Logging/lumbering lesson # 347B

My sawyer called to say I could pick up some sawn lumber from logs I had previouisly dropped off. He cut about 10% and gave up...too tough, blades going dull on the band mill in less than one pass (12 feet.) I let the stuff lay too long before taking it to the mill (he added significant delays as well.)

In all the old newsreels and movies the logs were sent down water lubricated flumes to the river where they were rafted up and accumulated till floated down stream to the mill. My over the head light bulb flickered dimly.. I started taking the uncut logs by tractor to one of my ponds, largest and best first. Of the first 8 only one floated.

Previously I tried to keep a couple prime hickory logs wet by floating them in a pond. They both sank like stones. I thought maybe pecan, red oak, and or white oak might float. Well mostly they don't.

I would like opinions regarding whether or not soaking dry logs will make them easier to saw AND how long it might take, 6 days, 6 months, 6 years, or forever and not work.

If this isn't going to work I can save time and just square up the ends and use them basically as is for columns above concrete piers to support a mezzanine floor in a barn ( the 35x70 one I moved intact a quarter mile)

Pat

The voice of inexperience just has to pipe up here.

Using my band saw on green poplar logs is frustration in itself. The cutting is slow and the blades do dull quickly. Cutting dry poplar wood with the band saw is easy. Fast cuts and the blades last a long time.

Maple and oak seem to cut a Little easier??? on the band saw when wet. When cutting dry maple and oak the blades seem to last a little longer??

All the woods cut a little harder if there is a slight tangential angle to the longitudinal grain. This seems to be slightly greater if cutting from what was the top of the tree to the bottom.

I have read that some trees will pick up local minerals and incorporate them into their cell structure making cutting more difficult. Silica may be one of these minerals.

It has been noted that the local lumber mills will only accept cut logs that have been down for less than a month. Then when they stack them they keep a spray of water on them. Note sure but this may be for dimensional cutting and shrinkage so the final product is all the same size.

The whole log may not have to be immersed in water. If the butt end is sitting in water the whole log should eventually become wet ? [This was a method used to treat fence posts back when on the farm]

Now that I been able to dispense some more pretty well useless information <font color="blue"> </font color> <font color="blue"> </font color> about the question asked I would suggest a chainsaw mill may work well for squaring the logs. [img]/forums/images/icons/grin.gif[/img]

The age of the original band saw blade and its former treatment may also be a factor. If the blade has been heated up it's temper may have been lost and it will dull quickly??? The same happens to chainsaw blades. [img]/forums/images/icons/frown.gif[/img] This I do know! [img]/forums/images/icons/frown.gif[/img]

Egon [img]/forums/images/icons/grin.gif[/img]

Pat,
I guess my question would be: what's the difference between a log that has "dried" to moisture content of "x" by "laying around" and a kiln dried board with moisture content of "x"? My point is that I would think a dried log would be easier to cut. After all, we cut dried "logs" as lumber every day. Without any scientific evidence to back me up, I think of cutting "wet" wood like cutting cheese with a knife, i.e. the moisture in the cells makes them less rigid and able to cling to the cutting device. (On the other hand, some might argue that the moisture acts as a lubricant.)

Did you (or your sawyer) measure the moisture content of the logs? If I were you, I'd measure the various logs just to see what variation you have in fresh cut/laid around/soaked/unsoaked and between the various species.

This brings to mind a show (Dirty Jobs) that highlighted recovery of logs from the bottom of Canadian lakes that were submerged for over a hundred years and then processed. I know they also do that in the South with river salvaged logs. I don't recall any discussion on whether that's harder or easier on the equipment that cuts them.

I would think that equipment, species, type of cut (plain sawn/quarter sawn), moisture content all play a part. I would also think that the opinion and knowledge of an old grizzled sawyer that does this for a living would be worth more than mine. [img]/forums/images/icons/wink.gif[/img]

I've been talking to a local sawmill periodically about getting some rough-sawn for corral fencing and he's expressed an interest in getting some timber off my property. Next time I talk to him I'll see what his opinion is.

BTW, I'm not sure what you hoped to get from your log-dunking experiment (other than a lot of exercise dunking and retrieving) unless you recorded moisture content of each log by species to develop some sort of a correlation. Even for those that "sank like stones", you could time the descent to see which ones were denser.

I brought back an entire dump trailer load of uncut logs from the mill. The Sawyer said the wood had been down too long and would dull a fresh blade in less than 12 ft of cutting. He did manage to cut a little oak for me.

Kiln dried wood has been heated. Heating wood "cooks" the sap and makes irreversible changes that are not only attributable to moisture content. To "set" the sap in certain woodworking situations where you don't want sap to "bleed" out of a finished project (furniture for example) you can "cook" the stock in advance.

In making concrete, after it cures you can't reverse the process by adding water and get uncured concrete. My concern is whether there are any irreversible changes in wood when it dries or if I can soak it and regain its first felled cutting ability. A friend of mine has a brother who just bought a band mill and was brought some logs that had been down for a year. He read in his literature that came with the mill that this was a BAD IDEA with standard blades and would require carbide tipped blades. This confirms the idea that delay is bad but offers no clue as to the reversibility of the process by soaking.

I didn't time the rate of descent which would have been related to form factor and not just density. I got little exercise as I used the pallet forks on the tractor and I had dumped the logs near the pond I used. The magic moment was when I pushed the last one out just a little further and DIDN'T GET THE TRACTOR STUCK!!! I am open ocean SCUBA qualified and will have little trouble retrieving the logs with a little snorkeling. My cousin-in-law is a diver too and volunteered to help retrieve them just for the fun of it.

A couple years ago I was given a couple nice fresh hickory logs by a neighbor. I wanted to prevent their drying before I took them to a mill. They sank like stones. Oh well, later this year with warm water temps and way warmer air temps retrieving logs will be fun.

What am I investing? I have logs the sawyer won't/can't cut. I don't have wood heat. It took about 5-8 minutes to put them in the pond as I had dumped them near it. Although I am a scientist, I have no practical interest in measureing the moisture content even though I have a bi-pin type electronic moisture meter. When I retrieve a submerged log it will either cut easier or it won't. I will get my answer in a few months with only a small additional investment in resources. The reason I asked the original question was curiosity. I am not the most patient man on the planet.

Regarding, "I think of cutting "wet" wood like cutting cheese with a knife, i.e. the moisture in the cells makes them less rigid and able to cling to the cutting device." I wouldn't push that analogy very far as the cheese slicer and the band mill cut in very different ways. At least using cheeses with which I am familiar and have cut.

Although my sawyer did not measure the moisture content, he did get hard empirical data on the difficulty of sawing the cured logs and the rate of blade dulling. If the difficulty is sufficiently ameliorated by soaking, I have achieved a good thing and made the old logs usable. This represents a considerable return on investment. The gambit I am playing, i.e. the material I am offering speculatively in hopes of significant gains is in the way of time and materials, quite small, so if nothing is gained the losses are quite acceptable.

Pat

Egon, There are two main families of oak, black and white. Red oak is in the black oak family. A major easily discerned difference between a black and a white species is longitudinal porosity. One has closed tubercles in the wood and the other has open ones that will pass air. If you take a piece of oak and place one end in a glass of water and blow on the other end whether or not you get air bubbles in the glass depends on which type oak you have. This is why red oak is not so highly prized as white. Red is more suitable for indoor use but white is better for outdoor use (than black) as it is sealed and does not wick water. Of course white can be used indoors just fine.

If you are soaking wood in a preservative, it just might be an advantage to having the porous type as it would wick creosote, cuprinol or XXX better than a sealed species.

Pat

Red oak we have. White oak does not grow up here.

Back in another life in another place we used poplar fence posts as that was the tree available. [img]/forums/images/icons/grin.gif[/img]

The band saw blade problems may have been caused by the set on the saw blades and feed rate to the blade? [img]/forums/images/icons/confused.gif[/img]


Egon

I may be showing my total lack of knowledge in this area but would a circular sawmill blade cut them better than a band saw?

Egon, good tip on the heat and temper for chainsaw chains. Thx

Given that you are comparing a ripping blade in the circular blade mill to a ripping band in the band saw (or ripping loop in a chain saw) they all go up in difficulty as the wood gets harder. Ditto with cross cutting variants of each.

Maybe it would just be easier if I bought a carbide tipped band for my sawyers mill to use on my "hard wood."

Pat

In this area (SE Ohio) log yards continuously spray their accumulated logs with water. Logs may be kept for 6 months or more with no loss of quality