Straightening a bent frame during welding.

[Johnseat]

So I'm building a kind of Fort Knox man cave (the other half can't put stuff in there to store ect..) and whilst fabricating the doors they have bowed slightly when welding in an angle iron frame to support my hardwood centers.
Now I haven't began to weld the rear of the door where the angle iron finishes so when I weld tomorrow will that bring back the bow which welding the front has put in today.

I'll post a new thread showing the small cave.

Cheers.

 

[james butler]

ive never tried it myself but an old school fabricator once told me to heat up the item that has bent and quench the opposite side to the bend which will pull it back straight.
like i said ive never tried it but it seems like a logical idea.

 

[Paul.]

Jack it out, then on the next one don't get too carried away with the welding when putting the angles in, you only want enough to hold it together, some of the secrets of fabrication lie in knowing when not to weld things.

 

[Bill Edwards]

Some good detailed photo's may help a lot as we need to see exactly what's what. There are usually ways to fix and prevent distortion but it can be a bit of an art.

 

[Kent]

ive never tried it myself but an old school fabricator once told me to heat up the item that has bent and quench the opposite side to the bend which will pull it back straight.
like i said ive never tried it but it seems like a logical idea.

Flame straitened and bending is beyond the skill set you possess at present if you managed to lock in the distortion in the first place. If it's bad enough scrap it, if it's not use it as is. Getting rid of distortion when it is in is pretty darned hard

 

[Johnseat]

Here are some pictures of the bow, it's only 10mm at the very worst so it should hopefully bounce out.

The door front showing the over welding

Now when I weld the rear frames together should this bend back the bow?

 

[Bill Edwards]

I'm not a daily fabricator so if someone like Kent, Paul etc say otherwise then take their advice but my answer is that yes, welding the back should pull it straight. I would start in the middle working towards the ends. Keep a close eye on the straightness and if it's not looking like it's pulling enough put a block under each end and some weight in the middle (such as you kneeling on it while welding) to give it a little help.

In the future tack one side, preferably with it clamped with a G or similar clamp as you've been left with a big gap to fill and then do some welding on the opposite side, then turn it over and keep doing some to both sides rather than piling it all on one then turning it over.

 

[Johnseat]

The gap at the back is nothing as it easily pulls flat to the box.
As previously said I have over welded the front thinking about security

 

[Welderpaul]

You'll get that back flat with 5 or 6 welds to the opposite side that you have welded hell out of

You could either live with it, get physical and jump on it (but try not kinking it), or weld the opposite side.

 

[Paul.]

Put a few short runs on the back, on the long sides just 4 or 5 at about 15mm long will be more than adequate, then if its stlll bowed (which it will be) then lay it on the floor with a block each end and use your body weight to push it out, dont hit it with a hammer or jump on it too hard, it needs to be a controlled push

 

[Kent]

Have you got a bottle jack anyplace? They work better than big hammers, bit by bit edging along as a spreader.
Good luck. Every now and then I get issues with galvanising distorting stuff - mainly when I think I can get away without a tempary brace bar and the bottle jack is a friend then