FYI: Purchasing Propylene Glycol

[Eric Woodbury]

I usually buy my chems online, but this product is heavy. I know one can get antifreeze, but I'm put off by using something for my car as a darkroom chemical. I discovered that Propylene Glycol may be purchased from a livestock and feed store. It is commonly fed to cows. It appears to be a food grade, 100%, no dyes.

If you live in a rural area with cows, here's another source.

[Jason Greenberg Motamedi]

I get mine at a local brewers supply store. No idea what it is used for, but it is also food grade.

[rdenney]

I usually buy my chems online, but this product is heavy. I know one can get antifreeze, but I'm put off by using something for my car as a darkroom chemical. I discovered that Propylene Glycol may be purchased from a livestock and feed store. It is commonly fed to cows. It appears to be a food grade, 100%, no dyes.

If you live in a rural area with cows, here's another source.

If you don't mind the red color, "RV Antifreeze" is propylene glycol, and is intended for winterizing potable water systems, and is therefore completely non-toxic. Note that propylene glycol doesn't necessarily stay liquid--if it gets cold enough it will freeze into a gel, but it won't expand and break things the way plain water does. RV Antifreeze is available everywhere for generally under $5 a gallon.

Rick "not knowing the intended application" Denney

[BrianShaw]

Rick "not knowing the intended application" Denney

Isn't that the stuff they make you drink gallons of to flush out the system for a colonoscopy? I remember thinking that it was very odd to be drinking antifreeze.

[c.d.ewen]

I get mine at a local brewers supply store. No idea what it is used for, but it is also food grade.

Beer is made by boiling its' ingredients, then crash chilling it to fermentation temperature (32-68F). Refrigerated glycol is used to absorb the heat. It's food grade, 'case there's a leak :eek:


Charley

[rdenney]

Beer is made by boiling its' ingredients, then crash chilling it to fermentation temperature (32-68F). Refrigerated glycol is used to absorb the heat. It's food grade, 'case there's a leak :eek:

If that's the case, then the worst that can happen if a bit of RV Antifreeze gets into the beer is a rosy tint.

Rick "versus a bit of ethylene glycol, which is deadly even in small quantities" Denney

[Drew Wiley]

Does it do the same thing to your darkroom as it does to your colon?

[Nathan Potter]

Isn't that colonoscopy stuff Barium Sulfite? Maybe there is an MD on board.

Nate Potter, Austin TX.

[nolindan]

"versus a bit of ethylene glycol, which is deadly even in small quantities"

LD-50 in rats is 5g/kg.

For a 70kG (154lb) man that would be 350g or 12 oz by weight. Not a terribly small amount - i.e. getting a small amount of anti-freeze in your mouth won't do much of anything.

Big problem with E. glycol is it tastes sweet. Spillage from an overflowing radiator often brings wildlife who slurp up the antifreeze to no good effect.

[BrianShaw]

Isn't that colonoscopy stuff Barium Sulfite? Maybe there is an MD on board.

I'd welcome that kind of input... even from a nurse. I found a site that talks about the variety of cleansing methods and makes me think I was wrong in my earlier post. What I was recalling might have been Polyethylene Glycol 3350.

http://www.endonurse.com/articles/281feat1.html

[c.d.ewen]

LD-50 in rats is 5g/kg.

For a 70kG (154lb) man that would be 350g or 12 oz by weight. Not a terribly small amount - i.e. getting a small amount of anti-freeze in your mouth won't do much of anything.


All it takes is enough for an LD-1 to ruin somebody's day :D

Charley

[Arne Croell]

Isn't that colonoscopy stuff Barium Sulfite? Maybe there is an MD on board.

Nate Potter, Austin TX.

Barium Sulfate ("Baryta") is used as contrast agent for X-rays of your intestines, not for flushing before a colonoscopy.

[HMG]

Per the OP, here's one example: http://www.fleetfarm.com/catalog/product_detail/farm-livestock/animal-health/supplements/farm-life-keto-aid-1-gallon

I have a gal that I plan to try with Pyrocat. Or maybe I'll buy a cow.

[Robert Hughes]

Per the OP, here's one example: http://www.fleetfarm.com/catalog/product_detail/farm-livestock/animal-health/supplements/farm-life-keto-aid-1-gallon

I have a gal that I plan to try with Pyrocat. Or maybe I'll buy a cow.
Let us know how that goes. I've got a handful of magic beans you may be interested in...

[Michael Cienfuegos]

I'd welcome that kind of input... even from a nurse. I found a site that talks about the variety of cleansing methods and makes me think I was wrong in my earlier post. What I was recalling might have been Polyethylene Glycol 3350.

http://www.endonurse.com/articles/281feat1.html

Do you mean 'Go Lytely' ? That stuff is unreal! Been there, done that in the colonoscopy department. Gawd! My brown eyes were blue for weeks after that episode. :(

Michael, RN

[Steve Hamley]

Too much information....

Cheers, Steve

[BetterSense]

What are you using the propylene glycol for, for photography? What is it an ingredient of?

[rguinter]

Yes I too am wondering what propylene glycol is used for in photography also. But I only shoot photos so far and I haven't done any processing myself.

But I am an Industrial Hygienist by profession which is someone who deals with the health & safety aspect of chemicals. The firm where I work stores both propylene glycol and ethylene glycol in large quantities (i.e., hundreds of thousands of gallons) for several customers.

They are both from the same chemical family (i.e., glycols) but are vastly different if ingested. Propylene glycol (PG) in pharmaceutical grade (USP grade) is used in many liquid medicines. It is non-toxic. It's cousin ethylene glycol (EG) however, is toxic and only a few hundred cc's is enough to be fatal. It causes kidney failure over a period of several days. Quite a nasty way to go. As one poster noted above it is sweet tasting and animals will lick it if someone spills prestone or some other antifreeze on the ground. It can be fatal to them too.

Both EG and PG can be used as an antifreeze because they are water miscible and reduce the freezing point of a mixture. Although EG is the typical one of choice for automotive applications. Probably because of cost I would guess.

PG is used sometimes in building heat transfer systems where toxicity is a concern. It is used in a vast variety of food and semi-food type products including lipsticks, gels, toothpastes, cough syrups, pet and livestock foods, etc. etc. etc. It is also used as a moistening agent in baby-wipes, humidors for cigars, and as a fogging agent in the film and pop music industry.

If anyone knows for sure what uses it has in photography I would be pleased to hear. Perhaps as some kind of moistening agent in printing.

Cheers. Bob G.

[HMG]

Yes I too am wondering what propylene glycol is used for in photography also.

Propylene Glycol is used in place of water for mixing developer. It greatly extends the life of the developer. HC-110 is said to be PG based. Pyrocat is often mixed with PG (http://www.largeformatphotography.info/forum/showthread.php?t=18006).

[Eric Woodbury]

HMG has it right. PG is used to mix a concentrate of developing agents. In this way, the concentrate is easier to measure than very small masses and the agents in the mix don't react. It is as if they are in suspended animation until water comes along to ionize the solution and get things going. Seems as though most of the organics are soluble in PG and PG can be used to thin (and keep from freezing) TEA (triethanolamine), an organic solvent that becomes alkalai in water.

[rguinter]

Propylene Glycol is used in place of water for mixing developer. It greatly extends the life of the developer. HC-110 is said to be PG based. Pyrocat is often mixed with PG (http://www.largeformatphotography.info/forum/showthread.php?t=18006).


OK that explains it. Eric and HMG have the answer. Then I would guess a bit of the PG in our tanks eventually winds up in photography service. It is one product that has been handled here for years in mid-size storage tanks for several of our chemical customers. I also forgot to mention in my previous post that it is used extensively in the dessert industry for certain cremes and fillings.

[rdenney]

Although EG is the typical one of choice for automotive applications. Probably because of cost I would guess.

My understanding, likely apocryphal, is that while both eliminate damage from expansion during freezing, the ethylene glycol will remain liquid and the propylene glycol will form a non-expanding gel. The latter is no detriment in most applications where it is used to prevent damage during winter storage vis a vis winter use.

If that is wrong, I'd love to know it. It's a common belief among the old RV rebuilders I sometimes hang out with.

Rick "would the pink color of RV antifreeze eliminate its use in lieu of water for developing?" Denney

[rguinter]

Rick "would the pink color of RV antifreeze eliminate its use in lieu of water for developing?" Denney

The pink color has to be an additive because pure propylene glycol is colorless. Bob G.

[HMG]

Given the viscosity (or lack thereof) of all the RV antifreeze I've used, I don't believe RV antifreeze is 100% PG. A quick non-expert look at the msds for one brand indicated (if I read it correctly) 27% PG.

PG is used for mixing (in place of water) "stock" solutions - not "working" solutions. I'm not a chemist, but I think the water in RV antifreeze would render it useless for use in mixing stock solutions.

Anyone out there try it? If so, your experience?

[rguinter]

Antifreeze with any of the glycol family of liquids is always a mixture with water. The mixture has a lower freezing point than either water or glycol alone. Bob G.