Hello everybody.

Yesterday i tightened a canon pinion and also cleaned the case.
After cleaning the case (including the crystal) in lighter fluid and rinsing it case in isopropylalcohol i noticed fine concentric hairlines in the crystal, that are so fine making it impossible to photograph.

Have i damaged the crystal this way or were they there before and i haven't noticed them because they are so small?

Thank you for your attention.
Have a nice day!
Lukas

 

Who told you to clean the case in lighter fluid and then alcohol….dishwashing soap and water is usually all you need…


We definitely need pictures

 

I thought there was less chance of rust if i don't use water.
Thank you for the tip. But it does not answer my question if the IPA is to blame.

You can see the hairlines over the hour hand.

 

The IPA may have made the crazing more visible if it seeped in and increased the refractive index contrast. But ultimately only you can tell us if the crazing was present previously. We don't know.

 

Thanks a lot! This post explained it quite well.

 

Alcohol will not damage an acrylic crystal...







No difference before to after applying 99% alcohol to this old acrylic crystal...

 

I recently got some experience with acrylic, more than I want, replacing around 30 crystals, one watch/crystal combo really wore me down and I got to test and go beyond the limits

Acrylic is a wonder material to me now

I think the main issue here is in the wonder, it's an extremely flexible material and there can be cracks that you can't see under magnification, so maybe the issue is related to this, if the acrylic is used or abused, it could be prone to discolouration or similar issues

As an unproved caution, these invisible cracks can move humidity and ruin a dial - I've seen 2 watches with patinated dials and the crystal was the only culprit, the caseback and the movement was clean and on one of them, the crack was easily observable as the crystal separated while pressing it out, but on the second one, the crystal was strong yet the discolouration path of the water movement inside could be seen

Edit: So maybe if the objective is water proofing, alcohol could be a test material too, if it fogs the acrylic, maybe it's detecting these cracks/zones

 

If anything thing I would think lighter fluid would be many times worse on acrylic than alcohol. Especially since soap and water is all that’s needed.

 

The solvent compatibility of PMMA is not a mystery, it is tabulated and readily available. As you can see, it has excellent compatibility with organic alcohols and hydrocarbons.

https://marketing.industrialspec.co...mma-chemical-compatibility-chart-from-ism.pdf

 

Agreed. I use eyeglass lense cleaner to remove dirt and smudges from my crystals. The main ingredient is alcohol and I've been using it for years. Never any damage.

 

My guess is a case of environmental stress cracking. Either the lighter fluid or the alcohol could have been a factor. No way to know which.
https://en.wikipedia.org/wiki/Environmental_stress_cracking