[PSUBS-MAILIST] Welding - was : warning for smyth

[MerlinSub@t-online.de (Carsten Standfuss)]

Alec.. and others

  My way for endcap to cylinder conection weld.. 

- step weld from outside to the double V border, outside
  V greater than inside V. (about 33 to 66 % up to 50/50)
- Than the smaller inside turn around weld, if multi layer - than only  
the first one. 
- If you make this first turn around weld (inside) - stop before 
  you have the 360 maybe at 350 degree and remove the first 2 inch
of      the weld - were you have started the weld - because this part of
the     weld is maybe to cold - special if you use MIG or mag process. 
  Than weld the 360 degree final. 
- than remove the tack weld from outside complete and grind deep
from     the outside until the first inside weld from the back is pure
plain   metal without any darkness, dirt or something else.. 
- remove any grind dust very carfully.. no dust or dirt should be there 
- than do the outside weld, maybe more than one layer
  do not stop the hole process without a longer break 
  so the weld area is good warm or better - still hot. 
- this way indicate - only 2 inch grind from inside nessesary..
- Weld only in a close shelter (special with MIG/MAG)
- preheat the weld area if the weather is cold, during winter time
  or if the metal is wet, has moisture, never weld a wet iron.. 
  (get hydrogen into the weld), prehead if you use high tension steel. 
- If you stick weld - use ticks which are dry and maybe preheated
  in a ofen.. 
- Ask a profesional welder to do the job if this sub is your first
weld   work.. and let him make all pressure tight welds.. 
- a boiler company can make perfect machinery weld on a roller gear for 
  only a little money.. ask before you do something yourself..
  sometimes its cheaper than grind everything out.. 
- leak weld finder spray is a cheap solution for homebuilders, any
weld   gear supply store has the bottles on stock.. 
- if you change something on your weld gear - sticks, wire, gas 
  currents - allways make a short test weld on a part of scrap-iron
  before do the thing on the real unit.  

Carsten

Alec Smyth schrieb:
> 
> I have a rather humorous photo of myself after about 3 hours of grinding inside the hull. My face is entirely black except for two circles around the eyes where I was wearing goggles. Grinding is by far the noisiest, dirtiest, part of building a sub, and doing it inside a small steel pipe will make you cherish other moments in life, like visits to the dentist. But above all grinding demands heroic stoicism from my family and neighbors. If anyone has an alternative method, believe me I'll volunteer to try it!
> 
> Alec
> 
> -----Original Message-----
> From: Gary R. Boucher [mailto:protek@shreve.net]
> Sent: Wednesday, September 25, 2002 10:44 AM
> To: personal_submersibles@psubs.org
> Subject: Re: [PSUBS-MAILIST] warning for smyth
> 
> Mr. Lauser,
> 
>      They radiograph and use ultrasonic methods to find cracks and flaws in
> a weld.  Exactly how would you suggest fixing a flaw?  Perhaps drill it
> out?  Of course you grind it out.  There is no way other than to throw the
> hull away and start over.  That is the method used by certified welders and
> has been since the beginning.
>      As far as grinding of a finished weld goes, it does tend to weaken the
> weld, but all must be considered in the larger scope of things such as the
> amount of stress the weld will be subjected to and the types of materials
> used.  If you want to see some grinding, I suggest you come look at my
> sub's sail section.
>      I have met Smyth, and sir, I can assure you he is paying attention.
> 
> Gary R. Boucher, D.Eng.
> Dept. Chemistry-Physics
> Louisiana State University - Shreveport
> 
> At 06:28 PM 9/24/2002, you wrote:
> >ATTENTION ALEC SMYTH:
> >
> >Alec,
> >
> >It was great to see your progress on the SOLO sub, but I read something
> >that caused me great concern for your safety, so if you're listening,
> >please pay attention! I'm sorry to post this over the list, but I didn't
> >have your e-mail address at hand.
> >
> >In your description from August 29th, you mentioned a few things needing
> >attention and in one you said "grinding out small welding flaws in the
> >hull". I don't want to be an alarmist, and perhaps someone else has
> >brought it to your attention (hopefully), but you should NEVER EVER EVER
> >EVER grind on a weld. It will weaken the weld and can seriously endanger
> >your submarining efforts if it is on the pressure hull. I say this only to
> >keep you safe. I can only imagine, not that I particularly want to, what
> >could happen to a weakened pressure hull weld at depth. Please be careful
> >since it looks like such a cool sub and I wouldn't want anything to happen
> >to the operator. Good luck and keep working hard!
> >
> >- Jacob Lauser
> >   University of Arizona Student Underwater Bouyancy System Initiative
> > (UASUBSI)
> >