Prestone for head anti-freeze?

[hlev00]

Is Prestone 50/50 premix, or similar ethylyne / diethylene glycol anti-free premix, appropriate for head winterization?

[transmitterdan]

Yes it will work.

[NahanniV]

But it's toxic/poisonous.
Should not be disposed of overboard or into sewers.
So NOT appropriate !

Use plumbing or RV antifreeze, (Propylene glycol I think).

[hlev00]

I thought the polypropylene is bad for neoprene often found in head plumbing.

[NahanniV]

I have used it for many years without a problem in my blakes Lavac Head, but I don't think the rubber is Neoprene.

Here is a chemical comparability chart that shows satisfactory comparability between Neoprene and Propylene glycol:

Rubber Chemical Resistance, Rubber Chemical Compatibility, Page 5 - Mykin Inc

[thinwater]

Originally Posted by NahanniV

But it's toxic/poisonous.
Should not be disposed of overboard or into sewers.
So NOT appropriate !

Use plumbing or RV antifreeze, (Propylene glycol I think).

Incorrect in all parts.

First, the toxicity to marine organisms is no different than polypropylene glycol. Look up EPA, Fish and Wildlife service, and MSDSs. Just as chocolate is bad for dogs but great for people, toxicity can be very organism specific. In this case, EG is only a danger to mammals. Look it up.

Second, there is no difference in biodegradability. I used to run and design waste plants and processed both. If anything, EG is better, because the COD is less and because less is required (it is more effective antifreeze agent).

Third, this is blackwater. No human is going to touch it, and there should be no pet exposure.


"I thought the polypropylene is bad for neoprene often found in head plumbing."

First, polypropylene is a plastic, not an antifreeze agent. You are probably thinking of propylene glycol (PG).

Second , you have it backwards. EG is OK with neoprene, PG is bad for neoprene. I've done the testing with head parts for publication.

[transmitterdan]

Originally Posted by NahanniV

But it's toxic/poisonous.

Should not be disposed of overboard or into sewers.

So NOT appropriate !



Use plumbing or RV antifreeze, (Propylene glycol I think).

In the amounts to keep a head from freezing regular antifreeze is not toxic to the ocean. It is most toxic to small mammals and people. But it quickly breaks down in the ocean.

[rwidman]

Use RV antifreeze. The stuff made for winterizing potable water systems. There's no good reason to use the toxic stuff where it's not needed.

[thinwater]

Originally Posted by rwidman

Use RV antifreeze. The stuff made for winterizing potable water systems. There's no good reason to use the toxic stuff where it's not needed.

Where in the heck is this myth that EG is toxic to the environment coming from? Not from the EPA or Fish and Wildlife Service. Not from MSDS info.

And there IS A GOOD REASON. PG is very bad for neoprene parts. Take two Jabsco joker valves and leave one in PG, on in EG, and note the results in 4-6 months. THE PG valve will be too stiff to function properly. This is why so many joker valves and raw water impellers (also frequently neoprene) fail each spring. It isn't time, it's the PG they were pickled in.

[NahanniV]

Originally Posted by thinwater

Where in the heck is this myth that EG is toxic to the environment coming from? Not from the EPA or Fish and Wildlife Service. Not from MSDS info.

And there IS A GOOD REASON. PG is very bad for neoprene parts. Take two Jabsco joker valves and leave one in PG, on in EG, and note the results in 4-6 months. THE PG valve will be too stiff to function properly. This is why so many joker valves and raw water impellers (also frequently neoprene) fail each spring. It isn't time, it's the PG they were pickled in.

Well if it is a myth it is being repeated by many government agencies:

http://dnr.wi.gov/files/pdf/pubs/wa/wa356.pdf
" Dumping used antifreeze into a storm
sewer or on the ground is illegal and may be
harmful to lakes and streams, people, pets
and wildlife.
 Discharging used antifreeze into a septic
tank and soil absorption field is illegal. It
may cause the septic system to fail and
result in groundwater pollution"

https://www.colorado.gov/pacific/sit...antifreeze.pdf

http://www.ct.gov/deep/lib/deep/long...ifreeze_08.pdf

...and many more...

[transmitterdan]

Nobody is talking about dumping it into sewers. Aren't we talking about boats in the ocean? Ethylene glycol breaks down rapidly in the ocean. The tiny amount in a head will hurt nothing when it goes out next spring.

The admonition about dumping in sewers has more to do with danger to mammals such as rats, cats and dogs. It is sweet and they will invariably drink enough to cause death.

Some government workers who put stuff on web sites are seriously uninformed.

[rwidman]

Everything breaks down eventually. There is no good reason to ever use products that are more toxic than necessary to do the job.

Non-toxic antifreeze is even cheaper than the toxic kind. Why would anyone pay more to poison the environment?

[boatpoker]

Practical Sailor magazine has a quite detailed article on Propylene vs. Ethylene glycol. including tests they have done on flexible head components.

[thinwater]

Originally Posted by NahanniV

Well if it is a myth it is being repeated by many government agencies:

http://dnr.wi.gov/files/pdf/pubs/wa/wa356.pdf
" Dumping used antifreeze into a storm
sewer or on the ground is illegal and may be
harmful to lakes and streams, people, pets
and wildlife.
 Discharging used antifreeze into a septic
tank and soil absorption field is illegal. It
may cause the septic system to fail and
result in groundwater pollution"

https://www.colorado.gov/pacific/sit...antifreeze.pdf

http://www.ct.gov/deep/lib/deep/long...ifreeze_08.pdf

...and many more...

This, let's look at the details and we will see this is not acurate. I have called several states in researching this in the past.

First, septic is completely different for a number of reasons. Dumping any strong waste into a septic tank is a mistake. Second, used antifreeze is not the same as antifreeze from a boat system. It has been in a car and is not contaminated with zinc and other metals. In fact, all EPA discussion of used antifreeze and whether it is "hazardous" relate to contamination with metals and benzene from cars. So that is a false comparison.

Finally, the state bans include PG that was used in a car, correct? The problem is that waste is strong and was contaminated by use in the car, not whether it was PG or EG.

Finally, many are just lazy and just copy other state sites. Notice you did not find a federal citation relating to boats. Dumping chemicals in the water is never good pracatice. I would rather see it recycled (I built two of the largest recycling plants in the country), I'm only saying there is no difference beteen EG and PG in this regard.

MSDS. Note that the LD50s for marine organisms are very high and are the same. You can look up more.
PG http://www.sciencelab.com/msds.php?msdsId=9927239
EG http://www.sciencelab.com/msds.php?msdsId=9927167

Quoting from the USEPAs 2000 report on airport deicer, an application where both EG and PG are used:
ENVIRONMENTAL EFFECTS
In a January 2000 report titled "Preliminary Data
Summary – Airport Deicing Operations," EPA reviewed the available data on ethylene glycol and concluded that ethylene glycol is "fairly non-toxic to the aquatic environment." The EPA report explains: "Although EPA does not use such a system, the U.S. Fish and Wildlife Service Classification System for Acute Exposures defines ‘relatively harmless’ as any chemical with an LC50 above 1,000 mg/L. The test results ... indicate that ethylene glycol and propylene glycol may be classified as ‘relatively harmless, ’as defined by
the U.S. Fish and Wildlife Service."

I would LOVE to see scholarly work or USEPA studies that show that PG and EG are signifigantly different in a marine environment. I've have demonstrated that they are the same. Show me how they are different.

A. EG is NOT more toxic in a marine environment. Unless there is one piece of evidence, which I have not been shown, this is simply inaccurate. A posting by a state gov. employee, without backup, is not evidence. Just on piece of independent evidence.

B. The reason is equipment damage. Refute that PF is not tough on neoprene.

[rwidman]

Well that's impressive alright, but the non toxic antifreeze is still cheaper than the toxic stuff. And, you are putting it into what amounts to a "septic system" (your holding tank).