MDO

[Ward]

I had thought about using MDO for the frames and went to pick some up today. It was finished on one side and was supposed to have some small knot holes on the other. It looked really good, until I turned the good side over to check the other side. It did have many small knot holes on the other and most were holes with out the knots. They were indeed small, about half the size of a dime.

Jeff had told me about Wurth Lumber near Chattanooga, so we took a bit of a ride and picked up some really pretty Baltic Birch in 5 x 5 sheets. If this stuff works as well as it looks, I'm really going to like it. Thanks for the tip Jeff. Not only does Wurth have some really good quality lumber but they also are a friendly bunch to work with. All in all a good trip.

[Hirilonde]

MDO comes in paper 1 side and paper 2 sides, but even the 2 sides has thick and knotty laminations with voids inside. So even if it looks good, structurally it is terrible for frames. Baltic Birch has thin clear laminations with few and very small voids. It isn't BS 1088 marine plywood, but then these kayak don't stay wet long. There is a lot more to plywood than the finished surfaces. And in spite of the fact that the greatest advances in forest products were pioneered in the USA we don't make the best plywoods here, they are imported.

[Ward]

Those of us that live away from the coast have problems getting BS1088 without having to pay an arm and a leg for shipping. I understand from one lumber yard guy that BS1088 from China is terrible. He said that there was no way that it even came close to spec. A buddy found some 6/4 cypress not far from here today so I'm going there tomorrow to pick some up. All rough cut so I'll have to build a squaring gig, but I think it will be worth it. .

[Hirilonde]

I understand from one lumber yard guy that BS1088 from China is terrible. He said that there was no way that it even came close to spec. .

I have no doubt. The BS 1088 specs have not changed, but the certification process has. Only known reputable manufacturers like Joubert can really be trusted to actually manufacture to the specifications. This has been a long and detailed discussion in the B&B section of the forum. There is a lot of deception in the lumber and forest products industry, not the least of which is misrepresenting woods by common names that are just plain wrong but will sell because the public just does not know better.

[chris.lewis.425]

I used MDO for my frames and the pieces I've purchased locally (2 sided) have shown no large knots or voids when cut. I guess it depends on the mill your supplier buys from.

Chris in Seattle

[Hirilonde]

When logs are peeled the frequency of knots is greater near the outside and diminish as the process continues. The specifications for MDO concerning knots in the interior laminations is not very strict. So yes, you will find some pieces better than others. But when considering structural applications only the worst case scenario should be considered, the minimal requirements. This is particularly apparent for visually graded lumber where you can see the variation in knots. Use what ever you want to build frames, but only by using plywood with many thin and guaranteed sound laminations like Baltic Birch or better yet BS 1088 can you be sure of the structural integrity of your frames.

[chris.lewis.425]

Interesting that our largest commercial lumberyard in the Seattle area has rejected most recent lots of "Baltic Birch" as being below their standards and therefore something they won't sell. I guess globalization has some downsides.

Anyone tried 12mm Okume?

Chris in Seattle

[Hirilonde]

Anyone tried 12mm Okume?

If you mean tried it for making kayak frames the answer is no. But I have used it a lot for building other boats and other applications on boats. The BS 1088 standard, if in fact you get plywood made to it and not Chinese knock offs falsely claiming to be, is specifically designed as a structural material for boat building. Okoume is light weight yet has great structural integrity. Then factor in that it would be very rot resistant (due to treatment) and resistant to delamination. I would think that BS 1088 Okoume would the the absolute best plywood there is for kayak frames.

[Ward]

The folks at Chesapeake Light Craft are big fans of Okoume. Went for cypress today and came home with WRC which was a much better grade of lumber, a couple of really clear pieces and a couple with minor (1 or 2) small knots. One piece is so doggone pretty that I might hang it up in the shop to just look at. It seems that finding any kind of real lumber has gotten harder and harder. I pity the furniture makers because I had to go through a whole stack to find a few good pieces since I didn't want to spend all of my time scarfing. I'm getting a real education from some of the guys at these lumber yards that sell quality material.

[Kudzu]

It seems that finding any kind of real lumber has gotten harder and harder. I pity the furniture makers because I had to go through a whole stack to find a few good pieces....

Tell me about it! Of course you are in my market so you understand. I have watching for some nice Cherry for a while now to make a Dinning room table. I want to pick it out but I am not willing to pay the price I seen. So I wait.

As for scarfing, if you think you might ever build another boat it's well work the time to build my scarfing jig. It makes it a simple and quick task.

[Ward]

A scarfing jig is definitely in my near future. I have a piece of pressed wood with a melamine type finish on one side that I have been saving for awhile and I think it will make a nice jig. A wood turner friend of mine told me about a sawmill in Franklin NC (I think) that has a mixed bag of rough sawn lumber of various types. The reason I didn't follow up is that most of the lumber is still on the green side. "She who must be obeyed wants me to build her an end table kind of thing so I was thinking about driving up that way next week to check out what this guy has so while there I'll check for cherry and let you know. Don (my friend) got some red oak, white oak and walnut from this mill. The bride's table will have to wait until Castaway gets wet though.

[Kudzu]

I appreciate that. I figure that will not be the next big project, the Chris Craft is the next big one. But we really need that table.