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Re: shield gas for MIG

To: <Shop-Talk@Autox.Team.Net>
Subject: Re: shield gas for MIG
From: "Nils O. Ny" <n.ny@intest.com>
Date: Wed, 20 May 1998 17:24:50 -0400
At 06:10 PM 5/19/98 -0300, Bill Ruof wrote:
>
>One more response on shielding gases can't hurt.
>
>CO2 gives the least penetration.  You are less likely to burn through on
>thin material.  The argon-CO2 is cleaner with less spatter and surface oxide
>but it is a hotter arc and a little more penetrating.  Argon-CO2 is still
>good for thin panels.
>
>Argon with a percent or two of oxygen is nice and hot and works well on
>thicker materials.  Without the CO2 you can run in spray transfer which is
>hot, clean and has deep penetration.  The oxgen stabilizes the cathode spot
>which yields a very smooth, controllable arc.  Gas mixtures containing
>oxygen and CO2  shouldn't be used on aluminum.
>
>Straight argon is good for aluminum but requires more skill and effort on
>thin material.
>
>If you REALLY want to dig into a plate try a high helium mix.  Bundle up.
>Any exposed skin will be sunburnt in a very short time.
>
>Bill

Thank you very much Bill !    Very informative, you seem to be a
storehouse of information on the subject.   I am about to weld up
a roll cage for my car I am using DOM SAE1010 or 1020 steel tubing
that is 1-1/2 by .095 wall thickness.

Is that reasonable thick?  Should I use a straight Argon with Oxygen?
if so how much O2.  Is there a particular reason for Argon .... or is it
just the cheapest of the totally inert gases?   I would like to get good
penetration as well as good looking welds.   Also what is "spray transfer"
that you mention?   I have not tried aluminum yet but would like to ...
what is the best mixture for the EASIEST welding on aluminum sheet?

My local gas supply house where I get my O2 and Acetylene has
what they call welding gas (75% Argon / 25% CO2)  Is there a better
mixture for the roill cage application?  Are most of the suppliers
willing to mix up whatever proportions that you ask for?

Any advice gratefully accepted

Regards  Nils
Yardley,  PA
59(100-6)  69XKE  72/73MGB  52MGTD


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