Anyone have much experience with antifreeze as a rot protector / preventer?

[Alan Lightstone]

I have a cypress cover for a fire pit table that sits outside 24/7 on the center of a fire pit table in the heat and humidity of South Florida. It was initially finished, about two years ago, with General Finishes Exterior 450 finish.

The finish lasted about two years, and it took me an additional year to get around to refinishing it. There were a number of areas (one in particular) that showed significant rot damage. I've cut out that area, replacing it with new wood, and have brushed on, and let soak in antifreeze (ethylene glycol), as there are a number of posts on the web saying that it works quite well as a rot preventer / killer.

My question now is, will I have issues with dye and eventually some more coats of the General Finishes Exterior 450 sprayed on top of the antifreeze that has soaked into the cypress?

Alternatively, I could do coats with penetrating epoxy followed by marine spar varnish (I did this on Charles Neil's recommendation on a Titanic Deck Chair and, while a total pain to use, and smelled terrible, it has worked extremely well. It's just a long two step approach, and is a pain to clean the spraying equipment).

Anyone done this technique? I really wanted to prevent further rot on the piece, as it looks very nice, and it was a real pain to steam bend the base of it.

[Bill Adamsen]

One of my mentors - an executive at Union Carbide, and top racing sailor (wood boats) - swore that epoxy itself was a strong fungicide. That may have just been a convenient excuse for lame boat repairs.

[Joe Kieve]

This probably doesn't answer your question but you might want to read this exerpt from an article I found on the web.

"There are two commonly available inexpensive materials that will kill rot in wood and prevent its recurrence. First, there are borates (borax-boric acid mixtures) which have an established record in preventing rot in new wood and in killing rot organisms and wood-destroying insects in infested wood.

Second, there is Glycol, most readily available as auto antifreeze-coolant. Glycol is toxic to the whole spectrum of organisms from staphylococcus bacteria to mammals.

Ethylene glycol and propylene glycol are clear liquids used in antifreeze and deicing solutions. Exposure to large amounts of Ethylene Glycol can damage the kidneys, heart, and nervous system. Propylene Glycol is generally regarded as safe for use in food. Antifreeze that is sold as "Earth Friendly", "Environmentally Safe", etc are generally based on Propylene...Make Sure You Buy The Propylene Glycol, NOT the Ethylene!!!
Source of Information : Agency for Toxic Substances and Disease Registry (ATSDR). 1997. Toxicological profile for ethylene glycol and propylene glycol. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

Here is the address for the article if you prefer to read further. http://www.alsnetbiz.com/homeimprovement/homemade.html

Stay safe!

[Alan Lightstone]

Thanks Joe. I am very aware of the toxicity of ethylene glycol, but this is not in a food area, and the amounts involved will be a fraction of the toxic dose.

That is very interesting about the propylene glycol. Didn't know that. Would have ordered that instead. It seems to be clear also, which would have been a plus. A question would be if it affects finishes, but I don't totally know the answer to that yet with the ethylene glycol.

[Prashun Patel]

Antifreeze will not dry hard. This means it may pose problems under the 450 which I *think* is a film-finish, correct? I would also think it would affect the dye. What kind of dye are you using? Have you had fade problems?

I am surprised your cypress has any rot damage.

[Bill Adamsen]

I am surprised your cypress has any rot damage.

Have to say that piqued my curiosity as well when I first saw it. Alan, any thoughts on why it might have suffered in as short a period as two years? Is it really bona-fide Cypress?

[Alan Lightstone]

I think it is cypress, though I also was surprised regarding how short a period it suffered rot. Pretty nasty weather, though with huge amounts of heat and humidity/rain. It also is directly in the sun for the whole day.

A few articles said that it doesn't affect the dye. I was planning on using Transtint. It looked gorgeous last time I used that under the Exterior 450.

And Prashun, you are right, the 450 is a water based varnish with UV protection. It's sadly ironic - the literature says that it keeps mold and rot at bay - not so much in my experience.

Here's a picture of the cypress:
IMG_0329 v1.jpg

And here's what the original piece looked like, 3 years ago:
Fire-Pit-Table-1.jpg

And the reason I just don't want to remake this:
Steam-Bending-Form-with-wood.jpg

Steam bending was an interesting learning experience. But I can't say it was a lot of fun.

[Mel Fulks]

This cypress thing comes up occasionaly, big difference between the old growth stuff and what is readily available. The new stuff has only a "moderate" durability rating. Since you mention rot ,as distinct from just finish failure, I would treat it with solvent based copper naphthalate then put new coating on. Some years back a guy brought us an old heart cypress circular sash with circular bars which had some cracks in it,the heart stuff is brittle. He wanted me to make a new replacement! I explained how nice a piece it was ,how inferior (and expensive) a new one would be and refused to take the job. Copper naphthalate has to be handled carefully by law and good sense ,but it should not be left out of the list of things that WILL work.