Pulsar Crystal Removal

[Chris S.]

Can anyone tell me the best way to remove the crystal from a pulsar please. I have a gold filled autoset model with a 402 module (although it says module 403 on the inside of the back cover. There's nothing wrong with the crystal, I just want to work on the numerous gouges and scratches on the case without risking damage. Thanks in advance.

http://img39.imageshack.us/img39/4272/pulsargf.jpg

[BENRUS]

Try this link:
http://www.dwf.nu/viewtopic.php?t=3544

[Chris S.]

Thanks Benrus. I'll get the oven gloves out!

[bruce wegmann]

DON"T heat-soak the case for 20 minutes in an oven...totally unnecessary! With a paint-stripper hot-air gun [at 400 degrees], I can have any crystal out in 60 seconds. Get the epoxy off the case while it is still hot and soft...don't let it cool and re-harden! Maybe another 30 seconds there...whole thing, start-to-finish, two minutes, tops. Taking 20 or 30 minutes to do this is turning a simple operation into an overly-complex project. I've done probably a hundred of these this way and have yet to have a problem.

[Led-Time]

With a paint-stripper hot-air gun [at 400 degrees], I can have any crystal out in 60 seconds.

I'll second that, Bruce told me the same thing and it works perfect...

[retroleds]

DON"T heat-soak the case for 20 minutes in an oven...totally unnecessary! With a paint-stripper hot-air gun [at 400 degrees], I can have any crystal out in 60 seconds. Get the epoxy off the case while it is still hot and soft...don't let it cool and re-harden!

I've removed several hundred pieces of glass at this point(from various models and makers) and still prefer the slow heat method as I feel there is less breakage likely to occur, as heating the case pulls the case away from the glass, as the hole expands away from the glass. Heating the glass alone expands the glass against the still cold case. And removing epoxy that has been exposed to heat is never a problem for me - it degrades nicely from exposure to heat, actually comes off easily if heated to 350-400 faren. for 10-15 minutes extra minutes after popping out the glass(allowed to do the extra bake also) and allowed to cool. Fully cured(old) Epoxy does not "reharden" to a harder state than it was prior to the heating so there is no downside, other than maybe the time.

Scraping brittle hard candy off a cool case or sticky taffy off a hot case?

From Wikipedia "The strength of epoxy adhesives is degraded at temperatures above 350 °F (177 °C)."

[Chris S.]

Thanks for the advice guys. I may try a mix of the two, get the whole thing nice and hot then finish off with a heat gun. I'll let you know how I get on!

[bruce wegmann]

If you have heat gun,use that ONLY! It will work fine on its' own. Just hold it an inch or so from the face, count to 60, and it'll pop right out. The airflow heats the metal and glass up together, and the steel expands more, and faster, so there's no chance the glass will find itself in a too-small opening, go into compressive failure, and break...can't hppen! And don't forget, there's a few thousandths of an inch of epoxy between the glass and metal [the crystals are deliberately made a bit undersize, to allow for that], which has some "give" to it, especially when hot. This all works best on solid gold and goldfill [gold, among other unique properties, has one called "inherent lubricity"...meaning things don't stick to it very well; one of modern technology's greatest accomplishments was getting gold to stick to teflon...two of the non-stickiest substances in the Universe]. In the great majority of cases, more epoxy will stick to the crystal than the case. The glue seems to get a better "grip" on stainless, so it's more important there to get the residue off while still hot. With all due respect to our fearless leader, unless I was doing ten or twenty removals at a sitting, I'd stay away from the oven.

[retroleds]

With all due respect to our fearless leader, unless I was doing ten or twenty removals at a sitting, I'd stay away from the oven.

Hey, maybe I just like playing with a hot box.

But seriously, I feel the glue degrades to a more safely removable product, especially on the glass, by some additional heating and then cooling which allows the glue's own chemistry to work against itself. It looses it's polymer cohesion and flakes off nicely. I also feel if the edge of the case is not being heated, the expansion of the case is being slightly thwarted, regardless of what is happening to the case directly adjacent to the glass. Finally, I really think that going from room temperature to 400+ in less than 60 seconds is asking for glass to crack, especially if already scratched.

I keep a small plastic box adjacent to my desk with a variety of mineral glass faced LEDs, marked "Remove glass. So yes, I generally try to remove several in one shot, while I am in the mode. CompuChron, Baylor, Novus, Zodiac, Pulsar....wrap a crystal protector around them and file away for later use.

[rewolf]

.... going from room temperature to 400+ in less than 60 seconds...

Just for the records: I guess you mean 400 degrees Fahrenheit? That would be 204 degrees Celsius (or 478 Kelvin):
AFAIK most of the world uses the Celsius scale. Just trying to prevent people from melting their Pulsar

(Similar problem with gallons - US or Imperial (or even metric)? And if US: liquid or dry?
And another nice question I came about recently: is 12:30 am half past noon or half past midnight? This is not obvoious to me as we use the 24h system. And even in "12h countries" like Japan and China there appears to be some confusion, read here.
Disambiguation is a hobby of mine )

[BENRUS]

[bruce wegmann]

Here, 12:30 AM is half past midnight, 12:30 PM is half past noon. And yes, I meant 400 degrees F [paint stripper guns won't go much past that, anyway..it's just under the charring temperature for wood]. The solder that secures the button cover plates melts at around 550F, so there's no danger of having those pop off...

[Led-Time]

paint stripper guns won't go much past that, anyway..it's just under the charring temperature for wood]. The solder that secures the button cover plates melts at around 550F, so there's no danger of having those pop off...

Bruce you must have pretty weak hot air strippers over there in the States..., the thing I have here will easily de-solder the buttons on its low setting I use an infra-red thermometer to monitor the temperature so when it reaches just over 100deg/C its ready to pop the crystal.

[retroleds]

Bruce you must have pretty weak hot air strippers over there in the States..., the thing I have here will easily de-solder the buttons on its low setting I use an infra-red thermometer to monitor the temperature so when it reaches just over 100deg/C its ready to pop the crystal.

Yeah, I was thinking 400 Farenheit(204 celsius) would be pretty wimpy for a heat gun...most I saw online go to 500-600 celsuis(900-1100 faren.). What is odd to me is Klippies idea that at 100 celsius the glass would be ready to push out - that would only be 212 faren, which is the temperature water boils at, not nearly hot enough to loosen the epoxy. You must be riding it up a bit beyond when your infra-red checker is telling you. Like light, infra-red levels change dramatically with distance so I'm thinkling you are hitting 100 cel., blasting for a few second longer and grabbing it when it actually is closer to 150 celsius, which understandably happens quickly with that type of heat source.

Most of the USA avoids the celsius system for everyday temperature systems such as living space and cooking temperatures. We like to think that the smaller temperature increments provided by our system is more reasonable for human factors. 70 faren is a nice temperature for a house, 75 faren is getting a little warm. That would be going from 21.1 cel. to 23.8, only a difference of 2.7 degree, rather than a difference of 5 degrees. Seems those larger gradiations or at least those fractional parts of a degree would lead to some bitching within a household occasionally. I can imagine some husband grousing to his wife, " damnit, turn it down a few tenths." Wife responding, "what kind of few? 2-3, 5-6, make up your mind you fool!" We avoid the metric system for everyday items, particularly mechanical connections, as our wrench/bolt/ pipe systems, even down to 1/16", are very easy for a mechanics to tell visually what size he is looking at, a high percentage of time. Whereas once we get into 1/32" increaement(about one mm.) the visual ability to tell between a 12mm and 13mm wrench/bolt/pipe is pretty much lost for most people of normal vision. Metric makes for easy math, but not always easily handling of the matter at hand. Fantastic for chemistry and electricity, possibly negligible advantage in some other physical sciences, where few calculations are base 10.

12:30 a.m. is 30 minutes past midnight.

From Wikipedia
PM will usually refer to post meridiem (also written P.M., p.m., and pm), "after noon" in the 12-hour clock, in contrast to ante meridiem (a.m., "before noon").

[rewolf]

Hehe, now that the crystal removing problem appears to be solved we can go a bit OT

Most of the USA avoids the celsius system for everyday temperature systems such as living space and cooking temperatures....

IMO this is only a matter of what you grew up with: if you're used to Fahrenheit, you find Celsius awkward and find many reasons why Fahrenheit is "better". And vice versa it's exactly the same (I can tell this...)
There is no "better", only "different", and conversion is easy.
It's just important to make clear what unit one is using when "cultural barriers" are crossed.
Personally, I know that US Americans commonly use Fahrenheit, so I assume Fahrenheit when one writes "400 deg" - but it's not CERTAIN. The writer could be an emmigrated European. Or a nice American who thinks "I'm talking with a European, so I make it a bit easier for him and use HIS units - it's already hard enough fo him to use MY language" (ok ok, very unlikely case ).
But many people are not aware of the differences. They read "degrees" and don't even think that it COULD be different from their "own" degrees - and then problems arise (like melting Pulsars or crashing Mars Climate Orbiter).

We avoid the metric system for everyday items, particularly mechanical connections, as our wrench/bolt/ pipe systems, even down to 1/16....."

Same as above, it's what you're used to, nothing else. Grow up with inches, feet, yards, miles, and you love them. I grew up with cm,m,km an I will never see ANY advantage in the "other" system.
"Water flows through an 10 cm wide pipe at 150 cm/s. How many liters/s are this?" pi * (10/2)² * 150 = 11781cm³ = ~11.8l
"Water flows through a 4 inch wide pipe at 5 feet/s. How many gallons(US liquid, to be exact)/s are this?" I'm quite sure the average US American knows cubic inches per US liquid gallon by heart, just as any Canadian knows cubic inches per Imperial gallon, but me poor European cannot solve this without assistance.
http://en.wikipedia.org/wiki/Gallon: "The U.S. liquid gallon is legally defined as 231 cubic inches, and is equal to exactly 3.785411784 litres or about 0.133680555 cubic feet. This is the most common definition of a gallon in the United States."
Errr, "most common"? Are there other "definitions"? OMG...
I can find plenty of reasons for my aversion to non-metric units, but hey, others are used to it, like it, so use it. Just don't try to convince or even FORCE ME to use it! But if you DO I'll draw my revolv... errr ...... cell phone and start the unit conversion application

12:30 a.m. is 30 minutes past midnight.
From Wikipedia
PM will USually refer to post meridiem (also written P.M., p.m., and pm), "after noon" in the 12-hour clock, in contrast to ante meridiem (a.m., "before noon").

Yep, USually, but not if you deal with a Japanese insurance company
Recently I had a discussion about this with some friends (after a beer or two ). Believe it or not: none of us (that is 5 graduated engineers) could tell for absolutely sure (nobody in Germany ever uses am/pm notation). I switched my cell phone to 12h mode to check this, and we found it awkward that the 12->1 and am->pm switchover is not at the same hour. Typical case of "overengineering" you might say with some right

Nevertheless, in Germany in spoken language 12h is much more common than 24h. My watch is always in 24h mode, but if someone asks me for time I'll never say "20:50" but "10 vor 9" (10 to 9).
For disambiguation we either use 24h notation (written or spoken) or add time of day (spoken only):
morgens (morning) ~3..~8am
vormittags ("forenoon") ~8..11am
mittags (noon) ~12..1pm
nachmittags (afternoon) ~1pm..6pm
abends (evening) ~6pm..11pm
nachts (night) ~11pm..2am
mitternacht (midnight) 12am
The exact hours given can vary a lot depending on personal life and season, but nobody would ever say "10 Uhr morgens" (10 am in the morning) or "12 Uhr nachmittags" (12pm in the afternoon).
You think this is more complicated than am/pm? Yes, it is, but I'm used to it

[Led-Time]

You must be riding it up a bit beyond when your infra-red checker is telling you.

I try to keep the laser dot on the crystal as this is the important piece after all the reflective surface of the stainless case and the crystal has a different emissive reading which may be why the crystal pops out when it reads 100deg/C.

On the subject of deg/F & deg/C here in the UK we used to use imperial measures for everything (its still the best by the way) when we joined the common market i.e. Europe in the 70's everything went to shit now we have a mixture of both which is a complete pain in the arse. Personally I'am used to working with both methods as the nuclear submarines I used to work on had British imperial and metric manufactured equipment on board and even now at work we have to convert everything to imperial for our US customers…

Does anyone know if the original poster got his crystal out OK...

[retroleds]

Does anyone know if the original poster got his crystal out OK...

For disambiguation we either use 24h notation (written or spoken) or add time of day (spoken only):
morgens (morning) ~3..~8am
vormittags ("forenoon") ~8..11am
mittags (noon) ~12..1pm
nachmittags (afternoon) ~1pm..6pm
abends (evening) ~6pm..11pm
nachts (night) ~11pm..2am
mitternacht (midnight) 12am
The exact hours given can vary a lot depending on personal life and season, but nobody would ever say "10 Uhr morgens" (10 am in the morning) or "12 Uhr nachmittags" (12pm in the afternoon).
You think this is more complicated than am/pm? Yes, it is, but I'm used to it

We use many similar terms in the USA.
Seven oclock "in the morning" 7:00 a.m.
Two thirty "in the afternoon" 2:15 p.m.
Six Thirty "in the evening" 6:30 pm.
Ten oclock "at night" 10:00 p.m.
And Noon, midnight. But generally speaking we all know(or should?), at least here, that a.m. is from 00:00-11:59.59, the rest of the the day is p.m.

[retroleds]

The am/pm issues remind me of something I noticed on a Gruen Airflight jumping dial watch....in the pm the dial shows 13-24. But two of the watches I had jumped at midnight and noon. 00:00 and 12:00. The other jumped an hour later. A third one I received jumped at 01:00 and 13:00 - that is much more emphatic as to what time it is from 00:01-01:00, as 24:30 can only mean one thing, but 12:30 COULD have two meanings. I sent the other two to New York and had the same guy set the first ttwo to change the same way...apparently 99% of them get set up wrong when they went in for routine servicing.

http://www.dwf.nu/viewtopic.php?t=2922& ... 44f62fa938

[rewolf]

You must be riding it up a bit beyond when your infra-red checker is telling you.

I try to keep the laser dot on the crystal as this is the important piece

Don't get mislead by the tiny laser spot. Infrared thermometers often have a distance to spot diameter ratio of only 5:1, that is from 5cm distance the measurement spot is 1cm in diameter. Good ones have 10:1 or more. But at short distances the ratio is actually worse because the aperture size (~1cm) adds to the spot size, that is a 5:1 thermometer has 2cm spot size at 5cm, and 3cm at 10cm distance. Only beyond some 10cm this becomes neglegible.

That Gruen jump-dial is interesting - and ist shows the "problem" very nicely. They had better made a 0..11 and 12..23 dial -> no doubt possible (as in digital 24h watches).

[retroleds]

That Gruen jump-dial is interesting - and ist shows the "problem" very nicely. They had better made a 0..11 and 12..23 dial -> no doubt possible (as in digital 24h watches).

I hadn't thought of that, but yes, a 0-11 and 12-23 dial would have avoided the issues very neatly, better than relying on 24:00 hours. Is it proper to refer to midnight as 24:00 hours?

I have one of the infra-red checkers - I used it when I was doing patina/finish work for the bronze sculptor who got me into digital watch repair. They have an optimal distance as Rewold notes, and unless you have a real high-end one, ambient heat given off by other things can skew their readings badly.

Back to the original post - bake them slow, bake them fast? Is glue harder to remove after minimal heating, or have you tried the "bake until it has given up" method(20-ish minutes at 350-400 faren., 175-205 cel.). This thread has made it apparent that I need to add a pop-up temperature conversion script, along with the currency and distance converters. DONE!

[rewolf]

That Gruen jump-dial is interesting - and ist shows the "problem" very nicely. They had better made a 0..11 and 12..23 dial -> no doubt possible (as in digital 24h watches).

I hadn't thought of that, but yes, a 0-11 and 12-23 dial would have avoided the issues very neatly, better than relying on 24:00 hours. Is it proper to refer to midnight as 24:00 hours?

I think 24:00 is proper to denote exact midnight, but rarely used (0:00 instead). But 24:01-59 appears very awkward to me and I have never ever seen it.

The temperature conversion script is a nice idea, but you can just as well simply type "400 fahrenheit in celsius" in the google search bar on top of your browser window to get an immediate answer. This works fine for almost any conversion (even currencies).

[Led-Time]

I know what your saying regarding the infra-red thermometers its a quality instrument not one of the cheap run of the mill items, a very handy bit of kit these things excellent for all sorts of uses i.e. crystal temp monitoring for LED watches, radiator balancing on heating systems, air conditioning, checking the exhaust temps for the air/fuel mixture on motorcycles..... etc etc.