Question: Sandblasting or beadblasting

[Matthew Evans]

Good afternoon and I hope everyone is doing well. I was hoping someone out there has had experience with beadblasting steel as preparation for engraving a firearm. At the moment I have stoned and hand sanded my Kimber gold match stainless 2 to a reflective finish with no scrape marks and the shape that I want and would like to take my time getting the right texture before a graver touches it. (An engraving is only as good as it’s weakest link)
My goal is to find the best form, whether it’s sandblasting , beadblasting, etc and then adding a French grey with things that have been discussed already. ( cold blue then phosphoric acid toilet bowl cleaner)
I would like to get a velvety, or satin finish on my Kimber project and I will not touch it with chemicals till I’ve practiced elsewhere, so don’t get scared I’ll do something rash lol. Last resort will be handing it over to Turnbull restorations as they can do no wrong from what I see.

My thoughts without said practice are that a beadblast would be sufficient to get an even texture and the chemicals would give it the porosity on the top layer that is so desired.
Side note, has anyone beadblasted gold to give a frosted look for background rather than doming or stippling?
Thank you for your time in advance,

-Matthew Evans

 

[Chujybear]

Take what I say with a pound of salt, because I haven't sandblasted engraved work.. I have done some sandblasting preparing large bronze castings for patina and on glass.
Caveat out of the way.
Strikes me, that if you are going to French grey, and your canvas is already level and clean, sandblasting might be redundant in the process.
I suppose if you are cutting through a toothed surface, the French grey might have a more aggressive appearance outside of your cuts. You will have to make sure you don't make any slips when you lay down your lines tho.

 

[Matthew Evans]

Take what I say with a pound of salt, because I haven't sandblasted engraved work.. I have done some sandblasting preparing large bronze castings for patina and on glass.
Caveat out of the way.
Strikes me, that if you are going to French grey, and your canvas is already level and clean, sandblasting might be redundant in the process.
I suppose if you are cutting through a toothed surface, the French grey might have a more aggressive appearance outside of your cuts. You will have to make sure you don't make any slips when you lay down your lines tho.

I appreciate that, I’ve never had the pleasure of seeing a gun in person with a French grey, only pictures. So that gives me a good idea.

 

[dms]

Sandblast is more aggressive than bead blast, soda blast even finer. The top of slides are mostly bead blast for anti glare. you can mask off areas to keep polished part for design. The biggest thing to watch is your pressure. I do not know about gold, but be careful you might end up with gold dust.

 

[Dave London]

Don’t get cold blue any where near gold it will discolor it, and stain and a #@%& to remove. Maybe TOS will chime in he has done a lot of French grey
I would not bead blast MTC YMMV

 

[SamW]

I don't know if I can help much. First, blasting prior to engraving is not the way. The surface will be easily marred as you engrave. I can never cut without at least a modicum of burrs which I constantly wipe over with well worn 600 grit w/d paper. The only time I have applied cold blue to stainless was to verify it was stainless. It was like putting water on glass...beaded up and rolled off without affecting the metal. When engraving stainless, the only "finish" I have applied was to matt (stipple) the background.

French graying I have done has been on gun steel after bluing...preferably rust blue but hot dip is OK. I mask off the areas I don't want to gray with fingernail polish then apply Naval Jelly to remove the blue where I want gray. I continuously dab the Jelly over the area to keep it from drying out until the blue has been eliminated then a quick rinse with hot water. It can take 3 or 4 applications to get the proper clean look. I then wipe with acetone to remove the fingernail polish and any oil and apply renaissance wax, the first couple of coats having lamp black added to blacken the details of the engraving. Then a couple of clear coats.

 

[Matthew Evans]

.

 

[Mike Cirelli]

Bead blasting on gold looks great with flush set diamonds. It makes the stones stand out beautifully. Glass beads work best sand doesn't have a uniform finish like glass.

 

[Matthew Evans]

I’ll give it a shot down the road, thank you sir.

 

[Andrew Biggs]

Many years ago I engraved a custom made bolt action rifle that had a very fine sandblasted finish on it.

It was a total pain in the backside. It made the surface slightly porous and rusted with fingerprints. Transfers (transparency ink jet) became almost impossible because of the very slight textured surface.

Any slips, burnishing and sanding to fix instantly changed the surface texture……….etc.etc.etc.

So I ended up having to sand everything to a 400 grit finish. After that I was good to go.

Other peoples experiences may differ but for me I would never do it again

I have seen selective bead blasting after the engraving and that looked very nice.

Cheers
Andrew

 

[Matthew Evans]

Many years ago I engraved a custom made bolt action rifle that had a very fine sandblasted finish on it.

It was a total pain in the backside. It made the surface slightly porous and rusted with fingerprints. Transfers (transparency ink jet) became almost impossible because of the very slight textured surface.

Any slips, burnishing and sanding to fix instantly changed the surface texture……….etc.etc.etc.

So I ended up having to sand everything to a 400 grit finish. After that I was good to go.

Other peoples experiences may differ but for me I would never do it again

I have seen selective bead blasting after the engraving and that looked very nice.

Cheers
Andrew

I owe all of you guys a beer or a steak when I go to a fega show. Thank you

 

[MoldyJim]

One place I worked at had a blasting cabinet with glass beads, about 1/2 mm in diameter.
It left a beautiful satin finish on steel. Very similar finish to the one on Starrett micrometers.

Probably illegal today, but it sure made a nice finish, that was not rough or porous.

 

[sam]

I've bead blasted many custom knives and a couple of gun jobs years ago. What I did was complete the engraving sans shading, mask off the area with frisket paper and cut through the frisket into the engraved lines with a scalpel under the microscope and peel away the area I want exposed with tweezers. Lightly blast with glass beads and then do the shading and blackening. It can be a very stunning effect.

Here's one I masked and blasted with aluminum oxide to darken the background around the scrolls. Done in the early 90s.

 

[sam]

A couple more. One with blasted background and one with blasted (frosted) scrollwork.

 

[Matthew Evans]

A couple more. One with blasted background and one with blasted (frosted) scrollwork.

It is very stunning, thank you for showing and explaining. Will have to make some money from a few jobs to fund it =)

 

[mitch]

What I did was complete the engraving sans shading,

Interesting. I always found the blasted surface so fragile, prone to scuffing or burnishing with a hard stare, that it was the very last thing I did before the black paint. I can't imagine getting the shade lines cut without marking it up with stray chips, especially with a work-hardened curl of stainless.

Selective blasting was the thing in the 1980s into the '90s. That matte grey finish did look pretty cool, tho...

 

[Proteus]

Has anyone tried steel shot blasting? Is it worth trying on steel engravings or it may damage the engraving?

 

[rmgreen]

My 2 cents - All of the above is right on and should be taken to heart! If by "cold" blue you mean the traditional rust bluing. SS will not rust! Therefore it can not be blued by this mean and/or this mean can not be used for the "French Greying" process. If cold blue means the coloring of metal from a bottle and dab it on or hot caustic bluing(tank) then it is possbile to get some coloration on SS. These process do not create the microscopic "pitting" of rust bluing. To get a "French Grey" on SS some mechanical means must be use to produce the soft matt finish you are seeking as to "French Grey". Few chemical processes can provide the microscopic etching/pitting of SS. Like engraving (graver tool) media shape, size and depth all produce difference "colors" "greys" refelective light. Experiment in like metal for the effect you desire.