I was hoping to share some experiences I had working with magnification glass.
I'm sure many of you have ideas on incorporating magnifying glass into mounts, and know there are numerous factors that need to be considered:
-The focal length of the lens (distance to the specimen).
-Height of post required to support lens (which also impacts the following two factors).
-Distance of the mount to the viewer (especially if inside a case).
-Viewing angle required to achieve an appropriate viewing height (keeping accessibility in mind, and keeping the specimen in line with the lens and with the viewing height).
I experimented with two types of mounts for a small fossil specimen. The first was constructed of brass with an acrylic base.
This method was a bit complicated, especially since I wanted to use square tubing, with wire passed through the semi-circular lens support and bent (then cut) to secure the lens on the sides. This way, the lens could be easily removed from the mount when required.
I was using a lens with a 4" focal length, and angled the specimen at 40 degrees (based on its distance inside the case, and a viewing height that was low enough for children to see.
Another option, one which I ended up using in this instance, was a mount composed entirely of acrylic. The key to this mount was using a magnifying lens with the same diameter as the acrylic tubing I was using (which I believe was 3")
I cut a ring of acrylic tubing off using the bandsaw, polished it and used UV activated adhesive to attach the lens to the tubing. I'm not sure what your experiences are with this adhesive, but it enabled a lot of time to set it up until I activated it with the UV light. The type I used came in a small convenient applicator bottle commonly used for fly fishing.
The adhesive dried totally clear, with no bubbles.
The post was acrylic rod, with a 40 degree angle cut out of the top. I attached these together with Rez-n-Bond. It also dried clearly, producing a polished result. I used a weight and tape to secure the lens to the post while the adhesive dried overnight.
The final result looked like this:
I was fortunate to have been able to match the diameter of the lens with acrylic tubing, which produced a clean result in the final product.
Very nice work. Thanks so much for sharing this with the group. I especially like the second version and how well it worked with the UV cured adhesive. That's not a technology I've used and I now want to know more. It would be good to know how the adhesive fares in an Oddy test. I would think it would be good as the UV curing should make it a very stable.
Thanks Jamie, I was also curious about Oddy testing UV glue. I did not see any tests on this material from the British Museum's Oddy Test database or the AIC wiki page.
One manufacturer I was looking into had this asked in a FAQ section on their website but replied that they had not yet Oddy tested the material either.
I will reach out to our conservation department and see if we can run the test here.
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