Frozen Antifreeze

bergger

Not sure if this has been discussed in the past but if so I apologize for not finding the discussion.  I watched this video yesterday and it got me thinking about the antifreeze I use and that I have never thought of actually testing the product prior to using it.  I guess I just trusted the manufacturer and assumed it would work.  Since I live in an area that has extremely harsh and long winters I decided to do a simple test with the antifreeze I had on hand.  Now this is certainly not a very scientific experiment and are just my observations.  But I recommend everyone who lives in a cold climate test what they are putting in their trailers.

I had two types, Camco and Super Tech.  Honestly I could not remember which I put in my trailer.  I think it was mostly camco with a little super tech to top it off.  Both rated with a burst point of -50 degrees.  I took a sample of each, and poured them into respective plastic cups and placed them in my freezer.  Each cup had contained about 1.5 inches of antifreeze in it.  The temperature in my freezer hovered between 0 degrees and -10 degrees as it cycled on and off.  I let them sit overnight and have to say I was not impressed with either brand.  The super tech was the worst of the two.  It was frozen solid and had evidence of expansion for sure.  Now I could still push a spoon into it, albeit with some effort, so the antifreeze was still able to separate.  It was not rock hard but I do believe it would not take much more temperature drop to make it so.  The camco was not much better.  It to froze and I was also able to push a spoon into it, with slightly less effort.  It appeared to have the beginnings of expansion.  Also when I took both out and set them on the counter the Camco definitely melted much quicker than the super tech.  Now where each was exactly in the different phases of the freeze cycle I do not know.  But they were frozen enough and at temps 50 degrees below the listed burst point that I was not comfortable with either.  Especially living in the extremes that I do.  It is very common to have temps below -10 here and very cold temps for extended periods.  In more mild climates they may do fine.  

I then went to the local auot parts store and bought some Prestone -100 RV antifreeze to test.  It certainly did much better.  Under the same conditions it was just a little slushy when removed from the freezer, mostly still a complete liquid.  And completely melted to a liquid in very short time when removed from the freezer.  A product I am much more comfortable using here at my location.  So this weeked I will be re-winterizing my 400 with the Prestone product.  Anyway just my thoughts and opinions and the video is probably worth a watch if you live in very cold climates. 

Well here's the video if you're inclined to watch it. 

https://www.youtube.com/watch?v=3fvywdpZGa8&list=WL&index=23&t=976s 

Sharon_is_SAM

Is the Prestone rated as GRAS?

Da_Birds

No expert on this topic and a bit concerning since I used Super Tech. However, if it wasn't frozen solid I don't believe there is much concern for it to generated the pressures needed to burst lines. I also wouldn't be too concerned about the expansion witnessed in the test as long as the expansion didn't put significant pressure on the container walls. If it merely expanded into "open space", that is less of a concern. Liquid freezes from the outside in and this can prevent the liquid from expanding into empty space and instead expand in other directions, putting pressures on the lines. As long as the AF isn't frozen solid it should still behave more like a liquid. For example, water will expand as it is heated but there is no concern of this generating the pressures on lines needed to cause them to burst. Again, I'm no expert but have dealt with enough "frozen things" to have some understanding how pressures are distributed when things freeze solid.

ScottG

The specific physics of RV antifreeze is a little out my pay grade, but I don't lose much sleep over it as I rely strictly on careful and thorough application of the blowout method. I know frozen air will not expand and break anything.  ;-)

Seriously, good sleuthing @bergger. I always appreciate real-word tests of hypothetical concepts or marketing hype. Thanks for posting your results.

pthomas745

The video above was by Mark T over on FB.  There was some further discussion about his batch of antifreeze in that test, and it "seems" that the mixture he had in that test was something like 80 percent water and 20 percent antifreeze. 

"

Fyi,...

I did some additional rudimentary test on my "bad" fluid. I was curious what was actually in it..

One of the ways you can tell what is contained in a fluid mixture is to slowly heat it, and measure the temperature when it boils. Alcohol boils at one temp, water at another, and glycol at another. Each will boil off in order of their own boiling point. By watching the "steps" of temperature as the liquid boils away, you can tell what is leaving.

As best as i can tell my bad fluid was approx 20% propylene glycol, and 80% water.

Looks like a bad batch."

Dalehelman

I to saw the YouTube video and was concerned. Since I used Super Tech. Tested it over night in our -2 degree freezer. It was slushy but not frozen. We live in eastern Washington. We rarely have temps below 0. So I am comfortable with the Super Tech product, but is was worth the test.

Denny16

My solution is an empty pipe will not freeze to bursting, nothing inside it to freeze….  But, then I no longer live in Minnesota either!

cheers

bergger

Yes the Prestone is considered gras, generally regarded as safe.  I think the take away I got from this little experiment is to simply test you antifreeze each year prior to putting it in you RV.  You may get a good batch or a not so good.  With my experience I can tell you I would not feel comfortable using the super tech in my climate.  It was very hard at 0 to -10 degrees, not what I would want in my pipes.  Maybe a bad batch?  And after sitting on the counter for 2 hours it was still mostly slush.  The camco was marginally better but still quite frozen at those temps.  However in a normal winter climate I would use it.  The prestone did very well.  Just a tiny tiny bit slushy at those temps and completely back to liquid in just a few minutes on the counter.  That is what I will be using this year.  I just re-winterized today.  However I do live at 10,200 feet and it gets very cold and windy here for extended periods.  I will probably go the route of Denny16 and others next year and just blow the pipes out with air and leave them all empty.  Nothing inside to freeze is probably the best here.   

PNWtabber

I saw that discussion on facebook.  The first bottle of RV antifreeze I bought was "Champion" brand at an Ace Hardware, but I was concerned after the facebook discussion and tracked down the Prestone, and that is what I used to winterize today.  

Now that @Sharon_is_SAM raised the GRAS question, I looked at the labels. 

• The Champion brand label states that the ingredients are considered GRAS. Ingredients listed as:  Water, Ethyl Alcohol, Glycerin, Propylene Glycol, Denaturants, Corrosion inhibitor, and Dye.
• On the Prestone product label, however, I cannot find the "GRAS" statement anywhere, although it specifically says "safe for use in potable water systems." The Prestone label says it contains ethanol, propylene glycol, and potassium hydroxide.

So, I really don't know the answer here.  I used the blow-out method of winterizing, so the antifreeze is only going to be in my waste lines, not my water lines, so I don't think the GRAS thing is worth losing sleep over now that I've already used it.  Or am I wrong???  

Denny16

No, you should be fine in the PNW, come spring, just drain the antifreeze into a bucket wind dispose of appropriately at a recycle center.
cheers

gulfarea

Years ago when I was in the military up North I read on the antifreeze can will freeze, which seemed odd, but not when mixed with the proper amount of water! When mixed with 50-50 water it was good to -46 Art

Dalehelman

Auto antifreeze 50/50 with water is correct.
RV antifreeze must not be diluted with water.

TABNewbies

Just when I thought I was finished winterizing ... I tested my batch of Supertech and was slushy after a night in the freezer. Looks like @Dalehelman observations. It is a quick and easy test to do.

Supertech (-50F burst) is an ethanol / propylene glycol mix - not found any claims of the %
Prestone RV waterline (-50F burst) claims 20-40% propylene glycol (AF222) ...  the exact concentrations are a trade secret 
Prestone RV waterline (-100F burst) is <5% propylene glycol and <24% ethanol (AF225) however again exact concentrations are a trade secret ...