Friday, January 21, 2011
Darth Vader Approved?
I recently added a Hobart Airforce 700i plasma cutter to my shop. Hobart really didn't provide much guidance as to what type of eye protection is required or even recommended when using the 40 amp unit. This being a hobby, me being inexperienced and after some of the lessons learned via the school of hard knocks I tend to err on the side of caution. I submitted several messages on the Hobart online forum and eventually got the recommendation to use "eye protection with a minimum of #5 lens shade". I already knew that much and had been using my #5 shade goggles from my oxyacetylene torch when running the plasma cutter. Most of the time the torch handle blocks the arc light. It's only when you cut at angles or are forced into an odd position are you exposed to more light and potential for sparks and other debris flying back at you. I also found that I commonly went back and forth from plasma cutter to grinder requiring me to switch to a clear face shield so I could see what I was doing. I wanted additional protection for my face while using the plasma cutter plus make it as easy as possible to go from cutting to grinding. Preferably without changing safety shields.
After a little Internet research, I found a combination face shield/drop down shade lens made by Hypertherm titled, "Hypertherm Multi-Purpose Plasma Cutting Operator Face Shield". I was able to get past the long-winded name and see that it might actually work. The clear lense provides protection to your face from sparks or other debris from the grinder and a flip down #6 shade lens for use with the plasma cutter.
Baker's Gas & Welding Supplies, who by-the-way has great customer support. I accidentally ordered the #8 shade model instead of the #6. A quick call Baker's fixed the problem and confirmed the order. The correct shield arrived on time as promised. An initial inspection showed it to be a quality product. It's both well made and well designed.
The shield is comfortable and not as bulky as the cheaper generic clear one I use for grinding. The lens itself is of better quality and doesn't fog up or scratch as easily as the generic model. I gave it a quick run through while using a grinder and found it to be very comfortable. You almost don't notice the #6 shade protruding from the top of the shield.
Next I tried it out with the plasma cutter. I had some initial problems. The #6 shade, while only one increment darker than my #5 goggles, made it much harder to see the workpiece prior to starting an arc. The distance between the shade and my face allowed light to enter from behind, causing a reflection, and further obstructing my view. Even indoors it was impossible for me to accurately see what I was doing if I had sunlight from a door or window coming from behind me. I eventually was able to set up my cutting table in such a position to keep most light sources in front, allowing me the visibility I need to accurately use the cutter.
I'm wondering if this shield is designed for more powerful cutters that cast a brighter arc. It's well made, provides great protection and works for grinding applications, but only work with my plasma cutter if I'm using it at the high end of it's 40amp range and I'm able to position myself without light sources behind me.