lastcowboy32
Well-known Member
I posted some questions about this project a week ago. I have my pieces cut and mostly coped out with fishmouth cuts. Right now, I'm at the point where I'm starting to weld up some of the frame.
I have 4 inch diameter tubing with 1/8" wall thickness. I need to make some perpendicular "fishmouth" joints with this. I welded a test joint at the end of a piece, so I could look into the end and see the penetration. I'm not in love with it. My little wire-feed welder is supposed to be able to weld up to 3/16." This tubing is 1/8" thick.
I took a scrap piece of tubing and laid a bead on it, indeed the welder could blow right through; if I sat on one spot too long.
However, when I butt two pieces together with one of these fishmouth joints; there is no way that I can lay a bead in the joint and penetrate both pieces. I'm wondering if that's because that would be equivalent to welding 1/4" material?
The only spot on my test joint that showed penetration was a spot where I welded by concentrating on the parent piece (not the fishmouth). I laid a bead right onto that, which built up toward the fishmouth piece. It then took two more beads to fill the joint. The last bead did seem to complete the fill of the joint by melting the previous bead and the end of the fishmouthed pipe.
Is that a good way to make a big joint with a little wire welder?
Would preheating with a torch make things better?
I have some pictures showing an example of a dry joint before final grinding to cope and a welded test joint.
Note that there is galvanization involved. I grind all galvanizing off before welding...I do that outside with a respirator...so I'm OK with that. It's strictly the joint size that's bugging me up.
I have 4 inch diameter tubing with 1/8" wall thickness. I need to make some perpendicular "fishmouth" joints with this. I welded a test joint at the end of a piece, so I could look into the end and see the penetration. I'm not in love with it. My little wire-feed welder is supposed to be able to weld up to 3/16." This tubing is 1/8" thick.
I took a scrap piece of tubing and laid a bead on it, indeed the welder could blow right through; if I sat on one spot too long.
However, when I butt two pieces together with one of these fishmouth joints; there is no way that I can lay a bead in the joint and penetrate both pieces. I'm wondering if that's because that would be equivalent to welding 1/4" material?
The only spot on my test joint that showed penetration was a spot where I welded by concentrating on the parent piece (not the fishmouth). I laid a bead right onto that, which built up toward the fishmouth piece. It then took two more beads to fill the joint. The last bead did seem to complete the fill of the joint by melting the previous bead and the end of the fishmouthed pipe.
Is that a good way to make a big joint with a little wire welder?
Would preheating with a torch make things better?
I have some pictures showing an example of a dry joint before final grinding to cope and a welded test joint.
Note that there is galvanization involved. I grind all galvanizing off before welding...I do that outside with a respirator...so I'm OK with that. It's strictly the joint size that's bugging me up.