Microcrystalline Wax Techniques?

[Frank Ladner]

The following link has been posted before, I think:

http://v3.espacenet.com/origdoc?DB=E...76&CY=ep&LG=en

Just some diagrams of how the MovieTube works - nothing too complicated, and not much more in principle than what we're already doing here - the main difference being the use of a prism(Schmidt, I think) and some sort of field lens.

However, I did a Google translation on some of descriptions, and thought some of these details may be of use:

...
The grain size is influenceable thereby also by suitable variation of the mixing proportion in the layer of wax. The wax mixture should contain 2 % to 60 % white bienenwachs and paraffin, whereby a portion of 5 % bienenwachs turned out as favourable. With a back projection lens with two flat-convex lens bodies on the vertices of both lens bodies cooling air is blown favourably. Before filling the liquid wax into the gap between the flat-parallel surfaces of the carrier bodies the gap is fixed on the necessary width. The layer thickness amounts to with the back projection lens according to invention less than 0.15 mm. A layer thickness of 0.08 mm is favourable thereby whereby also layer thicknesses from 2 to 3 hundredth millimeters or thin application find. Such a thin gap can be fixed before filling the liquid wax into the gap with india rubber threads. A remark example of the invention is below described on the basis the design more near.
...

[Bob Hart]

Sounds like a beeswax mix and elastic rubber bands around the junction of the two pieces of glass to keep the wax in until it sets? Very cunning. Under pressure, the molten wax will force past the rubber until all bubbles are exhuasted, then the rubber will settle back and stop air from getting in. I wonder why I didn't think of that?

[Jim Lafferty]

Wait, I'm not understanding what you're saying Bob -- would you be so kind as to explain that a little more clearly?

Thinking it over, is what you mean -- the glass is pressed together with very thing rubber spacers between the two pieces, whereby the wax and bubbles exit the space between the glass, then the pressure is released slightly and the wax cooled?

Thanks,

- jim

[Bob Hart]

My assumption and imagining is that they set their two pieces of glass apart, maybe with shims, maybe in a jig, at exactly the correct spacing between them then wrap a thick elastic band type thing around both glasses to cover the gap all round, pre-warm the whole assembly, then inject melted wax through the band, maybe with a special syringe even though the rubber band itself in the manner drugs are administered into intravenous drips through a membrane. There would have to be be enough wax injected with enough vigour to force all airbubbles out of the gap with the surplus wax out past the rubber band. Once all the bubbles were gone, then the syringe or injector is withdrawn. The rubber settles back and stops any air creeeping back in. That's my theory. The rubber band is in effect, the walls of a mold around the outside of the gap between the glasses. So far, attempts by AGUS/ALDU builders seem to have concentrated on dipping the edge of or the entire two pieces of glass in molten wax and relying on capillary action, gravity or mechanical closing of the gap between the glasses submerged under the wax to fill the gap and push bubbles out.

[Frank Ladner]

That sounds like something to try. The concerns are where to find a syringe that could hold the hot wax, and what kind of rubber to use. The thing mentions India rubber, but that may be a generic term (like "India ink") that means regular/general rubber.

Also, I wanted to let you guys know that I tried applying the wax directly to the space between two condensers. Of course, I still had the same problem with bubbles since I used the same procedure, but when I went back to do the hair-dryer-melt-and-squeeze (I sometimes do this after I have the wax inbetween the two pieces of glass to get a thinner layer and try to move air bubbles to the outer areas.), I could not get the wax to melt. I stood there for quite some time, trying to heat the glass enough to melt the layer of wax. At best, I could aim the hot air at the sides and start the wax melting at the thinner parts of the lens, but the thickness of the condensers insulated the wax. So that was proof for me of the insulating/heatsink benefits of the condensers.

NOW I want to try the 'injection' method with the two condensers and rubber.

[Keith Kline]

Okay so I made my first sorta complete wax gg tonight. I used a folded over piece of foil. It worked somewhat, but I got a big ait bubble. I didn't get to use the vacuum chamber so that'll be tomorrow's test. I just have a quick question for you guys. How do you guys clean the outside of glass? I scraped the outside lightly with a razor, but i can't get it completely off. Is there some type of cleaner or something that'll easily remove the wax from the glass?

[Bob Hart]

"Preen, the great unstainer". I don't know what you have in your part of the world. It is a trigger spray which you use to give grubby shirt collars and slobbered pizza sauce the treatment before you put your white business shirt in the wash.

Razorblade the glass first but only if it is glass. Plastic will scratch. Then spray with Preen, then rub the stuff around. The wax doesn't really dissolve all that well but it comes off and remains mobile.

Then rub over with neat hand-dishwash detergent, take it to the sink and wash off in water. Don't swim the disk but hold it above an empty sink under running water - and it is best if the water is cold.

Dry off then rub over with methylated spirit. I think you folks call this stuff wood-alcohol. Polish off the streaks and you have a clean groundglass.

(Then as you survey your wondrous creation, - the most pristine and well balanced wax composite agusdisk in the entire universe, it slips from your careful grasp of the edges and tumbles wild and free in slow-mo earthwards towards the hard tiled floor. You attempt an intercept with your foot but too late. It now looks like the windscreen in a car wreck.)

[Jim Lafferty]

I use rubbing alcohol and optical cleaner with disposable optical whipes whenever I do it. With a razor, of course.

Bob -- that last paragraph was great :D

- jim

[Bob Hart]

Precautions:

The condensers will need protection against sudden temperature change or they will shatter - bigtime. They also need to be warmed in air. If you take them out of warm water, the water will chill, = crackkk - bigtime.

My personal preference would be to have the working environment as warm as remains reasonably comfortable, prewarm the condensers slowly, already assembled, slightly apart, but with a spacer shim and rubber band already in place, fill a pre-warmed conventional diabetic syringe with wax, poke it through the rubber band and squeeze the wax into the gap. If the needle point can be placed near the center, probably all the better. You might have to use several syringes at once to get adequate overflow past the rubber band to carry the air bubbles out. There may be vetenary syringes of larger capacity and might also be made of metal.

I don't think the wax needs to be over water boiling point to be fluid but microcrystalline wax may be a different story which might be why the movietube people use the beexwax blend to bring the melting point down and reduce the risk of injury to the glass.

The rubber band itself might conveniently be made from a cycle tube and cut wide enough to give a good coverage of the gap. Cycle tubes seem to remain made of the original stretchy rubber whereas motorcycle tubes and auto tubes seem to be made of the less stretchy butyl material. I know these are now useless for making gings (= old aussie for "slingshots" or "shanghais".).

My guess is that the condensers would have to be positioned to that the gap is horizontal, not vertical, which would reduce the tendency for the bubbles to want to work against the flow to find the highest point.

To preserve stable temperature I would recommend the workshop surface be the reverse side of a ceramic tile on the bottom of an electric frypan on low setting. There would need to be something lese to protecthte glass from scratching. The rough surface of a piece of unpolished undyed leather would probably be adequate. Once the wax is injected, put the lid back on and turn the frypan off to cool down slowly. If it is a glass top lid all the better to slow the cooldown.

[Frank Ladner]

Keith and others,

I have uploaded some pictures of my adapter. You guys can check them out here:

209.214.235.122/mwtest

( "adapter_pic_01.jpg" through "adpater_pic_05.jpg" )

The primary parts are:
- 35mm lens (f1.8)
- PVC housing - 2"
- metal 'telescoping' piece from a telephoto lens or something (used to change flange-focal distance)
- 2 condensers (from glasses used in fly-tying)
- Wax layer between two circular glass pieces from 99 cent picture frames.

As you can see, it is held together by masking tape, which isn't visible once the main works is inside the PVC.

With this setup I am getting a really even picture, with no color separation, vignetting, hotspot, grain, etc...

[Rob Lohman]

That looks nice! Are you saying this works very well?

[Aaron Shaw]

Looks like you have a very interesting setup there! Can you explain what all the parts are and what you are doing?

[Dan Diaconu]

Frank,
What monitor size are you watching the picture? How are you connected to that monitor (what cable)
The stills are not from footage, right?
The inside looks very nice, but sharpness and vigneting are hard to tell since they are subject to possibly soft focus and uneven light in the room. Go for infinity (trees) and guaranteed evenly lit BK (sky)
It would be good to see a pic of the trees and sky with and without condenser lens, see the diff the condenser lens makes vigneting wise.

[Frank Ladner]

That looks nice! Are you saying this works very well?

Well, I started with the ground glass (using various grit sizes, down to 5 micron) made some spinning adapters, etc... and the microcrystalline wax adapter is the best thing I've used. Everything's a tradeoff though - with static you have to keep it really clean.

Looks like you have a very interesting setup there! Can you explain what all the parts are and what you are doing?

The layout is like this:

35mm Lens --> metal housing --> condenser --> wax screen --> condenser --> PVC housing

The metal housing is two metal pieces - one smaller than the other, allowing you to 'collapse' them, or in my case, slide them to adjust focal distance. As mentioned, these came from some other lens.

The PVC housing encloses the wax screen and condenser, and also acts as a coupler because it fits snugly over the macro lenses on the GL2.

I have since removed the front condenser and can't really tell a difference in the image. I don't have a hotspot problem or vignetting to deal with either way. This is due to the rear condenser and the properties of the wax, I think.

What monitor size are you watching the picture? How are you connected to that monitor (what cable)

I'm monitoring the footage with the little LCD screen on the GL2. It is pretty difficult to be sure you're getting the sharpest image, especially since I usually shoot with the Custom Preset feature with desaturated colors & sharpness turned all the way down (so even if an object is in focus, it still appears a bit blurry). I do this so that I can later take the footage, uprez it without bringing through a lot of the compression artifacts that come with electronic sharpening and bright colors, sharpen it, adjust color curves, etc...

It would be good to see a pic of the trees and sky with and without condenser lens, see the diff the condenser lens makes vigneting wise.

I'll try to get some comparison frames. I will say that just using a microcrystalline layer with no condenser has given me pretty acceptable results. This is relative to the thickness of the layer, though.

[Jim Lafferty]

Hey everyone...

I've been dragging my feet working on the latest go at a good, clean microwax sandwich for a variety of reasons -- biggest being I'm just taking a break from building things and doing other stuff (like building websites).

I'm still excited by the project and was wondering if those of you doing the bell jar or injection processes have things to share? Good things I hope :D

Meanwhile, today my girlfriend brought me along to a sculpture shop in Manhattan. While she was sifting through the piles of scrap marble, I spoke with guys there who do prosthetics and molding on the topic of our little project. After describing our submersion process and getting the arched brows from the group, I asked their advice. Here's what they suggested:

First, get a shallow metal pan and heat it with the filters in the pan. Setup your foil or tape spacers on one piece of glass before you do, so you can put the sandwich together when the time comes to do so. Heating the glass prevents the wax from semi-solidifying on contact -- this creates "stratification" in the wax layer, little lines that separate slight temp changes in the wax as it hits a given surface.

At the same time, melt your wax to liquid, being careful to not over heat it to burning or bubbling.

Once the glass pieces are significantly heated and the wax melted, pour a small amount of wax ontop of one of the glass pieces -- just enough of a drop at the glass's center and be sure that the drop is a solid shape.

With heat resistant gloves on, grab the other piece of glass and press it ontop of the wax. Get something like a flat piece of wood and put it ontop of the glass/wax sandwich and apply some consistent weight ontop until the wax solidifies.

__________

I marveled at the simplicity of the setup, because I'd figured this would create bubbles when I thought of it a while back. The guy basically looked at me and said "It shouldn't. I do a lot of prototyping and use this technique all the time. You should be able to squeeze and bubbles out with the wax -- the challenge will be in not squeezing out too much wax, but it seems like you've got that figured out. Submersing the glass entirely is a big waste of time and presents a greater risk of ruining the whole setup."

I came home with the parts to follow-up on this and will likely give it a try tomorrow. Wish me luck.

- jim