Jump to content

Can acrylic cracks be fixed ?


Chopin

Recommended Posts

Hello guys, I come with a question for those of you that probably have experimented around.

I have a watch with a crystal that has a few small hairline cracks (all the way down, so to speak) and I was just wondering if it wouldn't be possible to have them fixed/covered/filled by simply applying some type of adhesive that enters the cracks. I'm asking because I recently saw a video of someone fixing a cracked windshied by inserting some transparent adhesive into the cracks and they eventually disappeared as the adhesive dried.

The watch has a bit of an unusual crystal. I ordered an ATCH crystal but apparently it wasn't perfect. Apparently the vertical outer wall isn't as long as the old one (basically 2/3 through it starts to curve; measured bottom to top). (photo of the old one below, in case someone could help me name this type of crystal)

IMG-8559.jpg

Link to comment
Share on other sites

I suspect it may be possible, but equally it may be more problematic than it first appears.
 

  1. One major issue is that any dirt in the crack will end up set in the repair compound, so unless you can ensure absolute cleanliness then the crack may still be noticeable following the repair.
  2. You may need to pull a vacuum to get the repair material to enter the cracks.
  3. You will still need to polish the piece after the repair to ensure an optically acceptable finish.
  4. The repair material will need to set up (cure) with roughly the same refractive index as the original material.

    For the record, most of these crystals are probably a form of poly-carbonate, but this may not always be the case, and you would need to confirm what the crystal is made from to ensure the repair compound is compatible.
Link to comment
Share on other sites

Can be done . Have repaired some with acrylic powder and the solution for nails. Same that is used for prosthetics . But it doesn't work if it's in the middle of the crystal . It can be polished up to near perfect finish as it's the same material. You need to remove the old crack and get into the material that is good . Then fill it with acrylic. 

What size crystal do you need . And for what watch? 

I have a Certina DS 2 i crystals with similar cracks  can have a go at . And i can do a before and after. Have some powder left i think. Tomorrow evening. 

Edited by rogart63
Link to comment
Share on other sites

Thanks guys, so that would be a no on my part, then.

It's not the size that is the problem but the height of the vertical edge/wall of the crystal. The ATHC starts to curb halway while the one that I need needs to be straight/vertical almost to the top of the overall height of the crystal (as the photo shows). I just don't know what type of crystal it is since it's clearly not an ATHC.

Link to comment
Share on other sites



  • Recently Browsing

    • No registered users viewing this page.
  • Topics

  • Posts

    • Post some pictures , some good close ones of the parts you've described. 
    • Ive never used epilame H only information i have read and mentally stored about it mostly from Nicklesilver here and elsewhere ( the fork horns thing ), maybe the residue powder that is removed has some grinding effect ? So probably a good idea to limit its application areas to only the absolute necessary. Yes as far as i know epilame rubs off relatively easy, the technique of running the watch to make a groove through it first in the pallet stones where the lubrication is then placed. This i understand creates the barrier for the lube to sit up to. If i can find a good balance of pros and cons of its use then thats one process i can avoid by using a thixotropic lube on the stones. The epilame i would say allows for a more fluid lubrication to be used that would increase amplitude on low beat movements. The stearic acid powder is extremely cheap, the problem is the fuming process to coat parts, is not selective , the whole part has to treated in this method. If epilame residue can cause wear then thats not good, if I remember the conclusion was not proved entirely just a general assumption between watchmakers. The thread is out there somewhere, the same discussion is also old on a facebook group. Ive never used epilame H only information i have read and mentally stored about it mostly from Nicklesilver here and elsewhere ( the fork horns thing ), maybe the residue powder that is removed has some grinding effect ? So probably a good idea to limit its application areas to only the absolute necessary. Yes as far as i know epilame rubs off relatively easy, the technique of running the watch to make a groove through it first in the pallet stones where the lubrication is then placed. This i understand creates the barrier for the lube to sit up to. If i can find a good balance of pros and cons of its use then thats one process i can avoid by using a thixotropic lube on the stones. The epilame i would say allows for a more fluid lubrication to be used that would increase amplitude on low beat movements. The stearic acid powder is extremely cheap, the problem is the fuming process to coat parts, is not selective , the whole part has to treated in this method. If epilame residue can cause wear then thats not good, if I remember the conclusion was not proved entirely just a general assumption between watchmakers. The thread is out there somewhere, the same discussion is also old on a facebook group. If its a potential problem for amateurs to use then i would prefer not to take the risk .
    • Following on from my question about identifying screws in the AS2063 movement that basically fell out of the case in bits, I’m pleased to report that I’ve got it all back together, and the movement is running pretty well.    But… There’s something wrong with the keyless works and hand setting. It’s fine in winding and quickset date position - these work - but in hand setting position winding the crown turns the whole gear train.  I don’t really understand how it’s meant to work. It doesn’t have a traditional friction fit cannon pinion.  The second wheel is unusual with a pair of smaller pinions on it, which seem to interact with the barrel and the motion works.    Could this be the problem? I must admit I just cleaned it and popped it in place when reassembling the gear train. I’ve lubricated the pivots but didn’t do anything to the extra bits on the second wheel.    Does this make sense and is anyone able to figure out what I’m doing wrong? Thanks in advance, as always.    ETA - the parts list calls it the Great Wheel, not second wheel. 
    • You're thinking metal to jewel in general I guess. Maybe it would be a good idea to peg the pallet staff jewel hole on the main plate after the epilame treatment. I think that could work as it is my impression that the epilame doesn't sit very hard, but I could be wrong about that so feel free to educate me. I didn't remember that 9501 was thixotropic (thanks for the link). That would mean it's even runnier during impact (lower viscosity) so perhaps it's time I get some fresh grease as mine seems a bit too runny. What I have seen is a whitish surface after washing but it goes away if I scrub the surface with a brush in a degreaser (Horosolv). I don't think it embeds itself in the metal but sticks very hard to the metal. I don't worry too much about the cleaning solution. I just want perfectly clean parts and my solution can be replaced for little money (ELMA RED 1:9). Anyway, I quite often need "to strip back and rebuild" and scrubbing parts by hand isn't exactly the most stimulating part of a service. Just got confirmation that Moebius 9501 has a lower viscosity (68 cSt at 20° C) than 9504 (305 cSt at 20°). The viscosity of Molykote DX is 285-315 cSt at -25° to +125° C. I was surprised to see that the viscosity of Moebius 9010 (thin oil!) is higher (150 cSt at 20°) than my 9501 grease!
    • I’ve had a couple movements where it is clear the previous watchmaker was diligent with lubrication but the old epilam had turned to a fine white powder covering the pallet fork and keyless parts, which can’t be good for parts. I’m spare with epi since I don’t know how long it takes to degrade to that state…
×
×
  • Create New...