The best end cut preservative available

[nestork]

In an unrelated thread, one of the regulars in this forum was telling me that he had some wood preservative that was no longer made, called "Cuprinol 10" and was careful where and how he used what little he had left because it was no longer available.

I looked up the MSDS on "Cuprinol 10", and found it contained:

- 22% copper naphthenate (the active ingredient)

- 14% "paraffin oil" which is also called "mineral oil" (which you can buy at any pharmacy; people drink it for constipation, it's used as "baby oil" for treating diaper rashes and it's sold as "lamp oil" for making candles out of wine glasses and such)

- 60% mineral spirits (which is normally what paint thinner is)

So, I posted a response in that thread saying that you could pretty well make the stuff yourself if you could find a concentrated source of copper naphthenate since both other ingredients are widely available in pharmacies and hardware stores. So I did some digging to try and find concentrated copper naphthenate cuz that's the active ingredient in copper based end cut preservatives. Copper, zinc and boron are all natural fungicides, but the copper, zinc or boron has to be in a form that it can be absorbed into the wood. Copper naphthenate is soluble in mineral spirits, and wood will absorb mineral spirits. So that's all most end cut preservatives are; copper or zinc naphthanate dissolved in mineral spirits.

Home Hardware sells an end cut preservative to use on the pressure treated wood used for pressure treated wood foundations:

'Home Hardware - 3.78L Dark Green Preservative, for Foundation Pressure Treated Wood'

Now, this is where they build your basement out of wood, so this wood has to spend it's life in the ground! I figured this stuff has gotta have tons of copper naphthenate in it cuz a rotting fence post is a nuisance, but a rotting house foundation is a real serious problem. So, I checked out the MSDS on this stuff, and found out it's made by Timber Specialties and it consists of:

29.4 % copper naphthenate and the rest is mineral spirits (it says "greater than 60 % mineral spirits")

You can check that by noting the Home Hardware "Item number" for this stuff is 1874-825. At the bottom of the page there's a red MSDS link, and if you click on that MSDS link and enter 1874-825 as the HH item number and click on "Go", you'll get a Results list at the bottom of that page that gives you English and French PDF files.

But, it only makes sense that if copper is a natural fungicide, there may be other instances where copper naphthenate is used in higher concentrations to kill other kinds of fungii.

It turns out that copper naphthenate is used in higher concentrations to cure a hoof disorder on horses called "Thrush". Thrush is a fungal infection of the hoof, and it turns out that copper is also effective at killing the fungii that cause Thrush in horse hooves. This company:

'Kopertox (Fort Dodge) - 8 oz. | QC Supply'

sells a 16 fluid ounce bottle of a product called "Kopertox" for $25, and by the name alone you know it contains copper and is toxic to something.

If you click on the "Manuals & Resources" link on that QC Supply web page, it'll offer you the MSDS form on Kopertox. If you download that MSDS form, you'll find it's made by a company called Fort Dodge Animal Health in Fort Dodge, Iowa, and the Kopertox consists of:

37.5 % copper naphthenate, 62.3 % mineral spirits, and 0.12 % butyl alcohol.

I'm just guessing, but my guess would be that the alcohol is sprayed into the bottle initially just to sterilize it before it's filled. (just like they rub your skin with rubbing alcohol before they give you a needle to prevent infection) I can't think of any other reason for having such a tiny bit of alcohol in there.

So, it turns out that the product with the highest concentration of copper naphthenate that I could find isn't a wood end cut preservative at all, but something used to treat fungal infections in the hooves of horses. It's expensive, but in those instances where you're willing to pay more to get the best protection you can get, just Google "Thrush treatment" without the quotes, and you'll find several companies all selling 37.5% copper naphthenate in 16 fluid ounce bottles for $20 to $25.

Now, ... Since mineral spirits evaporates from the wood, leaving the copper naphthenate behind inside the wood cells and wood cell walls, you can increase the amount of protection with ANY end cut preservative by giving the mineral spirits time to evaporate from the wood, and then painting more end cut preservative on. Each time the mineral spirits will evaporate, and the copper naphthenate absorbed into the wood with the mineral spirits will be left behind inside the wood. So, the more times you let the wood dry and paint on more preservative, the more fungicide there will be in the wood to protect it from rot. So, the most economical way to treat wood to prevent wood rot is to buy a normal end cut preservative and use repeated applications to load up the wood you want to protect with copper naphthenate.

However, it takes a good few days for the mineral spirits absorbed into the end grain of wood to evaporate out of that wood, and if you haven't got the time for repeated applications of an inexpensive end cut preservative, keep in mind that you can use one or two applications of hoof treatment to load up the wood with copper naphthenate in a real hurry.

[The Daring Dufas]

**********Trim Some Great Stuff**********

Than you for posting some very useable information and going to the trouble to research it. I learn something new everyday and now there is something new for me to look into. ^_^

TDD

[Mr.E]

Thanks nestork- good info- I was fortunate to acquire two gallons of coppertox from a yard sale several years ago. I noticed one can rusting around the bottom roll and promptly put the coppertox into a glass jug with a piece of heavy duty plastic wrap over the top, then screwed the cap on. Both cans were rust pitted inside so if yours is in a metal can you need to check it.

[dadiOH]

Here's a better one...1 gallon, 68% copper napthenate for $62, case of six $195, 55 gallon drum $1,999, call for volume pricing. You might note that the per gallon price is cheaper for a case of six than for the 55 gallon drum.

Note also that the 68% is copper napthenate which resolves to 8% metal; some purveyors of "green stuff" say their product contalns, say, 2% but they don't say if that is copper or copper napthenate.

Another copper napthenate product I found after my initial discussion with nestork is CopperCoat made by Zinnser. _______________________

I'm still fuzzy on the legality of copper napthenate. I know that it was unavailable in the US (as a wood preservative) for some years but I get the idea from this site that it is now OK if the manufacturers step through EPA hoops.

The hoops are here...

Finally, here is a rather interesting discussion of various wood preservatives...

[nestork]

I'm expecting I'd have to pay at least $40 for that gallon of wood preservative for wood foundations, so I'd consider $62 for more than twice the concentration of copper naphthenate a pretty good deal.

[Robert Green]

That's an interesting discussion of potentially bad business decisions. Not sure if the folks that refused to pay for the required analysis will be able to ride the coat tails of Nisus and become certified. In any event, Nisus now has a monopoly on the market because they decided to cooperate with the EPA and do the required analysis.

I'm completely at ease with the EPA requiring information about new chemical products, especially something like a wood preservative that would likely end up in every corner of the US. The sad truth is that undocumented

*chemicals* have been *invading* aquifers and polluting the environment in ways we don't fully understand. And they're not going to self-deport. (-:

As a taxpayer I don't like getting stuck with the bill for cleaning up toxic waste sites of companies that have gone bankrupt. The huge number of toxic sites left as a result of bankruptcies is as clear an indictment of the weakness in the pure "free market" system as you can find. I suppose we could require huge indemnity bonds from any chemical company. Then it would be insurers, not the EPA, requiring that companies investigate the potential damage a new product could cause. If they didn't or couldn't, no bond and no business license.

As for CN (copper napthenate), I found this site about Nisus, the company now selling it:

These guys made it sound like the companies making CN previously were trying to create a shortage they could blame on the EPA to avoid the cost of certification required by the Toxic Substance Act. The Nisus CEO said: "In every instance through this process EPA did exactly what they said they would do and they did it exactly in the time frame given - or sooner," continued Kirkland. "Normally this process would take a minimum of six months, but in this case the folks at EPA got it done in just six weeks without lowering any standards. You always hear stories about inefficient government or government that gets in the way of business...well today, in our small corner of the world, EPA got it done!"

We can only hope that the businesses that refused to cooperate with the certification process will find that the sequester stalls any new applications from them for at least a year or two. Long enough for Nisus to at least recoup the investment they were willing to make in certifying the product as safe.

There's an interesting side issue here. In looking for "off label" products with higher concentrations of CN as Nestork discussed in the opening post, one could be walking down the slippery slope that got chlordane banned. Namely "if 1 gallon of chlordane is good, 500 gallons must be MUCH better." Not accusing you of anything, Nestork, just pointing out that it's human nature to almost always believe more is better.

With CN there could easily be a point where adding a higher concentration of the chemical to the target wood doesn't result in any better protection and might even have a down side. Like wasting money. (-: