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TIG Straightening?

Posted: Sun Oct 27, 2019 7:52 pm
by Chips O'Toole
I just made myself a much-needed bench grinder pedestal. On a forum member's recommendation, I used Fireball Tool squares because I don't have much of a table. They worked very well. Not a panacea, but I would feel comfortable building a welding table base with them, and that's something I'm hoping to do.

Anyway, the bottom of the pedestal base came out very flat because I used the squares, but I was not able to clamp the base down when I welded the column to it. I didn't take my time, so the base bowed a little. I wasn't worried, because I figured I could use heat to straighten it.

I have a gas rig, but I still don't have gas because I'm waiting for a good deal on tanks. It occurred to me that TIG was pretty similar to acetylene, so I decided to try to do "acetylene straightening" with a TIG torch and no filler. It works great.

Is this a popular practice? I looked around and saw that other people do it. I'm amazed that I never heard of it until I thought of doing it on my own.

Really happy with the squares and TIG straightening. This pedestal came out great. You can jump on it and ride it around without flexing anything, and the base is flat and square.
10 27 19 dayton grinder pedestal 19 finished front.jpg
10 27 19 dayton grinder pedestal 19 finished front.jpg (67.04 KiB) Viewed 4181 times

Re: TIG Straightening?

Posted: Sun Oct 27, 2019 7:56 pm
by Poland308
Not uncommon to weld stringers on the backside of a pipe that’s warped to offset the warp from welding on a saddle.

Re: TIG Straightening?

Posted: Sun Oct 27, 2019 8:10 pm
by Chips O'Toole
The reason I picked TIG was that I didn't have to add filler!

Re: TIG Straightening?

Posted: Sun Oct 27, 2019 9:19 pm
by Coldman
I have used tig for straightening many times. Works great.
You mean to say you just did fusion welds on the stand? For mild steel that's a bad idea.

Re: TIG Straightening?

Posted: Mon Oct 28, 2019 6:29 am
by BillE.Dee
Nice job ,, Chips. Which fireball did you get...I'm thinking of getting at least one for starters
Bill

Re: TIG Straightening?

Posted: Mon Oct 28, 2019 11:20 am
by Chips O'Toole
I don't know if I would say I did fusion welds. I held the torch close to the metal until it started to liquefy, and then I moved on. I didn't try to join anything. There was no filler rod. I was working in an area where there were no welds.

I used a straightedge to see where the bends were, and I applied heat on the opposite side of the tube.

https://www.youtube.com/watch?v=enpTFs2NZkE

I bought aluminum squares. Here is my reasoning. Cast iron can shatter when dropped, and I drop things. Fixing a broken cast iron square would be hard. If I dent an aluminum square, I can add and subtract metal, and I can also put it on the mill to remove any extra metal. Also, aluminum is light, and there is no hope that spatter will stick.

I got the Mega Squares. They have a space so you can weld inside corners, and I knew I would want that. I got one in each size. I figured one would always be too small and the other would always be too big.

I'm sure a good metalworker can use scrap to make jigs that will work just as well, but I don't have access to my mill right now, and I don't trust stuff made from crude angle iron. I felt like treating myself instead of doing it the hard way. I expect to make my own jigs in the future.

Re: TIG Straightening?

Posted: Mon Oct 28, 2019 12:00 pm
by Chips O'Toole
This will give you an idea of what I did.

Also, an obligatory photo of my project.
10 27 19 dayton grinder pedestal 14 tig straightening pre-grinding small.jpg
10 27 19 dayton grinder pedestal 14 tig straightening pre-grinding small.jpg (209.88 KiB) Viewed 4078 times
10 27 19 dayton grinder pedestal 20 finished side small.jpg
10 27 19 dayton grinder pedestal 20 finished side small.jpg (232.13 KiB) Viewed 4078 times

Re: TIG Straightening?

Posted: Mon Oct 28, 2019 12:16 pm
by cj737
Chips O'Toole wrote:I don't know if I would say I did fusion welds. I held the torch close to the metal until it started to liquefy, and then I moved on. I didn't try to join anything. There was no filler rod. I was working in an area where there were no welds.
This is defined as a "fusion weld". And his point about mild carbon steel is exactly correct. These welds will not be as strong and prone to cracking on the edges.

If that happens, a little V groove grind down the middle, and re-weld them with filler wire. :)

Re: TIG Straightening?

Posted: Mon Oct 28, 2019 4:36 pm
by Ballistic308
cj737 wrote:
Chips O'Toole wrote:I don't know if I would say I did fusion welds. I held the torch close to the metal until it started to liquefy, and then I moved on. I didn't try to join anything. There was no filler rod. I was working in an area where there were no welds.
This is defined as a "fusion weld". And his point about mild carbon steel is exactly correct. These welds will not be as strong and prone to cracking on the edges.

If that happens, a little V groove grind down the middle, and re-weld them with filler wire. :)
This^^^, but for a grinder stand you will be fine.

Re: TIG Straightening?

Posted: Tue Oct 29, 2019 11:47 am
by cornmuse
From the pics, it doesn't appear that a little bow would be an issue. If it 'wobbles', shim the high wheels.

FWIW, I would (actually did) bolt plates on the front H's "aiches!" using the screws holding the wheels on, then weld a piece of pipe/square tube across to them. You can put your foot on it to stabilize the unit while in use.

-c-

Re: TIG Straightening?

Posted: Tue Oct 29, 2019 12:00 pm
by Chips O'Toole
The bowing didn't make any difference in the pedestal's performance. I just wanted to learn about straightening.

Re: TIG Straightening?

Posted: Tue Oct 29, 2019 7:38 pm
by Lightning
cj737 wrote:
Chips O'Toole wrote:I don't know if I would say I did fusion welds. I held the torch close to the metal until it started to liquefy, and then I moved on. I didn't try to join anything. There was no filler rod. I was working in an area where there were no welds.
This is defined as a "fusion weld". And his point about mild carbon steel is exactly correct. These welds will not be as strong and prone to cracking on the edges.
When he talks about "no filler," I think Chips is referring to what he did to "flame straighten" his assembly -- not to the actual welds joining separate pieces. In other words, he didn't add filler just as you wouldn't add filler if you did the flame straightening with an O/A torch.

Re: TIG Straightening?

Posted: Wed Oct 30, 2019 2:14 pm
by Chips O'Toole
Right. I just heated the metal with the torch.

The welds that hold the piece together are MIG, not TIG.

Re: TIG Straightening?

Posted: Thu Oct 31, 2019 11:09 pm
by Poland308
Any time you bring carbon steel up to its flowable point and don’t introduce filler then you will create a weaker point.

Re: TIG Straightening?

Posted: Fri Nov 01, 2019 11:43 am
by Lightning
Poland308 wrote:Any time you bring carbon steel up to its flowable point and don’t introduce filler then you will create a weaker point.
It also gets weaker when you do add filler, generally in the HAZ. But usually not enough to matter, or structures wouldn't be welded.

Chips, you don't need to actually liquefy the metal to flame-bend it...just get it hot enough to soften it temporarily ... orange or so ... and the cooler metal restraining it will force the heated metal to upset (thicken) and then when it cools down, it will shrink in length, causing it to bend.

Then you won't need to worry about "weaker points" ... or annoying pedantry.

Re: TIG Straightening?

Posted: Fri Nov 01, 2019 11:58 pm
by Chips O'Toole
The melty bits have more to do with lack of skill than ignorance.

Re: TIG Straightening?

Posted: Sat Nov 02, 2019 9:06 am
by Arno
Keith Fenner does a lot of (shaft) heat straightening on his YT channel. An example:

https://youtu.be/MtnkkAzRgP0?t=45

Depending on the amount of bend/deflection it may not even need that much heat and some rapid cooling to pull things back into line.

Bye, Arno.

Re: TIG Straightening?

Posted: Thu May 07, 2020 11:58 pm
by LeevaMark
I have 1) been burned by this phenomenon, when I didn't anticipate it. And 2) successfully used it to compensate the anticipated tube warpage that happened in the intended structure. In my case it was MIG, so I had to grind off the sacrificial compensation weld beads, but it worked out great and the tube structure came out almost perfectly aligned. Just plan on applying equal but opposite weld effected zones, in order to compensate. be as symmetric as you can.

Re: TIG Straightening?

Posted: Fri May 08, 2020 3:02 pm
by v5cvbb
What about just long arcing the tig torch? You may have some arc strikes but you can add heat without creating a weld pool.

Re: TIG Straightening?

Posted: Fri May 08, 2020 3:41 pm
by Oscar
Yea you can try that also, that will definitely heat up a larger area than using a typical TIG welding arc length,