KDAT wood for sole stringers

deckhand · Post by **deckhand** » Wed Jul 02, 2008 1:10 am

With the replacement of my my sole (heh...) coming up, I've been sourcing materials to make my stringers out of.

Any thoughts on KDAT (kiln dried after treatment) pressure treated wood? I planned on encapsulating the beams in epoxy but the idea that they are rot proof is an interesting one.

Eats all fasteners but stainless though... (but not really a problem since it would be all stainless on the boat anyway...)

Hirilondë · Post by **Hirilondë** » Wed Jul 02, 2008 6:03 am

I'm not up on the newer pressure treating chemicals. They are supposed to be much safer than CCA was. With CCA treated lumber letting it air dry for 6 months was key to eliminating seeping out of the dip or emitting fumes from it. I don't know if this applies to the KDAT material. But if any needed precautions are taken it is a very good choice in my opinion. Many production boats, even high end ones use painted framing lumber.

heartofgold · Post by **heartofgold** » Wed Jul 02, 2008 8:57 am

I avoid treated lumber like splinters under my fingernails. I am an advocate of naturally rot-resistant woods, namely mahogany, teak, white oak, and my favorite in many applications, cypress. I like cypress because of it's light weight, high strength, and relatively low cost. Availability is important, and I am fortunate to have a (small) local mill that cuts nothing but cypress.

deckhand · Post by **deckhand** » Wed Jul 02, 2008 1:18 pm

heartofgold: I agree that naturally rot resistant woods are best but they come with a pricetag that makes me sad to encase them in epoxy and put them under the floor boards... I guess if its available and affordable, sure, but otherwise I try to find alternatives.

I also like to find responsibly harvested woods and many of the hardwoods are not, especially mahogany and teak (besides, I've been seeing teak prices hovering at $26/bdft @ 6/4x6"! )

heartofgold · Post by **heartofgold** » Wed Jul 02, 2008 2:28 pm

Dave,
I am not knocking you for using treated wood, and I certainly understand the necessity of taking cost into account. I pay about 3.00 bf for cypress at the local mill. I can get most any thickness, including rough milled 2x4s (I pay a little more than that at the local lumber supplier, but the quality is inferior and generally only available in 4/4). If you can find a good source, any wood can be an option.

And for the use you are suggesting, you're right that encasing in resin/glass is always a smart idea (regardless of the type of wood).
I did take a look at a map showing range of natural growth, and it appears that it does reach to the DelMarVa and into southern Delaware, so there may be a source near you (if you are interested).

deckhand · Post by **deckhand** » Wed Jul 02, 2008 4:05 pm

Hmmm, cypress, hadn't actually considered it. $3 a bf is very reasonable so I think I'll be taking a look. How does if finish bright (color, grain, consistancy) as I've never worked with it. Thanks for the heads up.

heartofgold · Post by **heartofgold** » Wed Jul 02, 2008 5:23 pm

It is kind of plain to work with (no pun intended), not unlike pine. It is very soft and does not stain evenly (sanding sealer helps). Very light color. Compared to hardwoods, it does not sand smooth completely smooth because of the grain. I like it for many out of the way projects.

Last year I finished some drawers for the boat. I did the front and back in cherry and the sides in cypress (all dovetailed, of course). For the purpose the cypress was a nice contrast to the cherry.

Triton 185 · Post by **Triton 185** » Thu Jul 03, 2008 1:31 am

Any thoughts on KDAT (kiln dried after treatment) pressure treated wood?

Hi Dave....pressure treated wood is designed for exterior use. Have a look at the material safety data sheets (MSDS) and it might make you think twice about interior applications. I would go with some other material.

Good luck with your project. It would be great to see some pictures of what you end up doing.

Shoalcove · Post by **Shoalcove** » Thu Jul 03, 2008 8:31 pm

A lot of strip planked wood-epoxy boats are built out of softwoods that are not necessarily decay resistant. The epoxy coating is intended to provide the protection from rot. Spruce, fir and pine all seem like a reasonable choice IF you do a thorough job coating them. They are pretty strong and light. It would seem that white oak or locust may also be available in your area and would be much cheaper than exotics. Locust is tougher than boiled owl.
Best regards,
David

Rachel · Post by **Rachel** » Thu Jul 03, 2008 9:27 pm

Shoalcove wrote: Locust is tougher than boiled owl.

You use some interesting materials up there in New Brunswick...

Summersdawn · Post by **Summersdawn** » Fri Jul 04, 2008 11:39 am

I read an article in Wooden Boat Journal where the other stated he would not put anything inside his boat that he wouldn't put into his living room at home. I always figured that that was a good rule of thumb for determining which chemicals etc. should be used inside of a boat.

Shoalcove · Post by **Shoalcove** » Fri Jul 04, 2008 4:48 pm

Rachel wrote:
Shoalcove wrote: Locust is tougher than boiled owl.
You use some interesting materials up there in New Brunswick...

Hi Rachel, it's only a matter of time before it replaces carbon/boron/unobtainium fibers in the America's Cup boats. Renewable AND environmentally friendly (Unless, of course, you are the owl...)
Best regards,
David

Summersdawn · Post by **Summersdawn** » Fri Jul 04, 2008 4:53 pm

Shoalcove wrote:
Rachel wrote:
Shoalcove wrote: Locust is tougher than boiled owl.
You use some interesting materials up there in New Brunswick...
Hi Rachel, it's only a matter of time before it replaces carbon/boron/unobtainium fibers in the America's Cup boats. Renewable AND environmentally friendly (Unless, of course, you are the owl...)
Best regards,
David

You must not have spotted owls on the East Coast then...

Shoalcove · Post by **Shoalcove** » Fri Jul 04, 2008 9:04 pm

Not anymore...

deckhand · Post by **deckhand** » Sun Jul 06, 2008 10:42 pm

ah boiled owl, I mean locust! I had looked into that a while back for toe rails and was saddened that I couldn't get long lengths. Might do the trick for the sole stringers.

After reading a bunch of Binghame and Mate this weekend I realize just how much good wood they put into unseen spaces. The abundant use of teak for things like stop blocks or glued up strips made me think about the "new" teak coming out of Brazil (cumaru and ipe).

Though I would like to stay north american for my woods and I'm leaning toward encapsulated dougfir or cypress (if I can get it) for the stringers, I can't help but stare at the hardness ratings in the 3000s and imperviousness to rot thing. The only drawback I've seen is that it glues horribly (unless you use a blow torch and acetone) and its a tropical with questionable origins.

The guy who owns the woodlot that my boat is on does a lot of decks and said that ipe is the most pain in the ass decking material there is but it does its job fantastically. Now if only it didn't have a bending rating in the 22000s I might consider it for toe rails .

Anyone work with ipe or cumaru in a non-decking atmosphere?

Quetzalsailor · Post by **Quetzalsailor** » Mon Jul 07, 2008 10:41 am

We're still talking stringers? Concealed? Putting screws into them to anchor sole components?

Taking a cue from the local watermen, I replaced the engine beds in the Morgan 27 with pressure treated yellow pine. I had old, dry stock. I encapsulated it with epoxy/'glass and arranged to continue the encapsulation around the engine mount bolts. Worked fine for the 5 years I continued to own the boat after that work. I had wondered at the time whether the chemistry would be incompatible. That would have been the no-longer-available arsenic treatment.

If you're replacing stuff that has lasted for decades then replacement in kind is certainly a reasonable alternative. The catch is the 'in kind'. Materials that used to be available or cost effective are not necessarily so today. I've taken to encapsulating lesser materials with the idea of getting decent service out of them. It's worth remembering that encapsulating a piece and then drilling it full of fastener holes is can be problematic based upon whether those fastener's locations get wet.

I also think about the next time a repair/replacement has to be made, and consider whether simple removal of an encapsulated component is preferable to wholesale demolition of a tabbed-in assembly. Generally, I tab where once tabbed, bond where once bonded, on the theory that, if I got it apart once I can get it apart again. I do not 'improve' the assembly by bonding everything in sight. Particularly important in wood piece-made structures and repair to historic objects, the repair should be reversible. An example is repair to morticed and tenoned joints in antique wood shutters; I knocked the wedges and pins out, repaired the components with epoxy, and re-wedged and pinned. I sinned (in my callow youth) when I repaired wood sash by pouring epoxy into the joints; those sash will be trash at the next repair.

The suggestion of cypress is interesting. The stuff was once used for water tanks (those sprinkler water tanks on building roofs and rooftop towers were cypress) and other industrial/chemical uses. That grade is pretty much gone. Centuries old Italian harpsichords were often cypress; when I built mine back in the early '70s I had to order up some pretty rare (Virginia Red) stock. Locally, cypress is still used for the tables in mushroom houses. It's a pretty cheap grade and a lesser species. I used it for basement window frames and they're still in service 36 years later (I haven't owned that house since the early '90s). Both species were quite soft and stringy so making the beaded mouldings on the window frames and the very fine profiles on the harpsichord were a pain.

Sultana was built in Chestertown of Locust and Osage Orange. Similarly tough and rot resistant, I understand that the local enthusiasts milled it from their own or friends' farms' trees.

The recently renovated Corinthian Yacht Club in Essington now has Ipe decks and stair treads. Miserably hard to work, fastenings were drilled for, extraordinarily heavy and stiff, long lasting.

Hirilondë · Post by **Hirilondë** » Tue Jul 08, 2008 6:16 am

Quetzalsailor wrote:An example is repair to morticed and tenoned joints in antique wood shutters; I knocked the wedges and pins out, repaired the components with epoxy, and re-wedged and pinned. I sinned (in my callow youth) when I repaired wood sash by pouring epoxy into the joints; those sash will be trash at the next repair.

Not only is this very true, but mortise and tenon joints allow for expansion and contraction and glued solid joints don't. Shutters and even more so panel doors are examples of how woodworkers long ago figured out that single pinned tenons and floating panels or slats survive the natural tendencies of wood far better than trying to control what you can't. Each type of wood will do what nature has determined it will do, the sooner the craftsperson learns to cooperate, the better. In the same vane: choosing a wood species that has characteristics favorable to the job is important as well.