Sliced Tubing

I'm looking for some advice. I sliced some 1.5"x1.5" tubing to allow it to match a curve. I'm looking for some advice on getting it welded back together. The gaps look large on the bend axis for welding. What's the best way to get this tubing and gaps welded back up?

 

By Sliced, do you mean long ways or crossways to the tube? If it is cross ways I do it all the time and while the gap at the outside of the bend is large as long as tack the gap and move to the next and fill it all in slowly you shouldn't have any problem. Then sand the weld smooth. Good luck.

 

If you sliced on the outside of the bend, that might be why the gaps are too big. I don't know if I've ever seen it done that way. Usually, it's little piecuts inside the bend.

 

I sliced thru 3 sides of the tubing. This was done to allow me to bend it. However along the bend axis the cut open up leaving a decent sized gap. I'm looking for advice on how others handle this gap and get the tubing welded back solid.

 

First question -- gas, arc, MIG or TIG?
Second question -- structural, exhaust or decorative?

When I've got a gap to fill I've used another piece of welding rod (usually a stub with the flux knocked off) as a filler rod. Tack one end, then the other, then fill what's left of the gap. Inside won't be pretty, but if that's not important it'll get the job done.

With MIG I'll just make short welds, just enough to get a puddle, then stop and let it cool and hit it again.

Or you can cut a piece to fit the hole, tack it in place, and build from there.

 

Personally I don't care for teh "pie cut" method unless it's a pretty gradual bend you're after. To often to get it to look right you end up with so many pie cuts that you eithher have big gaps like you mention or if cut from the other side you get welds so close to one another that it's nearly all weld when you're done - not necessarily the hot ticket especially if it's a structural member.

I much prefer sectioning the tubing - you get less welding and it's easier to finish IMHO.

 

I'd be asking why didn't u just bend it and what r u using it for? my thoughts would be to use a mig if possibly working slowly filling the gap webbing it across making sure it dosent get too hat and melt inwards.

 

Wild Turkey-
1-TIG
2-Structural. It's a piece for the subframe.

HemiRambler- That's I nice looking piece. The problem is my piece follows the contour of the back wheel well. Large continuous curve. I've seen pic's of other people on here who have done similar work. Just unclear on how they fill the large gaps along the bend axis.

 

I'd guess they normally cut from the opposite side - removing litt'e "wedges" and then bending them together. If your'e already comitted, and this is structural, personally I'd go ahead and just remove that piece altogether(that has all the gaps) and replace it with a "cap" that you weld in - similar to my example except on the other face.

 

With square tubing, you can collapse the inside wall which gathers up the material, effectively shrinking, in order to make a curve in the tubing. Use a punch to put a dent or series of dents in the inside wall, then weld them up when you are done. Practice on some scrap first to see the effect of the welding on the curve.

Another method is shown in Ron Covell's video "Working with Tubing" www.covell.biz He cuts the tubing in the middle along its length and bends the inside section first, then bends the outside section to follow it, and welds it back up. You can use a torch to heat up the metal making it easier to bend. The outside section has further to go so you have to add some material after you go around the bend.

John www.ghiaspecialties.com

 

I used that method to fab a grille guard like the one in this picture. Works very well. I picked up the idea from an article in one of the Rod mags.
Used a plywood bending form to get the radius/diameter correct and consistent on all bends.
Easy as pie...and once welded and ground is undetectable. Use longer than needed tubing to allow for the amazing "shrinkage" of the outer length.

 

Covell is brilliant, has some outstanding methods.

 

I think alot of them don't use tubing. They cut plate the same wall thickness as the tubing into the shape they want and then weld up a tube like structure with plate as the top and bottom caps bent to the same contour as the pieces they cut. Like this example from Eddie's Chop Shop Build.

 

Can you take a picture of it?? I'm still thinking that you ended up cutting the outside radius instead of the inside - you shouldn't have large gaps - unless you took some oversize pieces of pie


John Kelly - have you used "Covell's" method for bending tubing - cut it length wise instead of the pie cuts? - It seems like less work to me than the pie cut method.
My question is when you cut it lengthwise - do you lose some of the "height" of the tubing - or do you leave a slight gap so that the tubing stays the same dimesion 1x1 instead of 1"x7/8" (1/8" Cutoff wheel or whatever)

HemiRambler - do you have a mini-tech on the steps you took to do that? - I understand "sectioning" the tube - but how did you make the inside radius piece?

 

Arkracing, I actually used the same piece of tubing that I had cut out because I wanted the corner radii to match. I just sliced it close to the edge so it was easy to bend.

 

Here's a pic of what I did.

 

You made the slices on the outside of the radius. If you make the cuts on the inside, the gaps will pull together as you bend the desired radius, leaving only small gaps to weld

 

mosimpson, I'm no expert, and I'm sure someone will correct me if I'm wrong. If I were going to make that piece, I'd make my cuts through 3 sides and all four radii. It looks like that's what you've done. But then I'd bend it the other direction, so the uncut side of the tubing is on the outside of the arch. That way, the largest gap you would have to fill is the width of your original cut. Make sense?
The big drawback is that you can only bend it so far before your cut is completely closed on the inside of the arch.

 

OK - so if I understand the filler piece is actually 3 seperate pieces? - you used the tubing for the inside radius and then cut out the side from some flat steel?


mosimpson - yeh you made the cut on the wrong side of the tube - flip it over and see if it is close to the radius you need - you might be able to fix that piece of tubing - or it might be easier to start over.

 

Hi Arkracing,

I have not use Covell's method, but if you use a thin cut-off wheel the loss of dimension will be small.

Looking at the picture mosimpson posted, I would have done the other method I mentioned of collapsing the inside wall with a hammer and punch in order to shrink the inside radius. No cutting and a lot less welding.

John www.ghiaspecialties.scom

 

Yes, 3 pieces. It's hard to see, but if you look close in my first pic you can see one the top I had only welded 3 edges - the 4th edge (closest to the edge of the inside piece) has yet to be welded.


I'd like to try Covell's method as I wonder how easy/hard it would be to control the edges from pulling in/out. It sure sounds like a neat way to make a realy nice swoopy bend.

 

You can either trigger your welds and build those gaps back up but that'll take forever.
Cut some little pie pieces and fit them in before welding... or, some 1/8' wire. Anything to build your weld on.

You'd have been better off, as stated, to cut it on the inside radius... or just flip that piece over...

JOE

 

Thanks - I didn't see the gap between the inside radius piece and the side pieces in the pictures @ first.

I would also like to try Covell's method - my main concern would be losing the tube demension - espcially if you clamped them together for a tight "Tig" gap. - Or can you close a .035" gap with using the TIG???
the Mig would be ok filling in the small gap - but would be a pain to grind and make it look "natural"

 

Hemi:

Were you able to fill these gaps using the TIG?? - I assume that is what you were welding with anyway. If so than maybe Covell's method wouldn't be that bad. I thought that it would be hard to fill a gap like that

 

Yes, I TIG about 95% of what I do.

For this the gaps actually appear bigger than they really were as I purposefully ground everything to a bevel so I could be sure I burned the weld completely through the tube (knowing that I would later grind them flush) you may also notice that on the welds that are visible they are near flush to begin with. I normally don't advocate grinding welds (too easy to get into trouble) but IF you do grind them - then it is my personal opinion that the initial weld ought to be done such that you are removing VERY LITTLE of the weld metal - less than 10%.

Back many years ago I was talking with the owner of a chassis shop. He told me his rule of thumb was to keep the gaps smaller than 1/16" - since that was the diameter of his welding rod. Always seemed reasonable advice to me. I do try to keep my fitups much closer than that, but ocassionally circumstances don't allow super tight fits. I've had this happens when working with round tubing.

Filling .03 gaps - is a piece of cake - MIG or TIG - when working with metal of any thickness. Gets more challenging when you're working sheet metal though.