TOPIC:

I've got a nice dent in my tank for my GPz. I've heard people use Co2 and water to pop it out. Anyone tried this method?

I am not familiar with that exact technique, but if it is anything like putting compressed air inside the tank, and trying to pop the dent out, then I can tell you you gotta be careful, experience helps. I have seen guys split seams out and worse. The best method is to apply only 4 or 5 psi of air to the tank, and heat the dent up with a torch, until it is cherry, and it will start to pop out. as soon as it gets close, quench it with water. The best possible thing to do is get the dent pulled with a stud gun, resistance type welder. what it will do is tack weld a small brass stud onto the outside surface, and a special dent puller can be attached to gently tap out the dent. If you are located anywhere near Pittsburgh, PA, I could pull it for you. the methods where people claim they can preserve the paint on the outside of the tank is trouble. Most of the time, it won't happen as easily as it seems.

Of course, I could be way off, on my assumption, as I am not familiar wiht the technique. could you describe it?
Thanks,
John

I've not tried it but I've read that you put on some welding gloves and hold a piece of dry ice to the dent till the frost grows about an inch out all around the dent. Then you allow the sun to warm it and the dent is suppode to grow right out. It's ecpecially effective on hail damage, so I've been told.
Good luck
KZCSI

There was a few post made about this and it seems to work. Here's one link where it worked.
dry ice

Thanks for the info guys. I've easy access to dry ice and will try this on my holidays and post the results.

I've seen 2 stroke expansion chambers made by using the pressurized water method (hydroforming). They weld up flat metal and then put water under pressure to get it to shape. It is supposed to be safer than using compressed air (all the air must be replaced with water). Water does not compress (actually,it compresses very little) and if there should be a burst in the metal, it will just squirt out to releive the pressure built up. With air pressure (it compresses) in a tank or chamber, it can become a bomb when a leak is created.

Heres a link
www.eurospares.com/frame8.htm

You have to be careful when usung either method on a tank as the tanks tend to spread out and look odd.
Daniel

This might actually work at home if one were to make a die.
perhaps by casting concrete around the old tank with a seam,
splitting during early cure stage, working dent out of the die,
waiting for full cure, putting tank back in and clamping with some
angle iron and really big bolts, then pressurising tamk. It should
only expand to fill the void. You might coat the die with a thin
layer of plaster and sand smooth to keep the metal from taking
on a grainy appearance from the concrete.

I imagine one could use a model of a tank to make the die and
form each half individually out of Aluminum or steel and then weld the two together.

Would love to try here but way too many other things going on.

-Duck

I have seen the dry ice method work but that is on automobile sheetmetal. The metal on our tanks is much thicker. I think the best method is going to be a stud gun. Just think about the hood on your car. If you press down hard with your finger the metal will give way and then bounce right back. Try that with your tank and you are going to have one sore finger.