Getting the ‘57 beetle back on the road in 2024

What is the danger of hydrogen embrittlement when performing electrolysis to remove rust? I won’t pretend to know, but I have enough suspicion that phosphoric acid is my go to.
Found this..... The short version is yes, it can.... BUT... it's easily reversible.


"Hydrogen Embrittlement of Steel - A Cautionary Note

Atoms of hydrogen absorbed by steel are known to enter the lattice of iron atoms and prevent the layers from sliding past each other easily. This causes the steel to become more brittle and liable to crack. The absorption of hydrogen by steel is a familiar problem in industry which arises during steel refining, heat treatment, acid pickling or electro-plating. It can also happen as a result of simple corrosion. The standard remedy is to bake the objects in ovens to drive out the absorbed hydrogen (200°C for four hours would be a typical regime in industry). The simple passage of time is also known to cause loss of hydrogen from steel. Hydrogen embrittlement may occur to some extent during electrolytic de-rusting. This may be a cause for concern with saws or other edge tools. It might be wise to wait a while before setting saw teeth after prolonged, electrolytic de-rusting. Alternatively, baking the tool in the oven for hour or so at about 150°C (300° F) should remove absorbed hydrogen. Note that this baking temperatures is low enough to leave the temper of most steels unaffected. Since hydrogen embrittlement is reversible, it should not cause too much anxiety. I believe that the advantages offered by electrolytic de-rusting justify wider experimentation by tool collectors. As more experience is gained clearer knowledge of its advantages and disadvantages will emerge."

From here: https://htpaa.org.au/resources/rust-removal

Good info there. Worth a read.
 
Found this..... The short version is yes, it can.... BUT... it's easily reversible.


"Hydrogen Embrittlement of Steel - A Cautionary Note

Atoms of hydrogen absorbed by steel are known to enter the lattice of iron atoms and prevent the layers from sliding past each other easily. This causes the steel to become more brittle and liable to crack. The absorption of hydrogen by steel is a familiar problem in industry which arises during steel refining, heat treatment, acid pickling or electro-plating. It can also happen as a result of simple corrosion. The standard remedy is to bake the objects in ovens to drive out the absorbed hydrogen (200°C for four hours would be a typical regime in industry). The simple passage of time is also known to cause loss of hydrogen from steel. Hydrogen embrittlement may occur to some extent during electrolytic de-rusting. This may be a cause for concern with saws or other edge tools. It might be wise to wait a while before setting saw teeth after prolonged, electrolytic de-rusting. Alternatively, baking the tool in the oven for hour or so at about 150°C (300° F) should remove absorbed hydrogen. Note that this baking temperatures is low enough to leave the temper of most steels unaffected. Since hydrogen embrittlement is reversible, it should not cause too much anxiety. I believe that the advantages offered by electrolytic de-rusting justify wider experimentation by tool collectors. As more experience is gained clearer knowledge of its advantages and disadvantages will emerge."

From here: https://htpaa.org.au/resources/rust-removal

Good info there. Worth a read.
Great, thanks Jim, perhaps a bake on the bbq would do the trick. I wouldn’t be concerned about small brackets but maybe a hood treatment for the brake drums? Great article, it answers lots of questions.
 
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Great, thanks Jim, perhaps a bake on the bbq would do the trick. I wouldn’t be concerned about small brackets but maybe a hood treatment for the brake drums?
From reading that article it sounds like the H2 leaches back out over time. Figure a year 'till back on the road? You'll be well in the safe zone by then.
 
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More from that article....
"If the contact points are coated with rust, dirt or grease, little current will flow from one part to the next and de-rusting may be slow."

Tells me the part needs the oil AND rust needs to be removed at the connection point. I'd be curious to see what would happen if you de-rusted that oily drum as is.... just clean off a point where the alligator clip goes. I'm thinkin' the oil will turn to sludge and fall to the bottom along with the rust remnants.
 
And more....

"Other Variants of the Electrolytic Method
1. The bath itself may be made of stainless steel and used as the anode (positive electrode) while the rusty object is suspended in the middle of the solution without touching the container. This method maximizes the size of the anode and allows current to flow to the object from all directions - thus minimizing shadowing effects."
 
More from that article....
"If the contact points are coated with rust, dirt or grease, little current will flow from one part to the next and de-rusting may be slow."

Tells me the part needs the oil AND rust needs to be removed at the connection point. I'd be curious to see what would happen if you de-rusted that oily drum as is.... just clean off a point where the alligator clip goes. I'm thinkin' the oil will turn to sludge and fall to the bottom along with the rust remnants.
Maybe. I’m going to look through my stash of metal scraps for some SS to make the anode(s). Not sure if the surface areas of the part and anode need to be relatively equal? Do I do one side of the drum at a time or both at the same time using two anodes?
 
Maybe. I’m going to look through my stash of metal scraps for some SS to make the anode(s). Not sure if the surface areas of the part and anode need to be relatively equal? Do I do one side of the drum at a time or both at the same time using two anodes?
Think of it as the anode being a "light." Anywhere the light shines will get de-rusted, the shadows won't.
Two lights (anodes) shining from opposite directions will light up more area and reduce the amount of shadows.

So yeah... 2... maybe 3 anodes 120° apart would approximate the stainless pot mentioned above.

I don't think the area of the anodes matter much as long as they reach the bottom of your bucket (the shining light thingy) . More area equals more conductivity but "relatively equal" probably doesn't matter that much.
 
Maybe. I’m going to look through my stash of metal scraps for some SS to make the anode(s). Not sure if the surface areas of the part and anode need to be relatively equal? Do I do one side of the drum at a time or both at the same time using two anodes?
I don't think the anode and cathode need to be the same size, based on the success of the fuel tank rust removal I have watched online. The cathode in that case is the fuel tank and the anode is always smaller than the tank.
Re hydrogen embrittlement - I'm not concerned about the tank in my case as hydrogen of course is a gas and it will escape out of the filler hole.
That said, steel is porous and it does naturally have hydrogen in it. Welding on wet and or cold steel will cause hydrogen to be trapped in the weldment and could cause hydrogen induced cracking, which can occur up to several hours later as the hydrogen is naturally escaping from the steel. Proper preheat procedures will prevent this from happening. (The welded area takes longer to cool which allows the H2 to escape)

In the Beetle rebuild, I'm putting my money on time allowing any affected parts to be normalized and everything being just fine before it gets going again down the road.
 
Think of it as the anode being a "light." Anywhere the light shines will get de-rusted, the shadows won't.
Two lights (anodes) shining from opposite directions will light up more area and reduce the amount of shadows.

So yeah... 2... maybe 3 anodes 120° apart would approximate the stainless pot mentioned above.

I don't think the area of the anodes matter much as long as they reach the bottom of your bucket (the shining light thingy) . More area equals more conductivity but "relatively equal" probably doesn't matter that much.
Great way of describing it. I do have some SS sheet (3” x approx 60”) that I could cut into 3 equal lengths. I’ll confirm the length tomorrow.
 
I’m pretty excited about trying this out. I’ll get a Home Depot bucket and I think I’ll buy some flat bar to hang around the sides.
Go cheap, go re-bar (skinny stuff, like 3/8"). Cheapest new steel around. Flat bar is expensive these days. Any old steel is fine too, as long as its bare.
 
Anyone know what kind of plating was used on the Yamaha tools? Zinc maybe?
Was gonna bead blast these and re-plate. I might just try the 'lectric shock bath instead...


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Great way of describing it. I do have some SS sheet (3” x approx 60”) that I could cut into 3 equal lengths. I’ll confirm the length tomorrow.
NOTE: Do not use stainless steel for the electrodes. As pointed out by a commenter on the intro page (thanks!) "The chrome in the stainless will leach out during the electrolysis and form hexavalent chromium compounds (highly toxic) in your electrolyte.
 
I’m liking the idea of using a SS pot as the anode. Wonder if my wife would notice if one was missing. lol. Actually I started looking on line for a used one.
 
NOTE: Do not use stainless steel for the electrodes. As pointed out by a commenter on the intro page (thanks!) "The chrome in the stainless will leach out during the electrolysis and form hexavalent chromium compounds (highly toxic) in your electrolyte.
Hexavalent chromium is a known carcinogen. It is part of the nasty fume generated when welding stainless steels and warrants wearing respirator for sure so great advice Atom4488 :thumbsup:
 
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