Some questions from the new guy

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I had to weld together some pipe sections today to make a flag pole.They came up with some pipe about 4 inches wide,and probably 1/8" thick(Best they could do in the camp junk yard).I make a series of 1" welds completly encircling the joint (I'd post a pic but it's been painted over by now).I was using 3/32" E7018, 70 amps, the arc force was on 3,and the welder was set on negative ground.The welds seem to flow nice with the welder set like this.Ocasionally I'd burn a hole,but if ran the bead quick it wouldn't.My two questions are-Does this sound like the proper way to join these pipes,or was there a different method I should've used?Should I run a bead,chip,run another,chip....or just run bead after bead and chip when done? I started out running bead after bead,but didn't think this was correct and switched to run one,chip, run one.21st Century Mountain Man
Reply:It sounds llike you had things set right.  Was the weld done flat?  YES chip the slag away before making another pass.  They will tell you here CLEAN, CLEAN.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Yeah,it was almost flat.I tacked around the joint while it was on the ground,then had it leaning upon the table,so it was almost flat.I figured I was right about chipping first.21st Century Mountain Man
Reply:For structural joints it is better if you install a backing bar/sleeve.  That way you can fuse right through into the backing ring.  The ring can be made out of any scrap.  If you don't have anything handy cut off an inch of pipe then torch out a 3/4 slot.  Collapse it with a hammer and slide it in halfway.  Leave a 1/8th gap between the pipe ends.  Tack in three locations and then run your beads between.  If the pipe is bent at the joint run more weld on the long side and it will shrink over.
Reply:Originally Posted by lotechmanFor structural joints it is better if you install a backing bar/sleeve.  That way you can fuse right through into the backing ring.  The ring can be made out of any scrap.  If you don't have anything handy cut off an inch of pipe then torch out a 3/4 slot.  Collapse it with a hammer and slide it in halfway.  Leave a 1/8th gap between the pipe ends.  Tack in three locations and then run your beads between.  If the pipe is bent at the joint run more weld on the long side and it will shrink over.
Reply:Four inch diameter is nice and large.  I like to put pipe into a piece of angle to hold it straight while I am tack welding.  For your diameter of pipe you need a three foot or longer piece of five or six inch angle.  Several C clamps will hold it while you tack.  Large channel or beam will also work.  Just relax about it being perfectly straight.  After welding it is likely to have moved.  You can still shrink it with a torch.  Heat the bead red on the long side while holding a wet rag against the opposite side.  Let it cool then check again with a straight edge.
Reply:Thanks for the one about the sleeve lotechman.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:I got it decently straight laying on the ground,which is amazing considering the ground is 1/2 inch gravel.I did lay it in a piece of channel at the joint,and sighted down it length wise and it didn't come out too bad.It was a very quick job,but all of your good ideas and advice I can keep in my tool box for the next project.I'm currently building a replacement truck bumper,but I have get the photos cleared with our intel guys before I post anything.That's going to be another thread though.21st Century Mountain Man
Reply:You could still strengthen the weld area by grinding the weld flat, cutting a ring of the pipe you used, if there is any left over. Split one side of it so it is able to spread open a bit. Slide it up the pole, over the weld and weld the ring to the pole. You'll be able to see it but it will help to reinforce the area._________________Chris
Reply:They've already got it on top of the building and sandbagged down.I'm certain it's not going to come apart,but if I'd have know about the inside pipe trick I'd have taken the extra time to do it.It's typical I need it yesterday military stuff,but I did my best not to rush through the welding portion.I do have confidence in my welds,as I built a satellite dish stand for my internet dish that's survived super high winds,and hasn't budged at all.Also,I'm getting low on the rods I used and the supply system to get more is beyond useless...other wise I would do it.I wish I could've posted a pic of the welds,as I wanted critique on those as well.They weren't the greatest looking but I got decent penetration.It sucks when you're the only guy that knows how to weld and you're trying to learn yourself.Last edited by vtmtnman; 05-13-2007 at 01:39 PM.21st Century Mountain Man