I've been providing DLC service on a word-of-mouth basis for some time now. Most of the time, everything works out perfectly - but every once in a while, there's a snag...
Yesterday, I received a shipment of two cases, and several small parts. All of the part looked good at first glance, but when inspecting more closely, I noticed a small imperfection around the bezel of one of the cases. Thinking that it could be some oil or something, I wiped the area down with alcohol on a cotton swab. When I did this, the DLC coating actually lifted in the area:
I immediately suspect what happened...
Normally, I remove the bezels from all watches, and coat them separately. With this case, the owner had attempted to remove the bezel, and it wouldn't budge. When I received it, I also tried, without any luck. We determined that the bezel was probably press-fit metal. Not wanting to damage the case, we decided to leave it in place for coating.
Looking at the coating defects, I am certain that there was a gasket left in place inadvertently. PVD coating is done at a very high temperature. (DLC is applied at slightly lower temperature than most other coating, but the parts are still heated to around 350-400°F.) At these high temperatures, any rubber or plastic parts may melt, or give off gases. This "outgassing" can ruin the PVD coating. It is absolutely essential that all plastic or rubber parts (gaskets, O-rings, glue, etc.) are removed prior to PVD coating.
So I tried once again to remove the bezel. This time, I was able to pop it off...And guess what...
There it is, the little O-ring. It wasn't even completely destroyed, but it gave off enough gas to ruin the coating:
So, now that I know what caused the problem, it's time to strip and recoat!
You live and you learn...
Yesterday, I received a shipment of two cases, and several small parts. All of the part looked good at first glance, but when inspecting more closely, I noticed a small imperfection around the bezel of one of the cases. Thinking that it could be some oil or something, I wiped the area down with alcohol on a cotton swab. When I did this, the DLC coating actually lifted in the area:
I immediately suspect what happened...
Normally, I remove the bezels from all watches, and coat them separately. With this case, the owner had attempted to remove the bezel, and it wouldn't budge. When I received it, I also tried, without any luck. We determined that the bezel was probably press-fit metal. Not wanting to damage the case, we decided to leave it in place for coating.
Looking at the coating defects, I am certain that there was a gasket left in place inadvertently. PVD coating is done at a very high temperature. (DLC is applied at slightly lower temperature than most other coating, but the parts are still heated to around 350-400°F.) At these high temperatures, any rubber or plastic parts may melt, or give off gases. This "outgassing" can ruin the PVD coating. It is absolutely essential that all plastic or rubber parts (gaskets, O-rings, glue, etc.) are removed prior to PVD coating.
So I tried once again to remove the bezel. This time, I was able to pop it off...And guess what...
There it is, the little O-ring. It wasn't even completely destroyed, but it gave off enough gas to ruin the coating:
So, now that I know what caused the problem, it's time to strip and recoat!
You live and you learn...
