I am trying some hobby polishing on floorplates and curved surfaces just to see how it goes. Have learned about cross polishing with finer grits, the use of stones, and long even strokes.

But how does one get to that final finish that is suitable for a fine bluing job.

What are your metal polishing techniques?

Hot bluing or rust bluing? Makes a diff. And how shiny do you want it to be after bluing? Mirror, matte, or something in between. All that will determine what grit you use to polish with. Personally, I don't go for the mirror finishes so don't use the really fine grits/compounds. Any technique that keeps the surface flat is good, ripples are bad. I usually go to 320 and that's it. 400 at the very most.

With rust bluing you can't go much finer than #320 because the solution is going to etch the steel anyway and when the bluing is completed it will be pretty close to a 320 finish regardless what you started at.

With caustic bluing the rule of thumb is: "the higher the polish, the longer the finish will last."

No mater what type of polish you do you don't want to round edges or corners or wash out screw holes. Everything should be flat and ripple free and you want your polish lines all going the same way on all sides with no fishhooks in the finish. Hot bluing is all about the polish. Rust bluing, not so much. Rust bluing is very forgiving and can cover a lot of bad polishing, welding and heat treatment problems.

quote:

Rust bluing is very forgiving and can cover a lot of bad polishing, welding and heat treatment problems.

Damn, now you know my secret of how I cover up all my bad workmanship.

Actually, many years ago back when the earth cooled we used to cut the charging slots out of old 98 Mausers and glue them back together to make short actions. Yeah I know, pretty stupid but there were not a lot of short actions out there to build on. After spending all that time on them and cutting out barrels with quarter ribs, installing them and spending another 2 weeks on a chunk of fancy walnut they looked great. Until we caustic blued them and then those receivers would light up like a Christmas tree. Purple, green, blue and black all in the same square inch. The answer was to polish the receivers to about 320 and then dip them in diluted battery acid or acid rust remover for 20 minutes to etch the snot out of them. Then pull them out and soft wire wheel them and rust blue them. You couldn't even tell they had been welded sometimes.


ADD NOTE:

I have always said that you don't judge a gunsmith on the quality of his work. You judge him on how well he can hide or cover up all of the cluster-fucks that he's faced with on a day to day basis !

That looks like a #320 wet & dry polish. It could be the photo but it looks like he has some pretty heavy pitting that hasn't been cleaned up. Ether that or his etch got out of hand. Again, it could just be the photo.

Pitting by Rod Henrickson, on Flickr

I guess I should have said coarse polishing like 320 weight Duane. Rust bluing won't cover dished screw hole cross hatched polishing, fish hooks or pits. The rust bluing process will generally etch the steel to almost a 320 weight finish even if you start with a mirror finish. Rust bluing will and often does hide a lot of heat treatment and welding problems. That can't be argued. I have hot blued a lot of guns only to have stripped them and Belgium blued them to correct bad color problems.

As to the photo. I do see a lot of small pits that were dished out during the polishing. They should have been removed. But, just because they are there does not mean that they were not left there on purpose to preserve some lettering, engraving or to keep the costs down. They are there though and photos don't lie. It's impossible to say if it was good or bad management without being there at the time it was done.

How life-like is a photograph taken at such close range? I'd imagine this work would make any owner proud at a more realistic distance.
Sure would like to see one.

Pitting by Rod Henrickson, on Flickr[/QUOTE]

Well, just judging from sharpness of the engraving and the cross hatching on the rib, I would have to say that the photo is very life like. As far as the owner being happy, I guess it would depend entirely on what he was expecting and paid for.

still looking for techniques, recommendations on different types of polishing paper, stones, etc.

You need to answer dpcd's questions first. What are you going for? Hot blue, rust blue? Standard abrasives are silicon carbide(backed)papers, stones, and wheel compounds. For bright finishes you need a barrel spinner, soft wheel and skill. You can hand polish a barreled action with backed silicon carbide papers with oil or water to a pretty bright level. As pointed out, and even 320 grit finish is more than adequate for a rust blue.

Bob
www.rustblue.com

For final finish for a high gloss hot blue, you can use a felt wheel with rouge but you have to be very careful so as not to round, dish, etc. I have worked down to an 800 grit wet or dry then finished with a piece of leather and rouge backed by a file. I do a lot of polishing by hand because I figure it will be more work for me to screw it up and I might get tired before it happens! Once you have gotten to a 600 grit polishing roll, you don't have too much left to do providing you have not left any marks from the previous, coarser, grits. To be perfectly honest, I think the initial polish and shaping is more important than the final lustre. In other words, straight, flat flats, and smooth, uniform curves with no serious dips or humps. Regards, Bill Regards, Bill

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You need to answer dpcd's questions first. What are you going for? Hot blue, rust blue?

Since this is "hobby" polishing where I don't have to be quick to make money off of it, I am not concerned about what type of blue I am going to do after the polish. I will just polish for the hot blue each time, and then have the option of what type of bluing to use.

I don't have a buffing machine, so Mr. Leeper's idea for a final polish looks promising.

Thank you one and all for your responses.

I hand polish all up thru 320 wet or dry paper and then make the final polish with the SISAL WHEEL's about 1 in. wide. Use the fine sisal polish grease that Brownell sales and it will be a nice satin finish when hot blued. I like a shaft polish arbor about turns about 2800 rpm's. This has been my only polish wheel for years.

Polish?

I'm trying to match acid texture with hand stippled EDM

polish? we dont need no stinking polish!!

One key is to always back the paper. Try not to freehand. wrap the paper on a wooden block. Or a rubber eraser if if's an odd shape.

Also do the flat surfaces last.

Turnbull used to offer a polishing video/DVD that I thought was helpful.

The greatest invention in the world has to be the hockey puck. Cut it in half and flatten your saw cuts so that you have two big rubber woodruff keys and then wrap wet & dry sand paper around them and fix it with plastic thumb tacks. Then just dip it in kerosene and go to polishing. You can also regrind them on the belt sander to make all sorts of kinky curves and shapes.

ADD NOTE:
You can also concave them with different radius sanding drums so that you can use them on barrels without slipping from side too side as you polish. Just put the barrel loosely between centers in any lathe and run from one end to the other for dead straight polishing lines.