Laminating seat frames

[wingnut]

After making up a sliding seat for my solo I decided to take it out because the boat turned out to be too heavy at 49 Lbs. The seat is an Eds canoe contoured seat which weighed close to 2 Lbs by itself with the sliding mount adding another 4 Lbs. I was hoping to end up with the solo weighing 45 Lbs. Not a lightweight by any means but when It weighed in at 49 Lbs I nicknamed it, my little tank. So to get the weight back in line with my target I'm going to try a laminated seat frame with the same type of fiberglassed ledge that Wtsedave used on his Northwest solo build.
Conk has been laminating seats for a long time. I see they're used on Hemlock boats with the frames made of ash and basswood. I did some research on different woods weights and strengths to come up with something I could laminate. I found it Interesting to see that the weights of the different woods pretty much paralleled the strengths, The heavier the stronger. Here's a list of woods I looked at.
Birch- 44 Lbs per cu ft, with 8,170 lbs of bending strength
Ash - 42, 15,000
Cherry - 35, 12,300
D fir - 32, 12,400
Poplar - 28, 10,100
Basswood - 28, 8,700
WRC - 23, 7,500
I'm thinking of cutting the frame size down to 1 1/8" to trim some weight and probably use D fir and Poplar for the wood. I'm not sure how well the Poplar would hold up in marine use though.

 

[Iskweo]

We used some poplar recently and discovered that it makes really good firewood. Not so much for canoes. Your mileage may vary.
It doesnt sand well.

 

[Mihun09]

Ed has some beautiful seats and I bet, even with the exchange rate, I would be hard pressed to be able to build seats for less than buying them, but, I do enjoy the work and my labour at $5 an hour is cheap still, so I'll just keep making my own for now.

Plus, in making my own I learned how to do both pressed and regular cane when doing replicates for some of the w/c canoes I've restored over the years.

 

[Glenn MacGrady]

Conk also laminates thwarts and gunwales, as have others before him. Swift laminates wooden seat frames, although they are now moving to all carbon seat frames. Additional weight be saved by using light wood for seat drops, which aren't particularly structural, and by eliminating decks, which are functionally useless. (Unless there's something special about wood strip canoes that requires a deck. I'm not a boat builder.) Mike Galt used no decks on his Lotus canoes. I think Paul Meyer has moved to small carbon end caps at Colden.

 

[Glenn MacGrady]

Hemlock advertises the Conk contour laminated seat at 25 oz., so that's not very much less than two pounds. Hemlock also uses butternut for drops on its Lite construction, but I'm not sure that's included in the 25 oz. or not.

 

[yellowcanoe]

No Title

I think Paul Meyer has moved to small carbon end caps at Colden.

No, small rosewood end caps. I don't think they weigh more than 3 oz.
Just decorative to hide that usually ugly juncture of inwales. If you look closely forward of the dog..

 

[Glenn MacGrady]

No, small rosewood end caps. I don't think they weigh more than 3 oz.
Just decorative to hide that usually ugly juncture of inwales. If you look closely forward of the dog..[/SIZE]


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YC, I know Paul Meyer has carbon end caps because he sent me pictures and a video of them on an infused gunwale Wildfire. Maybe he has different options now and lets customers decide. Marc Ornstein has also used carbon end caps.

 

[Cruiser]

Maybe also look at the yoke and thwart(s) as well, they tend to get over built and add a few pounds. I will be paying attention to all the trim next build, I estimate I can likely reduce my trim weight by at least 5 pounds.

Brian

 

[wingnut]

Going to try to put the next boat on a diet for sure. I used ash gunnels roughly 3/4"x 3/4" inside and out on my little tank and was shocked when I weighed the shaped pieces before being trimmed and installed at almost ten pounds. That's four pieces 18' long.
My experience with poplar as firewood is not Impressive. I'll just say I don't want it in my wood pile. I think it does hold some promise at a lighter alternative to ash though. Looking at the list I made It's strength stands out as being strong for It's weight. I use stems when I build and am considering using poplar as the inner stem and as the first two pieces of the lamination of the outer with ash or cherry for the outer strip. Used in the stem it will be encased in epoxy so water and weather won't have an effect on it. Used in a gunnel I'm not sure if it would turn dark when moisture soaked in past the Watco.

 

[stripperguy]

I've really become a fan of pedestal mounted seats. If designed just so, you can still tuck your legs under. My glass over foam pedestals weighed less than a pound, and they allow 10 or 12 inches of seat adjustment. Especially, I like the freedom of motion inside the boat with the seat mounted to the bottom. No need to scooch over seat rails while hanging on to the gunnels to move fore and aft. Even when I wrestled, I was never the most flexible guy...today, much less so.

Unless you are absolutely married to the idea of wood trim, it's hard to beat carbon (or glass) over foam. The gunnels for my carbon copy added 3.5 lbs to my build. If I had paid more attention, I would have used bias woven glass rather than the thick, resin hungry carbon.

As far as decks, yes, they hide a multitude of sins, but they do serve another purpose. When you're clambering over 20 or 30 beaver dams in a day, it sure is nice to have that deck to step on when breaching those dams.
And look how the pedestal seat works together with a deck:

Beaver dam ahead.
Move aft to send the bow to the sky (figuratively)
Land the bow on the beaver dam
Step from the deck to the beaver dam
Throw the boat to the other side of the dam
Step on the deck again to reenter
Saunter back up and around the seat.

Anyway, that's how it is for me...my paddling has influenced, no, controlled, the way I build.

 

[Jim Dodd]

Nothing is perfect !
Try cutting your Ash outwhales down to 3/4"x 3/8" thick.
Use scoopers (gaps) on the inwhales . I like a 3/8 " thick inwhale with 3/8" spacers, that equals 3/4" x 3/4". That, right there should cut your gunnels by at least 35%, and still have plenty of wood to hang your seats. For maximum strength, glue them on ! Gunnels provide a lot of strength, and rigidity to a hull, especially when you hang your seats from them ! Good reason to go with a pedestal seat !

This weight issue, in my humble opinion, can lead to durability issues down the line ! The last place you want to be is out in the middle of a Big lake, and all of a sudden, the hull, on that 12#, 17 ft stripper, splits open !
Those two layers of 2 oz E-glass, and 1/16" thick Balsa strips, are just not going to do it ! If you make it to shore, that's when your real ingenuity will be put to the test.

I sure want the lightest, most durable canoe I can afford. So I build accordingly !

Jim

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[frozentripper]

My experience with poplar as firewood is not Impressive. I'll just say I don't want it in my wood pile. I think it does hold some promise at a lighter alternative to ash though.

The problem with poplar as firewood is it doesn't leave a long-lasting bed of coals that will glow for hours after the wood burns down, like sugar maple does. But for mild temps like now, poplar is great, doesn't burn too hot, lasts a reasonable amount of time if the pieces are large enough and if it goes out, it's easy to get going again with some newspaper and a match.


For woodworking, I'll repeat what Iskweo said, it doesn't sand well and light spruce, cedar or pine is what I'd rather be using. OTOH, paddles are being made from poplar so maybe there is something good about the strength vs weight characteristics. It seems like a brittle wood, seeming to snap easily when bent but since I haven't used it much I can't be sure. There are four native species of poplar in this area... balsam poplar, largetooth aspen, trembling aspen and eastern cottonwood, so there may be some difference in working characteristics between those.

PS... mixing of species is common in the lumber yard, and poplar is most likely sold as poplar without any differentiation between species. Just what species you're getting when you buy poplar probably won't be known, unless you buy from a sawmill.

There's even mixing between genera... boards being sold as spruce in this area may be mostly white spruce which is often light, resilient and flexible. But sawmill operators sometimes will say "there's the odd fir mixed in" which means balsam fir, poorer quality than spruce... brittle, snaps easily and lower in strength. Might be OK for 2x4 studs but not for canoes or paddles.

 

[wingnut]

Carbon and foam look like a good light weight alternative. I have been kicking the Idea around of wrapping a uniwale with carbon fiber then epoxying it in place adding the resin to the carbon afterwords for gunnels. Another Idea for thwarts and possibly a seat frame I've had is to use foam with a piece of wood added to the ends for mounting, covered with a carbon sleeve. I really don't know how much the sleeve can be shrunk down by stretching to get a tight fit. Any experience with that? On my current boat I'm going to stick with a wood seat frame because everything else is wood. Next build I'd like to try the carbon fiber.

 

[memaquay]

Quite a few big store budget paddles are made out of Aspen. I have snapped quite a few pf them in my early days of paddling. The shafts always broke when paddling hard.

I use stems when I build and am considering using poplar as the inner stem

I use white pine or just cedar for both inner and outer stems. Both have help up extremely well over many years. Of course, I have a brass stem band on the outside too.

 

[Alan Gage]

There's a good chance we're talking about two different Poplars here.

At least in the midwest (and I think in most of the US) Poplar is a normally stocked low cost hardwood for house trim. But this isn't the Poplar that's related to Aspen. It's a southern hardwood known as Yellow Poplar or Tulip Poplar. It has a yellowish tint to the wood and sometimes green. It's cheap, easy to work with and available in long, clear lengths. I believe the heart wood of old Tulip Poplar is pretty rot resistance and has a history of being used in boat construction.

Alan

 

[Alan Gage]

covered with a carbon sleeve. I really don't know how much the sleeve can be shrunk down by stretching to get a tight fit. Any experience with that?

I've worked with carbon sleeve quite a bit. Neat stuff. No problem getting a tight fit by stretching it. That's how it's designed to work.

Alan

 

[wingnut]

I'm in the midwest and the only poplar I have seen, Kiln dried anyway, is white sometimes with a green tint. It's low cost for sure and I've never considered using it for anything but after seeing it's strength to weight ratio I'm taking a closer look. Aspen's not available to me.

 

[Alan Gage]

I'm in the midwest and the only poplar I have seen, Kiln dried anyway, is white sometimes with a green tint.

I'm pretty sure that's Tulip Poplar. http://www.wood-database.com/poplar/

A little article on the name confusion and what's what: http://www.wood-database.com/wood-articles/poplar-cottonwood-and-aspen-whats-what/

Alan

 

[Jim Dodd]

If you have a Menards near you ? They have Aspen.
Poplar is just a nice word for Cottonwood around here. I wouldn't use it ! Seems to decay in short order, not to mention warping. You often find it in wood pallets.
Jim

 

[Alan Gage]

Poplar is just a nice word for Cottonwood around here. I wouldn't use it !
Jim

The Poplar you find for sale around here at lumber yards has no relation to Cottonwood. It's not a true Poplar (like Aspen and Cottonwood) It's stable and easy to work with. It's heavier, stronger, harder, and rated as being more rot resistant than Aspen or Cottonwood. I'm not saying it's great for using on boats but it's not trash wood.

Alan