Thread: Wood Selection in USA for a GIS

PAR, excellent input from someone who has hands on experience with cypress. I think I will pass on cypress - and do some 'woodpile searching' to put my "bill of materials' together. I REALLY like that birdsmouth mast you have designed - I think it would be a great addition to my GIS - but as this is my very first wood project I think I will stick with a wooden stave box mast. Great information. Thanks, Rick.

PAR, Like you said, selecting the right Cypress board will be important and prevent some of the internal stresses you mention, which I have yet to see milling a fair bit of the stuff (but will now look out for). The humidity issues is a non issue if the boat is sealed in epoxy, would you agree? And will cypress limited to just chine logs and the frames present these finishing issues?

Are the best boards the ones that have more quartersawn material? They do run the whole range from straight grain to grain that loops and turns. But it is still lovely to work unlike the wild grain of say African Mahog.

Sadly, clear Cypress in Oz is extremely scarce. It used to be used (may still be?) for house frames because termites will not attack it, but with cheaper treated Radiata it has disappeared. About the only use for it here that I'm aware of is for gate and fence palings and it is FULL of knots, which gives it a lot of character for that purpose.

I can only imagine that clear cypress must be a very pretty wood.

Even well coated with epoxy, cypress will eventually screw you, much like Douglas fir. It' checks from these internal stresses, so a perfectly coated surface will not remain this way and once a check does open up, the nightmare begins. With Douglas fir, the only recourse is a fabric sheathing of suitable weight to prevent a breach if a check does work it's way to the surface. The same is true of cypress.

If the logs are fairly small in dimension, you might get by, but I haven't seen a single piece of cypress survive long term without a bunch of surface splits and checks. Epoxy coating wood like this may not be the best thing, because you'll eventually trap moisture in it with a limited avenue of escape, where as a painted piece will just swell and contract normally without this issue.

Now, don't get me wrong, I love cypress, but only in large dimensions, where surface checking isn't an issue. My rental house is framed from locally available cypress. You can't even drive a nail in this stuff without a pilot hole and the bugs just don't like it. Big hunks of 2x8 or 4x6 aren't really affected by some surface checking. On the other hand a dainty piece of chine log, say 17x25 mm that has one good, deep check is compromised.

Rick, I build several birdsmouth mast each year. This year was a bit slow for sticks, I only built 3. Note the different stave arrangements below. I use the method on the left (the site above uses the right hand method), my way takes more setup time, but dramatically reduces rounding time. It also makes a slightly stronger mast and you can leave portions of it octagonal if desired.

Tapering the staves is easy with a guiding ramp (2x4 clamped at and angle) and a plane.

It has been good to hear this all about Cypress. I will need to see some older boats and see if they have shown any of the checking and movement mentioned in previous posts.

PAR, we should pick each other's brains about Birdsmouth stuff...I may pick yours more than you would mine, but I am doing some different methods. Check your PMs when you get a moment, thanks.

Cheers,
Clint

The cypress floors in my Simmons Sea Skiff haven't exhibited any problems so far. It hasn't seen any water (nor weather) since it's still inside my shop but I just laid the first coat of primer on and there're no flaws showing up in the stuff, anywhere. The floors were thicknessed to 7/8 inch per the original plans and are plain sawn. I've not had to bend any cypress so I'm wondering if that is what causes many of the problems PAR mentioned.

These floors were not sealed in epoxy, btw. I just put a coat of shellac on the faces prior to setting them up in the strongback. (The only epoxy sealed material in the boat is the inside (bilges) of the meranti 1088 ply I used for the bottom.)

Originally Posted by PAR

Even well coated with epoxy, cypress will eventually screw you, much like Douglas fir. It' checks from these internal stresses, so a perfectly coated surface will not remain this way and once a check does open up, the nightmare begins. With Douglas fir, the only recourse is a fabric sheathing of suitable weight to prevent a breach if a check does work it's way to the surface. The same is true of cypress.

If the logs are fairly small in dimension, you might get by, but I haven't seen a single piece of cypress survive long term without a bunch of surface splits and checks. Epoxy coating wood like this may not be the best thing, because you'll eventually trap moisture in it with a limited avenue of escape, where as a painted piece will just swell and contract normally without this issue.

Now, don't get me wrong, I love cypress, but only in large dimensions, where surface checking isn't an issue. My rental house is framed from locally available cypress. You can't even drive a nail in this stuff without a pilot hole and the bugs just don't like it. Big hunks of 2x8 or 4x6 aren't really affected by some surface checking. On the other hand a dainty piece of chine log, say 17x25 mm that has one good, deep check is compromised.

Paul,

I'm puzzled. Your description of checking in cypress and douglas fir lumbers differs from my experience. But - you're the second person whose opinion I respect who's said something similar. The other was from the South also. I'm wondering if perhaps your hotter temperatures, when combined with high humidity and intensive cycling - when compared to us here in the Pacific NW - would explain the different experiences. I have only done a few things with cypress, but never saw it want to check long term. I've done a mountain of projects with douglas fir. A solid, grown, stick - when used as a spar - will almost always check. A dried timber which is machined into a solid spar? Never seen evidence of checking except at the ends, and then only if the finish is skimpy or allowed to deteriorate then weather for a few seasons.

Someone also postulated that the issues you experienced with douglas fir might stem from a lesser quality being shipped out of this region. Perhaps... but the opposite would hold true for cypress, eh?

Any thoughts? Anyone?

The dimensions of the timber have a lot to do with internal stresses (eventual checks, splits or cracks) getting to the surface. The smaller the finished dimensions, the more likely the majority of the internal stresses have been relieved (during the cutting process). Larger bits of wood will have lots of these internal stresses, but this is no guarantee that they will show up in any one given piece. Both Douglas fir and cypress are well known for checking, though I think cypress is the far worse culprit of this despicable trait. In smaller sizes you can be reasonably safe, though never truly safe. These stresses can release themselves or can be released with movement, flexing moisture content. Personally, I think it's an attitude thing. If you talk nicely and constantly stroke it's ego, it'll usually behave itself and for God's sake don't talk about it's sister.

There are many different types of cypress. The stuff we see here checks like a bank teller going through 20 dollar bills. Baldcypress (Taxodium distichum) also called, southern-cypress, red-cypress, yellow-cypress, and whitecypress. Commercially, the terms gulfcypress, tidewater red-cypress, red-cypress and yellow-cypress are frequently employed. We generally call this stuff swamp cypress.

Mexican cypress (Cupressus lustianica) is common in areas where cypress isn't naturally found. This stuff is much less likely to check, but also less rot resistant. I've also heard of a wood called Arizona cypress, but have never seen it nor do I know much about it.

The Mexican stuff may be what you're seeing Dave.

Howdy,

A huge amount of Fir was used here for framing, planking and spars and there are lots of boats and bits of boats that are 40 or 50 years or older that are fine. I've varnished many of them myself during one of my former incarnations.

We don't have any suitable local species for quality spars so used some of the Fir that used to be imported for the housing trade.

The only real problem is when sanding it can be easy to lift up the edge where the grain is running out of a corner, with injury to both myself and the boat ... but never any checking problems. With boats of this vintage we are not talking epoxy coating at all of course.

I do know that fir PLYWOOD checks appallingly. I did read once that checking was a serious factor with rotary cut veneers (David has a serious plywood background, his family, way back when used to own a timber mill and plywood manufacture business in Astoria) and that sliced veneers are much less susceptible.

That might be an explanation of my experience with fir - fine in stick but the ply checks and checks.

Know nothing about cypress.

Just tossing this in for those who can see both the woods and the trees without using google earth. Though now I do know how to recognise a Douglas Fir or WR Cedar or Spruce (you can test with your pain receptors) courtesy of Andrew Linn in Oregon.

MIK

Mik,

You've pretty much nailed it when it comes to fir plywood... though I have far more experience with the rotary cut veneers in this species. Sliced veneers are more labor intensive = expensive, and so isn't used much for marine plywood. In douglas fir, it's mostly reserved for creating Clear Vertical Grain veneers for decorative indoor (architectural) use. Therefore, it is put on panels with glues and substrates either unsuitable or questionable for marine use.

I did lay up a control panel for a fellow with CVG fir face veneer over a marine plywood substrate. AFIK, it held up fine with only varnish over it, and with no checking. As you know... if it'd been made (for some unimaginable reason) out of standard fir marine ply (rotary cut face veneers), it would have required some fiberglass/epoxy sheathing under the varnish to hope to avoid a surface that checked and kept checking until a crocodile would have envied its hide.

I suspect you (out of USA) got most of the choice old growth Douglas fir and we got what was left, unless willing to pay for it. Here in the southeast, it's an available wood, but not as much as other more species, so we may also be seeing lesser grades.

I have some experience with the old growth stuff (lovely material), but this is becoming difficult to obtain. They're actually dredging it up off of river bottoms now, this is how valuable the old growth stock is.

I think most of the old growth timber around the world comes from under water. Kauri in New Zealand, Huon Pine in OZ, now Fir in the USA.

How clever those forestry people have been, nurturing the growth of underwater timber when the finest local woods become unavailable on land in such different countries..

MIK

There's still old-growth douglas fir being harvested here in the Pacific NW. Some. It used to come primarily from Federal forest lands, and was being harvested at an unsustainable rate. The realization of that dynamic and the resulting cutback on harvesting rates is one (of several) factors that helped put our plywood mill out of business. Now the old-growth logs come primarily from the much smaller stocks on private land, with a bit from State of Oregon land. I think these sources - in the aggregate - still supply the bulk of the fine old-growth lumber. Alternative sources, though, as y'all say, are coming into increasing play. River logging (hoisting sinkers off the bottom). Deconstruction of older, obsolete buildings for the large framing timbers. Urban forestry.

So... while we continue to struggle to arrive at a harvesting policy for public lands that takes into reasonable consideration the interests of all stakeholders... we're now in Scrounge Mode - to some extent - when it comes to primo douglas fir.

One silver lining is that we're - through necessity - rediscovering some species that actually are better suited for various applications. Two of my recent projects, which in years past would very likely have been built from cvg douglas fir, have been built from Urban Forestry produced black locust. For this shower door, and this vanity top, it's actually a better choice... but not one I would have been likely to track down before.

That's the same thing that has happened with the discovery of Paulownia here. It was imported to make shutters because WRC is too expensive but it is great for lightweight boat building.

And it is grown here is some volume now.

MIK