7 replies to this topic

[Howard]

Quick question for you guys to hash out for me. I am trying to make my wood choices to build a stem, stem cap and stem knee. These are about 5 to 6 feet long and from 2x stock (actually, more like 1 3/8" in todays lumber choices).

 

The two choices I have on hand are some doug fir I've had laying around for about 5 years or so, or, some SYP I picked up a few months ago. Both options were got out of 2 x 12's, taken straight out of the center of the tree, such that both had a center pith section, plus straight, quarter sawn grain on either side. The pith sections were ripped out and tossed, leaving residual pieces of long, straight, quarter sawn grain.

 

Issue is that in both cases, it appears the tree started out in life in a dense stand, that was eventually thinned and the tree took off growing. Both have an area of very tight growth rings in the middle, but then those widen to nice rings of around 12 or so per inch. In order to get the width I need, I'm either working between the sapwood and tight inner rings, or have to include both tight and not so tight rings on the same board. Because these have to be laminated together, I have been trying to avoid using flat or plain sawn pieces to avoid any cupping down the road. The boards in these pictures are remarkably straight, with nominal warping or cupping. For some reason, the doug fir pieces are bowed about 3/8" from end to end, but clamped as they are shown, these bows cancel out and the lamination would be dead straight.

 

Issue with the SYP is to get the width I need, I have to include the transition from fine to not so fine grain, and will include some of the very cupped rings along the side as well. Is this going to cause problems, or do I need to keep looking?

 

As an alternative to these two choices, I also have several flat sawn boards similar to the one shown in Doug Fir that I marked out for the stem knee. You can get reasonably wide pieces of quarter sawn from those, but the grain isn't as tight and the concern I would have about those is cupping when they are laminated together. On the other hand, the laminations narrow down a lot so the cupping issue may not even be a factor.

 

May sound like much concern about nothing, but these will be permanent, structural pieces. No reason to build in a problem if it can be avoided.

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[Oyster]

These days untreated SYP is a crap shoot.  There are some boards around thats kiln dried number one SYP that is used for decking material and comes in 5/4 x 6" which is not too bad. If you can find some 2 x 10 kiln dried stock, you can also split it down the middle and normally end up with quarter sawn stock, getting it from the flat sawn stuff that you will normally find. What are you building?

[Howard]

Princess 26. Plywood shipped today. More on that later.

 

My source for SYP is a truss builder. #1 kiln dried 2x stock in many different sizes up to 24 feet or so. Generally pretty clear. Costs about 1/4 what similar Doug Fir grade costs, at least around here. SYP is local. DF is 100 miles away.

 

For some of the more important stuff, like the tabernacle pieces, I'm looking at a grade they have called MSR (Machine Stress Rated). Its pretty good, but much more expensive.

 

I also have access to a variety of older lumber that has been stored in barns. Some used.......some new. Have not picked through all that yet, but will be moving a large pile of it during the next week and will keep my eyes open. That will be SYP, fir, etc.

 

If the quarter sawn edges of a flat sawn 2x12 would work better, I already have some of that.

[Howard]

Once you start looking through the lumber piles, you find that most of it is flat sawn. Most of the 2nd growth trees are not that large when harvested and it seems the sawmills just start working their way in from the edge so as to not waste any of it. They get 2x4 and 2x6's from the edges, then move into the larger sizes, eventually moving up to 2x8, 2x10 and 2x12 as they get closer to the log's center, but most of those are going to be very close to the pith in the middle. Some will have pith and sapwood in the same piece.

 

It seems to me that finding any piece of quarter sawn wood wider than 4 or 5 inches is tough. The flat sawn stuff is acceptable to most users in the construction trades, but most of them are not trying to laminate wider boards and don't care if they cup a little. I'm trying to avoid that if I can.

[RC Bill]

Howard, what is SYP?

 

Thanks, Bill

[hokeyhydro]

Southern Yellow Pine = SYP

[Howard]

Layed out the stem and stem cap on the pine boards shown above and unless something better shows up, will probably go with them. They are heavy and solid as can be. Will make an effective battering ram to put up front.

 

To help explain what my concerns are, a few graphics are attached. The one that shows how lumber distorts as it dries is the one that has me concerned. Quartersawn shrinks about the same on all sides. The greatest distortion is to the plain or flat sawn lumber, where it cups as it dries. For a lamination, that is the least desirable choice, yet when you go shopping for lumber, 90% plus of what you find will be flat sawn. I assume it is the easiest way to saw a log and certainly yields the most lumber. For construction uses, it may be preferred.......structurally stronger when set on edge and a little cupping is not an issue.

 

Those photos of the douglas fir (in that yard.......the select, clear, knot free stuff was called grade D?) show only one or two boards in the entire pile that are not plain or flat sawn, and then only parts of the boards. The only way I've found to get anything remotely like the quartersawn stuff shown in the graphic is where the board came from the center of the log and includes the pith and then it has to be a 2 x 12. That is what I did for the SYP. As far as a lamination is concerned, option B is to get the planks or pieces dried down as far as they are going to go (stable), then laminate them so that the cups are facing each other (bark side out).

 

There are at least five areas on a Princess 26 that have to be laminated by the larger structural lumber. They are the stem and stem cap, exterior keel, interior keel planks and due to the size of them, the CB and rudder, which will be 1 3/4 to 2 inches thick, so can't be got out of ripped laminations of 2X stock, which are 1 3/8 inch to 1 7/16 inch max, so even those will have to be ripped from these wider planks and set on edge. I do have access to some full 2 inch cypress planks that I could rip down and use for the CB and rudder.

The reason I'm going with SYP over DF is price. The DF shown was priced to me at $85 each for those 2" x 8" x 12' boards. Grade D and better, which they view as furniture grade. Judging from the dust accumulated on them, they don't sell much. It would be dry. If I was going to make a birdsmouth mast, it would be from DF and the lumber for it would come from that pile. If there was a knot in any of that stuff, I didn't see it.

 

The SYP cost around $20 each for 2" x 12" x 18'. It is kiln dried #1 and it too is generally free of knots. But while it was planed at the mill, it is rougher. It was dried to around 18% moisture, so still has some drying and shrinking to do before I start using it.

 

 

Anyway, all part of the thought process of a whack job about to start a boat building project.

 

 

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[Howard]

Found yet another source of high quality yellow pine lumber that many may not be aware of. A dense, mostly clear structural grade is sold as DI 65 scaffolding plank. This is a product that has specs outlined by OSHA (not graded by OSHA......specs are by OSHA). Some of the desirable specs include a minimum ring count, vertical leaning grain and minimal to no knots. Considering the liability involved, I doubt there is much fudging on the specs if it has that OSHA stamp on it.

 

Some might be able to find these locally and are not outrageously expensive. I have yet to find any locally, but plenty of samples to look at online and apparently vendors selling these will ship small quantities. Most samples I have seen are flat sawn but have mostly clear, straight grain up each side. Photo is from one of the vendor sites.

 

In short, unless you have access to the rare place that sells high quality lumber, this may be about as good as a person is likely to find. Certainly better than any box store is going to have.

 

If interested, do a Google search for:

 

DI 65 yellow pine scaffolding

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