preserving 6x6

[randy d]

We are planning on putting up a hoop house I would like to attach it to 6x6 tamarack what can we use to preserve the wood.

[Nebraska]

"Hoop house"??? Not sure  what that is.  Seen many hoop livestock barns, no houses.  Just displaying my ignorance.

[chet]

I'm putting another up this spring. It's going to set on 6x8 heartwood burr oak timbers. No need to worry about treatment and they will outlast me by a bunch. Another advantage is the white oak is very heavy, helping to mitigate wind problems.

[scsmith42]

Copper Napthanate (CuNap) is about the best preservative that you can buy w/o a license.  I buy it in concentrated form (8%) and mix it with diesel. The diesel evaporates after a few weeks, leaving the CuNap behind.

This site will tell you more about it.

Copper Naphthenates - Copper Care Wood Preservatives, Inc. | Wood Preservation Solutions

Here is where you can mail order it from.

Copper Naphthenate 8% (68% by Volume) Concentrate from Poles, Inc

[Southside]

Same concept Nebraska, just with greenhouse film over the top of it, also called a cold frame.

[bluthum]

Another vote for Copper napthenate, it is about the only preservative I'd want to use around growing plants. I don't know about modern times but back in the day it was considered the only preservative that wouldn't adversely affect plant growth.

[doc henderson]

I got mine on Amazon.  CN

[caveman]

Scott, when you have a little time, do you mind elaborating on how you use the copper naphthanate?  Do you soak the whole post for 24 hours or just the part that goes in the ground?  How many posts (size?) and how much copper naphthanate does it take to treat them.  I wonder how it compares to the CCA 2% pressure treated in durability. 
Thank you.

[TroyC]

I got my delivery of a 5 gal bucket from Poles today. Stuff works good but has an odor in the beginning that does go away. Seems to work well. I rolled some 2x12' pine and put them directly on a dock bulkhead. Been there 2 years and holding up well. I tried soaking 6"x6" ends overnight and seems like I only got about 1/8-1/4" penetration. Use 1 gal copper napthenate 8% in 4 gal diesel.

[doc henderson]

yes, it smells like it should do a good job.

It depends on how crazy you want to get.  you could heat and dry them well to get more absorption.  I think 1/8th to 1/4 is great as long as you do not then make a cut through it.  Larry does a thing to dry tenons on legs by putting them in hot sand first.  That will not work for this, but if you can dry them well and apply warm it might help.  do not heat the liquid as copper would not be good to inhale.

[scsmith42]

Scott, when you have a little time, do you mind elaborating on how you use the copper naphthanate?  Do you soak the whole post for 24 hours or just the part that goes in the ground?  How many posts (size?) and how much copper naphthanate does it take to treat them.  I wonder how it compares to the CCA 2% pressure treated in durability. 
Thank you.

It depends upon weather exposure.  Most posts get set into a barrel for 1 - 2 days with CuNap topped off as needed to soak into the below-ground portion of the posts.

Items that are exposed to the weather (shooting bench, horse mounting blocks) get saturated on the exposed surfaces. 

It soaks in better if the post is not green.