Why does 8/4 cost more than 4/4?

[Matt Furjanic]

It seems to me that 8/4 lumber should actually cost less than 4/4 per BF. Especially for species where the logs are very large.
There is actually less wood used to produce an 8/4 piece vs two 4/4 pieces if one considers the wasted material in the extra kerf to cut 4/4.
One 8/4 is easier to handle than two 4/4 pieces.
Less work to dry 8/4 as fewer stickers are necessary, and takes up less space.
Can someone explain this to me?

 

[chris_goris]

It has to do with yield and dry time. It takes longer to dry and is more prone to checking then thinner lumber (think higher internal stresses) . I m sure there are other reasons as well.

 

[Jeremy Scuteri]

I think the dry time that Chris pointed out is a large factor. 4/4 seems to be more commonly used than 8/4, so that may be a factor as well.

 

[CrealBilly]

It seems to me that 8/4 lumber should actually cost less than 4/4 per BF. Especially for species where the logs are very large.
There is actually less wood used to produce an 8/4 piece vs two 4/4 pieces if one considers the wasted material in the extra kerf to cut 4/4.
One 8/4 is easier to handle than two 4/4 pieces.
Less work to dry 8/4 as fewer stickers are necessary, and takes up less space.
Can someone explain this to me?

Some of what you said is indeed true but 8/4 is NOT easier to handle. I would rather fling 4/4 boards than 8/4 boards any day of the week.

8/4 also takes a lot longer to dry than 4/4.



"I carry a gun because a cop is too heavy" - Sarah Palin

 

[obxdiver]

Supply and demand, among the other factors mentioned. If you study economics the way I have, you come to realize that the cost to produce an item has very little to do with the price. It's all about what price people are willing to pay and how much your competition charges.

 

[cyclopentadiene]

Related to supply and demand, the majority of lumber sold is 4/4. The larger market leads to a higher supply and therefore lower cost. In regards to the accounting side of things, the 8/4 is a slower seller and has less inventory turns therefore leading to a higher carrier cost.

 

[CrealBilly]

As I said before 8/4 takes a lot longer to dry. You have to be gentle with 8/4 - time is money.

"I carry a gun because a cop is too heavy" - Sarah Palin

 

[Glenn1]

As I said before 8/4 takes a lot longer to dry. You have to be gentle with 8/4 - time is money.

"I carry a gun because a cop is too heavy" - Sarah Palin

I do have to agree with CrealBilly. Personally, I need to wait until the boards are under 20% MC before I will put them in the kiln. If I put them in too early, all kinds of bad things could potentially happen. Plus moving the 8/4 and 12/4 slabs is no walk in the park. Especially if you are over 40

 

[scsmith42]

Matt, there are several factors at play, most related to drying. The primary drivers are 1) degrade, 2) energy costs related to drying, and 3) storage costs related to drying.

Using oak as an example, a load of green 4/4 flat sawn oak will typically require 4-5 weeks to dry properly (irrespective of whether the kiln is conventional or dehumidification). Quartersawn material requires around 15% longer drying time, so it will be in the kiln for 6 weeks, give or take.

The drying rate for 8/4 oak is 60% or more SLOWER than 4/4; typically a load of green 8/4 oak will be in the kiln for 3-1/2 months, at a significant increased cost in energy when compared with 4/4.

For this reason, 8/4 oak is frequently air dried for up to two years before being placed in a kiln. Even after two years of air drying it can still require 3 weeks or so in a kiln to be brought down to 6% - 8%MC.

There are typically more losses due to degrade when lumber is air dried for 1-2 years before kiln drying, and these losses can add up to a 10% - 15% reduction in net sellable board footage. Additionally, there are costs associated with storing the lumber, as well as inventory taxes levied by the county.

Species that can be dried more quickly, such as pine and poplar, do not have the large deltas between 4/4 and 8/4 costs as do species that have to be dried slowly, such as oak.

Regards,

Scott

 

[CrealBilly]

Matt, there are several factors at play, most related to drying. The primary drivers are 1) degrade, 2) energy costs related to drying, and 3) storage costs related to drying.

Using oak as an example, a load of green 4/4 flat sawn oak will typically require 4-5 weeks to dry properly (irrespective of whether the kiln is conventional or dehumidification). Quartersawn material requires around 15% longer drying time, so it will be in the kiln for 6 weeks, give or take.

The drying rate for 8/4 oak is 60% or more SLOWER than 4/4; typically a load of green 8/4 oak will be in the kiln for 3-1/2 months, at a significant increased cost in energy when compared with 4/4.

For this reason, 8/4 oak is frequently air dried for up to two years before being placed in a kiln. Even after two years of air drying it can still require 3 weeks or so in a kiln to be brought down to 6% - 8%MC.

There are typically more losses due to degrade when lumber is air dried for 1-2 years before kiln drying, and these losses can add up to a 10% - 15% reduction in net sellable board footage. Additionally, there are costs associated with storing the lumber, as well as inventory taxes levied by the county.

Species that can be dried more quickly, such as pine and poplar, do not have the large deltas between 4/4 and 8/4 costs as do species that have to be dried slowly, such as oak.

Regards,

Scott

What that guy said well put Scott.

Not to mention wide 8/4 are nut busters to move around. Remember those 25" x 12' X 8/4 white oak diving boards I sawed? Good God man I had to use the bobcat to move one board by myself. If I recall correctly it took 4 of us to load one board of that on a trailer.

Even narrower and shorter 8/4 boards coming off the mill will give a guy a workout. You best be eating some Wheaties. I sawed and moved more than my fair share of 8/4 walnut and trust me when I say Wheaties is what you need to be eating.

The internet is a black hole - nothing can escape it

 

[scsmith42]

Remember those 25" x 12' X 8/4 white oak diving boards I sawed? Good God man I had to use the bobcat to move one board by myself. If I recall correctly it took 4 of us to load one board of that on a trailer.

Oh wow, as soon as you mentioned those massive planks my back started twitching with the memory :rotflm:.

Those darn things weighed 450 lbs each (or more).

 

[CrealBilly]

Oh wow, as soon as you mentioned those massive planks my back started twitching with the memory :rotflm:.

Those darn things weighed 450 lbs each (or more).

We be strong men or plum nutty - I can't figure out which one -:lol

The internet is a black hole - nothing can escape it

 

[mayszs]

Matt, there are several factors at play, most related to drying. The primary drivers are 1) degrade, 2) energy costs related to drying, and 3) storage costs related to drying.

Using oak as an example, a load of green 4/4 flat sawn oak will typically require 4-5 weeks to dry properly (irrespective of whether the kiln is conventional or dehumidification). Quartersawn material requires around 15% longer drying time, so it will be in the kiln for 6 weeks, give or take.

The drying rate for 8/4 oak is 60% or more SLOWER than 4/4; typically a load of green 8/4 oak will be in the kiln for 3-1/2 months, at a significant increased cost in energy when compared with 4/4.

For this reason, 8/4 oak is frequently air dried for up to two years before being placed in a kiln. Even after two years of air drying it can still require 3 weeks or so in a kiln to be brought down to 6% - 8%MC.

There are typically more losses due to degrade when lumber is air dried for 1-2 years before kiln drying, and these losses can add up to a 10% - 15% reduction in net sellable board footage. Additionally, there are costs associated with storing the lumber, as well as inventory taxes levied by the county.

Species that can be dried more quickly, such as pine and poplar, do not have the large deltas between 4/4 and 8/4 costs as do species that have to be dried slowly, such as oak.

Regards,

Scott

As always a wealth of information. I've learned the hard way how much slower thick cuts are compared to thinner.
Lover the past month I've sawn a few hundred board feet (It's taking me forever but as you know chainsaw milling isn't fast) of 12/4 Quartersawn Pecan. So far it's dropped maybe 1-2% moisture even with all of the wind we've been having.
This is one of those times where the idea of buying a vacuum kiln is attractive, to bad they cost an arm and a leg.