Welding without warping

[mitch_04]

Not sure quite which section to put this in, but since the idea behind the question is based in frame tables and frame assembly I figured the chassis section would be a good start.

Alright, during my research for frame tables I've seen, repeatedly, that fully welding is frowned upon to keep the warping down. Completely understand, makes a ton of sense.

Next, I see Roadster Shop build their frames out of plasma cut sections welded together and ground smooth to look as if it was made out of mandrel tubing. Obviously they are on another level compared to me... or a completely different building! However, I have to wonder....

How do they keep their frames from warping at all?

I picked up an issue of Street Rodder (Kindle be damned, I love paper magazines) and inside they showed the Roadster Shop's build of a frame for their car. The had pics where the frame was marked every 5" or so and numbered repeatedly. 1, 2, 3, 4, 5, 1, 2, 3, 4, 5.... you get the idea. It looked as if they would weld all the 1's, then 2's, so on and so forth.

I do have access to a plasma table large enough to handle frame sections, but I'm not sure I trust myself to weld such a frame without warping.



Cliff Notes - How does Roadster Shop (or any others) manage to weld together an entire frame from 4 (or more) sections of steel without warping?

Link (Couldn't find the pic with numbered sections) http://www.hotrod.com/events/coverage/1402-roadster-shop-chassis-2014-amsoil-street-rodder-road-tour-chevy/

[GregWeld]

I can't answer for The Roadster Shop.... but I will say there are several things to take into consideration when welding almost anything. CLAMPING is critical... and all welding EXPANDS first - then shrinks / moves as it cools.... if you know this then you can weld in such a way as to pull the metal back into shape. Take a T weld -- you weld on one side - it pulls - you weld on the other side - it pulls back... Obviously this is oversimplification. CLAMPING - Then Tacking - Then skipping around so that you have counter forces working to help you.

[Vince@Meanstreets]

practice practice practice.

Get a bunch of scrap and try different techniques and weld sequences. A tight fit also makes it easier.

[mitch_04]

I wish I could watch Roadster shop do what they do. I understand welding expands and shrinks metal, it's a constant fight when I weld in patch panels, but to try and keep a roughly 16 foot long frame from warping over the entire course? WOW....

[GregWeld]

That's part of the reason they use jigs....

[Vince@Meanstreets]

Cliff Notes - How does Roadster Shop (or any others) manage to weld together an entire frame from 4 (or more) sections of steel without warping?



When you are basically making a box with .120 wall material it isn't too hard to control temperature. Now sheet metal on the other hand. No matter what you do it still needs hammer and dolly to get flat. Huge difference between frames and sheetmetal.

Try it and you will see.

They tac every 3" the fill between and alternate locations.

[mitch_04]

I would love to try this, seems like the best way to get lots of nice looking contours.

As far as jigs go, I do believe that, if you put enough heat into something to severely warp it, it would show up as soon as your removed the jig. Granted, that would probably take welding a huge length without ever stopping, but I just wouldn't want a jig to give me false confidence. Obviously a jig is necessary for repeatable results, but I don't think it would stop warping entirely.

I've been wanting to build a go-car from an old 3-wheeler engine I have... could be some good practice on a smaller scale. Cheaper to learn the hard way ;)

[GregWeld]

No a jig will not eliminate warping - it helps - but first you have to know what you're doing.

Start watching videos - you'll need 'em!! LOL

[mitch_04]

I have a decent amount of experience with a MIG, just starting practice with TIG. I've been doing tons of sheetmetal welding lately, body repairs. I'm confident with a MIG, no worries there. I've always been amazed by RS builds and wondered how they could keep everything so nice. While I'm sure I could probably weld one up without too many problems, I always try to learn as much as possible first. This means asking a lot of questions that I already have an idea about, but it's more about trying to hear others opinions.

I recently found out I will deploy to Kuwait in August so I created a small bucket list of things to do before. Some household things I'd like to get inline, some fun things with friends, some work related things, and, of course, some car project things. I'd like to have a frame table built and it'd be amazing if I could get my C10 on a rolling chassis before I leave. With any luck (and a good tax return) I should be able to start building. Since it'll be a month or two before the materials will be purchase, I'm spending this time researching things that will pertain to both frame tables and frame building.

I've searched here and Pro-Touring quite a bit and I'm just trying to clear up the cloudy areas. Things I have an idea about but would like more opinions. Hope I haven't bored too many with my questions!

[GregWeld]

You'll love TIG welding over MIG... I don't MIG anything any more unless I'm just building something to tear apart. LOL


TIG on the chassis - will allow you to smooth your welds with ease compared to MIG. The fill is far easier to grind - and the weld just generally starts out looking better to begin with.

[mitch_04]

I can't wait until I get to that level. I've been following the TIG thread, watching Jody's videos, and staring at my lonely TIG in the corner. During the day-job I can't justify spending time learning, in my part time job (restoring cars) I have to use what little extra time I have to earn money for such tools, and any other time I have goes to family. Hard to go into the shop when a 2 year old is saying "Daddy don't go to work" over and over while holding you! If only you could learn by just reading...

[SlowProgress]

I used to work with a guy that build dragster chassis. First his technique was really good so he never put too much heat into any one weld. Being consistent he just moved from side-to-side and top to bottom as he welded on the chassis. You could see tubes pull away from the table but when he went to the other side it would pull back in alignment. I suspect he occasionally had to use a torch to straighten out a little warpage, but overall his consistency and balance side-to-side was all that it took. It also helped that the fit was very good and consistent. Obviously if one tube had a large gap it would pull differently than a tube with a perfect gap.

[Vince@Meanstreets]

I can't wait until I get to that level. I've been following the TIG thread, watching Jody's videos, and staring at my lonely TIG in the corner. During the day-job I can't justify spending time learning, in my part time job (restoring cars) I have to use what little extra time I have to earn money for such tools, and any other time I have goes to family. Hard to go into the shop when a 2 year old is saying "Daddy don't go to work" over and over while holding you! If only you could learn by just reading...

Well in that case you will have to make one of two things, make more time learning or make more money to have someone else do it for you.

If you have a TIG welder at your disposal start burning tungsten and if your in a shop already make an excuss to use it. Fix a bumper bracket, make a transmission crossmember.

With the tips here and experience you should be able to figure it out. BTW, that picture I posted was a practice piece I had an apprentice do. It's .120 wall 2"x5" flat that he cut. It's a fabricated square tube in a square tube slip fit. That was after playing with my TIG welder for about an hour.

[Vince@Meanstreets]

I used to work with a guy that build dragster chassis. First his technique was really good so he never put too much heat into any one weld. Being consistent he just moved from side-to-side and top to bottom as he welded on the chassis. You could see tubes pull away from the table but when he went to the other side it would pull back in alignment. I suspect he occasionally had to use a torch to straighten out a little warpage, but overall his consistency and balance side-to-side was all that it took. It also helped that the fit was very good and consistent. Obviously if one tube had a large gap it would pull differently than a tube with a perfect gap.

There's a time lapse video of a guy welding up a fabricated frame for a tri-5 Chevy. zbA4Uoq4vfA

Good stuff. The music is cool but it gets annoying after a few mins. Also, I hope you don't get seizures from flashing lights. :confused18:

[GregWeld]

The murdercycle mechanic across the street from the shop and I have become friends... he even came over to Thunderhill to get a case of "I need one of these"... His name is Kenny.

So Kenny came over the other day and I had the TIG out and was doing something. He says "I've never TIG'd before". I said - have you gas welded? Yep... and he can MIG... I set him up -- he lays a real decent bead his first time. Gas welding teaches you how to feed filler... and of course you have to keep the bead going with the torch head... so it's two handed coordination. Some people suck at it -- some people can pick it right up.

All of the settings can be found on the internet... there's so many of them on a decent machine that unless you're a professional you'll never remember them all.








Well in that case you will have to make one of two things, make more time learning or make more money to have someone else do it for you.

If you have a TIG welder at your disposal start burning tungsten and if your in a shop already make an excuss to use it. Fix a bumper bracket, make a transmission crossmember.

With the tips here and experience you should be able to figure it out. BTW, that picture I posted was a practice piece I had an apprentice do. It's .120 wall 2"x5" flat that he cut. It's a fabricated square tube in a square tube slip fit. That was after playing with my TIG welder for about an hour.

[mitch_04]

I have the Miller calculators, makes it pretty easy for quick calculations. I've played with the TIG and can weld with it, but I'm just not as proficient as I am with a MIG at this point.

[Ketzer]

That's part of the reason they use jigs....

I thought Rodger taught you better than that...



Jeff-

[mitch_04]

Saturdays I run the parts department from 7:30-12. It's slow enough that I can usually sneak in the back and work on some of my own things. I think I'm going to start trying to burn 30-60 minutes tig'n scrap together. It won't earn me any extra money....now....but I gotta learn how to do this.