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tndiverdude
10-23-2008, 10:40
I heard, that scratching your tank weakens. I was told thats a false idea. So now I have a question.. Can you get a tank engraved?
I know its stamped at the top, so can you get one engraved?

jimmy

navyhmc
10-23-2008, 10:53
It depends...the minor surfa e scratches from regular use are no problem-these are usually low impact and don't really harm the tank. I truth, they do weaken a tank, but the amount of strength loss is so small, it's all but nonexistant. The stamping on a tank is done on the shoulder or rounded end as that area is the strongest and is the strongest area of the tank. The sides, even though they are usually thick have the largest area of stress and anything there will weaken the tank.

Not a metalurgist and I can't say for sure but I would imagine that light engraving on the shoulder of the tank would be okay. I would avoid engraving on the sides of a tank.

If the engraving does weaken the tank, I would imagine that the weakening would show up on the next hydro.

MSilvia
10-23-2008, 11:17
I'm no metals expert either, but I agree with navyhmc's reasoning. That said, I personally wouldn't do it.

in_cavediver
10-23-2008, 11:28
I am not a metalurgist but as a tank inspector - I'd fail or refuse to sign off on a tank that was engraved. There is just to much risk for a purely cosmetic process.

The stamping process is defined. Its displacement of metal, not removal and there is no surface prep done. Engraving removes metal and who know what surface prep was done. The cutting action itself can add heat and do you really want a localized 'hot' spot where the metal thermal treatment was changed?

Just not worth it IMHO.

tndiverdude
10-23-2008, 16:00
I thank you for your response. I as going to have our anniversary engraved on the tank my got for me as an anniversary gift.

she was a little dissapointed it was not a good idea. But better safe than sorry.,

jimmy

MSilvia
10-23-2008, 16:43
No reason you couldn't have it engraved on the valve stem...

cummings66
10-23-2008, 17:22
In general on an al cylinder there is almost no metal that can be grooved without it condemning the cylinder. The markings are at the top, that's the thick portion of a cylinder and the rest is much thinner and that's why the hydro dates you get as it ages are supposed to be above or level with the original hydro date. That's where the thick metal is and it's for safety.

Paint the date on it if you want it on the cylinder itself, use a small paint pencil or better yet get a sticker done. Get several of those, those get removed during the VIP.

CompuDude
10-23-2008, 17:52
I see no reason she couldn't have the anniversary date stamped into the metal (above the shoulder, of course) with similar sorts of metal stamps they use for the hydro dates. That's permitted. Just be sure it's clear you're not stamping a hydro date! It won't be in a pretty engraving font, but it'll get the job done.

cummings66
10-24-2008, 06:59
It also might hurt the resale value of a cylinder if you mark it that way. I'd much rather buy a cylinder that's only got the traditional markings on it, the anniversary date would make me want to pay less for it.

Many people sell al cylinders eventually.