Getting rid of dents in a tank

[bobjohnson]

I bought a tank off ebay, its solid inside and out, but i couldnt tell from the picture its got a HUGE gash type dent near the front of it, that runs far enough back its gonna mess up my plans for knee dents. Whats the easiest way to go about pulling these out? I had 2 ideas:

1) Get a metal bar and put it in the gas cap hole, and use a hammer to lever the dent out from the inside. Im thinking this will probably mess up the filler hole or the tunnel though.

2) JBWeld some posts to the outside of the tank and "pull" the dents out, similar to when they weld posts and pull dents.

Will either of these ideas work? I dont have access to welding equipment, so if anyone has any input thatd be awesome.

 

[Tristan]

If the gash is that big, I'd be afraid of over manipulating the area and the surrounding. I found a video somewhere online a while ago that showed a guy repairing dents in his tank with hot glue and a wood dowel. It worked well for him, tried it myself and it didnt work so well. I bet jbweld would definitely do the trick though. OR you could just bondo it.

 

[Rocan]

sorry to say... strip paint, weld on a bar (jb weld seems messy imho) and pull carefully. cut the bar off when done, and then grind smooth and repaint.

make sure you pull DIRECTLY in the center of the dent. if its an ecliptic dent, then figure out where the two centers would be and pull from there (hope you payed attention in math )

 

[bobjohnson]

I think ill be ok with the metal, the gash is BIG (looks like it fell over onto a flat bar or something) but its not too sharp. I dont think bondo will work because the top end of the gash will come into the front of where i want the knee dent so i would be doing a lot of shaping with bondo, which id like to avoid.

I dont think jbweld will be too messy, i was thinking of getting some of those big concrete nails and using the jbweld to stick them along the dent (maybe 3 or 4 areas). After i pull the dent out, i should be able to grind/sand the jbweld down just like a real weld. Might go through a couple sheets of sandpaper, but i dont think itll be too bad. If im missing something here though, let me know. I did get the idea from the hot-glue video, but i dont think hot glue will work on the tank because its so smooth, the glue doesnt really have anything to bond to on the tank itself.

I know welding studs into the tank is the ideal way to fix this, but i dont have welding equipment and im pretty sure if i pay someone to remove the dents, ill be into the price territory of a custom tank (Paid 50 bucks for this tank on ebay, pulling dents is probably 100-150 dollars).

 

[Tristan]

I see no reason JBweld wont do the trick...if youre not familiar with it, make sure it stays perfectly level before it sets up, because it will just run.

We dont all have access to a welder...lots of people forget that.

post the results, I'd love to see the outcome. Good luck man.

 

[bobjohnson]

Oh i am familiar with JBWeld. You know the story they love to tought about the guy who fixed the cylinder walls on his tractor and then ran it another 200,000 miles? That could be me haha. I love that stuff so much.

Ill definately get some before/after pics when i try it. I figure, worst case scenario, if this doesnt work ill go on ebay and by a stud gun cheap. Ill only be out about 65 cents for whatever i end up using for studs.

 

[Firestarter]

I am in the same boat, and heres my plan:

I have flushed the tank with water and degreaser, and have let sit overnight and out in the sun to try and purge it as best I can.
Next, I am cutting out my knee dents, allowing me access to the inside of the tank and thus the dents.
Hammer out the dents as good as they will get, then weld in the knee dent panels
Skim coat the tank with filler then just prep and paint.

 

[Rocan]

yeah i often forget about not having a welder...


good luck with the jb weld... ive used it with partial success. i ended up disliking it after it failed on me twice (leaking radiator fluid tube on honda shadow not being fixed, and also a motor mount on a small scooter not staying on while using it).

keep us informed, and maybe post a how to

 

[Tristan]

yeah i often forget about not having a welder...


good luck with the jb weld... ive used it with partial success. i ended up disliking it after it failed on me twice (leaking radiator fluid tube on honda shadow not being fixed, and also a motor mount on a small scooter not staying on while using it).

keep us informed, and maybe post a how to

It really is pheonominal stuff if your substrate is clean and dry...maybe that's what your issue was with the coolant.
i used it on my benelli tank to hold a piece of threaded rod for mounting and it holds well enough for me to bend the rod. It's really great for fixes like that because when it hardens it doesnt get brittle if pressure is applied, but stays the slightest bit flexible.
I have noticed that it really sucks if it isnt recessed or sleeved..I mean the stuff isnt meant to make a butt weld.

 

[Tristan]

Oh i am familiar with JBWeld. You know the story they love to tought about the guy who fixed the cylinder walls on his tractor and then ran it another 200,000 miles? That could be me haha. I love that stuff so much.

Ill definately get some before/after pics when i try it. I figure, worst case scenario, if this doesnt work ill go on ebay and by a stud gun cheap. Ill only be out about 65 cents for whatever i end up using for studs.

Yeah I've heard those stories. Quite honestly, JB Weld is the last thing I'd consider using to repair a cylinder wall. Hey, why don't you post a picture of the tank...I'd love to see what youre tackling.

 

[slushie07]

I actually just saw this yesterday online some where and have no idea if it would work but you just heat up the dent and surrounding area with a lighter or propane torch and then freeze it with some time of aerosol freezing agent, and then dent pops out, but in your case I don't no if that would work at all.

 

[bobjohnson]

I actually just saw this yesterday online some where and have no idea if it would work but you just heat up the dent and surrounding area with a lighter or propane torch and then freeze it with some time of aerosol freezing agent, and then dent pops out, but in your case I don't no if that would work at all.

Yeah ive seen that too... I do have a bunch of mostly empty cans of compressed air, and i just bought a new 900 degree heat gun... Wonder if i should try it?

 

[Kanticoy]

I had a dent pulled at a local body shop for $20. Guy did it after work and it took him 10 minutes. It was so well pulled that I only had to use glazing putty to finish it out. Might ask around, it's cheaper than you think.

 

[Ogri]

I agree. I think you'd be surprized how reasonable it will be.

 

[CresentSon]

Hey Kiley, what about the incremental freezing?

 

[sumomo]

You can use a hair dryer or heat gun and those compressed air dust removal cans.

1. Heat up the dent (just the dent)
2. Invert the spray can (the liquid CO2 will come out of the nozzle) and spray.

I guess it depends on the size of the dent but the layman's term theory the heat will soften the metal making it more pliable (molecules looser) then the cold liquid CO2 will cause it to shrink quickly resolve the dent.

example vid w/ car dent:
http://www.metacafe.com/watch/501379/remove_car_dent_with_airduster/

 

[bobjohnson]

Yep im going to be trying it in a couple hours. Just soaking the tank in the bathtub right now ;D I opened the cap and it smelled like... Something, not exactly gas but like solvent of some kind, so i called my dad and he said before i take the heat gun to it, soak it for an hour in the tub with dish soap and then test the cap with a lighter. If it doesnt go boom then, it wont go boom when i take the heat gun to it. He said thats how they cleaned out tanks that actually had gas in them before they welded them, back when he still had his auto-shop.

If that doesnt work, ill look into pricing to get a shop to pull the dents, and if thats too much, ill see if i cant get some prybars jammed in there to hammer out the dent. And if that still doesnt work, ill go the jbweld and pull route.

Ill get pictures either way, and if theyre worth posting up, ill post em.

 

[Kanticoy]

Hey Kiley, what about the incremental freezing?

Yep. Fill with water about 1/4 way with the dent toward the top. Freeze. Take out, fill some more. Freeze. Do this until you are almost full with the water, but leaving a bit of room for expansion where the dent is...you don't want to warp it. Then freeze again. Always leave the cam and petcock off. I have done this several times with great results. Wish I had taken pictures now.

 

[bobjohnson]

Ok, the freezing didnt work too well.. I went through 4 cans of air, and the dent isnt completely gone. It took the sharpness out of the dent, but its still dented in. I guess bike tanks are too thick to pop back into shape using this method. I got pictures but i forgot to take a before shot, just got a bunch of pictures from the middle of the process and they didnt come out too well anyway, so i wont bother posting them up.

Oh and watch out if youre doing this in a shop, dont have anything flamable near by. Apparently the CO2 shooting out of the can will spark if it hits bare metal. I noticed this when it started to get a bit darker outside.

 

[Fix]

Ok, the freezing didnt work too well.. I went through 4 cans of air, and the dent isnt completely gone. It took the sharpness out of the dent, but its still dented in. I guess bike tanks are too thick to pop back into shape using this method. I got pictures but i forgot to take a before shot, just got a bunch of pictures from the middle of the process and they didnt come out too well anyway, so i wont bother posting them up.

Oh and watch out if youre doing this in a shop, dont have anything flamable near by. Apparently the CO2 shooting out of the can will spark if it hits bare metal. I noticed this when it started to get a bit darker outside.

Makes sense, I'd imagine you're generating quite a bit of static electricity.