The Fine Things are Always Hand Made

homemade parts escutcheons bezels etc

Inspired by a recent post from Dave Poland, I thought that I would show a method of reproducing dial escutcheons etc, first is epoxy and the second from a process I used to mess around with as a kid, electroforming,

Both methods first require a mould to be taken from an original,

the photo below shows the band selector escutcheon from my alwave fifteen, the holes are plugged with masking tape and the part is then stuck on to double sided tape, this is then covered with vaseline, to stop anything from sticking, taking care to remove any excess as this will leave marks in the finished item.

the object to be cast has a box built around, for this I used thin card and packing tape

The silicone I am using is a two part type purchased from ebay, this is first mixed as per the instructions, then poured over the item.

this version of silicone rubber takes a few hours to set but roughly 12 hours to cure,

when fully cured the box is then broken away and the original escutcheon removed.

The next photo shows the silicone mould, as pulled from the master, no air bubbles or voids so we can move on to the next stage.

There are now two methods we can use to reproduce the part, first is made from epoxy,

for this I used an old favourite JB Weld, this is mixed and hetated until it is runny and poured into the mould, heating helps remove air bubbles.

after it has set it can easily be removed for trimming and painting,

this is then painted, first coat copper paint, then flat black. Not perfect as I had trouble matching the original finish but it gives the idea,

The second part of this post shows the electroforming method, this leaves a reproduction part made from copper as per the original, loads of detail and about the same thickness.

First the silicone mould is wired with copper wire for the plating process,the face of this is then covered with graphite and worked in with a soft brush,

when finished the surface should have a metallic sheen with no loose graphite and no gaps, the resistance from the copper wire to the center of the mould is about 2k ohms,

this is then placed in a copper sulphate bath and plated for ten hours at 1 amp (160ma per sq inch).

care should be taken as not to plate at too high current as the copper coat will become soft and sponge like, the idea is to slowly grow the copper.

10 Hours later, the silicone mould can be pulled from the bath, the wires snipped off and the part revealed

At this stage it looks a little messy, the nodules are caused by the current being a little too high, dont worry too much about the finish as the front will be perfect.

after a quick trim and a rinse in clean water we have this,

on further cutting and polishing the escutcheon now looks like this, the item has been polished with a small amount of metal polish to show the highlights, and the diamonds have been painted,

the detail is very impressive using this method, and the escutcheon should get a better color with age.

To speed things up a little, I applied a chemical solution called liver of sulfur, this stuff is what they use to age copper and brass for modern antiques,

it stinks something horrible, imagine the smell of rotten eggs and then some, this should be done outside.

The escutcheon now looks like this, virtually indistinguishable from the original.

Update,

To prove that the system works and is repeatable, I have made copies of the volume and static escutcheons,

below is a closeup of the volume control, the scratch marks around the center are also on the original.

image showing the two escutcheons, cleaned up and aged with their mould,this is what the three finished escutcheons look like.

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Permalink Reply by Norman S Braithwaite on September 22, 2017 at 2:49pm

It takes much longer for the silicone product that I used to fully cure than it takes to set.
Norman

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Permalink Reply by mike hadley on September 22, 2017 at 3:02pm

The silicone I use takes roughly 4 hours to set and about 12 to 15 hours to cure, the tuning window bezel was made before the silicone had fully cured hence the reason it looks dirty in the photograph, there is some graphite residue embedded in the surface.
Mikr