Topic: Tank dent removal strategies

[gregwaits]

I got lucky and scored a replacement tank for my bike rebuild. The inside looks very clean and the outside isn't bad. It does have 3 small dents though, and I would like to get them removed rather than do the bonda thing.

What would a body shop do? I don't want to spend money for someone to cut the tank in half, pound the dents out and then weld it back together. Are there no other choices?

[mkramer1121]

What I've done for some, and what I've read others have as well, is that if you can reach them from the fueld neck with a long rod, see if you can press them out.  I was able to get one of the 2 in my old tank out with this method.

[cafe75-550]

There's dent pulling devices that you could use without cutting up the tank. The dent puller I've used spot welds a rod onto the dent which is then pulled with a slide hammer, pulling out the dent. This should maintain the integrity of the tank if used right. There are also types that drill a hole through the metal and then insert a "L" shaped rod attached again to a slide hammer, but these obviously leave a hole, and stretch the metal more from my experience...

[johnny-from-bel]

If it is a big dent. Cutting it out and TIG-welding a new piece is often the most economical.
The dent pulling works fine on shallow dents.

Ask if they can finish it off with tin (the metal) to smooth it out.

For small dents pussing out from the inside saves you the trouble of repainting the tank.

[bryanj]

Whattever you do DONT try air pressure! All it does is "Spread" the tank

[puppytrax]

Whattever you do DONT try air pressure! All it does is "Spread" the tank

And don't heat it while it's pressurized...it just "spreads" it faster!!!     (Don't ask how I know...)   

My friend is doing the spot-weld & slidehammer trick. He says it works great. He made a little slide hammer because the factory ones are too heavy for a gas tank.

I'm going to let him try one of my worser tanks to see how well it works.

[samfig]

If any of you guys have any before and after pictures please do show.

[mennedy]

There's a thread someplace from one of the "Old Hands" that suggests filling the tank with water and freezing it.

I have thought about this for a long time and I think if it was allowed to "solid" freeze, it would spread the metal. But if it was a "soft" freeze it might work. You would have to watch it carefully to remove it from the freezer before it freezes solid or when the dents pop.

I don't know. I just throw it out there and where it goes.......?

[Bob Wessner]

I can't recall anyone ever actually stating this worked for them, maybe they did and I missed it. However, I would be reluctant. Water will expand just prior to the freezing point, but, like using compressed air, why wouldn't it exert the same amount of pressure equally on all surfaces thus risking splitting the tanks, etc?

[sirg]

You could try the old football trick. Get yourself an old football, open it up and remove the air bladder from it. Stuff the bladder into the tank and pump it up with a hand pump. Sometime it works, sometimes it dont. Depends on the dent.
 SG

[kettlesd]

If the dents are smooth (no creases) you can sometimes get them out with an autobody type suction cup. Take the tank to a body shop. If they can do this for you they will only charge a couple bucks.

[petersan]

I had success with a dent on the top of my 550 tank - pulling out with a suction cup (sorry no photos)

growing up in Kansas, I also remember some places use to use liquid nitrogen drops (or dry CO2 ice) to remove small hail dents - but must admit I never saw it done.

[number13]

I was looking around the internet last week and came across this in a Brit
bike forum. It appears some people have had success using dry ice to remove dents.
I haven't tried it yet but it sounds promising.
Read here:

http://www.britbike.com/ubb/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=11;t=001448;p=1

#13

[number13]

oops, that's not a good link, sorry, look here:

http://www.gadgetjq.com/dentremoval.htm

[gregwaits]

I was looking around the internet last week and came across this in a Brit
bike forum. It appears some people have had success using dry ice to remove dents.
I haven't tried it yet but it sounds promising.
Read here:

http://www.britbike.com/ubb/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=11;t=001448;p=1

#13

That sounds like an easy thing to try, and it doesn't seem to be risky to the tank itself.

If that doesn't do the trick, I'll be going to a body shop for the paintless dent removal (suction cup).

Thanks for all the hints! 

[mennedy]

Here ya' go Bob. I thought it was strange too and have never tried it but.....what can I say?

http://www.sohc4.us/forums/index.php?topic=5811.0

It is about half way down.

Marty.

[kettlesd]

Sounds awesome! I'd love to hear from someone who has done it on how well it actually works.