Preparation of glass plates?

[djm]

When making DIY silver halide plates, 3-amino-propyltriethoxysilane is recommended for preparation of the glass plates to make the glass sticky to gelatin before coating. At Sigma-Aldrich this is very expensive, about $470 for 50 ml. Is there another way to make the plate sticky to gelatin to prevent the gelatin from detaching during processing.

[Martin]

When making DIY silver halide plates, 3-amino-propyltriethoxysilane is recommended for preparation of the glass plates to make the glass sticky to gelatin before coating. At Sigma-Aldrich this is very expensive, about $470 for 50 ml. Is there another way to make the plate sticky to gelatin to prevent the gelatin from detaching during processing.

Yes, there is:
you might try a thin, very well hardened gelatin sublayer prior to the actual coating. A 1% gelatin solution + chrome alum might be a good start.

As for the amino-propyltriethoxysilane thing I guess you might find it at other places. e.g. in the context of glass bonding.

[Joe Farina]

That's an amazing price for the silane. I have a 100ml bottle from Alfa Aesar (comparable to Aldrich), so I better hang on to it!

In addition to what Martin suggested, you could also try some plain chrome alum or sodium silicate (water glass) on the glass before coating. I don't have any specifics on this method, but I've emailed you a couple of pages from the book by Baker ("Photographic Emulsion Technique") where it's mentioned. I'm assuming the chrome alum or sodium silicate is applied to the glass, and then rinsed off, leaving the glass in a condition that has some "tooth" as Baker describes it, so the gelatin will adhere strongly. I've also found it's very important to de-grease the glass as part of the cleaning process, Baker mentions "hot soda" but I use trisodium phosphate (TSP) in hot water, with a long soaking time and scrubbing. I think the sodium silicate is worth a try, it's a fairly safe material and should not be difficult to find (it's available on eBay at reasonable cost). It's an interesting material for other uses also.

[djm]

Thanks for your input, guys.

I am not sure if the Sigma-Aldrich stuff I mentioned is the right kind. It was what came up when I searched for 3-amino-propyltriethoxysilane. It is a 65% solution in ethanol, CAS Number 7538-44-5.

I looked at Alfa Aesar and they have Silane at 32 Euro for 100 g. CAS Number 919-30-2. That is a more reasonable price. Not sure it can be shipped overseas though.

[Joe Farina]

Yes, that's what I have from Alfa Aesar (even though it's a liquid, they measure it in grams). Unfortunately I think there is no chance whatever of getting it from them, unless you have an established account already.

I would suggest proving you have a problem first. De-grease with TSP or something similar (with scrubbing) and see if the gelatin detaches. If there is a problem, try other alternatives involving chrome alum or sodium silicate. Finding that particular silane may be very tough.

[djm]

So far I have only tried to coat plain glass with gelatin to see how it behaves. I need to order some chemicals before I can test to make my own plates, but I will follow your suggestion and try out a minimal setup first, and go from there.

[Martin]

I guess these silane products are OK: http://www.bostick-sullivan.com/cart/home.php?cat=172

[Sergio]

Guess Jeff wrote somewhere about glass silanization easy method where?

[Valery]

Well, use beer..

[Valery]

Well, use beer..

but disturb with water.