Filling dents after sand blasting, and before painting tanks

[shortlid]

I know, I know this topic has been visited a lot but had a few questions.
The tank on my '80 GS850G I bought for $300 from a junk yard is a mess on the outside!! Inside is OK not to much rust; the petcock is leaking a little but hope to fix that while the tank is off. It has deep scratches; deep dents all over and has been re-sprayed poorly once. I have access to a sandblasting cabinet. I want to sand blast the tank, front fender and the tail section and have a body shop friend of mine respray it with any cool color he has laying around. I also have bars of LEAD and a lead melting pot. What is the best way to get the dents out of the tank or fill them? Bondo or lead? Is lead to heavy to use high up on a bike? :?

[Anonymous]

Re: Filling dents after sand blasting, and before painting t

I know, I know this topic has been visited a lot but had a few questions.
The tank on my '80 GS850G I bought for $300 from a junk yard is a mess on the outside!! Inside is OK not to much rust; the petcock is leaking a little but hope to fix that while the tank is off. It has deep scratches; deep dents all over and has been re-sprayed poorly once. I have access to a sandblasting cabinet. I want to sand blast the tank, front fender and the tail section and have a body shop friend of mine respray it with any cool color he has laying around. I also have bars of LEAD and a lead melting pot. What is the best way to get the dents out of the tank or fill them? Bondo or lead? Is lead to heavy to use high up on a bike? :?

The tank sounds like a candidate for the scrap heap. As bad as it is, sandblasting will only make it worse - it's not for sheet metal. Sandblasting the plastic fender and tail sections will destroy them.

If you insist on keeping the tank, remove the dents as much as possible, don't fill the big ones.

If it was my tank I would look for another. If I HAD to keep it however I would flush it with water and remove all traces of gasoline (for welding safety). I would then drill small holes in the dents and use screws to pull them out as flush as possible - sometimes it needs a few on each dent. Then grind the flash down and mig weld the holes closed. Grind flush again and fill with putty, or lead or you have the skills.

Finally, get some tank prep and sealer for the inside.

[shortlid]

Tanks then?

Thanks for the info will just hand sand the plastics. How about the front fender can that be sand blasted? Anyone got a complete tank and a NON leaking petcock for cheap??

[robinjo]

A car bodyshop should be able to get out a bif part of the dents with just a bit of filler needed to get it smooth. They have this device which is a spot welder/slide hammer, very clever.

[Anonymous]

Re: Tanks then?

Thanks for the info will just hand sand the plastics. How about the front fender can that be sand blasted? Anyone got a complete tank and a NON leaking petcock for cheap??

You cannot sandblast plastic and you should not sandblast sheet metal.

If the fender is metal use some paint remover on it then sand. if it's plastic - just sand.

That sandblaster may look convenient sitting in a corner, but it will ruin thin metal parts. You can use different media other than sand, but for the small amount of work you have it probably wouldn't be worth it.

Elbow grease - that's the ticket!

Robinjo is correct that bodyshops can take out the dents. They do it very simiarl to the method I described. Instead of drilling holes and using screws, they spot weld on a rod that they use to pull the dents out.

Take it to a shop for a quote on removing the dents and also check ebay for a tank, you may get lucky.

[bucketsofgs1000]

My tank was smashed in about an inch deep in the entire forward right corner. I first stripped all the paint off to bare metal using a combination of an old weak sandblaster and aircraft coating remover (that worked great: took about 30 seconds to eat through clear coat, base coat, and primer which sat curing for 27 years. It wiped off with a cloth. After that, I filled the big dents with many many layers of bodo, adding about 1/8" at a time and sanding back smooth, then cleaning with alcohol and repeating. Make certain the tank is extremely clean before using any fillers. After completing the filling process, I primed the tank black. Once primed, I put a carbon fiber overlay on it to hold all the filler in place in case anything vibrated loose. For this, the tank was painted with a thick coat of high quality laminating epoxy and then the carbon laid up and vacuum bagged onto the tank. It now is waiting for a coat of clear coat over the carbon to give it a glassy look. I am using dupont automotive clear coat for that. I just need to get a chance to do it.

In any case, I believe you can fill the dents, but cleanliness is key when doing any body work of any kind. Buy a lot of the strongest isopropyl alcohol you can find.

[SqDancerLynn1]

If the tank has some rust I would sugest having it boiled clean at a radiator shop, do the body work, then coat the inside with POR 15 Then do the painting work

[RobGS850L]

Use media blasting on all the parts when stripping in that fashion. When using a chemical stripper use aircraft stripper on the metal and use uerethane stripper on the plastic parts. After stripping the metal parts down to bare metal you must put on a protective coat. I would suggest epoxy primer it's waterproof and you can do body work on it. Just a little FYI for future reference.

[Cracker]

As the others have said, you can't sand blast thin metal. There are other, less damaging mediums that you can use in the blaster (shells, hulls, plastic beads,...) but sand will just tear it up too much.

[retrex]

Another option

I agree with all who say do not sandblast. I recently stripped (chemically)an 81 GS11 tank inside and out (had the Kreem crap on the inside, don't use this stuff) and did the inside with POR 15 US Standard Tank Sealer inside and the outside with POR 15 rust encapsulator paint. I had some dents which I filled after the POR 15 was applied. I used their fillers and it worked out very well. I finished off with two coats of their Blackcoat and one of their Glisten PC. From the look of it the tank is impervious to weather and corrosion. I still have to spray on the original stripping and give it another coat of clear when the weather warms up. Good luck

[ron bayless]

YOU CAN GO TO OLD BIKE BARN OR ANDERSON VINTAGE MOTORCYCLE PARTS AND GET A NEW PETCOCK FOR ABOUT $29-$42.00 DEPENDING ON THE MODEL.