Tip: fix delaminating Canon lenses

[RichC]

My Canon 28/3.5 lens had rear lens elements that were badly separated (eBay "perfect glass" 😡). Ferreting around the web, I came across a fix for lenses cemented together with Canadian balsam - which I assumed to be the case for this lens. The fix involves baking your lens in the oven!

I tried it out, and it worked brilliantly.

Anyway, the recipe:

• Dismantle lens to remove affected lens assembly

• Preheat oven to Gas Mark 2 (= 150°C = 300°F)

• Place lens assembly in the oven, ensuring that it's level. I also rested it on some skewers, to minimise contact between the glass and the oven)

• Bake for 2 hours, then allow to cool for several hours

• Assemble the components

• Serve with a glass of crisp Pinot Grigio...

 

[palec]

Thanks for the tip. Interesting.

 

[peterm1]

Would a crisp chardonnay be OK? 🙄

 

[radiocemetery]

Seems pretty drastic, but if it works why not? Makes you wonder how many other camera repair secrets there are that we don't know about. Could you provide us with a link? Oh, by the way, serve with sake, no?

Steve

 

[Bryce]

Great tip! I guess you're remelting the Canada Balsam and letting it redistribute itself between the lens elements?
Is homemade cherry brandy O.K.?

 

[RichC]

Chardonnay - fine, cherry brandy - yup, sake - yuck!

Yes, it's softening or only just melting the balsam (melting point: 150–180°C). You don't want your elements to fall apart, so don't go above 150/160°C – you may want to buy a cheap oven thermometer just to be on the safe side (which you can later use when cooking food...). Similarly, make sure that the lower element block is placed level in the oven and that the lower element is supported.

This worked a treat for me – but I guess it could go wrong...

Here's one link: http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00CqXu. As suggested by Huw Finney - the strange bloke who built a digital Leica before Leica and put a light meter inside a 1930s Leica III (http://www.huws.org.uk)!