Framer warmer problem / question

[eyedude]

I started a new job and they use a frame warmer. I guess I'm from the old school and have only used a salt pan with kosher salt.
I needed to ajust a frame with crizal coated lenses and the lenses crazed. WTF. I felt slightly better after learning that my predecessor did the same thing. Is this common? Do you have to remove the lenses before heating the frame? Never had this problem with a salt pan.

[Lelarep]

Do you know what temp it was at? I haven't seen that happen except at really high temps.

[AngeHamm]

I always avoid putting lenses in heat, whether to adjust or for initial mounting. I've been burned a couple times too many. Crazing is uncommon, but it happens enough to merit extra caution.

[ThatOneGuy]

It depends on the AR and the amount of time in the heat. Sometimes AR is poor quality OR it is manufactured poorly, and doesn't hold up to heat well at all. However, if you are holding the frame in the warmer for more than 6-10 seconds, you're probably giving it a lot more heat than necessary to do what you need to accomplish.

[cajzmere]

I remove lenses for almost any frame front adjustments. The newer, tougher coatings are way more sensitive to high heat. If your frame warmer has a thermostat, turn it down. If not, remove lenses or as said above, don't hold it in there so long.

[SithRico]

I have a tool that blocks the heat from the lenses. If I remember on Monday I will get the info on here on where to purchase it. It's been years since I got it, but I know the manufacture is engraved in the bottom. Just don't remember the name. Ever since this no one in the office has ever crazed lenses while warming up the frame. I'll also get a picture.

[mervinek]

We have both the warmer and the salt pan. Some things I like the salt for and some the warmer for. Just depends. I would say if you're going to put the lenses in the warmer, keep it moving. I never just leave it in direct heat, just like the salt pan. If it's a real bad adjustment that needs more heat, take the lenses out just to be safe.

[DanLiv]

Never used the salt pan. Does one dunk frame and lenses into to pan? That doesn't craze or scratch lenses?

I always remove lenses before heating the front. A little heat alone might not damage them, but then you put torque on the lenses while adjusting and that will craze the heck out of all but the thickest lenses.

[plculver]

Are there some AR coatings that are just more prone to crazing? Where I work now sells primarily Crizal Avance, and I swear this stuff crazes if you breath on it too heavily. The Zeiss coating from the first place I worked was awful to keep clean, but I could heat frames until they were almost like taffy and not craze the lenses.

[eyedude]

It was a Crizal ooating. Thank you for that!!!!

[Quince]

Also, be sure you are checking lens material. You never want to put a hi index lens in any heat source!

[finefocus]

Don't heat the whole front when you only need to soften the bridge or endpieces. Use a cone, or concentrator to direct heat to the small area that you will actually bend. If you need to recontour the eyewire, then remove the lenses (you would anyway). For my portable kit (I do house calls for hospitals, etc.) I made one out of a cheap metal funnel from the hardware store.