Lapidaryforum.net
Rock Art => Cabochons, Intarsias, Cameos => Topic started by: jerrysg on August 22, 2016, 10:21:32 PM
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Has anyone ever used front (first) surface mirrors to back cabs with transparent areas to enhance the reflectivity? I know that a different topic talked about using mylar tape but I'm thinking that first surface mirrors glued onto the back of agates with transparent areas would work better but I don't know for sure. I'm going to try it unless someone with experience says not to bother.
Jerry
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It works extremely well, I think. Here's a Saddle Ridge Sagenite I did that way several years ago. I have a new batch of other materials -- sagenites, plumes, etc. -- ready for the same treatment in the next few days. Let us know how it works for you.
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Back rose quartz with asterism with a mirror to get the star to show good.
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Gemfeller, beautiful cab and you can see the effect of the mirror. Thank you for the feedback.
Now, any suggestions for sources for the mirrors (found some on ebay and Amazon) and adhesives? Any tricks for getting the adhesive bubble free?
Jerry
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When I do doublets or triplets I have a procedure to reduce the bubbles. I clean both surfaces to be glued with denatured alcohol then place them under a 100 watt goose-neck lamp to heat them up. When they become quite warm to the touch, I then mix the Epoxy 330 on a piece of white paper with a small stick. When mixing the two parts do so by a swirling action, not by whipping it together. Do it slowly so you don't introduce any bubbles. Keep swirling it together until you see no more swirl marks. Be sure to bring the edges of the mix into the center so no unmixed material is overlooked. By mixing on a piece of white paper you can see the swirl marks better. Place the mixed adhesive under the lamp alongside the heated pieces and warm it up for about a minute. This makes the material thinner and more fluid. If there were any bubbles introduced in the mixing process they will now float to the surface where you can pop them with a sharp point. Using a small flat wood stick (found at craft stores) and pick up some adhesive and slowly spread it on one of the stone surfaces. Do not dab it on, this will introduce bubbles. When the surface is fully coated use the edge of the stick and draw it across the surface once to remove the excess adhesive. Do the same application process on the other stone. Place the edge of each piece together and close them together like closing a book. This will prevent trapping any bubbles between the pieces. Press them together between your thumb and forefinger and move them very slightly to squeeze any bubbles and excess adhesive out. When you feel the pieces start to drag against each other stop squeezing them and place the glued piece under the light for a couple hours. This will speed up the curing. I always let the piece cure overnight before doing the cabbing process.
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Bob, have you ever tried to thin the Epoxy 330 with Acetone? Also about what temperature does the 100 watt goose-neck lamp heat them up to? The reason that I ask is because I use a toaster oven for my heat source.
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The 100 watt light bulb gets the stone so hot you can't touch it if you leave it under the lamp too long. The bulbs are getting harder to find in an incandescent bulb. There is a halogen bulb that is readily available that gets quite hot also. I use them for all of my lapidary work because they have a spot of light coming from the center of the bulb. They can be found at Home Depot for about $3. a pair and they are a direct replacement for the screw in incandescent bulbs.
Bob