Re: DeRust, Refinish, and Spray

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Posted by Chris Ray on April 27, 1998 at 10:36:13:

In Reply to: DeRust, Refinish, and Spray posted by Elliott Schwartz on April 26, 1998 at 11:28:26:

How do I remove ALL the rust? Can I refinish with gunmetal brown and then spray with acrylic or polyurethane to prevent this from happening again. >">

Wax alone as a final top coat finish will not protect works from rusting in an exterior environment. Sometimes an emulsion made up of BOTH beeswax and boiled linseed oil is used for exterior work but this finish is not permanent and needs to be reapplied occasionally.

Now to address the question of removing rust, applying a browning finish then a topcoat. First a suggestion. Is the piece you want to refinish currently rusted all over with an even finish? If so then here is something you might consider. Use a penetrating oil (Penatrol is one good procuct, Valoil is another). Apply a penetrating oil over the rusted work after first lightly wirebrushing the loose rust. You might also try evening or blending the scratched surfaces with either a steel wool pad or even a wad of hard woven cloth.

When you are satisfied with the look of the surface, then apply the penetrating oil. Make sure to do this liberally and allow the oil to soak into the material. You want to be certain that the oil not only binds the rust together but also binds underneath to the parent metal. Before the oil dries you may then wipe off the excess oil or even keep the soaked cloth on the piece, continuing to rub down the surface, blending in the variations of rusted surfaces further. I have recently tried Thompson's Water Seal as a substitute for a penetrating oil but the test piece has not been exposed long enough for me to determine the viability of doing this yet. It might work for metal rust as well as it does to protect porous wood, I don't know yet.

Do keep in mind whenever you are keeping a rusted surface intact, that the metal underneath still needs to be protected from further oxidation so make sure that whichever penetrating oil product you use that it both binds the rust itself and seals the parent metal underneath.

Later when the piece is dry, then apply a final topcoat on the work using a good grade of marine spar varnish. You may spray this or apply with a brush. Polyurathane might be okay too but I prefer the spar varnish for a long term finish. On top of the dried varnished finish you would THEN apply a wax coating which will futher protect the protective finish and also kills the gloss. Over time, the sand, dust and grit that is swept over the work by the wind will give you a natural dulling of the surface.

Now, if it is the gun browning chemical finish you wish to restore to the work then you will have to thoroughly clean the work back to the base metal. A sandblaster or acid bath is the best way to do this. Then be certain that there are no oils on the work itself, either from your hands or other sources. Apply the browning finish, then apply a topcoat to seal and protect it using a varnish of your choice.

Chris Ray


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