Burnishing VS. Sandblasting for wax finish

eligius1427 - Saturday, July 12, 2008 - 6:01pm

Hi all, I'm coming to the finishing part of a rail that I'm currently working on and would like some input on cleaning the scale off. The rail is getting a beeswax, linseed oil finish over forgework. Does anybody have a preference between wire brushing the scale off versus having the piece sandblasted. I'm a little bit behind on this project due to my chair refinishing fiasco and the sandblasting would obviously save me some time. I'm assuming the finish coloring would be much more uniform over the sandblasting and more varied with the burnishing, correct? Would it look less "handmade" with the sandblasting? I don't want to sacrifice the final look just to save a few days.

Jake

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Jake, Sandblasting will give

Rich Waugh - Saturday, July 12, 2008 - 7:51pm

Jake,

Sandblasting will give you a very uniform, matte finish that is composed of bazillions of tiny little impact craters, the size of which depends on the specific blasting media they use. Black Beauty or coarse sand will be too "toothy" a surface and will both look and feel rough to the hand. Fine glass bead blasting would give a very soft satiny finish that would feel okay. Any blasting finish will be very good at holding the wax/oil mixture to get a durable finish, but they'll all be a very uniform, featureless dull lgray finish unless you tint the wax/oil or heat darken it. Also, if you fail to get finish on any area at all, it will rust overnight since the blasted finish has about ten times the surface area as a hammered finish.

The one exception to the above would be if you could get it "blasted" with a Wheel-A-Brator, a machine that whirls like a dervish and flings steel balls at the object until it is beat into submission. Generically called "shot-peening." That gives a micro-planished surface that pops all the scale off but doesn't open up the surface the way that grit blasting does.

I would probably opt for the Wheel-A-Brator if available locally, or the wire brush, and not do the grit blasting.

I hope this helps.

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Wheel-a-Brator

Nic East - Sunday, July 13, 2008 - 6:24am

The neat thing about a shot-peened finish is that it will have a burnished appearance and increased surface hardness due to the cold working by the shot. Imagine using a very small ball pein hammer all over the metal and that will be a macro of the way this process works. Rich is right-on with his suggestion from my perspective.

Nic East, Jim Thorpe, PA USA
Creativity begins with a novel thought.

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Thanks Rich and Nic, I'll

eligius1427 - Sunday, July 13, 2008 - 1:23pm

Thanks Rich and Nic, I'll look to see if there is a shot peening service around here.

Jake

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hmmmm...you can blast. so

feorge - Saturday, July 12, 2008 - 9:53pm

hmmmm... you can blast so the scale is gone and then go back over with a wire brush to add highlights.

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Hi Feorge, Hope all is well

eligius1427 - Sunday, July 13, 2008 - 1:24pm

Hi Feorge, Hope all is well in KC. I'll blast some pieces and try to create a mottled effect by using the wire brush in places. We'll see what it turns up.

Jake

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Jake, I am partial to wire

QuiQue - Wednesday, July 16, 2008 - 3:46pm

Jake, I am partial to wire wheel brushing because of the natural sheen that it gives to the hot forged steel. I also like it when it leaves just a bit of "hard scale" in recessed areas from the forging operation. Sand blasting is a great solution for painting, but I have yet to see a really nice natural finish on forged ironwork.

If your railings are for indoor use I would recommend the wire wheel finish and then a coat of WD-40. It's way easy to apply and to maintain. If any rust ever shows up, the client can easily remove the rust with steel wool and reapply the WD-40. I also recommend to my clients to use the WD-40 on a lint free cloth to clean/polish the metalwork.

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