homemade parts escutcheons bezels etc

[mike hadley]

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.

[David Wilson]

Hi Mike... thanks for posting this. I've done some casting using part of your process here. Thanks for laying all this out with photos and disciptions! 

David

[David C. Poland]

Impressive detail on the copper example.

The original escutcheon appears to be brass from the back side. You consider a spray coat of bronze or dark brass color lacquer? Then darken with a little thinned brown paint rubbed in to reveal contrast? I suppose the risk is to obscure some of the detail.

You mention 1 amp for 10 hours.

What voltage? what diid you use as a power supply?.

[mike hadley]

Dave;
The plating bath is a little like a cell from a car battery, when current is being passed there is a forward voltage somewhere around 1.5 to 2 volts depending on the solution makeup, so any potential above this will work,
I had the supply set about 5v and adjusted the current limit accordingly.

The plating current for copper is roughly 10-20 amps per square foot, this is devided by 144 to give the answer in units per square inch, this is then multiplied by the surface area of the cathode, in this case was 6 square inches, so somewhere around 750ma per square inch would do, because I used more current the surface began to grow lumps.
Mike

[Jon Ketron]

Mike,

Both methods are very impressive and spot on in terms of what an original would look like.  I prefer the copper method you demonstrated.  Your attention to detail is astounding.  I find your work very impressive.  Thank you for sharing.

Jon

[mike hadley]

After a converastion with Norman Braithwaite, the bezels were also made in gold plate,

so I made a couple of bezels to experiment with,

First the bezels were pickeled is a 10% sulfuric solution, then a layer of Nickel was plated on

the bezels were washed and dried before the gold was applied,

Wow.

I have since made a replica of the tuning window, there is a post in the picture forum.

[palegreenthumb]

THAT is very impressive!  I may have to give this a try.  Where do you buy your plating solutions?  How thick is one of your repro escutcheons, and how does it compare to an original for strength (say, resistance to bending)?

I've made a couple molds for resin reproductions of knobs, and it seemed like the latex mold material cured with tiny bubbles in it.  Upon molding a resin knob, it came out with tiny 'globs' all over it.  For the most part I could brush them off with my fingers, but they leave teeny tiny imperfections on the surface of the reproduced part.

I've asked this question before, but I haven't gotten an answer:  How were original brass escutcheons made?  Were they stamped?  And if so, how were the dies made?  Were they molded from sculpted parts?  How did they affect fonts and such?  How did they do the tiny little dots (the 'texture') all around those escutcheons?  Did someone carve the texture with a knife under a magnifying glass?  I'm very curious about the original processes used to create escutcheons like this.  True works of art in many cases.

[mike hadley]

Hi Palegreenthumb,

The plating solution is copper sulfate with sulfuric acid added, the recipe is quite a common one,

the finished escutcheon thickness all depends on plating current and time, most of what you see here takes 10 hours plus to make, the dial bezel here is approx 0.5mm thick.

when casting the mould with silicone make sure that you pour the material from about a foot or so above the casting box and that the silicone is poured as a thin ribbon from the lowest point, this stops trapped air from forming around the details.

the mould material I use is a two part silicone type and the hardness is shore 40, about the same as a pencil eraser in hardness,

to answer one of your questions,I think that the original parts were stamped from brass with steel punches, how they are made, with great skill I think.

I have attached some more about this process, please read on.

The silicone mould is first wrapped with wire as before ready for coating with graphite.

the graphite is applied with a brush and worked into the surface until it looks smooth and even, making sure that all nooks are covered and the coating covers the wires, the excess graphite is gently blown off with compressed air, leaving the mould ready for the next process,

the mould is then placed in the plating bath at about 500ma for 10 minutes, this will establish the 'strike',

it is at this time the job can be checked for air bubbles, these are the black dots or gaps in the plating, these are removed with a small brush dipped in the plating solution, and making sure the surface is fully 'wet',

be careful as the copper to silicone bond is not a strong one, if pulled from the mould the process will have to be started over, the mould was backed with some acrylic sheet to stop any flexing.

the bezel is left for another half hour and checked again, it should look like the next photo.

the plating can now proceed at a faster rate by turning the current up, to around 70 to 100ma per square inch although this is not too critical, if the current is too low then the object will have a fine rear surface but will take forever to plate, too fast and the coating will be crumbly, this all depends on the temperature and concentration of the bath, so a little experimentation is needed, the next photo shows the item after it was plated at 350 ma per square inch to show what happens to the plated finish on the back of the item.

you can see that after 12 hours there are nodules and some trees growing from the bezel,

despite this the item is good and thick, the copper is quite hard and it files and sands quite well,

despite all of this the front looks immaculate,

I hope others try this as there is room for improvement and the finished items look far better in real life than the photo's, and would make an excellent replacement for missing bezels,

Mike

[Norman S Braithwaite]

With Mike's help, I have been trying to reproduce the "phono - radio" escutcheon used on the AW-27 and Quaranta chassis.  We have learned that graphite powder sold over the counter at hardware, auto parts, paint, lock & key, and department stores here in the states is not satisfactory.  It appears more like coal dust than graphite and does not conduct sufficiently for this application.  Suitable graphite powder can be purchased on eBay at the link below.

http://www.ebay.com/itm/Natural-Graphite-Powder-Flakes-Micronized-5...

Also, copper plating solution comes in alkaline and acid forms.  The alkaline form is only good for very thin plating (<0.1-mm).  I have ordered the copper acid solution shown at the link below and will be trying it this coming week.

https://www.riogrande.com/product/midas-bright-acid-copper-plating-...

Finally, the mold was made using Oomoo two part silicone rubber compound which can be found all over the internet.

Norman

[Kent King]

All great work, this is amazing. Norman - if you fellows get the Radio-Phono escutcheon made, I would sure like to have one for my AW27...

[Norman S Braithwaite]

Kent:

You are on my list when I succeed.

Norman

[mike hadley]

Norman,
Thanks for adding the extra information about the supplies being different your side of the pond,
The silicone that you use is has a much quicker setting time than the type I use, this makes the prep time shorter by a whole day.
Mike

[mike hadley]

Norman,
Thanks for adding the information about supplies being different your side of the pond,
Also the silicone you mention sets quicker than the type I use, this shortens preparation time by a while day.
Mike