gas tank dent repair, what to do? picture inside.

[sm7482]

have a dent in the tank of my 75 cb400 4 project. was wondering what the options for having it repaired were. paintless dent removal places dont wanna touch it but thats ok because i'm not worried about the paint because it needs it anyway. i was thinking of trying one of those harborfreight suction cups and pulling it out with brute force then bondoing it up, maybe drill a few holes and pull on it with a slide hammer then weld it up. or use one of those cheetas they use at tire places. you know the ones were they fill a 2 gallon tank with a nozel on one side and a quick realease that realeses 150psi at once :p is there a possibilaty the area will be prone to popping back into a dent with a little force like a tin can? worse comes to it i'll just buy another used tank that more or less has smaller dents but what do you guys think?



<a href="http://photobucket.com" target="_blank"><img src="http://i116.photobucket.com/albums/o3/rock_krawler/1975hondacb400frightveiw.jpg" border="0" alt="Photobucket"></a>

 

[2strokerfun]

Keep eye open for a better tank. My exerience with trying air or filling with water and freezing is that it tends to swell parts of the tank you don't wan't swollen and you're left with a distorted tank that is still dented. I'd try the suction cup or take it to a professional to get dent removed. I wouldn't drill holes for a dent puller unless you can purge the tank with argon and grind the lip off the holes and fill them in with welding or brazing.
My 1.6 cents. I had 2 cents but the value recently dropped.

 

[spark250]

I seems like you could find a tank for it for well under $100 at a scrap yard?

If money is an issue just buy a gallon of filler and slap it on there with a shovel! LOL.

 

[VA Mud Dauber]

It's hard to tell from the picture but it looks like it involves the whole side of the tank. If that is the case, you should take it to a body shop and have them make the repair. If you have a dent that has a distinct crease in it, the metal has been stretched and will need to be shrinked. This is done with a couple different methods. Body spoon and a shrinking hammer or heat the area with a torch and apply a cold wet rag. This will tighten the metal and make it unlikely that it would sink back in. You can do this yourself if you drain the tank and use air to blow out any remaining fumes and then heat but you must make sure that it is free of fumes or you will likely get hurt from the explosion. This process is done as you work the metal with the body spoon and shrinking hammer. Tap a little, heat a little and cool with the wet rag repeat until you are satisfied with the repair the apply an all metal body filler. It is a little more labor intensive but will hold up much better than plastic filler. Apply as thinly as possible and it will save you a lot of sanding. If you are not familiar with doing body work, get an old body panel with easy access to the back of the repair area and practice, practice, practice. I hope this helps. Oh yeah, if you decide to try to remove the dent with a suction puller, as you apply steady pulling pressure tap any high spots with a shrinking hammer. You will still need to shrink the metal like I described above. Good luck and let us see a picture of your results.

 

[Ol'89r]

If you can't find a straight tank, you could work that dent out with a dolly. Not the same kind of dolly that Pred plays with ;) but a solid steel ball welded on a 3/8" solid steel bar. Place the dolly inside the tank through the gas filler hole and work the dent from the inside out. You can also make another dolly shaped more like a spoon to finish the dents.

If you decide to use the slide hammer method, be sure to de-gas the tank first. Regardless of how long it has been sitting without gas in it, it could still have enough vapor to blow when you weld up the holes.

If you use the air pressure method, be sure to wrap the tank with tiedowns so it can't expand in areas that you don't want it to under pressure. Under air pressure, some gas tanks can spread at the inside tunnel area and flatten out like a desert tortoise that just got run over by a tank.

IMO, the best way is the dolly method. It takes a little longer but works very well. Finish it off with a good quality glaze. The glaze you can buy from automotive paint stores is much better and easier to work with than Bondo.

Just my $ .02

Va Mud Dauber.
Didn't mean to steal your thread, looks like we posted at the same time.

 

[VA Mud Dauber]

Hey friend, it's not my thread I was just chiming in too. You can never get too much good advice, right? I would have also suggested the finishing glaze but not many first timers can work the metal out that close, know what I mean? Hey, cool suggestion on the home made dolly!

 

[mandark1967]

http://www.youtube.com/watch?v=sYqBxkMJrmo

 

[sm7482]

My 1.6 cents. I had 2 cents but the value recently dropped.

nice.... im going to use that. anyway thanks for the help guys, ill see what i can do but more than likely i'll just buy another tank. i was looking at it today and it's pretty distorted, the front of the tank is all tweaked and stuff. i cant believe the guy i got it from had his knee do that. thanks again.