Hello and a few Oxy-Fuel Questions

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  #1  
Old 10-24-05, 04:15 PM
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Hello and a few Oxy-Fuel Questions

First off I'd like to introduce myself. My name is Spencer Michels,im 19 years old and I'm fron St. Hgts.,MI. For the past two years I have been heavily interested in Automotive Studies. I took a year at the local comm. college of Automotive, recieved 4 certs and decided to take another year this year. I started getting into welding this summer and took two welding classes with the auto ones. I've been having a blast and recently bought a Lincoln Weld-Pak FCAW welder.

Now in this welding class we started off with Oxy-Acet welding. I didnt exactly pick-up on the whole concept till the 4th week. I was moving way too fast and finally after sitting there frustrated held the torch in the same spot and saw it start to spark a little. I grabbed the filler and really did some [email protected] beads.

I went into class today very excited that I finally somewhat know what im doing and today was informed that we'd be doing butt joints. We were instructed to use a piece of filler rod as a spacer and tack the two ends. This is where I first started having problems.

1) I had a very hard time tacking the two pieces together without making a molton pool of metal below the two pieces I was welding. Once I managed to get a decent tack on both sides I started a molten pool and began adding filler rod. I had finished welding the pieces together and looked underneath. My guess would be 50% penetration. Some spots came all the way through while others only about halfway through.
2) This may be related to the problem above but I was told i would see a "keyhole" where the molten pool was supposed to be. ex. =o======
I did see this "keyhole" but it wasnt on both sides of the joint, instead it was only on one side. My guess is that I had the torch at an angle and not directly above the joint equally. I am also thinking that if I could have started and maintained that keyhole over both pieces of metal that the penetration would have been better as the whole piece was molten.

And to top everything off, the acetylene guage started on fire while I was welding and that made me a little uneasy afterwards.

We were welding 1/8x6" mildsteel with rg45 filler. Im sorry, but i dont know the dia. of the filler rod.

If anyone can shed any light on #1 or #2 it'd be greatly appreciated.

I am very excited to find a welding forum(not many out there) and hope to stick around and learn as much as possible.
 
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  #2  
Old 10-25-05, 09:19 PM
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I learned on my own, what I picked up in Hi school was not much. you may know more then me.
Most of the people on this site and me use arc welders its a lot faster.
Not a lot of people do gas welding, I use my set up more for cutting and heating to get nuts off or welding an exhaust pipe.

Going from MIG welding to Gas is going to take patients.

I did some gas welding in hi-school a long-long time back.
After I got my own gas setup, I found out you need to turn up the pressure on the regulators and use a larger tip to get good penetration.

You may need to adjust the pressure.
Its slower then arc welding you need to take your time and heat both pieces.
I use 1/16" and 3/32" rods.
If the metal gets to hot I try to keep the rod in front of the tip. if you over heat the tip you get that backfire.
 
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Old 10-30-05, 08:15 AM
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Many years ago I was very proficient with a torch. I would weld 16-gauge sheet metal and thicker with 100 % penetration. And also 2 inch and 3 inch pipe in all positions with 100 % penetration. I am sort of rusty on doing the actual work but could pick it up again if I had to. Without watching what you are doing I would guess you have a little too much heat while you are tacking the pieces together. Move the flame back and forth across the two pieces until you see them molten then add a little filler rod. On a six-inch piece I would tack it in the center also. Sheet metal likes to move around a little. I am sure your instructor recommended a tip size for your 1/8-inch material. If you are not getting 100 % penetration you need a little bigger keyhole. You might need to weave the torch back and forth across the two pieces to get them equally hot, just a little. A lot and you will have a big mess. You can regulate the heat from your tip to a certain point by increasing the acetylene or decreasing the acetylene and adjusting the oxygen accordingly. If you decrease the acetylene too much your tip will pop and blow molten metal out of your joint. It is time then to go to a smaller tip.If your tip is dirty it will pop also, keep your tip clean. If your instructor can do it have him watch you and tell you what you are doing wrong. Then have him show you and explain what he is doing. I have seen where someone can watch and not catch on to everything the person is doing. You will need practice, welding is not something that you can do once and be perfect at it. Practice does not make prefect. Perfect practice makes perfect. Good Luck
 
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