Weld Helmet

Hello Been a long time since I posted on this site and am glad that it still exist , have been TIG welding a long time , A/C , Aerospace and Medical , always used the older transformer rectifier technology , have been using a Harbor Freight auto darkening helmet for several years , not because of the price but just like the lightness and they work great , Lincoln put on a seminar and some field training at our county airport and I went along for the ride , I wanted to try one of the new inverter welders , I finally took my turn at a steel sample with D.C. and was shocked to find out that my auto darkening helmet would only stay engaged for about two seconds and the disengaged and let a lot of light in , I lit up a older TIG and showed the boys how to weld Alum. with no helmet problem , somebody mentioned that the Inverter was OK on A.C. Alum. and caused a problem on D.C., would like to hear a Tech. explanation of this phenomenon, Thanks Phil L.

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I use two HF welding hoods. The cheap one and the cheaper one both. They both work fine using either my AC cracker box for dirty steel work, my Miller 212 for globbing on aluminum, or my chinese flux core for field work on steel.

I actually like the cheaper one better because it turns light faster when the arc stops. It's a lot easier when welding thin stuff, and the only way I can make it work is to stack tacks.

I'm not a real welder, so my experience is limited.

Reply to
Bob La Londe

I suspect that no one knows the answer to your question, including me, but I will hazard a guess: The Harbor Freight arc detection circuitry may depend on brightness ripple from the arc, rejecting steady illumination as a method of compensating for background light from indoor to full sun. All transformer based machines have AC ripple in their output even on DC, but the ripple on an inverter machine might be too high a frequency or too low in amplitude for the helmet to detect anything but the initial starting spike, which will pass through a simple AC only filter consisting only of a series capacitor between the photocell and the arc sensing circuit. More expensive helmets could use a different method, such as a sensor behind a UV filter, if I ever get one I will take it apart and look. (Still flipping down an antique with a head nod, which works well enough for my occasional welding.)

Reply to
Glen Walpert

The reason the ordinary helmets (which are designed mainly for MIG and stick) don't work so well for low current TIG is that they switch on when the light level increases rapidly (in order to give a very fast response), but switch off depending on the actual light level, which for low current DC TIG (AC is usually brighter than DC at the same current) may not be bright enough to keep the usual type of helmet switched on.

There is a delay after the helmet decides it's okay to switch off, to cope with restrikes and afterglow etc, probably set to 2 seconds in your case - in many helmets the delay is adjustable between 0.5 and 2 seconds.

You can get autodarkening helmets which are designed for low current TIG

- eg:

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Rating Totally stable down to 8 Amps

They are quite common.

There are ones which just stay switched on at low level TIG amps, and ones which also have lighter level shades, like 6-9, as well as the more usual 9-13.

They are a bit more expensive than ordinary helmets, but not a lot more.

I'm in the UK so can't really recommend helmets for usanians, but there shouldn't be any problem getting hold of one designed for low current TIG in the US.

On another point, many solar powered autodarkening helmets have two CR2032 lithium batteries inside which supplement the solar cell and which are meant to last several years - they may be and frequently are designed so that the batteries are not meant to be replaced, but a little graunching will often find a way - and if the helmet doesn't work because the batteries are dead, even if you end up having to glue things it may still be worthwhile trying to replace the batteries..

-- Peter Fairbrother

Reply to
Peter Fairbrother

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One safety issue - they may be ML2032 or LI2032 (or xx2032) batteries, which should be replaced with the same type.

I read these posts, then reread and correct them, and they seem okay - then I post them and only realise when I see them online that I missed out something important, or got something wrong. Sigh.

-- Peter F

Reply to
Peter Fairbrother

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