Another homebuilt coating machine....

[rmazzullo]

Brief notes below copied from the website (https://www.fotoceramicacostarica.com/). Lots of interesting information.
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This Handmade Machine I Built Around 40 Years Ago To Leave A Perfectly Even Solution On Many Materials. If Paper Is Coated It Is Moved By Hand Trough The Coating Tray At 15 Feet Per Minute.​

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After A Complete Revolution Of The Strip Of Paper,The Coating Trays Is Lowered And The Band Of Paper Is Moved Continously For About 3-6 Minutes Until It Is Dried Enough To Dismount It On The Bottom Roller And The Band Of Paper Is​

Hanged To Dry In Another Place.​

Then Another Band Of Paper Is Mounted On Top Roller, United At Its End With Duct Tape And The Handle That Moves The Rollers Is Hand Cranked After The Emulsion Tray Is Lifted Upward To Coat The Paper.​

After Each Coating The Emulsion Tray Is Lowered The Band Is Again Hand Rotated Until Dry Enough For Dismounting Off The Rollers And Hang To Dry Again. This Action Is Repeated Over And Over.​

I Coated 100 Sheets Per Session Requiring A Total Of About A Liter Of Solution. A Normal Coating Weight Of Gum Or Silver Gelatin Emulsion Is 10ml Per Sheet Of Letter Size Paper.Carbon Tissue Requires 3 Times That Much.​

If A Thicker Coating Is Desired The Paper Is Moved Faster Than 15 Feet Per Minute Under The Coating Solution. For A Thinner Coating The Paper Is Moved Slower.​

 

[mshchem]

Hmmnn?

 

[koraks]

Lots of interesting information.

I scrolled through that website a little and I imagine this is what it must have been like walking into a Medieval bazaar in let's say downtown Cairo, LOL!

Having said that - no, that contraption will not work particularly well for coating emulsions like carbon tissue. It's going to be a mess with a very uneven coating and runners all over the place.

 

[Don_ih]

that contraption will not work particularly well for coating emulsions like carbon tissue. It's going to be a mess with a very uneven coating and runners all over the place.

Maybe. That depends on the way the tray is constructed, which might spread and limit the thickness of the emulsion being applied. The paper is stretched taught, with positive pressure so it doesn't relax as it gets wetter.

And when you look a bit more carefully, you see that guy is quite accomplished.

 

[koraks]

limit the thickness of the emulsion being applied.

Exactly. So it's not going to coat to the thickness that's equivalent to 30ml per letter-sized sheet. Thinner - yes, probably. Not carbon tissue thickness. I bet he threw that "carbon" reference in because he though it 'should probably work' or something.

Have you tried lifting a freshly poured sheet with 0.5-1mm wet gelatin thickness on it before the gelatin had set? What happened?

 

[rmazzullo]

It does present some interesting variations...ideas that could be used in a small coating machine of a different, more robust design. Of particular note is the manual cam-operated emulsion tray lifter.

 

[imgprojts]

This is really interesting . But I agree with the comment about lifting a sheet that has not set yet. It just runs. But maybe there's something interesting to dig into here.