

[ScubaLawyer]

ScubaLawyer, check you PM's.
I found my stash of X-rings in the right size (214). Hopefully you don't have a crack in the cylinder neck, and maybe one of these will work.

Sent you an email. Thanks again for all of your assistance. Mark

[Ron]

I'm not a tank expert like AntiqueDiver and Captain, but that sure looks like a neck crack on a 6351 alloy tank. I have seen two others like that one. If you look close, it looks like it goes all the way into the threads if you zoom in really far. This is just my opinion, but I would just find two used tanks that are 6061 alloy and use them. I'm probably going to take shit for that comment, but it is cheap insurance. I had an old twinset of USD AL 63's and I swapped the 6351 tanks for some 6061 ones. Someone on the board still has them if I remember correctly.

[antique diver]

....that sure looks like a neck crack on a 6351 alloy tank. I have seen two others like that one. If you look close, it looks like it goes all the way into the threads if you zoom in really far. This is just my opinion, but I would just find two used tanks that are 6061 alloy and use them. I'm probably going to take shit for that comment, but it is cheap insurance.

I agree with Ron's assessment, but I hope I'm wrong in this case, and hope that Mark ends up with a good set of cylinders. I'm going to shut up about it now unless someone foolishly asks my advice on what to do with 6351's... but that should be in a new thread.