PCTEA anyone?

Photo Engineer · Mar 20, 2009

Sandy;

Gasoline would have been boiled away at that temperature, or at least boiling strongly. The BP of normal gasoline is about 30 - 50 deg C IIRC. I would have to look it up. This indicates that the low boiling fractions were coming off earlier, and it also indicates that you were lucky.

If you opened the door when the LB fractions were coming off or had a spark....... WOW!

PE

sanking · Mar 20, 2009

Ron,

Well, in an excess of caution I opened the front door of the microwave with my body on the other side.

Sandy

Photo Engineer said:
Sandy;

Gasoline would have been boiled away at that temperature, or at least boiling strongly. The BP of normal gasoline is about 30 - 50 deg C IIRC. I would have to look it up. This indicates that the low boiling fractions were coming off earlier, and it also indicates that you were lucky.

If you opened the door when the LB fractions were coming off or had a spark....... WOW!

PE

Kirk Keyes · Mar 21, 2009

Sandy, you must be joking, as the boiling point of acetone is 56.5C (133F). If not, how did it measure "well over 350F"??...

If you think it's a non-issue, then just say so. If not, please don't make posts that people will take at face value as fact when they cannot be... At least put those silly little smiley faces in somewhere to indicate you're not being serious.

Or, perhaps your thermometer is seriously out of calibration? :^)

MattKing · Mar 21, 2009

sanking said:
OK, today I set up a worst case scenario for TEA and Propylene Glycol.

A microwave was installed about 150' from the back of my sun room. In the microwave I put 250 ml containers of TEA, Glycol, Gasoline, and Acetone, open tops.

All in place I retired to the safety of the inside of my house and turned on the power. Left it on for 20 minutes. Nothing exploded. After a few minutes I carefully opened the door of the microwave and measured the temperature of the solutions. All were well over 350F.

Sandy King

Is this how your Mamiya 7 got so in need of a new covering ?

Matt

sanking · Mar 21, 2009

Kirk,

Please don't parse.

I did exactly as stated. The four solutions were left in the microwave for 20 minutes on full power, and there was no explosion.

You may be right in that the acetone was evaporated. I don't remember for sure as I was a bit hesitant in opening the door. In fact, the others solutions may have evaporated as well, not sure. What I know is that there was no explosion.

But basically I did what I stated. I hope you don't have a problem with this. Do I believe that heating TEA in a microwave is a non-issue? Yes!

Sandy

Kirk Keyes said:
Sandy, you must be joking, as the boiling point of acetone is 56.5C (133F). If not, how did it measure "well over 350F"??...

If you think it's a non-issue, then just say so. If not, please don't make posts that people will take at face value as fact when they cannot be... At least put those silly little smiley faces in somewhere to indicate you're not being serious.

Or, perhaps your thermometer is seriously out of calibration? :^)

onnect17 · Mar 21, 2009

Sandy,
I hope you're not testing the capabilities of your microwave at 1:30AM.
In any case I'll keep an eye on the news coming from Greenville.
Good luck! You will probably need it
Regards,
Armando

sanking · Mar 21, 2009

sanking said:
sanking said:

No, not tonight, but I could do a live streamer tomorrow just for Kirk!!

Like I said, the microwave was on the back of the property, about 150' from my house. I also had a barrier between the microwave and the house in the event of a really big explosion.

But there was nothing. Not even a small burp.

I did a lot more damage last year about this time in burning a huge pile of rubbish back there. Flames were up to 50-100' high in the burn, but no problem. Problem came several days later when some of the embers re-ignited and created a fire that resulted in burning down of about 200' of my wood privacy fence.

Man, I just love huge fires!!
(Smiley face for Kirk)

Sandy

Click to expand...

Sandy

onnect17 said:

Sandy,
I hope you're not testing the capabilities of your microwave at 1:30AM.
In any case I'll keep an eye on the news coming from Greenville.
Good luck! You will probably need it
Regards,
Armando

Click to expand...

gainer · Mar 21, 2009

And I thought I was a wild man!

sanking · Mar 21, 2009

Well, it was something I did on a lark. My wife purchased this microwave at a yard sale for $5 but turns out that the platform does not rotate so she was going to discard it. I thought, well with all this discussion of the dangers of heating stuff in a microwave why don't I just max out the dangers with several combustibles and see what happens. So I ran an extension cord to the back of my property and put the stuff in there. I figure no way this is going to do much damage even if something explodes, and even if that happens there was a barrier between me and the house, and several hundred feet to the next house.

So there we are. I think Kirk picked up pretty fast on my motivation for the stunt, which is basically that I feel that all this discussion about the dangers of heating TEA in a microwave are just way over the top in terms of reality.

BTW, talking about real dangers, some 10-15 years ago I saw an explosion at a gas station across the street from where I was filling up. Apparently some guy was smoking a cigarette while filling up his car with the engine left on. That was quite a sight.

Sandy

gainer said:
And I thought I was a wild man!

dynachrome · Mar 21, 2009

PC-TEA

I haven't looked at this thread for a while. I think several things have been overlooked. In the first place, I don't think Patrick Gainer is trying to start a revolution to lower D-76 sales. He came up with an experimental formula which quite a few people have used. Secondly, the results from PC-TEA are not much of a mystery. Phenidone's properties are well known. By elimination the sulfite you will get the appearance of more grain than if you use a developer like Microphen which has sulfite. The issue of heating the TEA has been hashed and rehashed here and elsewhere. When I mix up PC-TEA I use some nice nitrile rubber gloves from Gemplers. The water bath method is safe and easy to use and in my experience gets the TEA warm enough to get the other chemicals to dissolve after a time. What about the statement that chemicals shouldn't be handled in a kitchen? The very first roll of film I developed was in my parents' kitchen many years ago. I didn't use any of my mother's measuring cups to develop the film. What is probably more of a problem than heating TEA in a water bath is pouring powdered chemicals without proper ventilation. When my darkroom was in my parents' basement I used Ektaflo developer and fixer so I wouldn't have to mix up so many powders. I also used FG-7 for film but for the faster films I did have to make up the 9% sulfite solution. Leaving out the sulfite, one of the benefits of PC-TEA, has several advantages. You don't have to worry about inhaling the powder, you don't have to pay more and more for it over time and you don't have to pay for shipping something heavy. Sulfite also needs to be sealed well or it can absorb moisture. Most people do not have special ventilation hoods at home. I have heard that some people wait for a not too windy day and mix things up outside. If you are not downwind of the poured powder then this could be a good method.

Many of the household products we are used to are far more dangerous than the components of PC-TEA. I am not a chemist but I can think of a few now. They would include chlorine bleach, amonia, lye, concentrated laundry detergent, insecticides, motor oil, non-citrus-based tar remover, paint, methanol and others. The fear that some people have of simple b&w darkroom chemicals isn't justified. Using a phenidone based developer can help you avoid dermatitis from metol. Using citric acid based stop bath can cut down on bad smells and toxicity. Using a non-hardenng fixer can cut down on the amount of acid you handle. If you mix D-76 either from scratch or from a prepared package and do so in a safe way then that developer can be used without much fear of injury but the metol and hydroquinone it contains are still more toxic than the ingredients in PC-TEA. This is true both for the person working with the developers and what happens in the environment when they are disposed of. Advising people to be careful when handling chemicals is fine but worrying about a formula like PC-TEA is barking up the wrong tree.

Photo Engineer · Mar 21, 2009

Dynachrome;

While I understand what you say, the answer is not that simplistic for everyone. I too developed pictures in the kitchen, but my parents taught me right off that using kitchen utensils was a no-no and got me a cheap set of aluminum trays to use. That is where I first learned that photographic solutions could be dangerous, as they ate through the cheap trays right off.

So, we have some very lucky people here, but no proof either way. I reiterate that my reasoning is that I feel better stating all possible dangers so that I don't regret being silent. These dangers include solvent fires and contamination of foods.

Although I have not seen the quality yielded by this particular developer, I know there are quite a few who like to use it. Since I have no justification to use it, I use either my own formulas or D-76 or HC110. That said, I would have no qualms about using it as you and others including myself have described, namely, using a warm water bath in the darkroom to prepare the concentrate. I have nothing against TEA except the potential for misuse by people unaware of the potential danger that might arise from misuse or mishandling.

PE

Kirk Keyes · Mar 22, 2009

Sandy - I'm glad your experiment work out for you. And I wish you had been a little more observant about things like was there still acetone there, afterall, you said you measured it, so I have to take what you reported at face value. (And PE is right about the gasoline, I used to distill gasoline to measure how much boils off at various temps and he's close in his estimates.)

I don't care if people heat TEA in the microwave - I do want them to have an appreciation of the possible risks. You know, a lot of people have pumped gas over the years with a cigarette dangling from their mouths and not blown up the gas station doing it. But then there's always that one guy with bad luck that gets turned into a crispy fritter...

I hope people understand that there is a possible explosion risk from heating flammable liquids in closed areas. (By the way, I've seen microwaves blow their doors off in lab environments, so I know thay are not without risk.)

I want people to understand it is a VERY, VERY BAD practice to use the household microwave for preparing anything BUT food. If you want to use a microwave to heat TEA, get one and dedicate it to the darkroom. Food and lab chemicals should never cross paths.

I want people to understand that solutions can superheat in a microwave and they can explosively boil over. This can cause severe injuries and burns at the temperatures discussed ealier.

I would suggest that people may want to look into getting a stirring hotplate and use that. I suspect much lower temps for the TEA could be used if there was a way to constantly stir the TEA to get the chemicals into solution. It works great in the lab, why not try it at home. And I find a stirring hotplate to be a much more useful item for preparing chemical solutions than I do a microwave oven.

So that all I want. If a person decides to go the microwave route, then go ahead. As long as they are informed about the risks.

Kirk Keyes · Mar 22, 2009

sanking said:
Apparently some guy was smoking a cigarette while filling up his car with the engine left on.

So he had a lit cigarette AND the engine was running? Did he also answer the big, two-way radio he had in his pocket at the same time? I hope the shot-gun that he had on the back seat of his pickup truck didn't go off and shoot him as well...

Sounds like he should have made it into the Darwin Awards for that year.

sanking · Mar 22, 2009

Kirk,

My main interest in the test was whether I could provoke an explosion in a real worst case scenario. I did not actually open the door for quite some time after turning the power off because I was apprehensive about what might happen so I did not in fact check the temperature of the solutions at the time. Now that I think about it the acetone was clearly gone, and I think also the alcohol but there was definitely some TEA left in there and I guess that must be what I checked at least twenty minute after turning the power off.

I agree that it is not good practice to use the kitchen microwave for anything other than food. But I must admit that I have used it for other things many times, and some of them were much worse than heating TEA.

Just for the record, most reasonably bright people are well aware of the ability of a microwave to superheat whatever happens to be in there. There have been a number of lawsuits by persons injured in heating coffee, and on more than one occasion I have been rather severely scaled by hot steam on opening up a food package.

However, with regard to the subject of heating TEA in a microwave, I think it can be done vsafely so long as you don't heat to over 150-75F. Just heat it for a while, stir and check the temperature, heat again, remove, stir and check the temperature, etc. This will prevent areas of the liquid being superheated compared to other areas. I don't doubt but that given enough time some idiot will find a way to suffer an injury but given the very high flash point of TEA one would really have to be careless allow the liquid to reach that temperature, and even if it did the risk of flash fire would appear remote because you still need a spark.

That said, I don't heat chemicals in the house microwave because my wife won't allow me to use it for anything but food. This dates from the days when I was into boat building and would check the moisture content of the wood by first weighing it, then drying out in the microwave. I left the wood in there too long one day and the resulting mess from stench and discoloration from super dried mahogany was awful.

So I bought a nice hot plate stirrer for $40 that works a lot better than the microwave for dissolving chemicals.

As to the development characteristics of PCTEA, I have tried it and the results I got were every bit as good as what I remember with D76 and HC110. And since the stock solutions are very long lived (I have a bottle mixed several years ago that still works fine) I personally would find it much more convenient to use than D76. In general, however, I don't like the heavy viscosity of TEA developers, at least no unless diluted with something else to give better flow.

Sandy

gainer · Mar 22, 2009

I have a microwave in the kitchen and another in the darkroom. I heat my coffee in either one, but nothing but foodstuff goes in the kitchen one.

I have an oven, I believe it is called "brisker", that is used for rising bread dough, and keeps a constant 104 F temperature. It is now in my darkroom, and I use it to store things dissolved in TEA or glycerine. That temperature reduces viscosity to a manageable level for use with syringes or pouring into teaspoons.

Kirk Keyes · Mar 22, 2009

sanking said:
Just for the record, most reasonably bright people are well aware of [...]

Well, I think this is the basic problem. I beleive that most people are not reasonably bright, and the ones that are, are not reasonably bright 100% of the time.

sanking · Mar 23, 2009

OK, that is an opinion.

But I don't agree with it. Most of the people I know are indeed reasonably bright and know how to protect themselves. If anything, they err on the side of caution and are afraid to take any kind of risk.

We have a close friend, my wife's best friend for the passt two decades, who is dying right now from lung cancer. She was very health conscious all of her life, never smoke, never drank more than a glass or two of wine with her meals, exercised every day and was in great shape. In spite of that she came down with lung cancer, and though she fought it bravely for three years, is now with hospice and will probably not live more than a month or so.

Last time I spoke to her she said to me, "if I had known this was going to happen to me I would have drank a lot more wine in my life."

Using wine only as a metaphor, I hope that is not something I have to say when I am dying.

Sandy

Kirk Keyes said:
Well, I think this is the basic problem. I beleive that most people are not reasonably bright, and the ones that are, are not reasonably bright 100% of the time.

PCTEA anyone?

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