Here is my intake manifold after 24hrs. Had to clean the rebar twice and replenish the washing soda. Required some scrubbing and cleaning with a scouring pad and wire brush. This came out really nice. Has some flash rust but right before paint I will clean that off with some CLR and a scrub pad.

 

That looks like a shoe in.. lol

 

Got lost for a second. Realized after my reply the age of the last post.

 

@vintage56 Never saw your post. What was the question? Still happy to answer any inquiries!

 

It had to do with hydrogen embrittlement with the electrolysis process and if there is risk to changing the metallurgy of the metals - particularly structural components.

 

That is a very interesting question especially when talking about the intake and exhaust manifolds. Way above my mental abilities and education!

Maybe someone else knows?

 

Following this thread

 

I just googled “hydrogen embrittlement electrolysis” and found some of the threads and resources I remember.
I think the main part I would be worried about would be the leaf springs?
I don’t think I can post links to other forums here but here’s a try:
https://www.practicalmachinist.com/f...lement.156015/
Admin, please remove if disrespectful of our guidelines.

 

Hydrogen embrittlement will only occur when there are large currents employed over an extended period of time. In the process of rust removal the energy/current is focused on the surface and does not effect the steel below the top few millimeters. Hydrogen gas is a by-product of the electrolysis, most of this gas is released into the air during the process but some may remain in the metal...this residual hydrogen will dissipate into the air when the part is removed from the solution. It is good to know about embrittlement, but it is better to know that it is nothing to worry about at this level.

 

I just came upon this thread and thought I'd throw out an alternative I think is easier and might work better. And maybe a little safer.

I like phosphoric acid. I've removed a lot of rust from some really scaley rusty pieces of metal. These are parts for the spare tire mounts for my '37 Buick.



I had a three multipart wheels from an late 20s, early '30s Ford truck. The rims were really bad. I built a frame out of 2X8s that the rims just fit into and used some more 2X8 blocks to take up room. I then lined the frame with heavy plastic, placed a rim inside and filled the box with about 2 gallons of phosphoric. I left the rim soak overnight and in the morning the metal was rust free. I didn't take any pictures of the rims or my procedure, wish I had. Also, the acid leaves a protective coating that will hold off rust for while until you can paint the part.

There are a lot of phosphoric acid based products out there but some can be expensive. My son is a dairy farmer one one of the chemicals he uses to clean his milking equipment contain something like 75% phosphoric acid and it's about $20/gal. After I'm done using it I pour it back into the jugs it comes in and let the dirt settle to the bottom and use it over.



have reused it quite a few times but eventually it wear out and I neutralize it with backing soda from the dollar store and dump it down the drain.

 

DIY evapororust is citric acid and sodium carbonate, 40% of acid. Threads on the HAMB and utube.

for electrolysis tank, get some PH Plus in pool section at Wallyworld. Pretty cheap for a big tub. It is sodium carbonate. Have used it myself.

 

I've seen people suggest muriatic acid, no way I would suggest that. I won't allow that stuff in my shop. I used it once to clean some copper buss bars before tinning them with soldier. First, I almost passed out when I poured it into a small pan to soak the copper bars. First time I used it and didn't realize how nasty it was. I moved to just inside my overhead door so I could get better ventilation while using it. I cleaned the bars and poured the remainder back into the bottle. The next day I came into my shop and every piece of mild steel, bare or painted, within ten feet of my work area was rusted. Phosphoric acid is milder but still will bite into your skin.

 

If concerned about hydrogen embrittlement, one of the milspecs is to cook the part at 220* for 8 hours. Must be done sooner rather than later.

 

I agree, I would steer clear of Muriatic acid. It has to be neutralized, plus that would give a better chance of embrittlement. As you mentioned, can make a mess in your shop.

 

I've used muriatic acid and don't recommend it.
1. Don't leave small parts in the acid too long....you may not be able to find them later.
2. Tried it on an alloy wheel to see if it would remove the clear coat. It did, plus some of the alloy too. Good thing it was a junk wheel.