Pyrolosis: Standard Testing Labs:

Date 03-01-2010 19:52

http://www.youtube.com/watch?v=jBUVzgCHHuA

Over the past thirty years of welding and fabricating I have seen many accidenents! I've had a few accidents myself, but nothing too serious to stop me from my trade. When I was a senior in high school, I was going through the vocational training and my only real class my senior year in high school was english. I went to school at 8:15 and got out at 9:15. I was at work at the trailer factory by 9:30 everyday. By working on Saturdays I was able to hold a full time 40hr week and complete high school. I built every single part that went on a horse and stock trailer. I built the frames, topped em, measured, modified and installed axles, wired em, painted them, uphostered them. We made horse trailers with sleepers and did some specializing in the cabin area. We made the highest quality, best looking trailers in the country and we transported them from New York to California. I worked there two years before I went into the Air Force. The reason I learned so many different parts is because the boss was hard as hades. He was always telling me what to do, and if I didn't know how or understand he would show me once. He was good and fast.

One Saturday we were building trailers and I was going over the outer body/frame of a stock trailer with a 6" grinder with about 80-100 grit six inch disc. You had to be careful because if the disk wedged between a joint then the grinder would shoot back at you, and try to undress you if it ever got wrapped around your clothes. I saw one rip a guys shirt half off before he could get it stopped. Well, I'm sanding the sides down and the disk gets caught between a piece of square tubing and the sheet metal side as I was reaching over head as high as I could reach. The butt/head of the grinder hit my hard hat and knocked me silly, slinging the hard hat across the room, then the disc spun around and caught me right across the mouth and chin. Busted out two teeth and cut my bottom lip and chin about halfway down. Had to have several stitches. I ran in the bathroom and turned on the water and my face was a mess with blood and I looked in the mirror and it just made me sick, my two front teeth gone. The grinder in the meantime was out on the floor in the shop just dancing around looking for it's next victim. Since this was Saturday, nobody else was around to witness what had happened, the boss was in the office, and his son the foreman was off in another room. I guess he heard that grinder bouncing around or something and he ran in there and wanted to know what the deal with the grinder was, then he took one look at me and freaked out. He unplugged the grinder and took me in the office where they contacted my dentist and took me to his office. The dentist fixed me up, thankful for workmans comp, got new teeth out of it. That was my very first welding related accident short of a few burns and scratches.

I have welded many rims and wheels in my career, and never not once was I ever inclined to weld on a rim/wheel with the tire still on it. First of all, if a rim is leaking air from a crack, you really need to get to both sides to properly repair it. If one thinks he's going to get a really good weld with the tire on, then he's got some lessons to learn. Watch this safety video about Pyrolosis. It's what happens to the tire when you attempt to work/heat the rim.

Take Care,
Steve

By DaveBoyer (*****)

Date 03-02-2010 03:17

So dangerous You have to wear a hard hat just to talk about it...

I will send this vid to a few friends who might be inclind to weld on a wheel.

By mtlmster (**)

Date 03-03-2010 11:47

Yea Dave! I had those old fashion goggles, you know the type that are round and seal around your eyes, and the head strap was running thru and tied to my hard hat. When the head of that grinder popped me on the forehead, it knocked off my hat along with my goggles. I don't think I ever found the goggles after that. It was actually pretty traumatic. Maybe that's what's wrong with me today. Knocked me senseless! I know one thing though, if I had not been wearing the hard hat, I would have been pushing up daisies a long time ago. Guess It just wasn't my time to go.

Take Care
Steve

By 803056

Date 03-03-2010 16:31

This video is excellent. I wonder how many times something like this has happened on stock cars, tractors, etc. where there was no injury and no one really understood what had actually happened.

It is something I have never seen or experienced and hope not to.

Best regards - Al

By low_hydrogen (**)

Date 03-02-2010 15:13

http://www.youtube.com/watch?v=pNZ4siYGkag

Here's a good one also

By Lawrence (*****)

Date 03-02-2010 15:38

The host said it all:

If a welded wheel or rim ever fails, experts will agree that the wheel or rim should have never been welded in the first place.

By mtlmster (**)

Date 03-02-2010 19:56

Your right! Man how far did that test dummy fly??? Let me clarify also, that when a person brings a steel rim to me I simply tell them to go to the salvage yard and get a new one. It's actually cheaper to buy a new/used rim than to pay me my welding rates. It's not even economically feasable to try and repair them. Steel rims are very brittle and the heat/cooling degrades that portion which has been welded. On the other hand, I have successfully repaired many aluminum rims. The first one was from a guy who raced stock cars. He was running aluminum rims and had contact with the wall or another car, I'm not sure. Broke a big chunk out of the bead area. About 7"-8" busted out. This was back in "76" and I was getting pretty cocky with my aluminum tig, but I told him no. I tried to convince him to do something else, but not weld on it. He said he had checked every salvage yard in town and couldn't find the one he "had to have". He practically begged me to try! I told him if he could find another rim with the same shape of inner/outer bead area?, I don't know what that's called?, That I could try and add a new piece in. Well to make a short story long. He came up with another rim similar, close enough to match. I cut out the piece to match the cavity of the broken one, beveled everything and welded it with 4043. Front and back. Then I filed the part where the tire has to seal and shaped it to conform with the original shape. Sanded it down real good and left the bead on the front side, untouched. Aluminum is always stronger if you leave as much build-up as you can. That's why in most cases doing repair aluminum you want to have a not only good weld but also a pretty bead so you don't have to grind a mess away.

Anyway, he put the wheel back on his race car and ran it every week for the entire race season and the rim held out just fine. It held air, and never broke. I would check with him about every couple of weeks or so and he would tell me it's working fine. I admit I was a bit nervous never doing it before, and I was never sure it would hold. To be honest, I figured it would break after the first race.

I don't know how many aluminum rims I've repaired since then, but it is many, and have only turned a few away. These newer ones aren't as easy to work on as the older ones. These new rims are higher alloyed and a lot harder than what they used to make. Also a lot of these newer rims are harder to shape and file. I'm thinking the last rim I worked on I had to use 5356 as a filler. The rim was as hard as steel, almost. I don't feel real comfortable with those. I'd need to see some more successful repairs on them in order to feel confident in it's repairability. Also on the harder rims it's better to send them off to a machine shop so they can turn it and get it perfectly round. I don't have that capability. Actually, every wheel should be done that way. But sometimes people don't care how it looks, just as long as it holds air and they can get there 350 dollar rim fixed for 50.00, is a pretty good pursuader.

Take Care
Steve