Silicone for lens retention

[cramej]

Any reason not to use a few dabs of silicone caulk to hold a lens in a lensboard temporarily? I need to get a 32mm ring for a lens and it needs to fit inside an extended board. They seem difficult to find at this time.

 

[mshchem]

I've seen lenses screwed into Masonite (hardboard) Silicone may be overkill . Maybe acrylic caulk that gets a bit harder. Silicone gives off a horrible acetic acid stink. I wouldn't be too worried about most caulk, as long as the lens stays in place.

 

[Nicholas Lindan]

Crescent board (the cheap mounting board with the grey interior) makes a good wrench-it-in temporary lensboard. I used to cut an octagonal hole for the lens with a utility knife - easier than making a circular hole. Electrical tape plugs the light leaks and away you go. Keep the lens from falling out by wrapping some wire around the protruding lens threads and tightening it so the lens can't pull out of the hole.

I still use some lensboards that I made by laminating up cardboard from legal pads to get the right thickness, painting them black with water color and then varnishing them; I screwed flanges to the boards after I decided they would last.

I also made flat lensboards for Omega enlargers from copper-clad circuit board material. The boards need a block of something to keep the lens from protruding through the back of the board, I used scrap bits of 1/4" plexiglass but wood or chipboard would work just as well.

 

[cramej]

Now that I think about it more, maybe low melt hot glue would be even better. Easier to remove later for sure. I'll have to look for some Masonite in my pile of project scraps. Surely I can get a mostly circular centered hole with a dremel.

 

[Nodda Duma]

Do not use silicone, as the commonly available stuff will outgas creating haze on your optics.

Ask SK Grimes to make a custom ring for you

 

[gone]

I've made them from stiff cardboard or matte board. Just make the hole no bigger than the inner part of the threads and it will self thread onto your lens. Works fine. I usually paint them flat black.

 

[cramej]

I ended up using low melt hot glue last night. It holds it in place nicely with no movement. Plus it's ready to use in a couple minutes as opposed to waiting for silicone to cure.

 

[Auer]

I dont know why, but I assumed ppl that DIY as much as some folks here seem to do would also have a cheap set of hole saws and maybe even a tabletop drillpress...

 

[cramej]

As for me, I have a lot of tools, but not a large selection of hole saws, particularly metric or something close enough to allow for a good fit. Easier to mark the hole and drill smaller then finish the edge with a dremel.

 

[mshchem]

I ended up using low melt hot glue last night. It holds it in place nicely with no movement. Plus it's ready to use in a couple minutes as opposed to waiting for silicone to cure.

Perfect!!

 

[cramej]

Do not use silicone, as the commonly available stuff will outgas creating haze on your optics.

Ask SK Grimes to make a custom ring for you

This is a good point. Not only the lens, but the condenser and possibly film.

 

[DREW WILEY]

Horrors. Silicone potentially leaves a residue that must be thoroughly removed, perhaps aggressively, if anything else is going to stick later. Acrylic caulk? - what are you trying to do, make a spotting scope using a toilet paper cardboard inner and a couple of cheap magnifying glasses? If so, it might be appropriate. But so far, that does sound like the kind of project in mind : cardboard or masonite lensboard etc.