Porcelain Dial Repair?

[doug sinclair]

Maybe someone will give a more learned answer to your question that I am able to, but I am going to say that it is not possible.

When porcelain watch dials were originally fired, the enamel and the copper substrate were evenly heated to about 1,000 degrees F. During the process, the enamel melted and became molten at a time that the copper substrate expanded. As the dial cooled, slowly, the copper shrank while the enamel was still pliable. Thusly, it continued to edhere to the copper substrate.

When you attempt to reverse the process, the copper substrate reacts to the heat more rapidly than the now hard enamel, and the danger is it will separate from the copper. In addition, there is a great danger that it will simply break into smithereens.

So, if hairlines are your only problems and you don't want bigger problems, don't try it!

Regards,
Doug S.

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[Greg Crockett]

I have been informed that an altrasonic watch cleaning machine can clean cracks to the point they are not as readily visible.

In general, we must face the fact that antiques will show signs of age and a line or two on an original old dial is acceptable.

Greg

[doug sinclair]

Greg,

Ultrasonic cleaning machines can do a lot of other stuff to porcelain dials as well! Stuff like removing enamel, and removing subsidiary dials from single or double sunk dials! While I have never had it happen to me, I have heard of serious damage happening to porcelain dials with these machines. I would recommend using them on cracked or chipped porcelain dials only with the utmost caution!

Regards,
Doug S.

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[terry hall]

There are two sources for dial restoration that I know about.
One in England, One in Cary, NC.

It is difficult to justify the cost of just any old dial. I have seen the work from england. The artwork is excellent, but IMHO,
the finish is not a duplicate of the old fired method.

I have not seen in my hands the work from the other source.

If necessary, I will post the info.
You do not mention what kind of dial you have. That may help with justification.

Ultra sonic will take out the dirty hairlines, but as mentioned above, it can also damage things.
I know first hand.
I had a very small unit, like a denture cleaner.

The main thing to remember is short dwell times in the solution and if you have a triangular shaped portion, don't do it. It can lift the section of dial out.

There is a post on this board or the other regarding this subject. Michael Chamelin had a post that was very good about a cleaner he has found. A search by author will bring it up.

[terry hall]

Here is a link to the other post. http://www.pocketwatch.org/UBB/Forum13/HTML/000041.html

The cleaner mike is speaking of is Comet liquid. I have used it, it will work. There appears to be no damage from lengthy soaking in the solution.

[Tom Huber]

I have had good luck with Wayne's suggestion of the denture cleaning tablets. I have also had success with soaking the dial in bleach overnight. The bleach cleans out the hairlines and will safely remove any other dial stains without damaging the dial. Tom

[doug sinclair]

Tom,

I know of instances where soaking a metal object in chlorinated bleach can actually dissolve the metal! I would suggest that anyone who tries this method observe the soaking item frequently to assure that things like dial feet do not disappear!

Regards,
Doug S.

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[mikeh]

My 2 cents worth is that no method of cleaning [that I am aware of] will make the crack disappear. Therefore, I choose to make them look respectable and leave it at that. I like Comet liquid as Michael's post advised. It's safe even if you leave it in too long, and it does a great job. I also agree with the others regarding ultrasonics. Never ever use one on a dial that is even remotely important.

Regards,
Mike

[cmedsker]

I have never used Comet Cleanser on watch dials, and would be reluctant to do so. This is an abrasive type cleanser and I don't think I would use it on my dials. I have used Liquid Dial detergent and a small amount of bleach. I have used Smokers Polident (and the method I prefer now) many times on porcelain watch dials. I just use an old cottage cheese container. Fill it 3/4 full with warm water, lay 1 Polident tablet on the bottom and lay the dial face down on the Polident. Leave it overnight. Can be done again if not satisfied with results. As stated before, it will not remove the hairlines, but does clean dirt from them. I would not use an ultrasonic cleaner on these dials, having experimented with junk dials. Vibration will loosen the subsidiary dials in many cases, and if your dial has a triangular shaped hairline near the edge, this section may come out. One word of caution before using any type of cleaner; carefully examine your dial using a 10X loupe to determine if writing is indeed under the glaze. If the name (usually, or any added personalization such as an image or Lodge logo) is on top of the glaze, the cleaner will remove the name along with the dirt in the hairlines. Please don't ask me how I know!

[This message has been edited by cmedsker (edited 10-17-2001).]

[This message has been edited by cmedsker (edited 10-17-2001).]

[terry hall]

The Comet cleaner we are speaking of is NOT an abrasive cleaner. It is in a liquid form.
It contains NO bleach. It is described as disloving hard water film on contact. It appears the active ingredient is citric acid and alcohol ethoxylate [what ever that is]. It is biodegradeable.....and it works.....
We have found it will have an effect on the 'blue' hair lines that the other cleaners will not lighten.

The process makes for a more presentable dial, as the dirt in the line is washed out.
The line is still there, but is 'invisible' :biggrin:. A hairline is still a hairline. clean or not.

Don't confuse it with the comet scrubbing stuff.

[Tom Huber]

Doug, I was talking of soaking only porcelain dials in bleach, never a metal dial. I have done this with dozens of dials and have never had a problem. If you were referring to damage to metal dials, I agree with you, but my experience has never shown any damage to a porcelain dial. Tom

[cmedsker]

OK Terry, I wasn't thinking of the Comet liquid. Thanks for pointing this out.

[doug sinclair]

Tom,

If you will re-read my post, I specified that one should watch for the dial FEET to disappear. Any chlorine should certainly not harm a porcelain dial, I agree! But the feet are at risk in my view.

Regards,
Doug S.

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[drtime]

Hello All!
just to throw my 2 cents in. An old watchmaker's trick is to use a paste made out of water and baking soda. Make it fairly thick or thin. You can use a soft tooth brush but your finger does nicely too. The baking soda is not harmful and can be used when there is some damage to the porcelin. I have used my ultrasonic jewelery cleaner with good success but I only leave the dial in for a very few seconds. I'm using an L&R 2014 and it's action is very strong. A few seconds in the ultrasonic and then using the baking soda is very effective. Not for use on a dial with any significant damage though.

Let me know what you think,

Richard Rogers

[Jack wagner]

You guys are good. I am going to try a few of the suggestions.

The result of the smokers polident gave me very good results. There were 3 hairlines. One I cant't find with a 10x loop and I know where it was. No. 2 can still be seen with the 10x but it appears as a clean crack not visible to my naked eye. The third and worst you can judge for yourself. Obviosly still there but it doesn't draw the eye like it did.
http://members.aol.com/jackwagner999/hairline.jpg

BTW - Whitens and brightens!!!
Again thanks,
Jack

[This message has been edited by Jack wagner (edited 10-19-2001).]

[Sam Williamson]

Although I have never cleaned a dial with it,hydrogen peroxide 3%[standard store stuff] does an amazing job on enamel.I don't believe it would harm the copper substrate. Any chemists out there to confirm?

[mikeh]

Watchdude et al,

I was kind of hoping this thread would come back up. I was already a fan of the Comet spray, but just a couple of days ago I tried something a little different. In a small ceramic bowl, I sprayed enough liquid to completely cover the dial laying face up. Then I removed the dial and heated the liquid in the microwave until the foam started to bubble around the edges. This only took 10-12 seconds. After placing the dial the warmed (not extremely hot) Comet for about 90 minutes, I couldn't believe the results. :biggrin: Just a guess, but maybe the warmth caused the hairlines to expand slightly and allow the liquid to penetrate? Who knows, maybe the stuff just works better warm.

However, as a word of caution, I assume that too much heat could possibly cause expansion to the point that it new hairlines could be created, or small ones could be exacerbated. Thus, I suggest testing this yourself with unimportant dials, and in small increments with regard to heat.

Regards,
Mike

[Sam Williamson]

As most chemical reactions are accelerated by increased heat,I am sure that is why the comet spray works better when warmed.I suspect that most of the work is done within the first 15" or so

[mikeh]

Wayne, acme,

Regarding the warmed Comet spray, let me be clear. I would caution anyone intent on heating this stuff up too much. As I said, I suggest testing on common dials, and in small increments with regard to heat. As a general rule I wouldn't advise using anything, Comet or otherwise, that I could not hold my finger in for several seconds. As for the solder used, I would fear cracks caused by rapid expansion long before the solder begins to flow, but I'm no metallurgist!

Regards,
Mike

[ckeithjohnson]

A word of caution on the Comet for dial hairlines! I just tried the Comet on my first dial and the second bit fell out of the dial. The cleaner was not heated and it had only been soaking about one hour. The dial was from a series 111 Howard four digit serial number and the second bit did not appear to be soldered. The residue of the substance that was disolved by the Comet appeared to be some sort glue filler.

Be careful, Keith

[Tom McIntyre]

Not all dials are/were soldered. It was perfectly acceptable to assemble the dial with shellac. If you have such a dial, almost any treatment will disassemble it. On the other hand, if you want to restore it authentically, thread shellac and a little heating will put it back together.


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Tom McIntyre
Past President, NAWCC Chapter 174
Pocket Horology Web (http://www.pocketwatch.org)
Tommy the JOAT's Web (http://www.mcintyre.com/McIntyre)

[This message has been edited by Tom McIntyre (edited 10-31-2001).]