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To quantify the result, the two of you may be interested in this: https://prezi.com/rz8q_jockfxb/the-effect-of-ph-on-the-formation-of-coacervates-in-gelatin/

I wonder if the creation of bubbles may not speed up the process. The NaOH and/or the HCl forms coacervates of gelatin, the bubbles then act to lift and separate them, allowing easier removal (yes, I know it sounds like an ad for a item of cloithing!). Anyway, perhaps some bicarb of soda and a little vinegar added to the mix.

[quote="TonyDCG"]Yes true, Acetone I believe has less residue

Say one last thing Steven, do you strip used film in a particular way?

I've tried pure bleach or sometimes 10% Muriatic Acid with OK results. But sure would like a better method.

Thanks again

Tony[/quote]
Hi Tony,

I just use a weak solution of hot caustic soda.
I let it sit for a while and the old coating just falls away.

I lay the glass face up in an old photo developing tray and pour the hot caustic soda on top.
If I have several sheets to do, I just pull out the ones that are done and place the next ones in the tray.
I don't bother to reheat the caustic soda. it still works, but it's not as fast.

I sometimes reuse the glass for coating after it has had another soak in HCl,
but other times I just cut it down to my usual cover glass size of 5" x 7", so it doesn't go to waste.

Steven.

Yes true, Acetone I believe has less residue

Say one last thing Steven, do you strip used film in a particular way?

I've tried pure bleach or sometimes 10% Muriatic Acid with OK results. But sure would like a better method.

Thanks again

Tony

[quote="Tony DCG"]Thanks again for sharing Steven,

I some times use Methanol and Kim Wipes is there is some pit that will not be removed by air. Methanol does not leave much of a residue and evaporates very quickly.

Look forward to chatting some more!!

Tony[/quote]

I find that acetone is very effective.

Steven.

Thanks again for sharing Steven,

If you can find them or afford them try Kim wipes (KimTech). The tissues are ultra clean although it is not as soft as standard tissues.

I some times use Methanol and Kim Wipes is there is some pit that will not be removed by air. Methanol does not leave much of a residue and evaporates very quickly.

I am always amazed that when there is a booger on the plate is in enviably in the center where the object is.

Look forward to chatting some more!!

Tony

[quote="Tony DCG"]Many thanks Steven great read.
[/quote]

You are welcome Tony,

"I use Dawn soap when first washing glass I believe it has low amounts of sodium hydroxide"

Probably, but they don't list it in the msds: http://whatsinproducts.com//brands/show_msds/1/7115

I use Fairy washing up liquid. It's also made by Procter and Gamble.

"So a common problem with super clean glass is that they are dust magnets. Any tricks you have seen here?"

Yes, that's what I have found. There's often lots of small particles of Kleenex tissue clinging to the sheets of glass after I have dried them.

"Do you ever clean the glass using some glass cleaning prior to coating?"

Once the glass has been cleaned and washed with the final rinse of DI, water I do not apply any other chemicals or liquids at all.
I do mould coating, so before I apply my sticky tape to the glass, I first wipe the glass surface using a microfibre lens cleaning cloth.
I drag the cleaning cloth across the glass surface in one direction only, lengthways. As I'm dragging the cloth across the glass surface using my left hand, I'm following the cloth with my hairdryer held in my right hand. This way any particles that are dislodged by the cleaning cloth are blown off the glass surface. I just use cheap microfibre lens cleaning cloths brought off fleabay. I don't have a dust free environment, so I have to repeat the process just prior to applying the gelatin solution.

"I generally blow off the plates with canned air but would love to reduce the need of this."

I use one of these for blowing surface dust off optics as it's refillable:-)

http://www.ebay.co.uk/itm/2L-Water-Spray-Bottle-Pressure-Sprayer-General-Purpose-Weed-Killer-Chemical-NEW-/141080517424?pt=LH_DefaultDomain_3&hash=item20d90ddb30

I use dip and shoot, so I'm just applying a gelatin coating under plenty of light.
I tried coating using a AmDi sensitized gelatin solution, but only once!
I found it far too messy, it created lots of hazardous chemical waste, which is not what I want as I'm coating in the kitchen.
Using plain gelatin, I can just throw the surplus waste in the bin.
I don't keep any unused gelatin solution, I make it fresh for each coating session.

"Any thoughts on that?"
Not really, I don't have any sort of flow hood/bench here, so your work environment is probably less dusty than mine.
Is the air feeding your flow hood filtered?
The only other things to think about is clothing and maybe wearing some sort of hair net.
What about wearing a surgical gown and a disposable face mask?

I do wear a dust face mask when I'm working very close to the surface of a hologram after it has been dehydrated.
This reduces the chance of the hologram disappearing before it's capped, due to my moist breath.

My holograms are far from dust free.
Using dip and shoot, so the emulsion has a second chance to gather some dust:-(

Steven.

Many thanks Steven great read.

A couple of comments thoughts and questions

I use Dawn soap when first washing glass I believe it has low amounts of sodium hydroxide

[quote="Steven"]The next step is to place them in a 10% solution of hydrochloric acid for two to three days.[/quote] I do something similar here. I also like using a fish tank bubbler to keep the water moving. I feel that agitating the water helps.

So a common problem with super clean glass is that they are dust magnets. Any tricks you have seen here? I generally blow off the plates with canned air but would love to reduce the need of this. Transferring from wash to flow hood seems to be a prime time to get a booger or two on them. Do you ever clean the glass using some glass cleaning prior to coating?

I was also thinking about some high intensity red LED lights to add to my coating stations. The thought was to shine the light just prior to coating to see if any dust popped on. My hope is that the dust would glow when it sees light. Would rather use blue light since the dust would be more energetic when shined but that would not be smart for DCG. Any thoughts on that?

Nice to see some DCG discussions!

[quote="Tony DCG"] Does it scratch the glass?

Thanks again
Tony[/quote]

I have not noticed any scratches on the glass using my method.

Steven.

[quote="Tony DCG"][quote="Steven"]I now use a caustic soda scrub and a hydrochloric acid soak.[/quote]
Hi Steven

Can you expand on this?
Thanks again
Tony[/quote]
Hi Tony,

My long, tedious method for what's it worth:

I scrub both surfaces of the glass with a concentrated solution of sodium hydroxide using a non-scratch scouring pad, the ones that are not attached to a sponge, remember to wear rubber gloves and to protect your eyes. I also add a few drops of washing up liquid to the caustic soda solution. I normally prep two plates (18" x 5") at a time and find that 2-3 heaped teaspoons of caustic soda added slowly to 40ml of cold water is sufficient for the job. After scrubbing for a few minutes I let the plates stand upright for about half an hour, then return and repeat the scrubbing, flipping the plates so that they are standing the other way up. I do this over a period of about 2-3 hours, depending on how keen I am. The glass usually ends up with crystals growing on the surface if I leave it too long between scrubs. It doesn't seem to cause a problem and I suspect that it may be of benefit. After I'm done with the caustic soda scrub, I rinse the glass in hot running tap water, again scrubbing the surface of the glass. By this time the glass should be fairly well hydrophilic.

The next step is to place them in a 10% solution of hydrochloric acid for two to three days. I use a cheap large clear plastic (polypropylene) storage box with lid, the sort that you can get for storing clothes or kids toys. The container of acid is kept in the garage. After they have been in the acid bath and before I remove the two plates of glass, I get my bucket ready and turn on the garden hose. Wearing the appropriate PPE I slowly lift the first plate out of the acid bath holding it vertically, allowing the surplus acid to drip back into the container. I then hold the plate horizontally and quickly remove it from the garage to where the hose is running (it's just outside the garage door) and give the plate a quick rinse with the running water. The plate then goes in my bucket, remembering which surface is 'top' because I want to coat the surface of the glass that has had the best exposure to the acid, not the surface that was facing the bottom of the container. Repeat for the second plate. The bucket with the two plates of glass then go on to the next stage of cleaning.

After transporting the glass in the bucket to my kitchen:

I remove my thick washing up gloves and replace them with a pair of non-powdered surgical latex gloves to better handle the glass.
After a rinse under running hot tap water for a few minutes, the two plates are placed in a large photo developing tray, again noting which surface of the glass is 'top'. I add a little warm tap water to the tray, just enough to cover the 'top uppermost' surface of the glass. I give the surface of the glass another scrub with a non scratch pad. If I put too much water in the tray, the water will splash everywhere. This is just a short scrub of a few minutes, followed by a quick rinse under running tap water. The final rinse is done over the sink with DI water from a plastic squeeze wash bottle. I start at the top of the plate and work my way down, doing both sides. The plates are then dried with Kleenex tissues. I find that the side of the glass that has had the best exposure the the HCl feels 'sticky' when rubbed with the last drying tissue. Both plates are then placed on a cold hotray, 'top' side uppermost with a sheet of plain white printing paper between the surface of the hotray and the two sheets of glass to be coated. The paper makes it easier to lift one end of glass up to take it off the hotray. I just lift one end of the paper up so that I can get a grip of the glass. The hotray is brought up to a temperature of about 70C for 1/2 hour or so, then allowed to cool before removing the plates for coating. I think this last stage using a hotray, helps to drive off any moisture remaining on the glass surface.

It's a very tedious process, that's why I just hate coating:-(

I have never had the coating come away from my glass using the above method.
However, I'm using AmDi as a sensitizer and I tend to leave the plates for two to three days dark reaction after exposure, so the emulsion is quite hard before it gets to the processing stage. In the past when, I first started out in DCG I was using KDi and I found the emulsion more susceptible to lifting during processing. This was probably due to less dark reaction hardening.

HTH,
Steven.

[quote="Steven"]I now use a caustic soda scrub and a hydrochloric acid soak.[/quote]

Hi Steven

Can you expand on this? How much Sodium Hydroxide do you use? Does it scratch the glass?

I do use Muriatic Acid as well sometimes, about 1 cup per 2 gallons. What do you use?

The MA is also goo for removing gel from reprocessed plates.

Thanks again
Tony