[PSUBS-MAILIST] Weldings was :warning for smyth

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

Grinding welds for cosmetic reasons ? 

Sure I did this many times myself..
Special on stainless steel structures..
We build just now a 200 foot yacht and 
did it on our yard every day on pollers, anchor pockets, 
railing stations, bell-towers, main pillars etc.

but it depents clear how the preweld situation was.. 

if you have a pre-weld condition like this : 
 	 ____   _____
     	     I I
             I I
        _____I I_____   dont grind the weld away for cosmetic reason..
                         (and never build a submarine that way..)

but if you have somthing like this : 

       ______       ______ top
             \     /
              \gap/
        ______/   \________

you can grid the top side..

..but
- never on pressure hulls 
- never on aluminium structrures.. 

Carsten

protek@shreve.net schrieb:
> 
>     Grinding welds down does not make one "idiotic."  It is a standard practice
> in industry to dress welds by either machining or grinding.  There are even
> certain conditions that can worsen a weld if it is not ground.
>     I spent a few minutes on the web this morning at work and found several
> reverences to the grind or don't grind issue.  I have listed these below.
> 
> http://www.cycling.org/lists/mtb/mtb-archive-hyper/mtb.199503/1330.html
> 
> http://www.dot.state.ga.us/dot/construction/materials-research/Documents/ppt/vis_inspect/tsld016.htm
> 
> http://www.lambolounge.com/Building_Notes/Welding/Welding.htm
> 
> Gary Boucher
> 
> >Gary,
> >
> >I sure you saw my response to Alec, but if not, I was just making sure that
> 
> >he wasn't trying to buff/grind a weld bead down to make it pretty or more
> >hydrodynamic since I see such idiocy all the time in the aircraft industry.
> 
> >Thanks for the reassurance and restoring my confidence in PSUB builders
> >everywhere. BTW I speak from experience. I ground a weld bead down on a
> >liquid-fuel rocket engine I made a few years ago and when I pressurized the
> 
> >cooling jacket and fired it up, the bead cracked and shot out a jet of
> >steam, ruining the cooling capabilities of the engine. I never fixed it, but
> 
> >it was a good experience as I later learned, while in a welding class, that
> 
> >you should never grind on weld beads. consequently, I have applied this to
> 
> >my submarining endeavors. Hope all is well with everyone. I should have a
> >major update on the UASUBS Initiative soon for any interested party...
> >
> >- Jacob Lauser
> >
> >----- Original Message -----
> >From: "Gary R. Boucher" <protek@shreve.net>
> >To: <personal_submersibles@psubs.org>
> >Sent: Wednesday, September 25, 2002 7:43 AM
> >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)
> >> >
> >>
> >>
> >>
> >>
> >
> >