what do you use for gluing optics and components in place?

[ghosttrain]

Is it just a white two part epoxy? I need to remove some from a chinese projector and reapply after recalibration. And second question, what can be used to remove epoxy?

[absolom7691]

I typically use JB Weld, a two part epoxy. For removal of epoxy from aluminum or brass mounts, I use an oven. Bake for about 15 minutes at 200 - 250°F and it should come off.

[ghosttrain]

Thank you for the tip. So I take it that there aren't different kinds of two part epoxies with vastly different properties relevant for our use case?
What about removing epoxy from ar coated glass or optics glued to an alumnium or brass mount? Might 250°F cause damage to the coat or crack the thin glass?

[absolom7691]

Not sure about the optics. Generally, when I am removing epoxy from an optical mount, I am not reusing the optic. I seriously doubt the heat would hurt the glass provided that you let it cool very gradually. As for the dichroic coating, someone else will have to chime in because I don't know.

[dnar]

Yep, Araldite epoxy.

Just never use C.A. (super glue)! It will ruin your day thanks to out gassing.

[ghosttrain]

Do you use cotton swab to apply the epoxy or something else?

PS. Yeah I know what you mean about CA. Dont know about glass but once the vapor messed up a polycarbonate window I had made for a LED screen and made the edges look frosted.

[masterpj]

I use UV glue.. which is also sometimes just called glass glue in stores. Its usefull because you can keep correcting until you think it's right and then blast it with a bunch of UV light..(or even a 405nm diode that has gone LED) it's strong and doesn't warp or pull anything out of place.

[planters]

gosttrain,
You might contact Bill at Pangolin. About a year ago he and I tested about twenty different adhesives for gluing their mirrors onto the 506 scanners. I looked at the induced optical stresses from the glues and they looked at all the practical issues with the application. I don't know what was decides or if several candidates were selected.

If heat cannot be used to remove the epoxy then methylene chloride works well at room temperature. This is the active ingredient in paint stripper. I have used the pure liquid and the gelled paint stripper from the hardware store and the gel is convenient. Use a swab or wooden spatula to surround the epoxy with the gel and wait several hours. The solvent will slowly diffuse into the epoxy turning it to a soft rubber that is easily separated by finger pressure. The dielectric coatings on the optics appear unaffected and I have reused them many times.

[ghosttrain]

Thank you again planters. You guys helped me save hours of trial and error and possibly damaged optics.
Has anyone of you thought of setting up a wiki to place all this information there? I'd be glad to help and move all I've learned there. It could contain all the information about building a laser projector. buffo's laser tuning tutorial, tips like this, list of hardware and software could all be in one place

PS. How would you clean the paint stripper itself? I've usually use rubbing alcohol but not inside a laser projector...
And I could use a heat gun, Im only worried that heat will damage the anti-reflective coating.

[planters]

The idea of organizing this information has been proposed, but the evolution of the lasers and scanners favors an ongoing discussion with support for those new to the subject.

Clean the paint stripper with isopropyl alcohol. Heat should be applied slowly and for a significant duration and that is why placing those parts that will tolerate it in an oven, works well.

Rubbing alcohol is isopropyl alcohol. The idea of "rubbing" is an anathema to optics. Use the alcohol in a container where you can wash the part by moving it in the solvent and avoid physically touching the coating, if possible.

Most optics will last a very long time and it is the cleaning that will damage them. A toothpick can lift small debris from an optical surface and an optical tissue, wet with a high quality alcohol, can remove films from the surface. Try to get the alcohol/solvent to rinse the debris off the optical surface and this can be done in a projector. The solvent will evaporate. The dielectric coatings are inorganic and will tolerate heat well. It is mechanical abrasion that should be avoided.