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Drying Pine for Pressure Treating

Started by Tim/South, August 12, 2008, 11:02:33 PM

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Tim/South

I plan to saw boards and posts for some board fencing. This will be for myself.
I plan to have this pressure treated.
How dry should the boards be before I take them to be treated?

DanG

Hi Tim.  The treaters around here tell me they want to see less than 25%.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

Fla._Deadheader


Strange, we talked with a guy about pressure treating, and he wanted the lumber as fresh as he could get it.

  This is a vacuum-pressure treatment. He said, wet wood has not sealed the passageways in the lumber, so the vacuum draws out the water much better, and also allows the treatment fluid better access deep into the wood.

  Wadda I know ???  ;D ;D
All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

DanG

Maybe he wanted it wet so it wouldn't take so much chemical to make it look green? ::)  All I know is, both of the treaters who do custom work around here gave me that 25% figure, and the pole plant that does not do custom treating kiln dries their poles first.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

Tom

I was always told 19% or less, and that is what I conferred to my customers.  It wasn't too hard to get it to 16% in normal air-drying.  As a matter of fact, 12% was where air drying usually bottomed out.

The pressure treatment wouldn't go into SYP heartwood because the wood was naturally sealed and it wouldn't replace an water.  You could see the steam from the pressure tank as the vacuum was drawn, but the operator said that was just residual water and the vacuum couldn't take it out of the wood like a kiln would.

These were guys that treated veneer cores (landscaping timbers) to the point of refusal right on down to Salt water submerged treatment of pilings.  Point of Refusal just meant that it had some chemical in it, whatever it would take.  Usually it was around .2 or .3, but no guarantees.

Did you ever notice that the landscaping timbers from the box store will rot?  That's because they were wet when treated and are mostly just colored. Now  and again a batch might be dry enough to make a fence post.

'Course it matters as to what concentration the wood was treated. That number refers to the pounds of chemical retained in the wood per square foot.

numbers given for CCA treatment were:
.2 is for millwork.  things like exposed truss ends.
.4 is for ground contact, fresh water splash
.6 is for structural poles, wood foundation
.8 is for freshwater submerged and salt water splash
2.5 is for salt water submerged (pilings)


woodhick

I checked in to this a few years back for fencing also.  I was wanting creosote treatment to give me a black or darker look.   The guy I talked to told me that for creosote green was ok because they treat it above 212 degrees and it would boil out the moisture but for CCA treating the wood needed to be air dried.  He did not give me any % but said it would not take the CCA treatment green.  Keep us posted.
Woodmizer LT40 Super 42hp Kubota, and more heavy iron woodworking equipment than I have room for.

Tim/South

First, Thanks for the replies. The more information and points of view a person gets the better informed he is.

I guess my best move would be to call the outfit that pressure treats and see what they suggest. I do not want to be told something by the company that works in their best interest and not mine.
A friend told me the cost was around $100 per thousand BF. Does that sould about right?

DanG

$100/mbf is a good price.  That is what the local treater was charging until they stopped treating sawn lumber with CCA.  The outfit 60 miles away that will still do that is charging $150/mbf.

It makes sense to me that the drier the wood is, the more chemical laden water it can take up.  Get it as dry as you can within your allowable time frame, and you should be ok.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

Tim/South

Thanks for the information.
You guys have no idea how much of a crutch this forum ha become for me.
I can get caught up reading threads and be here for hours. There is such a wealth of knowledge and points of view here.

beenthere

Quote from: Tim/South on August 16, 2008, 12:33:24 AM
Thanks for the information.
You guys have no idea how much of a crutch this forum ha become for me.
I can get caught up reading threads and be here for hours. There is such a wealth of knowledge and points of view here.

We DO have an idea....as we get the same enjoyment and knowledge out of the forum. Your point is well taken.  8) 8) 8)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Tim/South

I attended an auction this past weekend. A lumber products company had closed and was selling pieces to the highest bidder. (Those Yates A 20 planers sure looked like work horses)

Another company bought the site property and equipment that did the pressure treating aspect. (There were 2 sites)
I asked both the new and old owner how dry pine needed to be before treating. Both answered 20%. They got over my head when talking about the cylinder and how much pressure could be applied.

I asked what they charged per thousand. When he discovered I own my own little mill, the new owner quoted me $75 per. That is $25 less than I was prepared to pay and much closer that the other place.



Tom

that's a good price.

To stay on their good side, make sure that the lumber you submit to be treated has had the sawdust removed from it.  You can do it with air as you cut it, or brooms, or a pressure washing with water.     If you leave the sawdust on the lumber, it comes off in the treatment tank and contaminates their pumps, as well as the holding tanks and filters.  They get upset real quick when they find out what is going on.


DanG

That's a great price Tim!  Did you ask any details about the treatment they're planning at that price?  One place here only does ACQ, and they charge $300/mbf.  The other one is 60 miles away, but they will use CCA at .60 lbs/cu ft for $150, which I consider a bargain these days.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

Tim/South

QuoteTo stay on their good side, make sure that the lumber you submit to be treated has had the sawdust removed from it.
Thanks for the heads up Tom.
I wonder if I could stick it to dry and blow the dust with a leaf blower? I have one of the 100 MPH leaf blowers I use to blow of the hay balers.
I also have a pressure washer. It would probably do a better job.
Can I pressure wash the boards after they are stuck? It seems like it would be easier if I could.

QuoteDid you ask any details about the treatment they're planning at that price?
Dan, I know very little about pressure treating.
The owner said the boards would be treated in a cylinder that applied a tremendous amount of pressure. I did not really know how the process worked.

The new owner already owns a much larger forest product company and is letting his son run the pressure treating at the now added site.
I bought a small forklift at the auction and let the Mennonite famlies use it to load the pieces they bought. A Mennonite man returned the key to me as I was talking to the owner about pricing. I refused to accept any money for the use of the forklift.
The owner commented on how much business he did with the Amish/Mennonite community. That is when he asked if I owned a mill, then gave me the $75 quote.


Tom

QuoteCan I pressure wash the boards after they are stuck?

I wouldn't risk it.  I would de-dust as the boards came off of the mill or before they were stacked.   Appearance isn't the object.  Getting rid of the sawdust is the object and you can't do that once the boards are stacked.

You will have instances when the sawdust is packed and stuck to the board.  Unless you are pressure washing, it will almost have to be scraped off.

DanG

Tim, here is what little I know about it.  The level of treatment is stated in pounds of chemical per cubic foot of wood.  Lumber that is intended to be out in the weather, but not in contact with the ground, is typically treated to .25, which would be a quarter pound of chemical to 1 cubic foot of wood.  Most of the 1 and 2 inch PT lumber you find in the box store is treated to this level.  Wood that is intended to be in ground contact, that would be your 4x, 6x, and 8x lumber in the box store is treated to .40 lbs/cu.ft.  Now that was the box store world.  In the real world, anything that is to be buried with an expectation of lasting for more than 10 years, will be treated to at least .60 lbs/cu.ft, and anything that will be in standing fresh water will be .80.  Treatment for salt water is even higher.

The treated portion of the wood is required to be at least 5/8 inch deep into the wood.  You will sometimes find a little plug in a board where it has been bored to test for this.  That 5/8 inch is supposedly sufficient to keep the inner portion from recieving enough oxygen to decay.  It seems to work pretty well, as long as you don't cut the board after it is treated.

Now, there are 2 types of treatment available, for the most part.  To avoid the embarassment of incorrect information, I'll just call the most common one ACQ.  That is the newest one, and considered to be the standard around the home.  The other is CCA, which was the standard until it was banned for use in the general public, because the A stands for Arsenate, or Arsenic.  From what I've been able to learn, it was the word more than the chemical that got it banned.  However, it is still available for use in farm applications, roadsides, and docks.  In other words, you can still use it for fences and such on your farm.  The A in ACQ stands for Ammoniated, and Ammonia is highly corrosive, and requires fasteners that are double dip galvanized.  The protection provided by each type is supposedly equivilant, but ACQ hasn't been around long enough for us to really know.

From what I've been told, if your guy is offering $75/mbf, it is probably CCA, as it is the cheaper of the two.  At that price, it is probably treated pretty lightly.  It would be worth it to pay him a little more for a more intensive treatment, especially on the posts.  You can probably get him up to .60 for a dime a foot, and that would still be a bargain.  If it is CCA, you may be asked to sign a form stating that it is for farm use, but that shouldn't be a problem. ;)

We talked about drying in response to your original question, so now let's talk about redrying.  PT wood has gotten a bad rap over the years for being unstable and prone to warping.  What is going on is, it has been rewetted, through and through, and behave's just like green wood that has never been dried in the first place.  If you take a soaking wet board and lay it in the sun, like Lowe's does, the top side is gonna dry and the bottom side ain't, and it is gonna curl up like a pretzel.  The PT plant will band your stack of lumber for you, so when you pick it up, leave it banded until it dries just as long as it took to dry it in the first place.  Both plants I've talked to will treat it on stickers, so do that if you can transport it that way, and leave it on the stickers until it dries again.  Do NOT load your trailer to the max with your dried lumber and expect to go pick it up again on the same trailer.  It will weigh twice as much after it is treated. ;)  Also, ask them what the maximum size is for a stack.  You don't want to show up with a 48" stack of boards when their limit is 42".

If I think of more, I will post it.  Good luck with your project.  We'll be looking forward to pics. ;D
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

Tim/South

Again, thank you both Tom and Dan for taking the time to reply and educate me.

I believe pressure washing will be the best route to go.

I asked about bringing the lumber stacked with stickers and was told they would rather me not.
I will be strapping the bundles myself. I bought a strapping cart and tools at the auction. Sadly my crimping tool walked away before I was able to pay and load the cart into the pick up. Live and learn.
I asked about bundle size. He said 36" x 42" If I understood him right, those dimensions would allow the bundles to be stacked into the cylinder X 2 . I am not sure if that was depth or width. I will call to get a clarification. He did not mention length.

One thing the new owner said surprised me. He said with the high pressure they were capable of creating, he could treat the bundles in the cylinder in 1.5 hours.
I asked if that would penetrate and he assured me it would be total penetration.

I have no problem paying a little more if I can get a better treated board. That is something I will offer.

QuoteIf I think of more, I will post it.  Good luck with your project.  We'll be looking forward to pics.
Baby steps. I have not figured out the bells and whistles here yet. :)

Meadows Miller

Gday Fallas

My famly has run CCA plants for over 30 yrs and all I can say is if its for Yourself or they are only charging by the Bft dry it as well as you can . But if there charging by the amount of CCA or CCQ used between 15 and 20 % MC will be just fine .

Also if the timber is been used in a exposed positon give it a coat of Oil based sealant eg Boild Linseed oil with a mould/fungas inhibitor as this will slow the effect of seasonal changes eg wet dry wet which cuts the service  life dramaticly

Reguards Chris McMahon
4TH Generation Timbergetter

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