Robe 700 sealant question

[ekul1978]

I have had a dichrofilter break on one of my 700's and have placed an order for a new one from Robe but I forgot to ask what kind of sealant to use in replacing it. I know I can ring them tomorrow and ask but I was wondering if anyone knew what kind is needed? I guess its a high temperature one but obviously don't want to get the wrong type.

[timsabre]

Bathroom silicone from B&Q works fine (make sure it actually is silicone and not one of the cheaper versions which are acrylic).

 

Use a toothpick to place very small blobs of it.

[ekul1978]

Thanks for the reply Tim. Does it not need to be high temperature silicon being so close to the lamp?

[timsabre]

It'll be fine, done it lots. I think normal silicone is good to 400c

[gyro_gearloose]

Not sure how true this is, but I did read a post a while ago about using the correct type of silicone sealant. You can buy neutral and acidic silicone sealant, and the acidic stuff smells like vinegar while it cures, and can apparently damage dichroic coatings. Neutral cure, or non-Acetoxic sealant is the stuff to use to avoid any potential damage.

[timsabre]

Fairly sure that isn't so, the dichro coating is not affected by the (very weak) acetic acid. I have spent a long time in a factory which assembled dichroic colour wheels for fixtures and they just used tubes of bathroom sealant with toothpicks. It was a horribly faffy job but they made thousands of the things and as far as I know none of them fell apart or dissolved the dichro coating.

[gyro_gearloose]

Fair enough. I have used acidic Silicone in the past and can't say I've noticed any damage to the dichroic coating. And it is indeed a faffy job trying to tease the stuff into place with a pair of toothpicks :)

[ekul1978]

ahhhh ok - thanks for that. I will wait till the new glass arrives then go and buy a tube :)