TIG welding - changes of light intensity: what's going on?

When welding both stainless and aluminium at low currents (typically 20 - 40 30A) I frequently find that the arc changes from a fairly dim to a very bright light, apparently for no reason and at random. This makes it very difficult to see what's going on because my eyes can't react quickly enough to the light level before it changes.

What causes this and how do I avoid it?

I'm using a Lincoln Invertec 205 with pure argon and 1.6mm rods (red ones for stainless, white ones for ali). (And no, I don't have the pulser switched on!)

Nick.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

seems like it gets brighter when the tungsten touches the weld puddle.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

On Fri, 20 Jan 2006 00:34:44 +0000, Sailor wrote

You may be right, but I don't think this is what is happening. Any other ideas?

Nick.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Are you using an auto darkening helmet?

Nick Williams wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

MK1 wrote:

+1 for auto helmet (if that's what you're using)

I had an issue with my cheapo Harbor Freight auto darkening helmet, where it would cut out intermittently. I complained, sent it back, and got a replacement, which now workes more consistently for aluminum. But for some reason it still cuts out when I'm welding steel. -- Ilya

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

snipped-for-privacy@gmail.com wrote:

This happens once and a while at low currents even with my NexGen helmet.

Frank

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

On Fri, 20 Jan 2006 12:58:28 +0000, snipped-for-privacy@comcast.net wrote

Full marks to all those who suggested the helmet problem. I put some new batteries in and the problem's cured. Disappointingly, it hasn't altered the fact that I'm not a very good welder though!

Nick.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

On Thu, 19 Jan 2006 23:58:20 +0000, Nick Williams

It might be caused by the input voltage to your welder temporarily deviating from standard. This tends to happen in industrial areas where the power distribution transformer is shared with other industries that place a periodic varying load on the power utility.

If you are certain that this is not a TIG torch operator error (ie. you are not dipping the tungsten into the puddle) you might want to call up your electrical contractor and have them attach a recording voltmeter on the power input side of your welder. A recording voltmeter is a device that graphs the voltage level on a roll of cash register tape over a period of time for later review.

If your input voltage is varying widely, you might want to take the matter up with your local power utility, using the voltmeter recordings to support your complaint. The typical solution is for the power utility to install a power distribution transformer for your exclusive use.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If you're using an auto helmet, try turning the helmet's sensitivity up ( more sensitive ). I had this same problem and that worked for me.

Paul

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.