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Old March 30th, 2004, 07:05 PM   #1
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Homemade Bosscreen

After reading Giroud's posts about making his own Bosscreen, I decided to give it the go ahead. I picked up a block of paraffin wax, which is supposedly what is used in Bosscreen, and some new glass from Hobby Lobby. After getting everything ready, I attempted to duplicate Bosscreen.

Fortunately, its easy to get the wax melted and smashed between the glass. Suprisingly, my first attempt turned out very well. It all worked wonderfully, nice bright image, 3/4 diffused hotspot, great shallow depth of field, and one air bubble just right of center. I have yet to duplicate that result.

So far I've tried many ways of heating the wax. With my first attempt, I used a blowdryer, but that seemed to blow all the wax all over the kitchen. Next I tried smashing the wax between the glass, then heating it up. That worked, but left noticible bubbles. Then I put a cookie sheet on the stove and heated up one of the burners, set the bottom glass on the sheet with wax on top, then when the wax melted I put on the second glass. Again, air bubbles. My final attempts were sandwiching the wax between the glass, and heating the top glass with a charcoal grill lighter. All of these worked well, but I just couldn't get the bubbles out.

I tried the border idea and it didn't go so well the first time, but I'm about to go try some more. Like Giroud said, the big thing here is going to be getting the proper thickness. Too thin doesn't work, too thick diffuses well but is too dark.

I'm going to keep messing with it for a while. If anyone has ideas, I'd love to hear them. Hopefully this will turn out similar to the ground glass.
Nicholi Brossia
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Old March 30th, 2004, 08:45 PM   #2
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This is going to be at the very least challenging to get repeatable results and with this part of the adapter so critically important to the ultimate quality of the video its likely to make more sense to just buy the professionally made screens at around $100. But if you want to keep trying to make your own one thought that came to mind was to mount the glass horizontally and spin the glass at high speed while you heat the glass/wax. Perhaps this will force the bubbles to the outter edge of the glass while its in its liquid state. Then again it may make one hell of a mess. Just a idea. Dont kill yourself trying to cut too many corners to save that extra dime because your time is worth something as well.

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Old March 30th, 2004, 09:10 PM   #3
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Yeah, after about 6 hours of trying to get just one halfway acceptable result, I also realized that this isn't a corner to be cutting. You're right that this "ground glass" is the most crucial and delicate part of the entire adapter. Even if all the visible bubbles were smashed out, once zoomed in, the camcorder would see all kinds of imperfections. I am, however, glad that I did this experiment because it has given me a better idea of how Bosscreen will effect the outcome. I haven't gone down to 3 micron WAO yet, and still plan to, but at this point using a brightscreen is pretty enticing. Hopefully the 3 micron works out because I really like my current design and don't want to change it to accomodate a standard sized Bosscreen.

As far as the spinning idea, I think I'll pass on that one. I already have a super gigantor mess to clean up, and can just imagine having to clean wax off the walls and ceiling too.
Nicholi Brossia
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Old March 31st, 2004, 07:48 PM   #4
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Taking the hit

Thanks Nicholi for taking the hit for the team!
I was literally heading for the store to pick up some paraffin when I read your post. Thank you for saving me hours of frustration. Glass grinding is frustrating enough. My wife already thinks I'm nuts (I get emotional when I see a fresh scratch on the GG I just spent hours to remove the previous scratch from) She really didn't need to see me making a mess in her kitchen with the wax. Thanks again! joe
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Old April 2nd, 2004, 07:05 AM   #5
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I would be inclined to get an oblong metal container such as a spam, hamper or smeat can, melt the wax in it with a heater or gas ring underneath, put the two pieces of glass in on edge. glasses to be held together by springs and plates either side, held apart slightly by match sticks, preheated to avoid cracks of course, submerge the glasses completely, continue to keep the wax melted for a while, bring the two pieces of glass together under the surface of the wax by removing the match sticks and letting the springs pull them together , turn the whole thing off to cool and set, open the bottom off the can with a can opener, warm the sides over a heater to melt the edges to let the wax plug out without melting the wax between the glasses, chisel and shave the wax block off the glass, clean the surfaces, seal the edges and you should have a bubble-free boss-glass.

I am going to try this with two glass cd disks when I get them.
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Old April 6th, 2004, 12:08 PM   #6
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Go here for a discussion on "Bosscreen vs. Vaseline":
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