Air Drying Wood

[Lee Bussy]

I came across an article today on air-drying wood.  One of the bits of wisdom was talking abou avoiding checks.  Painting the end was one tip, and then it said "put double sidebyside
stickers under them. The check won't go past that second stick."

That's one of those "huh?" moments.  Is this true?  And if so, how the h*ll does that work?

 

[drzaius]

23 minutes ago, Lee Bussy said:

"The check won't go past that second stick."

 

I guess that might work, as long as the second stick is way far in from the end. Like, make sure it's in farther than the check will possibly go   

It reminds me of the theory that putting a dirty sock around your neck will cure a sore throat.

[Lee Bussy]

But ... I read it on the Internet!

 

[Cliff]

I read that same thing, As I'm going down this route as well. But I am not sure I've seen anyone doing it and they seem to be doing fine. 

[mat60]

I was fooled again..I use kd but I did think paint would help

[Lee Bussy]

30 minutes ago, mat60 said:

I was fooled again..I use kd but I did think paint would help

Paint doesn't work either?

[mat60]

Wonder what other crap I thought was true...LOL

[Cliff]

I think paint works fine and helps stop checking. But it's the 2nd sticker next to the first that I think may be BS. 

I'm picking up this - http://www.woodcraft.com/Product/150809/Anchorseal2-Grn-Wood-Sealer-Ga.aspx?gclid=CJmV98eUscoCFYU9aQod1ywBxw

[tomsteve]

reading the article i see it says

 

"Paint the ends of all boards with latex paint [or a commercial sealant such as Sealtite 60 or Mobilicer-M]. OR, put double side-by-side stickers under them. The check won't go past the second sticker."

so it reads like if painting the ends isnt possible the double sticker thing works

which ive never heard of. i wonder if that second sticker, in the authors opinion, is some sort of.......heck....i got nothin.

but would be interested to know.

[Lee Bussy]

It sounds like BS but ... you know these things get around for some reason or another.  

[Tpt life]

Ok, noodling here with no proof...

If water travels grain like straws, then compressing the outer layer can potential trap some moisture and slow evaporation on the outside. So, why double? Is it possible that two side by side wick and trap moisture between them? Again, just brainstorming. 

[Brendon_t]

38 minutes ago, C Shaffer said:

Ok, noodling here with no proof...

If water travels grain like straws, then compressing the outer layer can potential trap some moisture and slow evaporation on the outside. So, why double? Is it possible that two side by side wick and trap moisture between them? Again, just brainstorming. 

I see the line of thought.  I would think though that 2 stickersat the end would spread the force compressing it less.  

My sawyer buddy uses anchorseal and a sticker about 4" in from the end saying if it cracks,  it shouldn't pass the sticker. 

[tomsteve]

really intrigued me so i posted over in their forum with no replies. then thought whynot go to the sawyers on the forestry forum? this is what i got:

 

Drying end checks can be controlled buy limiting the drying on the end, which in turn limits the shrinkage and therefore limits stress development.

Many of the drying checks on the ends of a piece of lumber will go back to the first sticker.  This is well known.  Checks or splits that go further are tension created splits (growth stress) and not due to drying.  So, one or two stickers placed close to the ends of a pile will seem to control drying end checks somewhat.  However, any technique that slows the end drying will work even better.  Latex paints pass too much water to be very effective.  The commercial coatings (UC Coating's Anchorseal, Sealtite 60, Mobilcer-M, roofing sealer, etc.), if put on thick enough, do slow drying and do an excellent job of controlling all drying related end splits.  Sometimes for squares, paraffin wax will be used.  One property that the coating should have is that it either must get really hard or it must evaporate when the kiln goes over 130 F or so.  We do not want the coating residue to enter the manufacturing plant.

In my many visits to sawmills, probably half do not put the coating on thick enough for it do to its job perfectly  A thick enough coating put on fresh ends will eliminate 99% of all drying related end checks at a cost of about $4 per MBF.  Some of the coatings can be sprayed on, which is really a plus for fast and good applications.  (Warming:  Do not park a blue pickup nearby when the wind is blowing and they are using orange Anchorseal end coating.  Two runs through the car wash using the "super wash cycle" cleaned it off.)  Probably 90% of the mills end coating their lumber use Anchorseal I or II; it can be sprayed or brushed and it has an antifreeze.  It is probably obvious that the ends must be fresh ends, as a coating will not stop preexisting checks.  Also, snow or ice on the ends will stop the coating from attaching to the wood under the snow or ice, so the caoiting does little good.

With two sticks at the end of the lumber, the check will not go past the second stick (about 4"), at least on the surface; we see this often.  However, most drying end checks do not go much further than that anyway, at least visible surface checks.  So, double sticker is very rare to see...an extra sticker that does very little good.  (The same thing if you put a second sticker at 12" in...the check will not go more than 4" and will never go past the second stick.  

But here is the problem...if a stack has stickers right at the end and then a lift picks up the stack and moves it, but hits a little bump or if the forks are too close together so the pole sags when lifting, the end stickers will fall out from time to time.  So, very few mills will stack with a sticker right at the end of the lumber; rather they put the sticker a few inches inward.  In this case, they will see that the single sticker, which is about 3 to 4" back, stops end checking from going any further.

So, in answer to the OP, if you want to control end checking related to drying, use a commercial, properly applied, end coating.  DO not use the stickers to try to prevent drying related end checking.



Incidentally, they do not dip the board in an anti-stain sealer; it is a fungicide chemical that prevents most fungal blue stain, but it does not do any sealing at all.  Some of the chemicals have optical brighteners too.

[Lee Bussy]

Thanks for finding that.  I'd still like to know why "it is well known" that a sticker will stop checks.

... my OCD wants to spell check that so bad ...

[drzaius]

I'd have to see some real science based testing that shows checking doesn't go past the sticker to believe that. Seems to me that checking from drying only goes in a few inches from the end & that happens to be where the first sticker is usually placed. I just can't think of what mechanism would be to prevent the checking going past the first sticker.

[Lee Bussy]

3 minutes ago, drzaius said:

I'd have to see some real science based testing that shows checking doesn't go past the sticker to believe that. Seems to me that checking from drying only goes in a few inches from the end & that happens to be where the first sticker is usually placed. I just can't think of what mechanism would be to prevent the checking going past the first sticker.

All I can think of, IF this is real, is that a sticker creates a n effective thickness increase and therefore slows drying.

[drzaius]

Or, towards the bottom of the stack there is enough pressure on the sticker to physically prevent the the wood from checking? That seems unlikely though.

[tomsteve]

yeah, the "why" of it has me intrigued. i might dig deeper and send an email to a few different universities that have quite a bit of information on processing lumber and ask the why part.

[Tpt life]

Some pictures float around of stacks 40' high. That is a lot of weight. I would love to see data from top to bottom to see if weight matters. 

[Coop]

I have cherry, walnut and pecan stickered and water base paint on the ends, drying now. The cherry has checked past the single sticker a bit, but the other two have not. I'm inclined to believe it's the spices of wood? None have double sticker sticks. 

[Lee Bussy]

9 hours ago, K Cooper said:

None have double sticker sticks. 

Well there's your problem!  You need these special stickers.  You're in luck, I am having a sale on them for $9.99 a dozen.  Send me PayPal and I'll rush them right out to you.  If you follow the directions, they are guaranteed to stop checks from passing.

Directions:  Seal end of wood carefully.  Place normal wood stickers at no more than 1 foot in from the ends.  Place the Perfect Stickers™ 3 feet from the end and every 2 feet from there across the board, finishing the other end as you started.