Having a problem seeing the weld pool with very low currents

Jul 15, 2008 6 Replies
A

I'm currently TIGing some thin stainless (0.55mm) sheet and this requires very low currents.



The problem I'm having is that my auto-helmet only goes down to DIN 9 and it seems way too dark.



I don't really want to go back to a fixed filter (and even if I did, none of the local welding stores have anything lighter than a DIN 9 anyway) so I've tried using a spotlight to illuminate the work -- which means the auto-helmet simple goes dark anyway (damn!)



Is DIN 7 or DIN 8 an uncommon shade or something?



I tried using a pair of sunglasses but they seem to be only about a 5 (I estimate) and don't shade enough and my oxy goggles seem to filter out the wrong part of the spectrum because it's still very bright - but also very green :-)



Any ideas folks -- or do I just hunt down a DIN 7 or 8 from somewhere?



And yes -- it's a pig of a job doing a good fitment for a long butt or lap weld with metal this thin. I'm using a chill-bar behind the seam but trying to do a fusion weld on a 2mm lap still causes problems now and then when the two sheets aren't quite touching.



I also have to do a lot more practice on filling holes (how did they get there? :-)



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R

Make sure there is no light behind you, turn out the lights in the shop if needed. Just a little light coming in the back of the helmet can really hurt what you see in from of you on low amp jobs.

Thank You, Randy

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J

If you can get the cup between your eyes and the electrode tip, it will help immensely. Some people fashion shades that clip onto the torch and block the light from the electrode.

Jon

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J

Oh, I fix that by throwing a towel over my head and the top of the helmet. It helps a lot, and lets me still see what I'm doing while setting up. Turning the lights out in MY shop is a dangerous thing to do!

Jon

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C

Mine goes down to something like 5 I think. You could always shop around for a new autodarkening filter that goes lower.

Maybe you could try your sunglasses in combination with a shade 3 face shield? I use a shade 3 face shield for oxy.

I think the shade numbers are designed to be additive so if you could find low value face shields that add up to about what you think you need you might be able to overlap them and make it work.

I've not tried shopping for shields in that range, but most arc work is in the 9 and above and gas is 5 and below so those numbers probably are hard to find.

I've had lots of practice with that! :)

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G

Bruce, You have (I think) one of the cheap autodark helmets, made famous by Harbor Freight etal. When I was doing my ME in the Uni lab in Christchurch, we had a Speedglass helmet there. You had to remember to turn it on, but it was noticeably clearer than my cheapie one I got from HF via a friend. It was also 5x the price, but if I was welding all day, it would be the go. Are you using the pulser? makes thin stuff easier,but can upset some cheap helmets. Geoff

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A

Hi Geoff,

Yeah, my helmet is an ultra-budget type :-(

I'm going to play with the pulse a little more -- I'm just working the pedal right now instead.

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