Stringer material

[Pushboater]

I'm new to the Forum and just starting to gather up the materials needed to start my Weekender. This is my first post. Question: Has anyone used or heard of anyone using the new composite decking material, (1"X 6"X 16') to rip and use for stringers on the Weekender? This stuff looks like weathered decking and is supposed to drill, sand, saw and cut just like a regular 1"X 6" using the same tools you'd use for wood. It's made of Wood mixed with a plastic resin and formed into decking. It's guaranteed not to chip, peel, crack, or split for 20 years! Sounds like the perfect stringer material to me! Any comments would be greatly appreciated. Thanks

[Barry Pyeatt]

Welcome to the group.

An exciting time for you, we've all been there and asking questions about appropriate materials. Lots of good materials to use out there for stringer stock. Some criteria that you may want to consider:

Ability to hold a fastener.

Ability to hold a glue joint, either epoxy or urea resin.

Strength and resistance to splitting.

Not break down under exposure to moisture.

Formability, sanding, shaping, routing, cutting.

Accept a finish.

Bend to shape.

The new resin decking is an attractive consideration when you first look at it for the reasons you've stated.

Good uses for it on a boat:

Rub rails, deck material, cleats (possibly), trim.

It looses its grain appearance once cut. It doesn't sand particularly well, but it will accept a routed edge. It can be cut with ordinary woodwoorking tools. It can be painted with latex paint or latex stain, but the bond in marine use is questionable. On the factory surface (rough) it holds pretty well, on a cut edge (smooth) it peels off with exposure to the elements.

It can accept a screw or nails (with pre drilling).

It doesn't glue up well with epoxy or normal adhesives. Some construction adhesives will work, notably concrete adhesive.

In smaller dimensions it doesn't hold a fastener particularly well under stress.

These are the things that I have discovered since looking into it.

It has been used on decking successfully. It makes good rub rails. If you like the look, it works for trim material.

It doesn't make good structural material.

It doesn't glue well or finish well.

It makes good sacrificial strips for the keel edge, it will take abuse without splitting, cracking or deterioration. It does chip on impact with sharp objects. It doesn't accept fillers well to repair holes or damage. It works well when it can be fastened with a thru connection into other material.

It is quite strong in small pieces such as a cleat.

It does have some deterioration under UV exposure.

It works well on work boats that have a lot of abuse and not much time to to maintenance.

I've seen it in two different colors, gray and a russet brown.

Conclusion on my part thus far is that it has some good uses in decking for homes and stair treads for outdoor use. Makes good fencing for decorative use. Use on a boat? I think I would use if primarily for rub rails or a keel strip perhaps on a plywood keel for protection. Thru bolted it will hold up quite well. I wouldn't use if for structural parts.

Now then having said all that, there is a nice river dory (drift boat) that used it for stringers, ribs, rails, keel strip, deck, seats and transom doubler as well as most all of the trim that is exposed. It is put together with construction adhesive, thru bolts and screws. It is not finished, but left as is. The plywood was glassed both sides before assembly and latex painted.

It has been on the river one season and looks good. School is still out on how well it will hold up over time. Impact scars can be seen on the rails, keel strip and the seating. He tried to repair the largest of them with epoxy but it wouldn't bond. He had one seat slat break on him and he just cut a new one and replaced it by bolting it on.

Cost wise, I really don't know if you would be saving anything or gaining anything by using it other than maintenance over the years.

See if anyone else has any experience with it.

[tomstock]

I'm new to the Forum and just starting to gather up the materials needed to start my Weekender. This is my first post. Question: Has anyone used or heard of anyone using the new composite decking material' date=' (1"X 6"X 16') to rip and use for stringers on the Weekender? This stuff looks like weathered decking and is supposed to drill, sand, saw and cut just like a regular 1"X 6" using the same tools you'd use for wood. It's made of Wood mixed with a plastic resin and formed into decking. It's guaranteed not to chip, peel, crack, or split for 20 years! Sounds like the perfect stringer material to me! Any comments would be greatly appreciated. Thanks [/quote']

I think the only concern I would have for this stuff is will weldwood glue wick into it and bond. I dont think glue is used for outdoor decks, so this isnt a consideration for deck builders... but it is for us. I've never seen the stuff so I can't answer your question.

Tom

[Frank Hagan]

I built a 10 x 16' deck out of the composite material. Actually, I used it as decking, and "had to" use regular wood for all the structural support. It doesn't work well as a structural material.

Barry really captured all the attributes of it in his post, but for the Weekender, I don't think it is appropriate as stringer material. The stringers are there to receive screws and glue holding the plywood box together (the Weekender really relies on the "torsion box" construction of stressed plywood glued together into a monocoque assembly like a modern car.) The stringers have to be able to both receive fasteners ... not a problem with the composite materials ... and to glue the plywood to them. That's where you absolutely will have a major problem. The composite material just won't glue very well, even with epoxy.

You might be able to use it as decking material over the plywood, but then its just an extra layer. Because of the "torsion box" construction of the Weekender, you can't easily replace an entire panel of stressed plywood with something else, even if you install deck beams, etc.

I used the 5/4" material, and its pretty heavy. That might be advantageous for putting on the cockpit and cabin floor ... it provides some nice non-skid and would add about 75 pounds of ballast (that's a guess!)

The one thing I see happen with the stringer that I think is unneccessary is people paying a lot of money for clear, vertical grain wood to rip into stringers. I was able to get long enough stringer material out of construction grade lumber. Find a 2 x 6 or 2 x 8 with grain fairly close together, and at least half of it without knots and rip your stringer material from that (if you have a saw to do it). Barring that, the 1x poplar, douglas fir, southern yellow pine or even hemlock (not hem-fir) can work well.