Why not hot tank.

I know we've discussed my gas tank before but if it has to be painted anyway, why not just hot tank it?

Assuming you mean giving it to a radiator shop and they keep it in their stripping tank then what you will get back is a piece of bare metal with all the rust/paint/coatings gone. You will know exactly what is left and can then get it repaired by welding/brazing or scrap it if its too far gone as there is not enough good bits left.

kommando said:

Assuming you mean giving it to a radiator shop and they keep it in their stripping tank then what you will get back is a piece of bare metal with all the rust/paint/coatings gone. You will know exactly what is left and can then get it repaired by welding/brazing or scrap it if its too far gone as there is not enough good bits left.

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Didn't think of a radiator shop. Talked to a machine shop. Wonder if they use a different solution.

Should work. Some time in the early 80s I did similar with a '57 Norton Model 50 frame. There was a shop locally called Strip Nu that hot tanked whole car bodies. The frame came back like new...beautiful with gold color braze on silver bare metal. Almost didn't want to paint it.

No reason why you can't hot tub it.

This is a sidecover I did recently.
I was surprised, it had been silver...

Radiator shops are dying out in UK but those that are left use a caustic solution followed by phosphoric acid dip but the caustic does the work.

kommando said:

Radiator shops are dying out in UK but those that are left use a caustic solution followed by phosphoric acid dip but the caustic does the work.

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Getting fewer and far between in the states too. I tried to get a couple of the closest local shops to my house, to do a Yamaha tank for me, but they both declined saying something about liability and how they no longer did anything except their customers radiators :?

Its not that impossible to do your own hot tubbing. !

A plastic garbage bin is large enough to hold a roadster tank.
A couple of small cans of drain cleaner (caustic soda, sodium hydroxide)
and some hot water, and you are in business.
BE EXCEEDINGLY CAREFUL IN ADDING THE CAUSTIC TO THE HOT WATER
AND WITH SPLASHING THIS STUFF ABOUT.

The sidecover above is sitting on the hot tub - $4 can of caustic, and some boiling water.
Be exceedingly careful with all of this, that stuff can burn, damage clothes and stuff and damage eyes.
Drain cleaner can be tipped down the drain after - filter out all the paint remnants FIRST.
It does a wonderful job of cleaning out your drains...

Phosphoric acid can (probably) be bought from your local auto store, only takes 250 ml to do several tanks.
Its one of the active ingredients in Coca Cola, although more concentrated as purchased.
Again, makes your drains spotless - makes the garden grow too - very diluted.

Hot caustic will positively eat aluminium, so keep alloy parts well away...
As well as clothes, flesh, eyes and small children and pets.
Keep the lid on the tub at ALL times and well secured when not used.

Note that some modern paints are quite resistant to hot tubbing, and old baked enamel finishes can be pretty tough too, so don't assume this will work for everything...

Make sure too that adding boiling water to your garbage can won't melt it....

For $25 @ the machine shop I think I won't mess with it. Thanks guys. I kinda remember doing my Triumph tank in the late 70's. Other then the tank being full of bondo from when my buddy the previous owner ran a stop sign & literally stuffed it into the back seat of a Ford LTD it came out looking very new..

Wolfman said:

For $25 @ the machine shop I think I won't mess with it. Thanks guys. I kinda remember doing my Triumph tank in the late 70's. Other then the tank being full of bondo from when my buddy the previous owner ran a stop sign & literally stuffed it into the back seat of a Ford LTD it came out looking very new..

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What do you use to remove varnish(old dried up stinky fuel) in a tank without hurting the paint? New fuel?

jimbo said:

Wolfman said:

For $25 @ the machine shop I think I won't mess with it. Thanks guys. I kinda remember doing my Triumph tank in the late 70's. Other then the tank being full of bondo from when my buddy the previous owner ran a stop sign & literally stuffed it into the back seat of a Ford LTD it came out looking very new..

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What do you use to remove varnish(old dried up stinky fuel) in a tank without hurting the paint? New fuel?

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The radiator shop I spoke to recommended Dawn dish soap to clean out the old gas. It worked like a charm.

Also, It's been months so I can't remember why, but The radiator shop recommended Not to boil the tank. So I purchased the POR 15 kit from Eastwood. It was cheapest at Eastwood and has everything I needed.

My tank is clean and waiting for a dent repair.

Rohan said:

Hot caustic will positively eat aluminium, so keep alloy parts well away...
As well as clothes, flesh, eyes and small children and pets.

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Funny it will melt aluminum but not solder.

It doesn't melt it, it chemically attacks it.
Aluminium is a very reactive metal with hot caustic, steel (very much) less so.

Hot water will just lightly rust your steel if left for a while. (and hot tubbing should be all over in seconds)
Thats why you then treat it with phosphoric acid after - it phosphates the surface and forms a barrier of sorts.
Auto painters use it by the drumfull...

Some hot tank chemicals will cause embrittlement of bronze welded joints like gas tap fittings

Hot caustic could well dissolve some zinc out of brazed joints (brass), but bronze should not be affected.
It would have to be long term though, and hot tubbing should only take a few seconds for a tank.
Remember, they use this to clean up iron V8 engines etc...

If any brass joints were affected, you'd only need to wave the oxy torch over it.

Rohan said:

Hot caustic could well dissolve some zinc out of brazed joints (brass), but bronze should not be affected.
It would have to be long term though, and hot tubbing should only take a few seconds for a tank.
Remember, they use this to clean up iron V8 engines etc...

If any brass joints were affected, you'd only need to wave the oxy torch over it.

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You have never used a cleaning tank have you ?
About 2hrs to remove the paint minimum
Wave a oxy torch over any affected joint , you wont know its been affected until there's petrol pouring out

Not a commercial one, no.
Got my own backyard version.
Cheap as chips, no need to wait....



Should only take seconds to strip the paint off, if its going to work.
Just comes off like a skin.

If its as badly affected the braze as that, you should be able to see it !!!
Rebrazed a few fittings, not to mention a few soldered ones.
Just general wear and tear though....

P.S. The fittings on most Norton tanks are steel welded there, and have been for a very long time..

BTW, hot tubbing is useful for all sorts of steel or iron items.
great for oil tanks and oily engine bits, the caustic is a perfect degreasing removal agent,
and nothing abrasive to get trapped or stuck anywhere.
And good for thin tin items too, where blasting may distort or even blow right through them !

https://s10.postimg.org/4bgincz7t/iron_head.jpg
https://s13.postimg.org/iaovvhk7r/otank.jpg
https://s1.postimg.org/64ildmz9r/thin_tin.jpg

Note that hot tubbing doesn't remove rust, that is an entirely separate process.