Thursday, May 2, 2013

Chair Repair

The chair I use finally broke due to a serious design flaw I saw coming from a mile away.  As illustrated below, it has a geometry for weight distribution that puts all the stress on the weld joints on the front.  This would only be a problem if the manufacturer used paper-thin tubing, and they did.  Also, I had taken off the back of the chair and have been sitting on it backwards which may have added to the problem.
The breaking point
I'm pretty sure it was designed this way on purpose per planned obsolescence, or to give it a nice "spring" effect, but I have a welder and can show them who's boss.  If I had paid any money for this chair, I would want it back.

My solution for this was to weld some pieces of 1/8" plate to either side to support the "back" of the chair as well as re-welding the cracked area.
The potato peeler was not part of this project

After cutting the pieces, I took the welder outside and got to work.  I had a really hard time maintaining an arc to weld, probably because of the massive power requirement to weld.  At max setting, which I was running, the welder would draw 26.6 amps from the 115v circuit, and the highest rated circuit breaker in my apartment is 20.  I should have at least tried lowering the amperage setting to see if that helped. 
I tried 3 different welding electrodes.  For those unfamiliar with welding jargon, an electrode is a  metal rod coated with protective flux to prevent oxygen from contaminating the weld.  The rods performed as follows:

E6013: moderate success
308 Stainless: low to no success
E6011:  wouldn't maintain arc

This is a shame because 6011 is one of my favorite electrodes, I like how it welds and how it smells, gotta love that cellulose and potassium.  Anyhow, I would like to thank Arclight from 23b for donating some electrodes, otherwise I would've bought a case of 6011 only to find out it wouldn't work.
After welding on one of the supporting pieces, and flipping 2 circuit breakers in the process, I called it quits.  The chair works and I'm happy with, even though it isn't pretty.  It also is a bit sloped upwards because I didn't cut the plate too accurately.
To add insult to injury, I threw on a terrible coat of white paint.


The chair after repair was so slanted, it was really uncomfortable to sit on.  Remember kids, measure twice, cut once.  As for now, I'll be using the welder as my chair.

In the American spirit of solving a problem that was caused by solving another problem, I stacked a bunch of shims under the back chair legs to make it level again.  I feel stupid for not realizing this earlier.

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