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Homemade Mouthpiece

Started by JimNY, March 07, 2021, 02:24:47 PM

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JimNY

I enjoy collecting 'clunkers' and fixing them up to various stages of restoration, but at a minimum make them operational.  I tend to look for inexpensive items, but with that comes the problem of filling in missing/broken parts. This can often tilt the deal scale from good to bad. One common problem is missing or badly chipped mouth pieces on candlesticks.  I have bought repros in the past but with cost + shipping it often is not worth it.  I decided to try and make my own out of epoxy resin using a one piece silicone block mold. I've done two molds and I am getting close to a decent end product. I still have some issues creating the proper profile on the underside of the threads, aside from that resin makes a nicely weighted piece the feels very much like the original.  I was curious if anyone else has tried this and if they have any tips for successfully reproducing complex parts.


< Edit 03-16-21: image removed, rotated, reattached >

Doug Rose

Jim....for WE MPs that are really nice, OPW does an outstanding job. Forum members get a discount. MPs and the celluloid Dial covers are all I get from OPW, but both are superb....Doug


http://www.classicrotaryphones.com/forum/index.php?topic=17220.0
Kidphone

countryman

Great job Jim! Like you, I love to get the cheap, often busted stuff and see how it can be mended.
Would you mind to elaborate on fabricating the mold? The mouthpiece you made looks perfect at first glance, very encouraging.

JimNY

Countryman,
Thanks. They definitely pass the 10 foot rule (maybe even 5 feet  ;) ). But closer inspection would reveal flaws. However, considering this is my first time working with the process I'm hopeful I can improve things significantly.

The process in theory is simple.

To make the mold:
1) make a water tight 3 sided container to hold the original MP you are copying (I used scrap wood and a hot glue)
2) Put the original in the form and fill with liquid silicone until fully covered
3) After the silicone cures, carefully cut the mold along the center line just enough to remove the blank

Challenges:

1)Creating the 'cavity' on the back side of the mouthpiece. To do this I glued two dowel pieces to the bottom of the MP, ensuring the diameter of the dowel overhangs both sides of the bottom edge of the mouthpiece.  The void created by the dowel has two functions, one is to ensure the poured silicone gets
underneath the MP to fill the cavity, second it creates a fill spout for the resin.

2)Dealing with the holes in the MP. There is no way to do this with a one piece mold (At least not that I can figure).  To address this I covered the holes on the bottom side of the MP original with painters tape. The finished copy has holes on the front (where the star is) that don't go all the way through to the back). When the copy was fully cured I drilled them out with my dremel.

Casting the Copy:
I used a generic clear, two part epoxy resin with black resin dye. 
1)mix the desired amount, add 2 drops of dye and stir. 
2) Prepare the mold by wrapping some rubber bands around it. Be careful not to put the rubber bands on too tightly or it could deform the mold. (you can also use a demolding agent to help things get free from the mold more easily, i found this was not necessary).
3) Then carefully pour the resin into the mold until its settled into all voids of the mold

Challenges: Ensuring there are no bubbles in the resin. (I put the cup of resin into an ultrasonic cleaner for a few minutes.)

Materials (all easily obtained from Amazon or a local craft store):

2 part liquid silicone
2 part epoxy resin (clear)
resin dye.

Finally the economics... I spent about $50 on the resin, silicone and dye.  However, once I get a good mold the copies would probably cost less than $1 to produce (they use about 3 tablespoon of resin). I will have to do a few to get to a break even point but the creative process is very satisfying and adds to the fun in my opinion.




FABphones

Quote from: JimNY on March 07, 2021, 02:24:47 PM
...I decided to try and make my own out of epoxy resin using a one piece silicone block mold...

Could you add photos of your mold. End result looks good.
:)
A collector of  'Monochrome Phones with Sepia Tones'   ...and a Duck!
***********
Vintage Phones - 10% man made, 90% Tribble
*************

kleenax

Quote from: JimNY on March 07, 2021, 02:24:47 PM
I enjoy collecting 'clunkers' and fixing them up to various stages of restoration, but at a minimum make them operational.  I tend to look for inexpensive items, but with that comes the problem of filling in missing/broken parts. This can often tilt the deal scale from good to bad. One common problem is missing or badly chipped mouth pieces on candlesticks.  I have bought repros in the past but with cost + shipping it often is not worth it.  I decided to try and make my own out of epoxy resin using a one piece silicone block mold. I've done two molds and I am getting close to a decent end product. I still have some issues creating the proper profile on the underside of the threads, aside from that resin makes a nicely weighted piece the feels very much like the original.  I was curious if anyone else has tried this and if they have any tips for successfully reproducing complex parts.


Hey Jim;
you have done a great job on your first casting process!
I have been casting vintage telephone components and even complete phones for about 15 years now, and COMPLETELY understand all of the "problems" that you are experiencing! I have an LLC formed around my casting/molding business, and I am happy to help with any casting/molding questions that you may have. Facebook page (still working on it!) @recumbentcasting

The biggest change I might make if I were you was to change to urethane resin instead of epoxy resin. Epoxy is the BEST for making VERY then parts and using as a almost impervious "varnish", but becomes WAY too hot when curing to make very thick parts.
Ray Kotke
Recumbent Casting, LLC

JimNY

#6
FabPhones: Sorry for the delay in replying, below are some pics of my one piece cut mold and a piece that was just removed.

Kleenax: Thanks for the advice. I have been looking into the urethane resins. I see most are colored, white, gray, etc.. is coloring done with a dye or painting afterward? It seems it would be difficult to change white to any dark color especially black using a dye.


< Edit 03-16-21: images removed, rotated, reattached >

kleenax

Quote from: JimNY on March 13, 2021, 09:01:02 AM
FabPhones: Sorry for the delay in replying, below are some pics of my one piece cut mold and a piece that was just removed.

Kleenax: Thanks for the advice. I have been looking into the urethane resins. I see most are colored, white, gray, etc.. is coloring done with a dye or painting afterward? It seems it would be difficult to change white to any dark color especially black using a dye.
On nearly ALL castings that I do, I utilize water-clear resin and add either colorant, dye, pigment, depending on what I am trying to achieve. If you want opaque, you use a solid pigment, translucent, dye, etc. Water-clear resin is about 2-4 times more expensive than the opaque, white/beige resins, and are much more difficult to work with.
Ray Kotke
Recumbent Casting, LLC

scottfannin

Wow.  My mind is reeling from the possibilities now that I saw this exciting work of yours!  I'm thinking maybe this method can make the magneto crank handles that so often crack while the rest of the crank is good.  Bonus points, a shell for a receiver, and then something inside for a weight to go and the speaker capsule for a WE 500?

kleenax

Quote from: scottfannin on April 08, 2021, 10:58:29 PM
Wow.  My mind is reeling from the possibilities now that I saw this exciting work of yours!  I'm thinking maybe this method can make the magneto crank handles that so often crack while the rest of the crank is good.  Bonus points, a shell for a receiver, and then something inside for a weight to go and the speaker capsule for a WE 500?
Here is a MS-Word doc of the "successful" molds that I have made. Incidentally, "SB&C" in the list stands for "Siemens Bros & Co", for British phones.
http://www.classicrotaryphones.com/forum/index.php?action=dlattach;topic=20051.0;attach=234121
Ray Kotke
Recumbent Casting, LLC