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Warp Prevention?



mountain eagle
04-21-2011, 01:44 PM
Tips for warp prevention besides don't get so much heat to it?

2811

So when I welded the 1x1 to the front rail starting at the corner, about half way to the open end it started to pull. Ended up with about a half inch swing. I was able to correct for some of it when attaching the other side to the main support, but were it to be a visible construct I wouldn't be happy with that result.

So, add less heat? Wait longer between welds? How do you address warpage on plate?

SICFabrications
04-21-2011, 08:05 PM
clamp, tack, skip around, post heat... dont weld piece after piece in a row, weld one, then move elsewhere on the work and weld there.... all in all, there is no absolute way to get sound welds without drawing the metal. there are tricks to shrink the warpage after welding.... heat a spot with the torch on the side opposite the draw, just enough to start it turning red, then wipe it with a rag soaked in water and watch it draw towards the "hot spot" dont over do this... just a little will go along way

atcig
04-21-2011, 08:20 PM
That is just what I was gonna say!

Actually I was going to say clamp and tack.

Nick
04-24-2011, 03:37 AM
Mountain,

That looks like an orchestrated piece. Spend some time developing a clamping system (or a jig). Something that will lock down the critical angles without interfering. I'm a huge fan of T-Nut fasteners. You can use them with MDF and just about anything that will accept a threaded input. :D

A 4x4" block of mdf cut to hold your angles is worth more than its weight in gold if it works. :mrgreen:

rustycase
05-06-2011, 02:15 PM
I've heard that 'backing bars' of heavy copper stock can be used near the weld placement to absorb heat and prevent warping, yet I've yet to try it myself.
Good luck
rc

Gadget
05-06-2011, 02:24 PM
A good idea but have you priced copper lately? Ouch.

WookieWelding
05-06-2011, 08:53 PM
you can use aluminum too but that is normally used on sheet metal applications but on your application i would do as sic suggested

mountain eagle
05-06-2011, 09:18 PM
A good idea but have you priced copper lately? Ouch.

Pushing $4/lb for bare bright......... hmmm At some point I might get to demo some old CU buss bars out of some gear, that would work for heat absorption....

mountain eagle
05-15-2011, 11:01 AM
I welded up a simple frame for a gate yesterday and made a point of doing more tacking and or moving around and it seemed to help. What was most noticeable was my lack of patience........ had to make a very conscious effort to move around.

arandall
05-15-2011, 12:37 PM
I welded up a simple frame for a gate yesterday and made a point of doing more tacking and or moving around and it seemed to help. What was most noticeable was my lack of patience........ had to make a very conscious effort to move around.

I have the same problem Mountain Eagel.

odleo
05-15-2011, 09:09 PM
I use a lot of clamps and learned the hard way to move arouind when welding. I have seen Stan's (SIC) work up close and when he suggest to move aournd and use a lot of tacks, you can take it to the bank. Untill I saw them use a torch and wet rag I would have not believed how good it works

BradBlazer
05-15-2011, 09:52 PM
You got good advice. I look at the effect as when you weld or heat metal to the annealing temperature it will relax all stress in the hot, expanded state. As it cools it gets it's strength back before it finishes shrinking. The last thing that happens is high strength shrinkage of the area that was heated.

Moving around reduces the heat affected zone which reduces shrinkage. It also lets you get an assembly square before you lock in the warp. As you become more familiar with the effect you will learn to use it to your advantage to get the final shape you want.

It's still tough to break it off when you get a good bead going...

mountain eagle
05-16-2011, 11:40 AM
Moving around reduces the heat affected zone which reduces shrinkage.

Hmmm.......... anyone else think Seinfeld?

rustycase
05-16-2011, 11:50 AM
I've seen where it was advised to clamp thick copper blocks near the HAZ to act as heat sinks.

AND, I found some 1/2 - 3/4" thick by 3" wide copper stock at my favOrite scrap yard.

He wants $5 a lb. ...There's always a fly in the ointment!
I'll need to get some of that copper if it's available next time I see xtra $'s.

rc