Help!! I warped my reverse flow plate!

[SmeltshackBBQ]

500 gallon Cookers and Grills 12' 'restaraunt' model...

So, I'm in the process of restoring this old trailer, and have gotten to the part I dreaded the most: The reverse flow plate got warped fairly badly when I first got this thing. A hot grease fire later, and now there is a nice dome in front of the fire entrance to the cook chamber. It wouldn't be a big deal, except that this caused the plate to come away from the sides of the tank where it's domed, and now we're getting major temp spikes over there. I fixed it by stuffing wads of aluminum foil in there to make a gasket of sorts, and that was all still in there when I just cleaned the tank all out so I could try to tackle this little job.

I blocked up a bottle jack just now, and got it to push the plate back to flat without too much trouble by pushing down from the top of the tank.. My brain says 'just heat it with torches while it's jacked back into place, then let it cool while you keep pressure on it'. That's great, except that my brain is forgetting that I no longer have access to torches.

I do have a 110V MIG machine here, and kinda thought about just tacking it down while it's jacked there.. It's a 6 ton bottle jack, and it's got quite a bit of pressure on it.

I don't want to do that, something tells me if I ever sell this thing, the next owner thanks me for not doing that. Especially if they ever need to replace that plate due to rust, or more major warping. It's only warped by a couple inches, but the poor person holding that grinder probably says it still hurt when it let go and cut their fingers off or something...

It seems that welding a piece of round rod, angle iron, something like that to the plate while it's jacked down there is my best option short of heat straightening this warped plate.

So, if anyone has any ideas about how to force this thing to stay straight that sounds better than adding more obstacles to the plate to scrape grease around... I'd love to hear them. And yes, I've already considered fighting grease fires with bigger grease fires, by emptying all this cleaned up grease into a pile in there, and then lighting it.

Thanks!

edit for the added pics.

 

[JIMSMOKES]

Push it past where you want it and let off and see how much it comes back.
You could use some map gas in hand held torch to put some heat in it to help a BFH shrink it back. Use a wet rag to cool it.

 

[civilsmoker]

If it were me, I would release it from pressure and then cut a few horizonal cuts across the warped area, then put the jack on so that section can "bend" and then once back in line weld it back up..... Just "v" bevel the cut before welding back up.....

ps edit, try what JimS suggested first then angle grinder time....

 

[SmeltshackBBQ]

Push it past where you want it and let off and see how much it comes back.
You could use some map gas in hand held torch to put some heat in it to help a BFH shrink it back. Use a wet rag to cool it.

I got a tiny bit out using the 'let's go til she don't sound good and then look away while we do two more' point.

As for the mapp, I don't think I could get the area hot enough with that, it's about an 18" by 20" section that warped. And feels like at least 1/8" plate in there if not more. It has angle bar edges, so I can't quite see the thickness.

 

[SmeltshackBBQ]

If it were me, I would release it from pressure and then cut a few horizonal cuts across the warped area, then put the jack on so that section can "bend" and then once back in line weld it back up..... Just "v" bevel the cut before welding back up.....

ps edit, try what JimS suggested first then angle grinder time....

Yeah, that's what I was afraid of.. lol. I'll go out and look at where the cuts would need to be now, this may be a job for later.

 

[seenred]

Either of the suggestions already made might work. Another thought - have you considered just cutting the warped section of the plate out...and simply scab-welding in a new piece of plate steel? With some care and a good angle grinder, you could smooth it out where nobody would every know it was replaced.

Red

 

[indaswamp]

All good suggestions above^^^^^^^^

 

[civilsmoker]

Either of the suggestions already made might work. Another thought - have you considered just cutting the warped section of the plate out...and simply scab-welding in a new piece of plate steel? With some care and a good angle grinder, you could smooth it out where nobody would every know it was replaced.

Red

18x20 and 1/8 to 3/16 this is a one and done......less than an hour.....

 

[JckDanls 07]

Either of the suggestions already made might work. Another thought - have you considered just cutting the warped section of the plate out...and simply scab-welding in a new piece of plate steel? With some care and a good angle grinder, you could smooth it out where nobody would every know it was replaced.

Red

This is what I would do as well... Just replace it

 

[SmeltshackBBQ]

Well, thanks everyone! I think I'll cut it, jack it down and weld it back together. It's been done before on this one by the looks. I'll clean up that existing weld while I'm in there. I'm on the 'I don't have much money to put into this thing right now, but I have a bunch of tools and some time' team right now... lol.

 

[JIMSMOKES]

I got a tiny bit out using the 'let's go til she don't sound good and then look away while we do two more' point.

As for the mapp, I don't think I could get the area hot enough with that, it's about an 18" by 20" section that warped. And feels like at least 1/8" plate in there if not more. It has angle bar edges, so I can't quite see the thickness.

Start in highest point red dot then hammer and cool. Start workin your way out. It'll draw back in place.
Old school body and paint man.

 

[SmeltshackBBQ]

Start in highest point red dot then hammer and cool. Start workin your way out. It'll draw back in place.
Old school body and paint man.

Once we get out of this rain and cold spell, I'll give it a try before I cut anything. I think I have a can of mapp around here somewhere.

 

[seattlepitboss]

It sounds like your plate isn't welded to the smoker. Take it out.

Here's one approach I used once (although my warp was a potato chip warp and yours is apparently an even dome):

It helped that I'd cut a 13" circle out of the center, made it easier to bend. But mine was 3/8" thick and I think yours is thinner. Note that I'd drilled holes in the corners and dropped bolts through which kept the cable sling from coming off the corners. Yours would probably need 2 such slings. I just used what I had.

If you did have a torch, where and how would you use heat to straighten your plate? Because you can also straighten plate by judicious weld beads. You are right - bend it to hold it flat first. Then you could weld circular stringer beads on the convex side, like a target. Just try one, then let it cool until you can put your hand on it and try loosening your jack or whatever to see how much it moved. If it's still warped flatten it again and do another weld circle. Everyone who's done much welding knows how much you can warp things by welding, this is trying to use that capability to save your plate.

The last idea I have is to make a ring of bricks or something and put your plate on it and drive a car over the middle of the ring, bending your plate down towards the ground. Just bend it cold back to straight.

seattlepitboss