tank dent

[rman]

Hello all,
I am working my 79 XS1100. I have a rusted gas tank and will probably be using the POR15 tank sealing method. However, there is a large dent in the top of the tank, sorta like you would get from punching the top of the tank???? I want to repair this before I seal the tank. I also found a small hole in the underside of the tank that I have closed up with JB weld.

What would be the best method to pop out the dent. One person had suggested sealing up the holes and slowly applying compressed air to the tank. I am not sure I want to do this as I usually dislike exploding tanks. Is this possible and safe to do? I am a total dolt as far as this kind of repair goes so please type slowly so that I can understand you.

Again thanks to all for your assistance.
Ray

[fredintoon]

Ka-Boom!

Hi Ray,
Air pressure is inherently dangerous,
(can you say "bomb"?) and won't work except to wreck the tank because that dent is now the tank's strongest part. Filling the tank with water is far safer and won't work either. You can pull out the worst of the dent by brazing a large-headed machine screw at the middle of the dent and using a slide hammer (aka dent puller) on it. While you have the torch out, remove the JB Weld and braze up the leak. Torch the screw off again and use body filler to smooth things out.
Before using the jollop of your choice to coat the tank's innards clean it out with the old washing soda & battery charger electrolysis trick.
Fred Hill, S'toon.

[rman]

Hhmmmm
Brazing. Heard of it never done it. Can it be done using a propane tourch, I have sweated pipes before with solder but I think that what you are talking about is different. I am going to google brazing.

[DiverRay]

Ray,
If you get a MAPP gas bottle, you can braze with that. I like to use solder on any holes in the fuel tank. I had to fix the tank on "daily ride", and used solder with a torch to fill and plug some holes left in the top of the tank. The PO had it fixed, and they drilled and used a slide hammer to take out a dent, welded up the holes, and then ground them out farther than they should have. the bondo they put on lasted about six months before it developed a crack, and leaked gas down the back of the tank!

[HobbyMan]

If the dent is large, try dry ice or the hot glue gun method. If those don't work or the dent is small, it may need to be pushed out from the inside. I now have a little experience in the field from my last dent repair. See thread "shameless guilt"

[BLUEJEEPLAB]

Pops a Dent works pretty well if the dent is no larger than a baseball. Works like the Hot Glue gun pull, but I think it provides a little bit better control.

[Boothman]

You should use, what they call in the body shop industry, a stud welder. It uses an electrical current to spot weld a copper stud to the afflicted area. You then attach a dent puller to the stud and remove any depressions and then grind down the remaining material - make sure there are not any residual gasoline vapors or you will make a blow fish out of your tank and possibly find out what chemical hair removal is all about!!!!

The heat from the stud welder helps to "shrink" any stretched areas. You then grind, fill, and form the area with a lightweight body filler. Any other tank conditions should be addressed at this time.

The tank should receive an inner lining, of your choice.
If you are not experienced at any of this, visit your local body shop for assistance. You will find local body shops are craftsman and love to assist you in the restoration of your machine.
Any other questions, let me know.

[HobbyMan]

They only problem is that you will loose your paint.

[rman]

Thanks for the information. I tried to pull the dent using the glue gun but it did not have enough ability to stick to the tank. I used the electrolysis method and cleaned all the rust from the tank. I will just use it as is for the summer and over the winter will try tack welding a stud and pulling out the dent. I will then be able to take my time and fix it the right way and give it a new paint job.

The bike will look like hell this year but at least I will have something to ride. Hopefully I will get one or the other bike restored over the next winter.

[Brian_D]

Originally posted by rman
...
The bike will look like hell this year but at least I will have something to ride....

my LH has had a large crease in the left-side for the past 5-years Long story short, bike was dropped when attempting to unload from pickup truck. only damage was to the tank where it impacted the side-rail of the truck.

[mro]

originally posted by Ray
The PO had it fixed

Hey Ray,
was that the standard tank I gave ya?
Thought it was cherry


mro

[DiverRay]

MRO,
No, it was the tank that was on the bike when I bought it. I still have the tank you gave me, and I don't think I'll be needing it. I'm going to set up and paint a tank for the project bike, I now have a 6 gallon for daily ride that needs a LOT of work, and I still have one I'll give to E.Liberty so we don't have to stop for gas so often when we ride.
If you know of a good home for the one, let me know. I'll be happy to pass it on to someone that needs one.

[planedick]

Brazing...

I didn't see any referance to the dangers of using a torch on a gas tank. Can you say "KABOOOOOM"?

Put a hose on your lawnmower engine exhaust and put the other end in your gas tank, start the mower and let it run for a minute or two before you start welding and keep it running with the hose in the tank while using any kind of flame around that tank......

[fredintoon]

Darwin lives!

Hi Dick,
I know a guy who's SOP on torches & fuel tanks over a 50 year period has been to blow the tank dry with an air line then shove the lit torch nozzle into the filler hole and let any remaining fuel vapours go "poof" to make the tank safe to weld on.
Now a coward like myself prefers washing the tank out with hot soapy water before taking a torch to it and of course your lawn-mower exhaust gas trick will work too so long as you don't breathe the fumes.
Fred Hill, S'toon.

[planedick]

Long ago...

I worked for a boat Mfg and he was into racing. Several times I repaired an aluminum tank he had and I flooded the inside with Argon that we used on the TIG torch, that worked too, but I have also used the lawnmower method and I didn't figure many here had a bottle of Argon.