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Bakelite Restoration |
I recently paid a visit to Gavin Payne's attractive sales outlet in the
Battlesbridge Antiques Centre*, not far from Chelmsford in Essex. He has some
fascinating phones for sale there, all on working demonstration, and all
agreeably glossy.
We started to discuss the best way of keeping Bakelite phones black and shiny.
In Gavin's view Bakelite can easily deteriorate, especially in sunlight so the
best ways of keeping the gloss are:
Beeswax responds well to polishing with a duster. Silicone polishes leave a
very slippery surface, so slippery in fact that you might drop your treasure
when picking it up!
Afterwards I asked a friend who's an expert in chemistry what he could add and
he told me the following:
Bakelite is a cross-linked polymer of phenol and formaldehyde. Neglecting the
filler material for the moment, a Bakelite object is actually just one big
molecule. There are no polymer chain ends to be attacked so the material is
quite resistant to all solvents. But unfortunately, getting the exact
proportions of the materials right is difficult. The formaldehyde boils off at
lower temperatures and can be absorbed into the filler easily.
Once Bakelite has started to deteriorate you will notice a roughness of the
surface, where the top layer of phenolic resin has been rubbed away, exposing
the coarser filler material (wood flour or asbestos dust). These waxes tend to
fill in the surface pits and micro-cracks and make the surface look better. But
they can only slow the breakdown; they cannot stop it.
You can try and flatten this rough surface to make it smooth again; sometimes
you'll be lucky. The recommended product is automobile rubbing compound, which
you can buy at car accessory shops (retail) or motor factors (trade). It's a
paste the consistency of warm butter, smelling of ammonia and tan or ochre in
color. Rub heavily with a hard cloth, then remove the
residue with a clean cloth and buff with a duster. It's certainly effective,
although you'll have to rub long and hard to disguise badly pitted surfaces.
Buffing with an extremely fine abrasive can sometimes help bring back a shine. I
like to use what is called "automobile rubbing compound". This is diatomaceous
earth or fumed silica in a solvent and wax base. It is similar to jeweler's
rouge in that it is extremely fine and not exceptionally hard [the diatomaceous
earth is similar to the White Cliffs of Dover, a calcium carbonate material,
harder than talc. The fumed silica, however, is quite hard. Go for the softer
abrasive with Bakelite.] A buffing wheel will speed things up but watch out for
the polishing to go too deep.
You may find the Bakelite has faded badly; your options are to dye or paint.
Black shoe polish can be quite effective to fill the minute pits; let it harden
for ten minutes, then wipe off the remainder with a kitchen paper towel and buff
with a duster.
There are two other automotive products you can try, with confusingly similar
names-Back-to-Black and Black Bright. The former comes in an aerosol spray can
and is a clear silicone varnish intended for rejuvenating black vinyl trim on
cars, although being clear, it will work on other colored surfaces as well.
Black Bright is an intensely deep black (mauve-blue-black in fact) dye or liquid
pigment that you 'paint' on with a felt applicator. Because Bakelite is
non-porous, it takes a while to dry (leave it for an couple of hours, then dry
off the surplus with a paper towel); for a consistent finish you really do need
to cover all surfaces of the telephone in order to make all the parts match.
This finish benefits from a coat of polish afterwards and do take great care not
to get any of the dye on your skin or clothes; it's extremely permanent!
Black shoe polish is not a perfect solution; it's basically wax and pigment. The
dyes do not work on Bakelite as their solvent cannot swell the Bakelite for them
to penetrate. Even though the surface may now be roughened, the Bakelite is
still chemically resistant. I have sometimes found that repainting was a last
resort. Unfortunately paint does not stick well to the Bakelite. You will have
to roughen up the surface first to get mechanical adhesion. This is also where
you do not want any silicones present so if you use silicone waxes, forget about
painting.
If you use a slow-drying paint like epoxy, you can often get a good finish over
fairly deep scratches. This is good as the deeper scratches will make the paint
adhere more. Lacquer coatings tend to be thinner and dry fast, so the Bakelite
cannot be roughened up as much. They have the advantage that a soak in solvent
will remove them and allow you to repaint easily. Like
everything we do in restoration, some experimentation is necessary to get things
like we want.
Since Bakelite is pretty inert, silicone wax can be cleaned off by soaking in
dilute sodium hydroxide (lye) for a few hours (note that the hydroxide will
attack metals such as aluminum). This will roughen the surface somewhat, but
normally cleaning off silicone is preparation for painting anyway. A silicone
wax on phenolic will last longer than any other wax and give the best
protection. I hesitate to suggest this to too many people since if you do get it
on other surfaces (such as a painted panel) it is
very difficult to remove. One additional thing about repainting is that if the
Bakelite has a fabric or cellulose filler, the paint will seal this, keeping
moisture out and allowing you to retain the finish longer. I hope this helped a
little. Unfortunately there are no easy fixes (and few not-so-easy ones either).
Another helpful comment I got was:
I just want to add one little bit about surface preparation before painting.
As the surface of even reasonably well preserved Bakelite contains deteriorated
phenol, washing with a strong cleaner will wash away the deteriorated phenol
leaving a roughened surface. That is the first step to getting the mechanical
adhesion you need.
Depending on how rough the surface is before painting, one or more coats of
paint or clear coating (like polyurethane) will fill the opened pores and some
rubbing down between coats will restore a smooth finish. If using a rubbing
compound before applying a clear coat be aware that all of the rubbing compound
may not wash out of the pores leaving a speckled appearance. It's better to
varnish first and then polish the varnish. A swirled pattern Bakelite cabinet
will thank you.
Fired with enthusiasm, I bought some rubbing compound to see what it could do.
In a nutshell, it's rather like T-Cut, with the same ammonia smell, but with a
much thicker consistency. You rub on this paste with a damp cloth, then remove
the residue with a dry cloth. It's certainly effective, although you'll have to
rub long and hard to disguise badly pitted surfaces.
There must be other secret remedies for putting the gloss back into Bakelite, so
if you have one, please share it with us!