How to clean my surface gage?

Patrice Lemée

Patrice Lemée

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Aug 13, 2002
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I found this surface gage at my Dad's. It looks very much like a Starrett but I am not sure. Anyway it looks to be of pretty good quality. The only problem is light surface rust as you can see on the pics. What is my best course of action to clean it up? Simply use some light oil with a very high grit sandpaper on the granite plate or should I go the electrolytic rust removal way which I haven't tried before my the way?

What do you think?

Patrice
 

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You are right about the sand paper and granite plate. Although it is precision Tool. The surface is not a critical surface it could 1'' or .990'' thick. It will not effect they way you use it.
 
I'd say try either a good naval jelly rust remover, or electrolytic. Afterwords Sand the base flat to ensure a good flatness to the bottom. I'd say start at 400 and go up from there to about 1000 and you'll be set.

I'd probably strip it down, hit it with some steel wool and WD-40 or oil, flatten the bottom, then put er together. Most of the rust on that is black oxide a good coating for steel tools.
 
Electrolytic is the way to go Patrice. :) I use it all the time, and it's very effective and VERY SAFE to use on fine tools such as this one. :)
 
Steel wool and WD40 get my vote. Then lapping on the plate with no paper. I don't love the idea of sanding on that.
 
It looks to be a old scribe holder, there should be a rod that goes in the hole and a scribe attaches to the rod.
I agree with the steel wool and WD 40 method.
Richard
 
The steel wool and WD 40 works great, I used it on a double barrel shotgun I bought that was rusty. When you get her cleaned up make a rod that can hold a scribe, a shank off a broken 1/8 carbide endmill works great and a clamp for your dial indicator and you are all set.
Paul
 
Steel wool and WD40 it is then. And yes it did come with the rod and attachment thingy.

Thanks a bunch, I'll post pics of the result.

Patrice

PS: Nick, the electrolytic method sounds cool. I have to try it. I am sure I can find some rusty something in the shop.
 
Electrolytic gets rid of ALL the rust and not just what is easily accessible with WD40 and steel wool.

This is the kind of project that electrolytic was made for... returning old metal parts to their previous condition. It will help you get rid of all the rust and without abrading the surface of the part.

And it's VERY simple to do. But what do I know??? :foot:

:)
 
Ok I tried on a small part to start. It is working but too slowly, something is wrong. Of course I used Tide laundry detergent and eyeballed it. that is probably the reason. :(

If I may ask Nick, what do you use for your solution and at what ratio?

Thanks

Pat
 
I am not Nick but I have a little experience with the electrolytic rust removal process. I cleaned up my dad's old shop vise - it sat for 13 years on a bench with a roof leaking on the bench. It took about a week as I had to clean one part of the vise at a time.

As to your question: sodium carbonate (aka soda ash), the stuff in Arm and Hammer Washing Soda is the recommended product. I used a 5 gallon Homer bucket and about a tablespoon per gallon of water. The purpose is a PH adjuster and to increase the conductivity of the water. Some folks say baking soda works also, just have to use more of it. I am not sure how much more to use.

I found internet sources that purport baking soda can be turned into washing soda by: pouring the baking soda on a cookie sheet, put in an oven at slightly above 300 degrees F for at least an hour. I cannot confirm nor deny if it works.

As for the process working slowly.. that is ok because it is a slow process. I came to the realization that, for me, a good visual indicator the workpiece was 'clean' was if the bubbles were 'whiter' or 'cleaner' than earlier, i.e., not red or rust tinted. Remember, it is getting rust off the surface of the metal, then out of the pores of the metal... just takes time. I used a piece of cheese cloth to clean the surface of the solution of the scum. That will help you see its progress.

If it were summer, I would say put on the back porch and let it run all night. You may already know this... it generates hyrdogen gas... no sparks, no flames or it makes a loud noise and then your wife makes loud noises...

Hope this helps...
 
It is working but still a little slow. There's nothing wrong with slow but I am sure the process could be improved. I am only getting 2 amps flowing through with a 10 amps battery charger. I used the recommended solution, the piece and electrode are close without touching. Not sure where the weak link is. I have good contact on the piece and electrode.
I may try adding another electrode to see if it helps.

Patrice
 
I do it like jorasco said.

I usually use baking soda as it's what I have out in the shop. About 2 tbls. per gallon of water.

I set the charger at full charging rate.

Every now and again I'll take the part out and clean it up as the crud will impede the rust removal.

Grey scotchbrite works VERY well for this and for the final cleaning. :)
 
Nick, cleaning would help if the amps actually diminished but the 2 amps I get are with clean electrode and part. I'll try multiple electrodes tonight and post my results.

Another question. How far should I take it? I rather like the dark patina look and I think it would help fight corrosion. As far as precision goes, it feels as smooth as clean steel even more so.

Patrice
 
Well the second electrode did nothing but a new stronger solution did raise the amps to 4-5. I am getting there. :D

Patrice
 
Patrice.
Your charger can deliver 10 amps,through a perfect conductor, but the electrolyte is not a perfect conductor. The actual current draw is a function of the resistance and the voltage. If the voltage is raised, or the resistance lowered, the amps go up. For your pieces of metal and the electrolyte you are using, 2 amps is what you are going to get. That isn't a problem, as the slower the electrolysis, the better it works. On antiques that have severe rust and corrosion, the process can take many years for restoration. Also, be aware that the process will remove rust and corrosion, but the pits and holes formed by them will still be there. A good coating of protective oil or wax will always be required after the electrolysis is done. The item will need to be completely desiccated (dried to the bone) of all water and electrolyte before the oil/wax is applied.

Stacy
 
Thanks Stacy. I will continue with the set-up I have then. When they are finished, I will heat the parts a little in the oven to dry them good.

Patrice
 
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