DIY anamorphic lens

[Mark Techer]

Well keep reading and I will keep updating this thread.

I am trying an optical store tomorrow. There is guy there that supposed to know about CR39...

Mark

[Mark Techer]

Here is a couple of photos of the vacuum system. The whole rig costs $1500 and the pump itself costs up to $800 (pending supplier), but I have got one (new) lined up for $400. The gage is about $100 and shows negative pressure upto -100PSI.

Then there are the other accessories like the chamber itself (that is a 25mm Perspex lid) which I can probably get made for around $100, and the steel reinforced hose and release valve are extra...




Mark

[Foghorn17]

Mark, I thought you'd given up on the 2-part resin.

Does the new one part Gel still require a vaccuum chamber too?

[Hezz]

Mark,

It is good to see you keeping this DIY thread alive and thriving. Good luck with your resin prisms.

There is a type of clear polyester casting resin that uses only a small amount of liquid hardener. It is primarily one resin. It might be easier to mix without causing the swirl effect that you are seeing. It is also available in a super deep clear that is used for casting coins and things like that.

Also, while a lot of work and extra expense it is possible to polish and finish off the surface to an even flatter and better quality by hand methods. It however, raises the cost of the parts considerably by the time you get all of the stuff.

[Mark Techer]

Mark, I thought you'd given up on the 2-part resin.

Does the new one part Gel still require a vaccuum chamber too?

Not quite. After speaking to the optics specialist (a guy from OPSM - did I post that yet?) who makes prisms out of CR39, I realized that all was not quite lost. He has experienced the heat swirls too, but has the right gear to ensure that the resin cures properly.

The GEL (not available until after easter) I was looking at will also bubble if poured too quick. The problem using it is reactive time. It goes off in the sun, but how long for a large mass needed for the body of the prisms is one question no-one seems to be able to answer.

Looking at the four prisms that I have made, and the best one was done from two methods (at the time I wasn't really aware of), and that is -

1. During the pour, it seems best to let the resin run down the mold, rather than pool at the bottom, and

2. I used a heat gun to draw out the surface bubbles, but I also used that heat gun on the sides of the mold. It would appear that the resin really needs a warm area to re-act in rather than the normal room temp as there are hardly any swirls in that prism.

I want to try it one more time, but use maybe two of those flood lamps (one on each side) to keep the resin hot.

Mark,

It is good to see you keeping this DIY thread alive and thriving. Good luck with your resin prisms.

There is a type of clear polyester casting resin that uses only a small amount of liquid hardener. It is primarily one resin. It might be easier to mix without causing the swirl effect that you are seeing. It is also available in a super deep clear that is used for casting coins and things like that.

Also, while a lot of work and extra expense it is possible to polish and finish off the surface to an even flatter and better quality by hand methods. It however, raises the cost of the parts considerably by the time you get all of the stuff.

Thanks Hezz for the positive feedback. The resin I have used so far is the one pictured back a few pages with two eaual parts. It is clear. The other resin cost about half as much, but it's hardner is amber. Even though you only add a very small amount, how much colour change will there be?

The reason I elected to use Perspex as the sides of the molds was to provide a clean flat surface that I didn't have to pollish. Perspex has a lower refractive index than glass anyway, so with the exception of the possible light reflections that can occur off the surface, will give better results.

The angles is also less than liquid. I used 30degrees for the water prisms, so they are physically big (thick) and that means the light has to pass through a lot of liquid. The resin prisms are just 10 degrees, and if I can pour these without the swirls will will (do) work better as there is less for the light to pass. Note that the amount of stretch is the same, but the lens can be made smaller.

I quoted lines from the early pages of this thread as there was talk about using resin for the body of the prisms instead of a liquid, but that never went anywhere, so I have decided to give it a go.

Whilst not perfect, I belive that this will work. These four prisms were the first time I had ever mixed and used resin for casting, so there is bound to be room for improvement in technique...

Mark

[Foghorn17]

Thanks for the detailed reply Mark. You're still in the R&D phase here, so the final product is just a matter of refinement. Keep up the great work, we're with you all the way.

[Mark Techer]

Thanks Foghorn17,

I'll email you with some good news...

Mark

[Bud Bray]

Hey, talk about DRIVE...way to go guy! Was looking up resin casting and came upon this info, thought it might be helpful.
Bud

[Mark Techer]

Hey thanks Bud ray

This multi pour method would work based on the very first effort (flat mold), but would not work for method 2 (vertical molding) as you would see the line between the layers as we look through the casting.

Either way, you still need to de-gass the resin, and flame and or heat will only do part of the job.

It seems resin casting is an art form...But one I want to master...

Mark

[Mark Techer]

I just got sent this link from a guy in the States(?).

HERE is a cool how to on making prisms. Did anyone during the glass prisms phase use a hot glue gun?

Mark