Seat backs

[kydocfrog]

Okay, Charlie Girl II and I could use a little help here.

Anybody got some advice on the seat backs; particularly that last odd, somewhat extreme curve into to the cuddy bulkhead. It seems like a perfect example of the kind of curve that plywood, even 1/4 inch which is the thinnest I can get, isn't supposed to make. My next try, and the word next is intentional, will involve some serious kerfing, but so far I'm not having much luck. A friend suggested masonite style hardboard -- much thinner and more flexible -- but I'm worried about durability since I can't find the type with both surfaces oil finished. I guess I could stop the seat back a bit short and then scupt in a massive fairing of epoxy and woodflour, but that seems a bit crude.

Pictures? Advice? Alternate approaches?

KyDocFrog

[capt jake]

Masonite is not durable at all. I use it on my workbench surfaces as a sacraficial top. I know you said that you can only find 1/4", but if you could find 1/8" and laminate the two together?? I have had success with that in the past.

Kerfing would require filling the kerf with goo after the fact. That may not be so pleasant.

Interesting delema. :?

[PAR]

Most of the box stores have 1/8" plywood in the "door and window" department of all places. They call it door skin, probably why they sell in the "door" area. It's cheap and I use it for templates all the time. It will conform to a tighter radius then 1/4" and you could laminate a couple of layers in place for the bulk you need. Typically it comes in 3 x 7 foot sheets for less then 10 bucks (I paid less then 8 last week) I wouldn't use masonite, it's not even close to water proof. It will swell up and deform at the sight of moisture.

[Dave R1]

You might try kerfing the plywood in the area of the extreme bend to make it more flexible there. I would be tempted to work with thinner (1/8") stuff and do a couple of layers.

I didn't end up with a seat back like the plans and the ones I've seen don't make that curve but just run straight to the bulkhead. You could just cut the seat back to fit below the side deck at that point where the deck turns inward. If you don't like the look of the deck over the back in that area, you could make a cove of solid wood to fill in the curve and carry it down to the seat bottom.

[Andrew]

KyDocFrog

I'm using a similar approach to the one Phil Gowan used (check out his site - it's got piccys - link is on the weekender page of messing-about)

I have run the 1/4" ply STRAIGHT to the bulkhead and then filled the curve with bondo - I think Phil filled it with epoxy and ceiling insulation (fluffy fiberglass).

I have also 'borrowed' Phils storage compartments in the seat back - Phil I promise to pay all royalties incurred

Andrew

[Mark Gudschinsky]

After I ran the seat backs into the bulkhead I fitted a vertical piece of 1/4" plywood in the corner on a forty five degree angle which greatly reduced the amount of fairing needed.

[capt jake]

Ah, we are talking about a Weekender, dummy me. I was able to make 1/4" make that curve, at least pretty close; I then filled and faired with thickened epoxy. It took attempts to get the proper shape of the seat back. I had installed cleats top and bottom to screw the back to. These were curved and I began screwing the back in the middle to draw it into the curve.

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[kydocfrog]

So many good ideas; thanks much!

[Craig]

I made the seatvbacks out of ply and the comings from kerfed fir filled with thickened epoxy. That part worked very well. The problem is the angle of the coming relative to the seat back. The plan called, at least for the Vac, for a much lessor angle. This tips the coming right into you shoulder blades when setting on the seat. After a few hours this is quite bothersome. Try to keep the angle of the coming the same as the seat back if possible. You'll be glad later.....

[Arnie Eaton]

I too am making a Vac. I ran the seat backs up and over the deck about 1.5 inches so they are the same angle. A 1/2" half round along the top outside egde finishes the coming right nice. Where the coming meets the cabin side and back, a small wedge of ply fills in nicely.