Does anybody know the technique for sticking on fresnel prisms?
Do you wet the prism?
many thanks
Does anybody know the technique for sticking on fresnel prisms?
Do you wet the prism?
many thanks
I've always cleaned the lens real well with warm water and then get the prism wet with warm water. Put the prism in place and push all of the air and water from between the prism and lens. Then just pat dry. They hold quite well, some say to use soapy water. Terry Agin
We use isopropyl alcohol - it dries much faster. If you have a hand stone, you can use it to trim the prism to fit very nicely (after it is applied)
shutterbug
I always use a little sugar to add to the water.
Holds greate!
I wrote 3 M they said to trim, and then mount under warm water. Do this, have also tried contact lens wetting solution, dry mounting and God knows what else, and some of them are still a b____!
I also use the Isopropyl alcohol. I works great and quickly get adherence and no bubbles.
When using isopropyl alcohol, I assume both surfaces are dry. Do you apply the alcohol to the fresnel or CR39 lens, or both?
Placing the fresnel prism on the lenses has never been very easy. Always keeping in mind that the "ridged" side of the prism is the side that faces the patients eye. Making sure that the prism is going in the right direction is also quite important. After you have cut the prism "a hair smaller" than the lens surface you should run some tap water at a consistent slow pace.
Not at a "drip drip" level but also not at a gushing "put out the fire level" either.
Just a slow even level of pressure you should place the lens and the fresnel prism under the stream of water and slowly adhere the 2 together slowly working out all of the bubbles of air. This process has worked well for me and many people have taken to it pretty well. The reason why you cut it "a hair" smaller than the lens surface is so that the frame will not come into contact and interfere with the marriage of lens and prism. Either by way of the nose pad arms of the frame or the eyewire rim, or if a zyl frame the whole frame could work completely against you and cause you to lose any patience that you might still have after this process.
I always do them underwater in a sink of warm water. Start at the bottom and work upthen you get no bubbles. Still cant wallpaper well though...Originally Posted by chip anderson
I use a pyrex breadpan half full of warm water for mounting prisms This allows me to immerse the frame completely and keep it entirely underwater while pressing the prism and lens together. I then use a paper towel to wick the excess water from the lens and finally pat it dry. If you then dip the entire assembly in alcohol it will remove all residual water and dry quickly on its own.
Ed
Get Milk......use spit. Chocolate milk for a nice brown #1 :bbg:
Chris Beard
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At an office I worked at several years ago, we did Fresnel prisms a couple times a week. I would wash the lens with warm soapy water, then dry, and after tracing the lens pattern on the prism, wipe it clean with an alcohol pad. I'd apply the prism to the lens under running water like PNKansas stated. Then using my lab towel wrapped over my finger, pushed any bubbles out towards the edges (learned the hard way to use my fingertip and not my nails :hammer: ). I got to the point where I could do all this without removing the lens from the frame.
That's not to say I didn't totally mess up bunches of them. I had a gal hand her glasses back to me one time and say "Can I get one that fits?" all snide-like. I was pretty new at it, and had cut it a little small. A good lesson in keeping my thoughts to myself.
If you get to practice at it, it's not too tricky. Just pay attention to your base direction before you cut out the lens shape. If it's a low power, it's easy to get it turned around!
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