Re: [PSUBS-MAILIST] Re: Propane tank

["Problah" <problah@zonenet.net>]

/something I learned as an airframer in the Nav called the ten percent rule.
When corrosion takes effect on any container (not a plate which will rust 
from both sides easily) sealed on one side from the outside influences. Rust 
can roughly only penetrate ten percent thru the metal. therefore I took ten 
percent off of the propane tank, but that is assuming it wasn't exposed on 
the inside to outside elements for too long.

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---------- Original Message -----------
From: Ian Roxborough <irox@ix.netcom.com>
To: personal_submersibles@psubs.org
Sent: Wed, 4 Sep 2002 12:43:27 -0700
Subject: Re: [PSUBS-MAILIST] Re: Propane tank

> Sorry, I didn't mean to undermine your calculation, I was
> just implying that without examining the pressure-vessel
> nobody on this list can accurately predict the crush
> depth, we don't even know the diameter (althought your
> 40inich guess would seem like a good guess).
> 
> I'd be interest in how you where accounting for rust
> and weakness in your calculation.
> 
> Thanks,
> 
> Ian.
> 
> On Wed, 4 Sep 2002 11:51:57 +0900
> "Problah" <problah@zonenet.net> wrote:
> 
> > Wow, thanks for the support fellas, but I did do a calculation accounting 
for 
> > rust and a higher flexibility (weakness). The absorption was a good note 
> > thoe, I'll give you that, I just figured for crush depth, not for diving 
in.
> > 
> > Support your local zonenet
> > 
> > 
> > ---------- Original Message -----------
> > From: Ian Roxborough <irox@ix.netcom.com>
> > To: personal_submersibles@psubs.org
> > Sent: Wed, 4 Sep 2002 11:13:40 -0700
> > Subject: [PSUBS-MAILIST] Re: Propane tank
> > 
> > > Hi Mike,
> > > 
> > > if you don't have access to resources to make a 1-ATM
> > > submarine, have you consider making an ambient sub
> > > instead.
> > > 
> > > I'm not saying that ambient subs are easier to build
> > > than 1-ATM subs, but it does remove the issue of finding
> > > a safe pressure vessel to use.  After learning more
> > > about ambient subs at the psubs conference I think they
> > > look like a LOT of fun.
> > > 
> > > You don't mention a lot about the propane tank you want
> > > to use, any estimation of crush depth that people have
> > > give on this list will be working with the assumption
> > > that the propane tank is new and in perfect condition.
> > > I'm sure you are aware that any small (invisible) cracks
> > > or dents could drastically reduce the usable strength
> > > of the propane tank.  If it is a used propane tank, then
> > > you'll have to deal with the propane that has been absorbed
> > > by the metal.
> > > 
> > > Ian.
> > > 
> > > On Mon, 2 Sep 2002 22:39:23 -0500
> > > majerus@iowatelecom.net wrote:
> > > 
> > > >     To anyone that might know, 
> > > >         I have a 500 gallon propane tank with a .312 thousands 
thickness 
> > and was wondering if that might be able to stand pressure of 75 feet or 
so, I 
> > know that some are not keen on using one but I really want to build a sub 
but 
> > do not have some of the resources that some might have. Also, I was 
wondering 
> > how to make a depth gauge.
> > > >         Thank you, Mike
> > > > 
> > > > 
> > > 
> > > -- 
> > > The moon ate the sun on Monday and it was an awsome sight to see.
> > ------- End of Original Message -------
> > 
> 
> -- 
> The moon ate the sun on Monday and it was an awsome sight to see.
------- End of Original Message -------