Electrolytic derusting advice

[mattthemuppet2]

thanks for the tips everyone, they're very much appreciated! I took the chuck out last night and all the stuff that I thought was left on it just wiped right off. As Bill said, the finish was a dull grey, so I'll give it a whizz with a scotchbright pad and some Mothers to pretty it up. It wasn't heavily rusted, but it did clean up very nicely and came apart easily too, once I figured out how to get it apart.

I'm going to keep my eyes open for some steel plate (or even graphite plate!) next time I'm at the scrap yard and work on a better connection from the +ve lead to the plate/ rebar as it's a bit ghetto right now. I have wirebrushed the rebar and I'll keep an eye on it as I do more electrolysis. Good tip about the sacrificial piece of steel to clean off the anodes, I'll remember that.

Overall I'm really pleased with how it's working - does a good job, costs peanuts and I can leave it to do its thing while I'm doing something else I'm planning on having this going 24/7 with different bits as I take them off the lathe - that way I'll have a constant stream of stuff stripped, stuff being undercoated and stuff being topcoated. It shouldn't take long to get it back together if I can keep that up!

 

[Billh50]

Matt,

Good job. I only use the electrolysis now for all rust removal unless the part will not allow me to. A friend of mine uses a 50 gallon plastic drum so he can put large parts in.

 

[ed_h]

I've done electrolytic derusting, and it works fine, but no better than what I consider simpler methods.

The clean part of this exhaust manifold was immersed in a 50/50 solution of phosphoric acid for an hour or so. (My tank wasn't big enough to do the whole thing at once.) No power supply, no wires, no anodes. No line-of-sight issues--it even derusted the inside. Phosphoric is easy to get, safe to use, and lasts quite a while.

Electrolytic derusting seems to be a bit of a fad right now, and to each his own, but there are other worthy methods that might be easier.

Ed

 

[mattthemuppet2]

For sure Ed, what ever works best for the job. I took this approach as it cost me nothing bar the washing soda and that's amortized with the clothes washing

 

[Billh50]

I also would think acids are not safe to dispose of just anywhere. But then I only slept at a Holiday Inn once.

 

[MozamPete]

I have had great results with electrolytic derusting, but I use a weak sulphuric acid mix as the electrolyte - battery acid from the automotive shop mixed about 1 part to 5 with water. Doesn't seem to break down so I just keep using it, topping up for evaporation, and don't have any 'disposal' to worry about (apart from the odd filter paper that I run it through when it starts to get a bit mucky).
Watered down it is only about as acid a vinegar - wont burn you skin but hurts if you get it in a cut.

Speaking of which I have also recently be doing some de-galvanising with pain vinegar - slow but works well.

 

[shoeboxpaul]

I also would think acids are not safe to dispose of just anywhere. But then I only slept at a Holiday Inn once.

Another alternative is the molasses method. Youtube has several videos covering the process. I like the ones from Australia, the listing shows and old car from the late 30's. Others are good also. The molasses is a feed grade and not what you can purchase in the grocery store for baking. The process does work, I have tried it for some small items. My cost is about a dollar a gallon and I have to supply my own jugs for a minimum purchase of 10 gallons. At 9:1 - water to molasses - it will last me a while, hopefully sealed it will store. It is a slow process, up to 2 weeks, possibly longer, sometimes shorter, depending on the amount of rust. The solution is environmentally friendly, you could dump it in your yard. There is a farm supply store within driving distance, they cater to livestock. Not all farm stores carry it. No electricity involved.

 

[mattthemuppet2]

I've heard of that one too, lots of ways to skin this particular cat I've tried white vinegar too, for drill bits and taps, which works okay. Tends to turn non-tool steel matt grey/ black for some reason, but doesn't affect the finish of HSS pieces. Still, works in a pinch to renovate an old tap or drill.