Fusing glass powder in a kiln for lens like enamel

[Mustafa Umut Sarac]

I think I found a interesting way for do it yourselfers.
I was watching enamel making videos at youtube and i discovered two things.
First : enamel is made by glass powders
Second : you can reach to glass powder melting point and finish the fusing process in 1.5 minutes in a small electric operated kiln.
It seems to me a promising way , canon uses similar techniques and finaly they press the fused glass in to the shape by very basic stamp presses.
May be all of these positive things sum under a method and prepare lenses at home in a electric kiln with a pyrometer aid.
May be powder can be melted and fused in cnc carved graphite or steel molds.
May be result will be with non transparent surfaces. Than the 200 year old technology comes and surfaces polished by hand.
I will not stop here and i will start to build a kiln and calculate for most exotic small lens.
But let me learn your opinions first ,

Mustafa Umut Sarac

 

[freygr]

I think I found a interesting way for do it yourselfers.
I was watching enamel making videos at youtube and i discovered two things.
First : enamel is made by glass powders
Second : you can reach to glass powder melting point and finish the fusing process in 1.5 minutes in a small electric operated kiln.
It seems to me a promising way , canon uses similar techniques and finaly they press the fused glass in to the shape by very basic stamp presses.
May be all of these positive things sum under a method and prepare lenses at home in a electric kiln with a pyrometer aid.
May be powder can be melted and fused in cnc carved graphite or steel molds.
May be result will be with non transparent surfaces. Than the 200 year old technology comes and surfaces polished by hand.
I will not stop here and i will start to build a kiln and calculate for most exotic small lens.
But let me learn your opinions first ,

Mustafa Umut Sarac

To get bubble free glass, you need to pull a vacuum. And the shape of the lens will be close to but not the same as the die used to make the powdered glass lens form. You will have to hand grind and polish the lens not mater what.

 

[DarkroomExperimente]

I made a couple plastic lenses by hand once...

took an acrylic rod 1" diameter or so...and turned it by hand onto coarse sandpaper to get a rough lens shape....then I'd put fine sandpaper on my left palm and press the rod with my right hand into the sandpaper and constantly turn it...then eventually I buffed it

I then cut the lens off the rod and sanded/polished the cut side flat

I still have it somewhere...it would focus an image, but I never tried it in a camera

 

[Mustafa Umut Sarac]

i found something at youtube , expert was mixing the powder with special liquid and than fire 90 seconds.
it produces excellent glass ornaments. May be die might be half milimeter bigger than the original shape and you reach to the reference by hand polishing. if we think telescope mirror makers reach to the max within hours , each lens will take few days.
May be kiln would be ultrasonically vibrated. I am thinking to press the fused glass now , if you visit canon virtual plant , you see it.

 

[3Dfan]

To be good, an optic has to be made to a very fine tolerance. Something with variations of less than 1/4 of a wavelength is considered in the good range but for revealing detail in a low contrast image even finer is desirable. Tolerances of 1/8 or even 1/16 is preferable. Polishing is necessary to achieve this level of refinement.

 

[3Dfan]

If you want to experiment with powdered glass on the cheap, I'd suggest using water glass - no kiln needed and it should be easy to get because it's used to preserve eggs.

Alternately, you could used sugar instead of glass and an oven instead of a kiln for proof of concept. Hollywood used to use baked sugar for the fake bottles that the Stooges would break over their heads.

 

[DarkroomExperimente]

Van Leeuwenhoek ...the microscope guy made his lenses ( I THINK it was him ) by melting beads of glass

this is a great book about him btw:

http://www.amazon.com/Single-Lens-Story-Simple-Microscope/dp/0060153660

 

[DarkroomExperimente]

I just remembered...when I was a kid we had a small "kiln" for melting powdered glass onto copper objects

it was actually more like a stove than a kiln....you placed the copper object ( flat plate in a 2d shape ) onto the heating element then covered it with a pyrex cover

I once cast tin onto a glass lens to make a convex mirror....it had a focal length of maybe 2" or so and would focus an image...this also how I learned that eyeglass lenses are made from plastic...the first time I tried it...Oooops the plastic melted when I poured the molten tin onto the glass.....for the 2nd attempt I used a real glass lens

 

[DarkroomExperimente]

here's a site that describes a method for making small lenses with a glass rod and propane torch for Van Leeuwenhoek-style microscopes:

Dead Link Removed

the focal length will be wayyyyyy too short for a camera, but it might give you ideas

 

[richard ide]

You could test using borax powder. It has a low melting point and when cooled is clear. I don't know the suitability of it for a lens. When grinding and polishing a lens, tolerances are measured in millionths of an inch. A good experiment which will give you experience would be to grind a mirror for a telescope. It would be a reasonable size and you would have one element of an optical system. With mirror grinding and polishing, you can end up with tolerances like I mentioned and test the result with very simple but accurate home made instruments. Kits are available which have all components necessary including abrasive and polishing powders. I ground an 8" mirror many years ago and IIRC it took about 65 hours.

 

[DarkroomExperimente]

here's a site describing grinding small lenses:

http://www.microscopy-uk.org.uk/mag...croscopy-uk.org.uk/mag/artapr07/hl-scope.html


good luck with your project...sounds very interesting!!

 

[Steve Smith]

When our company used to make its own PCBs we did regular micro-section tests on through holes. To prepare a sample for testing, it was placed in a mould about 1" diameter and 3/4" high and filled with an epoxy-like liquid which solidified. It was then ground down so that the hole in question was visible at the surface.

A bit like those shown at the top of this page: http://www.ctg-web.co.uk/circuits/microsection.htm except that ours were in a clear material rather than opaque as shown here.

The resin/epoxy (i'm not 100% sure what it was) was a powder mixed with water which set after about half an hour. It could be ground and polished and was fairly clear. Not as clear as glass but clear enough for lens experiments.

I will try to find out some more information on this process.


Steve.

 

[ZachInIsrael]

If you are interested in griding glass you may be better of starting with a telescope mirror. A newtonian telescope has only 1 surface that has to be figured, while a camera lens will have to have at least 8-10. Check under "ATM" over on cloudynights.com. There are also a lot of good books. And of course there is nothing to say you can't attach a camera back to your telescope and shoot that way.

 

[Mustafa Umut Sarac]

I dont know that its called grinding , its making nontransparent surface transparent , may be called like polishing. I think I will apply a AgX - apug member - way and polish the surface at a lathe. He described many ways to do it , look at his posts.
I am not believing grinding is necessary for telescopes , spin casting , inflatable films - vacuum formed aluminium mirror coated films , doe s and many other way. I attached a book to my older posts from archive org on grinding polishing lenses.its a old book , may be 120 years old. you can find it under lens making at archive org.

 

[DarkroomExperimente]

back when Scientific American still had the "Amateur Scientist"...there was a method for slowly rotating very slow curing epoxy to make parabolic mirrors....the solid epoxy was acoated with aluminum like a regular glass mirror