Re: [PSUBS-MAILIST] CSX-1 technical inquiry.

["Captain Nemo" <vulcania@interpac.net>]

Hi Carsten!

Just wanted to explore the technical side of sub-building for a while.

When I asked what kind of "joint" you were using: this is a structural term
describing the way the steel plates are positioned next to each other before
welding; has a lot to do with the final strength of the finished product.

For example, when two plates are simply set side-be-side, touching on the
edges, and then welded, we call that a "butt joint" because the two plates
"abut" each other.  If the edges to be joined are beveled slightly with a
grinder, this gives deeper penetration for the weld, and is sometimes called
a "beveled butt joint."  When the plates are slightly overlapped and then
welded, this is called a "lap join", and so forth.  I was just wondering
what kind of joint you were using.

If I understand your description of the welding process you're using, it
sounds very strong.  I'm visualizing a butt-joint with one bead over the
seam; two more beads (one on either side of the first pass); two more beads
riding the crease between beads 1, 2, and 3; and a final "cap bead" pass
made down the center again.  If we cut a slice out of it perpendicularly,
and looked at the weld beads from the end, it would look something like a
diamond shape.  To me this sounds very strong.

I just came up from the shop and am taking a break.  Just welded in a
bulkhead for a small hatch which will allow me to access the end of the
tailcone for maintenance of the control shaft packing glands.  Also
installed a big coupler which will increase the emergency escape lockout
flood valve diameter by 325%, so I'll be able to get out faster if I get
into trouble.  Installing the watertight coupler for the underwater
telephone transducer next; then it's weld in the supplemental systems
battery box, and after that the hard stuff is done.  Time to vacuum out the
pressure hull, paint the inside, start putting her back together, and finish
up the exterior detailing.  Then, it's time to go diving!

Pat


----- Original Message -----
From: "Carsten Standfuß" <MerlinSub@t-online.de>
To: <personal_submersibles@psubs.org>
Sent: Thursday, June 21, 2001 9:10 PM
Subject: Re: [PSUBS-MAILIST] CSX-1 technical inquiry.


> Hi Pat..
>
> > Captain Nemo schrieb:
> >
> > Carsten,
> >
> > In welding your pressure hull together:
> >
> > (1) What kind of joint are you using between mated plates?
>
> My translation book is not very helpful with "mated plates".
> But in general I use O-rings for pressure parts and flat rubber
> gasket for non pressure parts. The main Machinery hull joint
> will be a mixture between a o-ring, a hard rubber flat gasket
> just a little smaller in tickness than the O-ring
> and on the outside a fluid rubber sealer to prevend rust.
>
> >
> > (2) Are you welding in single or multiple passes?
>
> In a single passes if ever possible on multi-layer weldings.
> The regulator tank joint flanges has 6 layer weldings.
> I pre-heated the steel with a gas flame and make all layers during
> the time the material was hot from the welding process.
> It is clear vissible that the last layers on the hot material
> gets much better than on the cold material.
> Sometimes I work overnight - because of something went wrong and I
> lost time by repair work (grinding) on the weld etc.
> Single layer welds I did on different days - but I grind the first
> 1-2 inch were the old weld starts or end - specialy if I use the Mig
> welder - this parts can be to "cold" with a bad conection.
>
> >
> > Pat
>