Regulators, Tanks, and Hydro Test

[BlindFaith429]

Is there a big thread explaining about these three items, and how they all relate?

I know a little about hydro-testing, that it needs to be done every 5 years if i recall correctly, and i know about the 2" rule.

What I don't know about is the regulators, and assembling your own tanks (if thats even a thing). i assume some people must do it, as you can buy regulators and bare tanks (though not as common as assembled tanks).

Reason I ask, is that I just won an old-school in line Max Flo on ebay. It is just a bare regulator right now.

Id like to put a tank on it, but dont know if this is something I can do, then take it to be tested. Or if this should be brought to someone to do it "correctly".

My local store does hydro testing in house for $25-$30 per tank. I may be able to pick their brain too next time I'm in there.

Maybe a pinned thread about testing and tank building would be helpful.

Thabks!

[Toestr]

Building a tank is as easy as buying a regulator with the appropriate rating for your tank. Hydro testing requires a tank only as you're testing for expansion of the tank. The reg would have to come off anyway.

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[BlindFaith429]

Ah, gotcha. I thought the hydro-test was to test the tank, reg, and assembly all at once, like the whole packaged unit.

So really, I could rebuild my reg, slap on a brand new tank, and be good to go? No hydro-test after I assemble the parts?

[latches109]

Correct. Hydro is specific to the tank only. The reg uses burst disks for safety. Be sure you put a 4500 reg on a 4500 tank. And do not use any combustible oils in the reg. Dow 111 is what is used in the scuba world.

[BlindFaith429]

This is the pic from eBay. Not sure what burst disk is in it. I was thinking its a 4,500 due to the right gauge, but I could be wrong. Ill double-check either way.

Interested info latches109 , ZDSPB has a write-up and rebuild video on these, and he uses Dow 33. Not sure how different that is from Dow 111.

[latches109]

I haven't used it, but he knows what he is doing, it's probably fine. You can pull the SDS safety data sheets from the links below.

https://www.dupont.com/products/molykote-111-compound.html

https://www.dupont.com/products/molykote-33-medium-extreme-low-temperature-grease.html

burst disks look like an autococker detent that will be stamped with the burst pressure. 1.8k, & 5k(3000psi) or 7.5k(4500psi). if they are not broken don't touch them. they should be torqued to spec 86-100 in-lbs (100-115 kgf.cm) depending on the burst rating.

[Macdave06]

I don't think those inline maxflows were made in 3k so it should be 4.5k.
Shouldn't be any problem with swapping tanks. Other than some pcp metric tanks they're the same thread.

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[BlindFaith429]

Thanks for all the replies guys.

Quick question. Is there any way to test the reg or the burst disks? Or just air it up and listen for leaks?

Would it be best to replace the burst disks (would have the local shop do it) due to the age of them? Or do they not really deteriorate like an O-Ring does?

[Euphie]

To test just screw it into your cylinder, take a remote line with a degassing ASA and hook it to a known working tank, and fill that tank with your other tank. It will only fill to 800 PSI or so (unless your known working tank is adjustable or LP, etc). If your reg doesn't leak from everywhere, then degas the remote line, if it slowly leaks out while you degas the line then that means your fill nipple is leaking and needs to be replaced. Otherwise just make sure the reg doesn't leak and adjusts properly and that you didn't leave any o-rings out of it while rebuilding it lol

I would always rebuild and replace the burst discs/fill nipple piston on a new tank build personally

[lhamilton1807]

Just wanted to add an item here. If you’re in the USA and want to find a place to hydro test your tank, there’s a DOT site that lets you search near any zip code. Enter your zip, select the number of miles away you’re willing to drive, and then hover your mouse cursor over each of the testing sites marked with a blue icon (the orange icons can do visual inspections only). The name of the business will appear.

You’re welcome.

https://portal.phmsa.dot.gov/rinlocator

[JeeperCreeper]

You are the man