Fresnel Prisms, what are you charging for them?

[optilady1]

I have found that I am incapable of making a razor cut the freznel in a smooth enough cut to make it look good. It ends up looking more chunked than sleek cut. I have found for me, a really good SHARP pair of scissors does the job nicely. Other than that, I do it pretty much the same as Barry.

[Mick]

As Barry indicated a fresh double edge razor blade works great for a clean smooth edge.

[Judy Canty]

I always cut mine using an Xacto knife on a kitchen cutting board. Clean up the edges with a single edged razor blade, because I am too clumsy to chance using a double-edge one.

[mdeimler]

Scissors work great. One smooth, continuous line the whole way around. Comes out perfect.

[eyeguy21]

I always cut mine using an Xacto knife on a kitchen cutting board. Clean up the edges with a single edged razor blade, because I am too clumsy to chance using a double-edge one.

You should try the old phone book trick rather than the cutting board. I got that tip here on optiboard and it's great. It lets you put a slight pressure on the lens without damaging it and the phone book conforms a little bit more to the curves of the lens than a counter our cutting board would allow. The old way I used to do it was to trace the lens on the prism and cut it with a sharp pair of scissors. The problem with that was that the trace wasn't as accurate at the above method and it meant a lot of trimming in the end.

[optilady1]

The Xacto knife I use could slice your finger off before you even knew it it's so sharp, but I must not have the technique down for a smooth cut. What I do is take a good minute or two to get the impression of the lens into the plastic of the fresnel, which is visable enough for the first cut, and that gives me a 90% true to size cut, and then I slowly take it down from there. The nice thing about pushing the lens into the plastic is allows it to conform to the curve of the inside of the lens and it ends up being a pretty exact match. When I simply trace the lens, it always ends up off.

[idispense]

I don't get any edge lift but I think it is because of the quality of the silicone I apply to the edge after doing the sawzall cut.

[SoopaTroopa]

We charge $50... don't see them very often though.

[mervinek]

I agree with a really sharp pair of scissors. I feel like I have better control. Or better yet... have mdeimler do it for me!

[idispense]

On a serious note, it is possible to do this another way. Place the clean and wet lens and positioned fresnel prism in a heavy duty zip lock bag, zip the bag but leave a straw protruding from the interior, apply a vaccuum source to the straw, when the vaccuum is applied the plastic bag will press the lens into place and remove all air bubbles. you can stil work the position of the fresnel through the ziplock bag.

Many plastic parts are moulded this way.

[fjpod]

I was also taught to use a hard lens soaking solution on both the fresnel and the lens, then rinse it off, to lower the wetting angle of the materials, which would result in a better bond.

[Barry Santini]

I was also taught to use a hard lens soaking solution on both the fresnel and the lens, then rinse it off, to lower the wetting angle of the materials, which would result in a better bond.

This I will try!

B