welding on pipes and where to go from here

[emzdogz]

Hi folks, could you give me your opinion as to how to proceed? My left pipe I was able to lengthen by just adding one section. (2 bands of weld to attach) but the right side pipe has been more difficult and I've had to add 2 shorter lengths, meaning that it had to be welded all around in 3 bands.
At this point, some of it is welded nicely, and grinds down so the metal is continuous from original pipe metal through weld and on to orig pipe. i.e. it grinds down seamless. (if a bit lumpy)

Still, some crevasses remain that I just can't seem to get to weld - PLUS I think I've actually made a small hole or 2. (by burning through)

I think I'm using too large a size of MIG wire. I just can't seem to get nice small flat welds. I'm wanting it to look like nice TIG welds, and I know that won't happen, but in order to end up with good penetration that grinds down to seamless, I have to apply these big blobby welds. Am using CO2.

How else could I fill these remaining holes? Besides welding over and grinding down? I could see doing that on the thin cracks, but not sure how to fill the holes.

I don't mind the lumpy appearance...I like it in a way, looks like someone suffered here a bit, lol. But of course I can't have holes or cracks. I would just keep on and on the way I've been doing, but am afraid to destroy the pipes.

Thanks!

here are a couple of pics:

 

[Inked Monkey]

You should be able to just weld it up. Have you messed with the heat and speed of the wire?

 

[emzdogz]

You should be able to just weld it up. Have you messed with the heat and speed of the wire?

yeah, I have. Maybe I should just keep at it.

thx

 

[Inked Monkey]

I just stitch weld thin areas to prevent blowing holes. Little tack welds overlapped with adequate cooling time between.

 

[emzdogz]

I just stitch weld thin areas to prevent blowing holes. Little tack welds overlapped with adequate cooling time between.

thanks, I will give that a try.
Do you grind more or less each time you do a weld? (after cooling etc)

 

[Travis]

MIG is great for filling in holes. The thinner the material the harder it is to fill the hole though obviously. Those should be no problem with the right settings. I would just keep at it... weld over all the holes and cracks a little bit at a time, then carefully grind it all down again.

What size wire are you using? I would probably use .024" wire for that job.

 

[emzdogz]

hey Travis, thanks for chiming in. My wire is .025. I think I just ran out of gas today so I may be done until Monday now anyway.

 

[angus67]

all good points, but remember, the more you grind, the thinner that tube gets.
your doing a great job. keep at it. I had the same problem. if there wasnt people around when I kept burning hole thru, I probably wouldve taken my pipes intothe woods, and wrapped them around a tree. it is frustrating as all hell, but you'll get it.

 

[Teebs]

You should watch how much your taking off the pipe. I circled what looks like a fairly significant low spot.

Just remember that you can get straight lengths of pipe at any real auto parts store, so keep at it and if all else fails, you can chop that section off and drop 20 bucks and get 10 more feet of pipe... Never say die!

 

[angus67]

isnt most of that stufff at the parts house galvenized? tricky to tack weld galva.
go to a metal recycler.

 

[Teebs]

LOL I said a REAL auto parts store. Go to a NAPA. They usually have 10 foot lengths of mild steel in 16 gauge in 1.5", 1.75", 2", 2.5" etc.

Metal recyclers are great if you have access and if you can find what you need. I usually tell people to go to a parts store because the pipe is reasonably priced and always available. More and more scrap yards are limiting access for liability reasons and not all areas have actual "recyclers".

 

[kent_in_kc]

Got acetylene? Braze the holes shut, dips and crevasses too. Sand it down with 80# aluminum oxide, then 400# to finish. Don't know how to braze? You Tube it.

 

[Fatman]

you can use a brass rod (punch) to backup weld, brass won't melt as fast as steel. old farm trick.....

 

[emzdogz]

thanks again to everyone who responded.

 

[MOFOKKER]

After you weld it, wrap it with header wrap..

 

[rezsst]

tig weld it, purge with 5psi argon, sand flat with 120 grit than buf to mirror finish then recrome

 

[olddude13]

Try to hold tip at slight angle not straight at seam my help on blow through

 

[Ebola Monkey]

I'm no welding expert, in fact I'm a complete beginner.

I have welded 1/2" EMT conduit for practice though. It's a much thinner wall than the exhaust tubing you're welding. I turned the welder down almost all the way as well as the wire feed speed. I made a series of ~2 second tacks when I was having trouble with burning through.

Might be worth a try.