Can a warped firebox be straightened out?


 
Stefan H

Stefan H

TVWBB Guru
I have this one grill where the firebox is bent out at the front by almost 1/2 in the center so that the grates don’t have nothing to rest on in the center. It probably had a grease fire at one point. I know one cannot bend cast aluminum but is there a way to get that somehow straight again or should I don’t even bother and wait for the next cheap donor grill with a straight box?
 
My 2007 Genesis has some warping on the front and rear. I've had some success using the good old rubber mallet to get things closer to square. I don't think I ever had a fire, but it did get left on overnight here in Las Vegas in the summer. Not sure if you have checked the back side to see if that is some of the 1/2 inch you describe. I've got a Jawhorse, but I haven't tried using that since I would have to disassemble the grill to take the chance on cracking the firebox. Good luck.....
 
Yes, stephen, you CAN bend aluminum. But, you do run the risk of cracking it. I have personally bent back several of my rehab grills with out cracking the fire box. I just lay it on it's back on a semi soft surface like wood and then apply pressure carefully to the front area that is bowed outward. I start in the middle and then move the press 3-4" to the left and then 3-4" to the right until it is straight again.

Again, I have done several but with care and not damaged any.
 
Thanks guys. Yes cracking is what I am afraid of. I always thought one cannot bend casted metal because of its structure. But on the other hand I have nothing to loose. I cannot use it as it is. So either it goes well or not. I will give it a shot.
 
Slow even pressure preferably with copious amounts of heat. The person describing pounding it just got incredibly lucky. I have broken cast fire boxes and kinda shatter like glass when they do (break). Not good to strike them in ANY way even with a center punch. Have to be very careful
 
I have moved a couple of bowed fronts back in, but can't be exact as to how much travel there was as I never put a tape to any of them. I use a couple of 36inch bar/spread clamps (or whatever you call them.) Put a strip of 1x2 along the front lip and one along the back to distribute the pressure. Strips should be about 1/3 the length of the cookbox. Reason for this is that while you want to distribute the force a bit, you still only want the middle to move. Might not be necessary, but that's the way I've been doing it. Anyways, put the boards in place, put the clamps in position and tighten then down til snug. Then crank them just a little bit more. Give it some time, then crank down even more. At some point, you need to get it to where the front lip actually bows inward just a bit. Leave it there for a day or two. When you remove the clamps, it will move back out a bit, but hopefully it will be closer to true.

Just an FYI, I don't know if all these steps are necessary. That's just the way I've figured out to do it.
 
Dave describes a great way to do it. It is probably the most cautious approach. But, since I have always had a spare cook box or two laying around, I haven't had to worry about destroying one and that is why I simply lay the cook box back on its back and press down along the front edge until it moves back into alignment. If you go the more cautious route described by Dave, I don't think it is necessary to leave it clamped for extended periods. I understand the concept, but in reality, I don't think it is going to make much difference in how far the aluminum "bounces back" after you release the clamps. I would think that using his method with the clamps that you could do it all in about 15 minutes. Of course, if that is your only cook box, then you might want to follow Dave's more conservative instructions to the letter.

Oh, and Larry makes a good point about heat. If you can heat up that top front edge of the fire box prior to trying to push it back into alignment, that is preferential. It will soften and make the metal slightly more malleable which will not only make it easier to push back into shape, but reduce the chance of cracking it. You could do this by using a propane torch probably, or you could maybe heat it up on another grill, I suppose....Just make sure you use some gloves.
 
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DaveW said:
I have moved a couple of bowed fronts back in, but can't be exact as to how much travel there was as I never put a tape to any of them. I use a couple of 36inch bar/spread clamps (or whatever you call them.) Put a strip of 1x2 along the front lip and one along the back to distribute the pressure. Strips should be about 1/3 the length of the cookbox. Reason for this is that while you want to distribute the force a bit, you still only want the middle to move. Might not be necessary, but that's the way I've been doing it. Anyways, put the boards in place, put the clamps in position and tighten then down til snug. Then crank them just a little bit more. Give it some time, then crank down even more. At some point, you need to get it to where the front lip actually bows inward just a bit. Leave it there for a day or two. When you remove the clamps, it will move back out a bit, but hopefully it will be closer to true.

Just an FYI, I don't know if all these steps are necessary. That's just the way I've figured out to do it.
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Thanks Dave. This is what I was thinking doing. I have enough long clamps to do that kind of job. I will give it a try in the next few days.
 
Bruce said:
Oh, and Larry makes a good point about heat. If you can heat up that top front edge of the fire box prior to trying to push it back into alignment, that is preferential. It will soften and make the metal slightly more malleable which will not only make it easier to push back into shape, but reduce the chance of cracking it. You could do this by using a propane torch probably, or you could maybe heat it up on another grill, I suppose....Just make sure you use some gloves.
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Agreed. I have see if there is a way to clamp and heat at the same time. I can still light it and I have some old fashioned steel clams which should be able to bear some heat. I just need to find a way to clamp it and keep the lid closed all at the same time to retain the heat inside the box.
 
Stefan, if you are doing this with the grill box still installed on the stand, then I suggest you leave the grates in and place aluminum foil on top of the grates covering it from edge to edge and light it up. It will heat up the inside of the cook box really well and quickly and then you don't need the lid at all to be on the grill.

Just be careful, the inside of the cook box will get really hot really fast doing this. I would envision temps inside to hit 1000 degrees pretty easily if left on high for more than 10 or 15 minutes. But if you run the grill at low it won't get too hot inside. I am guessing 5 minutes on high will have the inside over 500 degrees.
 
Bruce said:
Stefan, if you are doing this with the grill box still installed on the stand, then I suggest you leave the grates in and place aluminum foil on top of the grates covering it from edge to edge and light it up. It will heat up the inside of the cook box really well and quickly and then you don't need the lid at all to be on the grill.

Just be careful, the inside of the cook box will get really hot really fast doing this. I would envision temps inside to hit 1000 degrees pretty easily if left on high for more than 10 or 15 minutes. But if you run the grill at low it won't get too hot inside. I am guessing 5 minutes on high will have the inside over 500 degrees.
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Yes I still have the grillbox still in the stand with the burners installed. Aluminum foil sounds like a good idea. But I need to clean the grill box out. It is still a bit nasty and last thing I want is another grease fire. And yes within 5 minutes I assume it will be at 500 or more. I can then shut of the rear burners off and just use the front one. Sounds like a fun "science" project... ;-)
 
Just an FYI FWIW, but while doing some research/reading on bending cast aluminum, quite a few folks who seemed knowledgeable said to refrain from using any heat. That heating could actually make it more brittle. Again, FWIW as I have no idea.
 
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