Wooden Boat People
By McKenzieDriftBoat.com
Scarfing gunwales
What's the typical angle for a scarf cut for joining wood to form gunwales on a McKenzie style drift boat? I'm looking to use Sapele or Mahogany.
Thanks,
Austin
Views: 1523
Replies to This Discussion
-
Permalink Reply by Rick Newman on
-
Austin, the common ratio is either 8 to 1 or 12 to 1. So a one inch thick piece of Sapele would have the scarf 8 to 12 inches long. I am hoping that others will chime in here on bending these woods this much. White oak is quite common for gunwales, some like the bendability of white ash and other are using Douglas Fir. Another method to bend these woods would be to do a scarf and then rip into thinner pieces, say 1/4" or so and then laminate them in place. More clamps and work but it would be very strong and reduce the possible breakage factor. I am unclear as to how well these woods would bend, hence my concern.
Rick N
-
-
Austin, I found some info on steam bending woods, they list several species. It might be interesting reading. Are you able to find air dried Mahogany or Sapele in your area. I have had a bad time bending kiln dried wood. Keep us informed.
Rick N
-
Permalink Reply by tungsten on
-
I used sepele 12;1 after they were glued I ran them threw the planer to finsh at 5/8 thick,had no trouble bending them.
- Attachments:
-
-
boat041.jpg, 103 KB
-
-
Permalink Reply by Mike Baker on
-
Another nod for 12-1. DON'T OVER CLAMP (don't ask how I know this).
Mike
-
Permalink Reply by Austin Waggoner on
-
Thanks Guys - My local woodshop does not have a scarfing tool, is the West System 875 Scarffing tool the ticket?
-
Permalink Reply by Tom Anderson on
-
Hi Austin . . .
If you have a table saw, you can make a simple taper jig to the correct angle (I did 8-1 for my white oak chine caps).
-
Permalink Reply by Richard Elder on
-
Want to REALLY make those gunwales and chine logs strong and tough? Rip your material into 1/4" thicknesses. Put a thin layer of cloth into the epoxy that glues each layer together. For gunwales use 4 oz carbon biax and for chines use kevlar. I guarantee you won't need to worry about scarfs coming apart and kiln dried wood splitting!
-
-
Richard, that would be quite a combination! Sounds very tough.
Rick N
-
-
I built a set of spreaders for a large sailboat mast this way. Tested the first one by suspending it between two blocks 4' apart and jumping on it with my 225#. Damn near broke my foot!
-
-
No, the West System scarfing tool is for plywood edges, up to 3/8 inch thick.
In addition to Rick's pictures see the post by Ben Kittell February 15, 2011: Scarfing chine logs, rails, et.
I had pictures of the scarfing jig I built for a table saw to cut a 10:1 angle on 3/4 x 1 1/2 inch stock. A plywood base slides in the miter slot on the left side of the saw blade. Plywood form at a 10:1 angle is glued and screwed to the base and used to clamp stock for ripping. The ripped stock is cleaned up with a hand plane before glueing with epoxy adhesive.
Laminating thin strips (1/4 or 3/16) into 5/8 or 3/4 inch gunwale stock is an option, but I have no experience with it. Most folks that use that method mention assembling the laminate on the boat - and glueing it to the boat. There could be glue all over the place. Perhaps that could be accomplished with System 3 gel magic (or similar) without dripping epoxy.
If laminated on a table rather around a boat I don't know if the layup could be bent around the boats sheer.
-
-
Eric, thanks for the credit on the photos, but Tom Anderson did the fine work and pictures.
Rick N
-
-
Awesome, thank you.
© 2024 Created by Randy Dersham.
Powered by
