Anyone know if this is dodgy or not?

[mcyr]

Iman,

I did a little patent searching and found that the phosphine oxide that is used in your material is not cured at visible wavelengths...it still needs UV to cure. Is there something on the bottle that gave you the impression that it could be cured with visible light? Is the preferred source of light for curing mentioned?

Geof,

You're right. I mis-read your post. My apologies.

[ImanCarrot]

Erm.. yes. It's "specificaly designed to cure in the visible wavelengths (above 400nm).

http://www.henkelna.com/cps/rde/xchg...UID=0000000N6B

I got the MSDS on it, but it's like reading hyroglyphics in a mirror after a bottle of JD with one eye closed.

The LD50 and LC50 figures don't seem too low, so I guess it's ok.

Anyway, it's still tacky after an hour on unbonded surfaces so no use to me.

[Fe56]

Originally Posted by ImanCarrot The LD50 and LC50 figures don't seem too low, so I guess it's ok.

LD50 and LC50 figures aren't that important for safety purposes. That's just the amount required to kill half of a test batch of rats, the amount required to kill half of a test batch of humans would be pretty enormous by comparison.

Look for stuff like skin transmission and health effects, and check for terms like 'reproductive hazard', 'mutagen', 'teratogen', 'absorbed through skin', 'carcinogen' and if you see any of those err on the side of paranoia. Latex gloves are cheap, non latex examination gloves only a bit more expensive (doesn't stop my sister the doctor with the latex allergy griping about the cost though) and no amount of money can buy your health back if you've wrecked it by neglecting clean techniques.

[mcyr]

LOCTITE

® 3556™ cures rapidly when exposed to visible light
of sufficient intensity.

You'll need something like this since the amount of visible light is very poor from halogen bulbs:

http://equipment.loctite.com/product...0Flood%20Units


Also, the technical information mentions that the material that doesn't cure can be easily cleaned with a solvent like acetone.

[Geof]

Ditto to what Fe56 writes.

[ImanCarrot]

It's not possible to clean the remaining residue off using acetone- I'm making lenses here, it would smear all over the critical surfaces and take as long to clean the stuff off as it would to actualy make the lens. By the time you'd smeared all the stuff all over the lens sod's law states that the thinning layer would cure and become very difficult to remove and the more you tried, the more you'd scratch the lens surface. Oh, and beleive me, I do know about cleaning optics, it's been the bane of my life.

Here! if any you guys want to read about proper optics n stuff then get Frank Twyman's book "Prism and Lens Making" the man was an absolute genius, on a par with Einstein in my opinion. The techniques he used are still used today, sadly by a diminishing few as there's no- one to pass the knowledge on to *sadness*

Oh, erm, the reason I can't have any contamination on my lenses is: the optical system will not work