Subject: Cleaning cracks before TIG welding.

From: [email-masked] (David William Jenkins)
Date: Thu, 27 Jun 1996 19:37:33 GMT

Perhaps someone can help...

My son's bike is cracking at the ends of the front forks, where the
axle sits in the U-shaped slots - they are propagating from the
top of the "U". Before going off and buying a new set of forks (if I
can find any to fit, that is), I thought I'd have a go at TIG
welding the cracks.  If it works, fine, otherwise nothing is lost
by trying - and don't worry, they won't go on the road until I'm
REALLY sure that the welds are good! The forks are made of mild
steel tube, flattened and shaped in this area. 

My problem is, the cracks are dirty due to the oil and dirt from
the axle. In their current state there is no way that the weld will
be good, if it flows at all.  I don't want to "cut off and refit"
as there's quite a bit of metal remaining that will add to the
strength of the work if left alone.  It will also mean that I
won't need to do any special clamping to hold the surfaces together.

Can anyone suggest a way of cleaning out the crack sufficiently
well for TIG welding, using commonly available domestic materials.
By "domestic" I mean stuff found in a house or garage. For example,
I have methylated spirits (denatured alcohol with offensive
flavouring added), cellulose paint thinners, white spirit. Also
citric acid (used to "pickle" when silver-soldering brass and
copper) and boric acid (for removing rust). All the other things
you would expect to find!

Whatever process is suggested would have to involve dipping the
parts in jars, or similar - I have no access to exotic machinery
or industrial cleaning plant.

David Jenkins              -- aka --             Lathyrus Computers Ltd
***********************************************************************
* All incorrect spelling and grammar is intentional.  Corrections are *
* superfluous and will be ignored.  So there.                         *

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From: [email-masked] (Chris Kantarjiev)
Date: 27 Jun 1996 19:21:34 GMT

If you don't care about the paint, let the fork end sit in a
boiling solution of trisodium phosphate (from your hardware store)
in water, for about 20 minutes.

---

From: [email-masked] (ErnieLeim)
Date: 28 Jun 1996 03:37:56 -0400

[email-masked] (David William Jenkins) asked about how to
prep a crack in a bike frame before TIG welding :

Try a super solvent, like Methyl Ethyl Ketone. I know it is really nasty
stuff, but it will disolve any dirt and grease.
On a safer note you could try one of the new citrus cleasers.
I use the ZEP citrus cleaner. It is incredibly powerful, and safe.

On a related note, I would recommend using either Inconnel or Stainless
steel as filler for the TIG weld. I almost never use regular steel filler
anymore. I use Inconnel 82 and 316L SS for most of my mild steel welds.
They also work pretty well for cast iron to steel welds. They are both
stronger and more corosion resistant. They are also less prone to cracking
>from  contamination. Since they melt at a lower temp than steel , it is
almost akin to brazing.

Also try washing it with a propane torch after cleaning to burn off any
traces.

Best of luck

@}---------------------------------------------------{@
                    Ernie Leimkuhler                                      

                  Stagesmith Productions                                  
                                          
                 Custom Metal Fabrication                                 
               
*    ABANA   SCA     AWS    USITT   IATSE local 15, 488   *
                        Renton, WA                                        
   
*    "Death is like being on holiday with
          a group of germans" ---- Rimmer ( Red Dwarf )
@}------------------------------------------------------{@

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From: [email-masked] (Robert Galloway)
Date: 28 Jun 1996 09:29:33 -0600

>I use the ZEP citrus cleaner. It is incredibly powerful, and safe.

Have you given any consideration to opening up the crack with a hacksaw?  
Not seing the crack, I can't get a feel for whether this would be 
practical/desireable but I often find that "V"ing out or opening up 
allows better cleaning and 100% penetration although I doubt penetration 
will be a problem on a bicycle.

rhg

---

From: [email-masked] (David William Jenkins)
Date: Sat, 29 Jun 1996 13:46:06 GMT

>will be a problem on a bicycle.

This is a possibility - I was considering "Dremelling" a channel
along the crack, but I want to minimise the loss of material.  Of
course, if I save material but make a poor weld instead...

---

From: [email-masked] (C.J. Frederick)
Date: Sat, 29 Jun 96 15:56:12 GMT

In article <[email-masked]>,
   [email-masked] (ErnieLeim) wrote:
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2.news.
aol.com!not-for-mail
->From: [email-masked] (ErnieLeim)
->Newsgroups: rec.crafts.metalworking
->Subject: Re: Cleaning cracks before TIG welding.
->Date: 28 Jun 1996 03:37:56 -0400
->Organization: America Online, Inc. (1-800-827-6364)
->Lines: 34
->Sender: [email-masked]
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->Reply-To: [email-masked] (ErnieLeim)
->NNTP-Posting-Host: newsbf02.mail.aol.com
->Status: N
->
->[email-masked] (David William Jenkins) asked about 
how to
->prep a crack in a bike frame before TIG welding :
->
->Try a super solvent, like Methyl Ethyl Ketone. I know it is really 
nasty
->stuff, but it will disolve any dirt and grease.
->On a safer note you could try one of the new citrus cleasers.
->I use the ZEP citrus cleaner. It is incredibly powerful, and safe.

Plain acetone works well.  It is one of the few solvents that 
doesn't 
leave a residue during welding.  The process I use to repair cracks 
is:

1. Clean surfaces on and around crack of paint, mill scale (with an 
abrasive if present), dirt and anythink else that could find its way 
into 
the weld area when heat is applied.  The weld joint and surounding 
area 
should be clean enough to lick.

2. Flush the cleaned area with acetone one last time and wipe down 
with a 
clean lint free cloth.  If heat will not upset any metalurgical 
properties, 
heat the area with a propane torch or the TIG torch set at low 
amperage.  
This will drive off the acetone from inside the crack and show if 
any 
contaminants remain.  This is especially a problem where lubricants 
are 
present.

3. Grind out the crack.  Even on thin materials, take the edge of a 
cut-off 
wheel or router and grind out the crack as best as you can.  You 
don't 
necessarily have to grind through to create an "open" joint.  This 
may be 
undesireable, but by removing the crack face, complete penetration 
is 
insured and contaminants in the weld crack are removed.  "Vee" out 
heavy materials.  Grind past the end of the visual crack to make 
sure it is 
all removed.

4. Place a few tack weld along long cracks.  This will maintain 
allighnment 
and reduce distortion.  Weld slightly past the end of you joint prep 
to 
make sure all the crack was fused.  Don't be suprized if crud boils 
out of 
the crack ahead of your weld.  Guess what?  More cleaning and prep 
required.  Fill all weld creaters.

5. Congradulate yourself on a professional repair.

---

From: [email-masked] (David P. Anderson)
Date: Sun, 30 Jun 1996 15:23:56 GMT

>or industrial cleaning plant.

	The suggestion for acetone, or MEK is probably your best bet, a good
blowing out with compressed air after cleaning will usually evaporate
the solvent, and show you where the crack actually ends.  The one
thing no one seemed to mention that we commonly do with cracks on
tooling in aerospace is stop drilling the crack, just drill a small
hole (somewhere between .125 and .250 dia. ) where the crack ends, and
then fill it with weld when you weld the crack. Otherwise, even if
your weld holds up, the crack will continue to grow above it!

Dave

---

From: [email-masked] (C.J. Frederick)
Date: Sun, 30 Jun 96 21:03:26 GMT

---

From: [email-masked] (Stan Malyshev)
Date: 1 Jul 1996 14:48:12 -0700

In article <[email-masked]>,
ErnieLeim <[email-masked]> wrote:
[]
>anymore. I use Inconnel 82 and 316L SS for most of my mild steel welds.

I recall being warned about welding with/to stainless steel, the reason
being the possibility of forming nickel carbide inclusions.

Stan

---

From: [email-masked] (ErnieLeim)
Date: 3 Jul 1996 02:55:31 -0400

>>anymore. I use Inconnel 82 and 316L SS for most of my mild >>steel
welds.

>I recall being warned about welding with/to stainless steel, the >reason

>Stan

Actually the only time I would worry about carbides forming is if the
piece was going into a corrosive atmosphere, or was going to be flexed
excessivly. I just find that using Inconnel and stainless makes for strong
clean welds with fewer pinholes and gas pockets. Basic steel has a
tendency to boil when tigging if there is any contamination at all.
Inconnel and stainless are more forgiving.

I would never mix metals if the piece was to be used underwater, since the
galvanic action would accelerate corrosion at the weld.

Thats all.

                  Stagesmith Productions                                  
                                          
                 Custom Metal Fabrication

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From: [email-masked] (Don Clarke)
Date: Wed, 03 Jul 96 05:47:10 GMT

In article <[email-masked]>,
   [email-masked] (David William Jenkins) 
wrote:

>In article <[email-masked]>, Robert Galloway 
>>Have you given any consideration to opening up the crack  
snip
>>allows better cleaning and 100% penetration although I 
snip
>along the crack, but I want to minimise the loss of 
>material.  Of course, if I save material but make a poor 
>weld instead...

Dave, I would advise "V'ing" out any crack before TIG 
welding. Otherwise, you are just putting a patch on instead 
of fixing the problem. And the crack could work it's way out 
through the patch. One advantage of TIG is that you can 
control the amount of material you place in the weld, so you 
don't "save" anything by not properly preparing the 
weldment. However, if it is a bicycle frame you are welding 
on, I would recommend that you make very short, small welds 
and cool the area between each "weld". Myself, I use a 
pencil grinder to chase out a crack, but I suppose a dremel 
tool would do the same job...

Don