3/8 wall pipe T joint tips

BigD · Wed Nov 02, 2016 8:40 pm

Hey guys,

Could you give me your suggested procedure if you needed to join a 2" schedule 80 pipe (the one being coped) to a 3.5" 3/8 wall DOM tube? Also settings, passes, amps, tungsten, filler?

Currently my plan is to get a good fit with the fish mouth/coping and bevel it back and do multiple passes. I have a pile of 3/32 ER70S-2 but I can go get 1/8 if you guys recommend it instead. I'd use a 1/8" 2% lanth electrode with a lens.

I would especially appreciate amperage recommendations. The machine is a Dynasty 210DX and no water cooler so I don't have enough jam to do it all in one hot pass.

Thanks in advance!

Poland308 · Wed Nov 02, 2016 9:50 pm

The 3/32 should work fine. If you have it bump up to 1/8 for the filler passes. I'd start out with the 3/32 at about 120-130 amps. After 2 or 3 passes I'd bump up to the 1/8 and if the pipe is still hot you might not have to up the amperage. If it's totally cool then you might be able to go up around 150. If you keep a tight arc. Watch your interpass temps it's easy to get rammy on heavy wall. Usually it only affects quality but there's potential to warp things or stress crack things if you rush. Don't worry about how many passes it takes. Just layer it in.

BigD · Wed Nov 02, 2016 10:03 pm

Thank you, Josh!

Poland308 · Wed Nov 02, 2016 10:13 pm

Any time that's what makes things here work.

Rick_H · Thu Nov 03, 2016 7:09 am

Josh is right, just make sure you get a good solid root, make sure you start with nice clean shiny metal. Just stack the beads in or walk the cup.

BigD · Thu Nov 03, 2016 9:24 am

Rick_H wrote:Josh is right, just make sure you get a good solid root, make sure you start with nice clean shiny metal. Just stack the beads in or walk the cup.

Will do! I'll clean up both sides nicely. Walking the cup is still on the to-do list of skills to learn

Hey for the 3.5" pieces, I'm going to cap one end with 3/8 plate and it will also be load bearing. I'm torn on how to cut the cap. The tube sections are 3.5" OD with 3/8 wall so 2.75 ID. Should I cut the cap to 2.75 and fill in the 90 degree cutout, or cut the cap to 3.5" and bevel it down to 2.75, and bevel the top of the tube (don't know if I'm describing it right, so the joint looks like either a top hat vs hourglass).

Boomer63 · Thu Nov 03, 2016 11:01 am

Hey for the 3.5" pieces, I'm going to cap one end with 3/8 plate and it will also be load bearing. I'm torn on how to cut the cap. The tube sections are 3.5" OD with 3/8 wall so 2.75 ID. Should I cut the cap to 2.75 and fill in the 90 degree cutout, or cut the cap to 3.5" and bevel it down to 2.75, and bevel the top of the tube (don't know if I'm describing it right, so the joint looks like either a top hat vs hourglass).[/quote]

This might not be the best description, but here goes! I would cut the cap so it was just equal to the inside diameter of the pipe to be capped. Then, holding it with a magnet or a piece of weld rod tacked to it, I would place the cap piece so that edges of the cap matched up with the edges of the pipe to be capped. I would be looking to form an outside corner joint. This way, you will get full joint penetration and should be able to fill out the joint with a nice looking bead that will take minimal grinding to detail - if you do it right!

I have always done those types of caps that way. They were always water tight, air tight and look fairly decent. I have welded them with stick, wire and TIG, but liked doing it with TIG the best. Lately, I have discovered the easiest way to do this is to have one of the students do it for me. Or not.
Gary

BigD · Thu Nov 03, 2016 12:00 pm

Sounds good, thanks Gary! Yeah I gotcha, that's the "top hat" version I was considering. That's the one I was swaying towards as well.

BigD · Thu Nov 03, 2016 10:30 pm

Going well so far I think. Definitely need to invest in a cooler.

What do you guys think is this ok or a few more beads?

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Poland308 · Thu Nov 03, 2016 11:04 pm

That looks pretty solid. You should only need to build it up more if you want to round it off. Or if you need enough material to make it look like it is one piece.

BigD · Fri Nov 04, 2016 8:23 am

Perfect, thanks! No I just need it to be a strong joint. There will be a 2" sched 80 pipe between these two sockets and the sockets will go over hoist pad extensions, to allow my hoist arms to swing out wide and for my wife's SUV to fit under the racecar (one end of which will rest on the pipe). I'm sure it's overkill times three since the car weighs 2500 lbs wet and that end will have no wheels and engine removed so its probably holding up 700lbs or so

Boomer63 · Fri Nov 11, 2016 11:09 am

Hey Big D!! Looks like "game on" to me!! I also like describing the joint as a 'top hat'!

Carry on, brother!
Gary

BigD · Sat Nov 12, 2016 8:20 pm

Thanks Gary! She's ready to go but getting the cups to stay aligned while tacking was a challenge. Can you guys share your tips for this? I got it to work but it almost screwed me up. I tacked it on the sides and I assumed it was ok on the vertical axis because the tacks were horizontal but I must have tacked off center because it pulled the cup in vertically. I noticed it last second and hammered it straight but its wild how much it pulls and after it does and you tack it on 3 of the 4 sides it's pretty set... do you align things offset with the pull in mind?

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Rick_H · Sun Nov 13, 2016 9:05 am

Tack, adjust, adjust some more, tack, measure, measure again, swear, drink a beer, repeat..lol

A fixture would help but you still need to check, everything moves. When I do stainless frames Inset it off a few degrees since I have figured out how far it pulls. Planning out the tacks is critical, and I prefer at least a 1/2" long tack.

BigD · Sun Nov 13, 2016 9:12 pm

LOL thanks Rick, yeah that sounds like my algorithm is correct, that's about how it went for me

BigD · Tue Jan 03, 2017 10:20 pm

Just wanted to show the finished product finally installed. It was to hold up my end of the bargain where I got to claim the other side of the garage as a workshop if I could provide a way for my wife to park the truck under the hoist in the winter. Needed to get the racecar higher up and the rear arms out of the way.

"Stack em, pack em and rack em"

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