home made watch crystals...?

[RJSoftware]

Anyone ever try to make homemade watch crystals..?

Seems like something could be done to make those hard to find watch crystal sizes.

Making a form for the plastic to be molded upon doesn't sound too impossible. Especially for round pieces. Maybe something turned on the lathe to fit, maybe wood...

Seems like there's allot to choose from in the way of plastics materials. I was even thinking of clear plastic liter bottles. Or might be too flimsy weak.

Ideas, yes no, chuck it out the window...?


Update: Here is link to youtube video showing how to do homemade vaccum molding.
http://www.youtube.com/watch?v=eUB58z8apTE

 

[Phil7153]

My good friend is a glass blower, and I had him make a crystal for me. While he is a very talented and accomplished glass blower, it took him quite some time to do (about 2-3 hours). It does the job, but there are a few bubbles, which is just not suitable for me. So plastic might be the way to make your own, but then you are stuck with the dreaded plastic crystal...

I do have an industrial vacuum press and numerous plastics though....

 

[RJSoftware]

I tell you I have some watches that surprized/shocked me totally that the crystal on them was plastic. What happened was I found a acrylic glass polishing kit. It contains various grades of embeded sand paper that goes really high like 25,000 grain. By the time you use that one the acrylic is shining like brand new. But the kit wont do glass, nothing happens. So I checked out my watches with crudy lenses and was surprized by how many where plastic.

But the point being I don't think it's that uncommon. I like the vaccum molding process and now it just looks like the problem is finding a supply of clear acrylic the right thickness.

I suppose that in the vaccume molding process I would have to have excess so to cut off and then later square off with maybe grinding wheel.

Making the mold would be the hardest part. I guess you have to reduce the diametor of the mold by acrylic thickness X 2. Then maybe add .01 or something for the snap in quality. Or not...!

How to make square/rectangular crystals. I don't know. Maybe carve wax, but I bet that is difficult. Maybe mold something with clay, test fit with pieces of the acrylic. Maybe first use clay to get the shape, then use that to form some wax, trim the wax for crystal thickness on sides and rub back smooth.... I don't know...

 

[Skutt50]

I read somewhere (probably Chicago School of Watchmaking) a description on how to shape plastic crystals from a flat sheet. If I remember right it involved heat and shaping over some curved "mold".

I also remember an old TV documentary about a watch maker/collector who demonstrated how he cut a crystal from an old light bulb. Perhaps a bit thin!? It was not the ordinary small bulbs but an oversized of some sort. (It was many years ago and I do not recall if it was for a verge watch or what!)

Polishing acrylic crystalls is not that hard. One have to use a fins abrassive paper and remove any deeep scratches and then polish back the clearness with e.g. Polywatch.
I have also tried with CD polishing kits and it seems to do the same job as Polywatch but at a much better prize.

I recently bough a kit for repairing arylic headlights on cars which also sounds promising but I have not yet gotten round to try it out.

 

[R.G.B.]

I've made a few using dollar store reading glasses for blanks. Shaping with a rotary tool and finishing by hand sanding to get the final shape. From there a quick once over with the acrylic polish.

 

[dAz57]

you know it still surprises me that people are surprised to find plastic or acrylic glasses used in watches, when I started in the trade in the early 70s practically every new watch had acrylic glasses, this includes the Rolexes, Omegas, Longines, Certinas etc, etc, only makers like Patek would use paper thin sapphire crystals in their thin gold cases,

so that 1972 $1400 Rolex GMT master used an acrylic glass.

sure it scratches easily, it also polishes out easy too, a quick touch on the buffing wheel with some Crystal Kleer compound took most, bar the deep scratches out.

the 200 metre dives watches of the day used 3mm thick armoured acrylics, even when they came in every few years for a service with the glass scratched so badly you could hardly see through it and would quite often have cracks in the plastic and yet would still be watertight, the acrylic glass would survive underwater impacts with objects that will break a mineral glass.

the Japanese started making watches with mineral glasses around about then, then years later most makers followed, and the cost and manufacture of mineral crystals became cheaper and better that even the $5 cheapy has a mineral glass.

the use of plastic bottles for watch glasses is not a bad idea, although probably a bit thin for open faced watches, way back when wrist watches started to first show up, they would have glass in them, this was the same stuff as used in a window, soda glass, quite brittle, not a real problem in a pocket watch, but a wrist watch, one option was to use celluloid, a watchmaker would buy flat sheets, use a tool to cut a circle out of the sheet, this tool would cut a bevelled edge in the thin sheet, the idea was to cut the circle oversized, the Robur Glass tool was made to fit these glasses, the cup and dome dies would curve the flat circle and spring fit it in the bezel, the only real downside of celluloid it would go yellow after a while.


making a square glass, well one way is to take a flat metal block, drill a small hole in the centre, fit a short bit of tube so a hand air pump like a very large syringe or dust blower can be attached, a piece of the acrylic is placed on top, this needs to be 2-3 times the size the finished glass, make a die out out of 1 or 2mm sheet brass or aluminium to the size of the bezel fitting and clamp that over the acrylic, warm the whole lot in an oven until the acrylic is soft, then with the air pump puff the acrylic up to dome or curve it and hold that until it cools, then you only have to cut out and file it up to fit.

rectangular curved cases like in post #5, find something that matches the curve, warm a strip of acrylic and bend it around the former and let it cool.

the stuff I use is Shinkolite, made by Mitsubishi Rayon, easy to form, takes a great polish, thickness from 1mm
http://www.mrc.co.jp/shinkolite/technical-info/index.html

 

[NC Plumber]

I made one out of a cassette tape case, it was an octagon shape, 12 size. All of watch people I showed it to were impressed.

 

[R.G.B.]

Thanks for the Shinkolite link dA. Worth looking into.

 

[John A]

I am having a problem finding a crystal for my Certina. Has anyone tried casting with epoxy resin?
I have the original in reasonable shape except fine cracks so should be easy to make a mould with casting rubber
any ideas?

 

[R.G.B.]

I've never tried epoxy for forming and it might be problematic with the mix being cool or hot. Being too brittle or soft would be the result. An alternative might be to fill the cracks with cyanoacrylate and then sanding and polishing.

Rob

 

[dAz57]

I am having a problem finding a crystal for my Certina. Has anyone tried casting with epoxy resin?
I have the original in reasonable shape except fine cracks so should be easy to make a mould with casting rubber
any ideas?

did you look here? http://www.ofrei.com/page_164.html

 

[davestanda]

I once tried useing RGB's method of making a watch crystal,but with no luck...the i couldn't get the glass thin enough, and it was taking forever...using a Casette holder might be a good idea, since it is the right thickness....the only trouble now is finding a old one that wouldn't be all beat up,worse then the crystal you are replacing.....anybody try just using crystal blanks

 

[dAz57]

I once tried useing RGB's method of making a watch crystal,but with no luck...the i couldn't get the glass thin enough, and it was taking forever...using a Casette holder might be a good idea, since it is the right thickness....the only trouble now is finding a old one that wouldn't be all beat up,worse then the crystal you are replacing.....anybody try just using crystal blanks

watch plexis or glasses are made from Acrylic Resin, this can be machined, filed and polished to a high luster and is crystal clear, some plastics which are moulded for components don't polish well.

you can buy shaped blanks already curved to suit, you could get one close to size that will only need a bit of filing to fit it.

the style of plexi on this one appears to be a cylinder style, that is a curved top with flat sides, might have different names elsewhere.

otherwise make your own from Shrinkolite sheet, can be heated and moulded, http://www.mrc.co.jp/shinkolite/technical-info/index.html

 

[doug sinclair]

My late father was a Depression era watchmaker. This was a time when there were no fax machines, Internet, UPS, no on line catalogs, and sparse supplies of what a watchmaker would need. He showed me about 50 plus years ago how watchmakers would take a square piece of zinc sheet about 3" by 3", turn the corners down, contour the curvature of the sheet to match the profile of the bezel, then saw a hole in the zinc to match the shape of the recess for the crystal. Place a glass crystal that was too large over the hole, the slowly and uniformly heat the glass crystal until it reached the flow point (not the melt point), and a nicely formed crystal that required only a bit of finishing would drop through the hole in the zinc to the bench top, I had watched him do it, but i've never tried it.

 

[dAz57]

what was the material, glass or plastic, around that period celluloid was a common watch glass.

 

[John A]

An alternative might be to fill the cracks with cyanoacrylate and then sanding and polishing.

Thanks Rob, would cyanoacrylate remove the gunk in the cracks?

 

[Tudorp]

I wouldn't think it would. You would have to get all that out. Maybe soak in bleach, or amonia?

 

[RJSoftware]

Doug; One day if you ever do decide to try your fathers way, please tape it for youtube. I think I speak for all of us when I say it'd be a great video to see.

My late father was a Depression era watchmaker. This was a time when there were no fax machines, Internet, UPS, no on line catalogs, and sparse supplies of what a watchmaker would need. He showed me about 50 plus years ago how watchmakers would take a square piece of zinc sheet about 3" by 3", turn the corners down, contour the curvature of the sheet to match the profile of the bezel, then saw a hole in the zinc to match the shape of the recess for the crystal. Place a glass crystal that was too large over the hole, the slowly and uniformly heat the glass crystal until it reached the flow point (not the melt point), and a nicely formed crystal that required only a bit of finishing would drop through the hole in the zinc to the bench top, I had watched him do it, but i've never tried it.

 

[doug sinclair]

With 30,000 NOS glass wrist watch crystals in my garage, I can usually find what I need. So I very much doubt I will ever have occasion to make one!

 

[davestanda]

like i said before i am looking into crystal blanks,, i don't have the room for 30k nos crystals, and finding good crystal lots are getting harder,plus chance are you will only end up using one or two crystals,out of the lot,for years.... I like dougs method, but i was wondering if i could find suitable plexiglass or Acrylic , from local arts and craft stores...Chicago Watchmaking school has a very good article on making crystals,also it saids you can make a cyrstal fairly quick after practice...if i could find a good lot of crystals i would buy it but till then,i hate buying one at a time and rather try making them...pocket watch crystals might be a pain,but again buy crystal lots for those is hard because the measurements could be off by a .5 mm and the crystal won't fit,there are just too many bezels...

 

[sderek]

Anyone ever try to make homemade watch crystals..?

Seems like something could be done to make those hard to find watch crystal sizes.

Making a form for the plastic to be molded upon doesn't sound too impossible. Especially for round pieces. Maybe something turned on the lathe to fit, maybe wood...

Seems like there's allot to choose from in the way of plastics materials. I was even thinking of clear plastic liter bottles. Or might be too flimsy weak.

Ideas, yes no, chuck it out the window...?


Update: Here is link to youtube video showing how to do homemade vaccum molding.
http://www.youtube.com/watch?v=eUB58z8apTE

I understand that some people might enjoy making their own crystals....I replace a lot of crystals, and I've only been stumped once when trying to find a vintage fancy crystal. I sent the watch to a custom crystal maker in New Jersey, and they were able to cut a glass crystal to fit for about $30.

 

[davestanda]

the object though is not to send it out, or pay 10-20 dollars plus shipping for a crystal that you need that day..also it is not even the money issue, it is the ability to be able to make one if needed or wanted...plus there have been times even after i gave correct measurements and model name , i still recieved the wrong crystal...like said crystal lots ,aren't really that great because you might end up using one crystal out of 40 for like a year....

 

[R.G.B.]

I thought about having some hardwood forms made for shaping glass or acrylic but decide to stick to ordering. Acrylic is easy enough to work with but glass is too messy and takes too long to make it worth it IMO. Besides, the boss of me said no.

 

[blue92]

I am having a problem finding a crystal for my Certina. Has anyone tried casting with epoxy resin?
I have the original in reasonable shape except fine cracks so should be easy to make a mould with casting rubber
any ideas?

Send the case to Casker's with the old crystal and they will fit a new crystal in it and return it to you.

I used to make my own plastic crystals out of large flexible plastic pocket watch crystals. I made a mold out of hard thick acrylic plastic. The mold fit the inside of the case, and using the case itself to make the crystal by pressing the softened pocket watch crystal in on my crystal press. I made a special gig to fit my crystal press for this. These were the days when Zales and Gordon Jewelers were big and had their own watch brands and replacement crystals didn't exist.

 

[davestanda]

so basically blue you used Pocket watch blanks ,then shaped them....i was wondering where i could just get a sheet of Acrylic,that is thin enough, to make cyrstals...i tried calling local art craft stores,but no luck, although they said that acrylic used for picture frames might work...some of the really cheap frames have very very thin acrylic on them,since the frame is so very thin too....also i am wondering what is better for shaping crystals,,,using a file or emery paper

 

[neighmond]

You used to get blank sheets of acrylic from your material houses, and you could cut the blank slightly oversize, heat it with a hair drier and shape it well enough to fit.

 

[davestanda]

Right that is how the Chicago School of Watchmaking tells you how to do it...Do you know what material house still sell that type of acrylic sheets....

 

[R.G.B.]

Some mentioned a product called Shinkolite in another crystal making thread that looked promising. Another thing I use for square crystals is cheap reading glasses from the dollar store. It's optically clear and dense enough to take grinding and buffing.

 

[davestanda]

yes i tried that but it is to hard to get on thin enough to work on a watch...about that product i could only find the website of the company that makes it,, and i am sure they only sell lots and lots of it at a time...

 

[blue92]

yes i tried that but it is to hard to get on thin enough to work on a watch...about that product i could only find the website of the company that makes it,, and i am sure they only sell lots and lots of it at a time...

The reason I asked for a pic of the watch is to see the shape of the case. I have a lot of old GS plastic crystals and maybe have something close to fit with some shaping. Measure the case from 9 to 3 then 12 to 6 on the end side lip of the case where the crystal rests.

 

[davestanda]

hello blue sorry but my GF took the camera and i can't find it but the crystal i need is for a Gruen Madison the measurements are 21.59 long by 20.55 ...i am pretty sure that is the name of the watch, although gruen named the same model different names depending whether the watch was 14k gold, 10k gold filled , hell they even changed the name depending on if the band was leather or gold filled stretch band..... http://books.google.com/books?id=RkEEAAAAMBAJ&pg=PA9&dq=gruen+watch+ads+madison&hl=en&sa=X&ei=4CedUPOVH_Ot0AGQj4DYBQ&ved=0CDAQ6AEwAA#vnepage&q=gruen%20watch%20ads%20madison&f=false .... here is an old ad of the watch, my watch is LETTER C in the ad.....

 

[luiazazrambo]

Chicago Watchmaking school has a very good article on making crystals,also it saids you can make a cyrstal fairly quick after practice..

Where would I find such an article? I failed to find it using the usual search engines. I have a machine in the attic somewhere which theoretically can make a new acrylic "crystal" by copying the old one, assuming that the old one is still in one piece. I have not tried it out so far.. not even sure where I put it exactly.

I also have the tool someone mentioned in this thread: cutting tool and two other ones. One is English, one is Austrian and one Hungarian.

And i got some of these because i found them interesting: watch crystal dies

You can buy acrylic sheets on eBay in different thicknesses, at least in the UK.