View Full Version : Wood for Mast
01-06-2011, 02:43 PM
I am building a John Dory (gunter rig) and am about to start on the mast, boom and yard. The mast will be about 12 ft.
I would like to use 2x4 spruce construction lumber from the local lumber yard and I will be epoxying two pieces together for the blank to minimize warping, but am concern that even using the best pieces I can cull out that it will not have the integrity that is needed for a mast. Are my concerns justified?
I can get straight grain fir locally but it much more expensive. Any suggestions on alternatives?
Thanks in advance for your advice
01-06-2011, 03:00 PM
If it is straight grained with only small knots (e.g., less than the diameter of a pencil) that are perpendicular to the mast's surface (like in a whole tree), it should be fine. You can also scarf longer pieces from shorter ones to work around the larger knots.
01-06-2011, 03:04 PM
2x4 local spruce will work just fine for a tiny little mast like what you're making. Don't fret overly much about it. Plus, if you do break it, in a boat like that John Dory you can easily row home, so no worries.
01-06-2011, 05:13 PM
If you can't get spruce that's adequately clear, there's always douglas fir.
01-06-2011, 05:28 PM
Mr. McMullen and Mr. Palmer are offering good advice. But do try to get the densest growth rings you can find. This photo clearly shows the 2 lamination joints in my 21' mast for Lady Grace. Notice the growth rings, at 20+ per inch, this is good stuff with the same small knots mentioned above.
Stock of this quality is generally easier to find in the longer lengths. My mast was made from 24' long 2 by 6's found at the local lumber yard. (The big box stores are not the place to do this.) This mast cost less than $70.
Go there early on a Saturday morning, you will find you have the yard pretty much all to yourself, and can take as much time as you need to rummage through the stacks. Don't forget the courtesy factor, if you assure the staff that you will neatly re-stack the unit, you should have no problems.
Good luck, and keep us posted.
01-06-2011, 08:15 PM
I made both of my 18'8" (I think) masts for my Bay River Skiff 17 by scarfing lumberyard spruce 2x4x16s to length and then laminating 2 pieces as you're considering. I had some small knots I think. I have only used them for one season but had no problems. I will say that one thing I learned is that even small knots in this stuff creates large areas of difficult grain. Maybe that's the case for all wood. It let me to believe that using better material saves time. I got 2 masts for about $35.
01-06-2011, 08:44 PM
Another source for clear, straight-grain fir might be to look for old tongue-and-groove floorboards. They are usually free of knots and you could laminate them easily. The tongue-and-groove joints would add strength, I reckon.
Lumberyards often have a rummage bin where unsold bits end up. Poking around, I got several 14 ft. x 3/4" floorboards which, steam-bent, made perfect cockpit coamings. I recall there being a few other pieces of 12-14 ft. fir.
I need to build a new mast and two spars, so I'm going back for another poke in that dusty, far-corner bin. I also cut some standing dead lodgepole pine last year and laid it down. Guess I'll see what looks best.
01-06-2011, 09:53 PM
For a spar that small you might well consider the big box 2x? white lumber.....
Pick through it and you can find some beautiful straight tightly close grained lumber from some high elevation slow growth forest right next to a piece that came from a tree that narrowly escaped being pulp wood.
Some may think that if you pay ten time more for the wood the spar will be ten times better but my SWAG is that it will be less than twice as good and the big box white wood spar will still be much better than it needs to be to function well for years to come. Not unusual to see workboat spars with the odd split, shake or knot and they usually made it home.
01-07-2011, 06:42 AM
I've had better luck ripping small stock out of wider stuff. A 2x10 or 12 will have more vertical grain than the 2 2x4's will. However, I've had mixed results with 2 laminations; putting one opposite the other. This is a nice theory, but it doesn't always work.
01-07-2011, 07:07 AM
Agree with all the above. I make a habit of cruising the racks whenever I'm in the store just in case. Last weekend the 2x4x8 rack at L....'s yielded these:
It's a little hard to see the grain but it's pretty straight with no runout especially along the edge. What looks like runout on the face of a couple of them is actually some nice figuring in the facegrain. They're flat and straight. What knots there are are small and confined to one side of the pieces so they'll be easily avoided. It looked like there were a lot more like these in that bundle but I was a little short on time and there was someone else waiting to get at the pile.
My son wants to make new spars for his Nutshell. These should do nicely, esp for the boom and yard. Preferring not to scarf if I don't have to on small spars I'm staying on the lookout for longer stuff for the mast.
01-07-2011, 08:05 AM
I think I would do it out of 1x material- nothing wrong with lumber yard spf if you take your time picking through it.
01-07-2011, 08:13 AM
Should work just fine, and as mentioned above, cheap and easy to replace if it doesn't. My unstayed 16' mast is glued up from two nice lumberyard DF 16' 2x4s and has held up to some serious wind.
01-07-2011, 09:20 AM
Have you thought about doing the birdsmouth method? It's really not that much more work than shaping a solid spar, and you have more options for working around knots in the wood... might be cheaper too... plus make it about 6 inches longer than it has to be, cut off that end before shaping but after gluing, and keep it on your desk, everyone will think you have crazy skills as a carpenter when it was actually a very easy job :-)
01-07-2011, 09:58 AM
I can get straight grain fir locally but it much more expensive.For a 12' spar, how much more could it be? It's just a few bucks, right? That's like skipping a six-pack ... better yet, take the wife to McD's instead of KFC this week;)
01-07-2011, 10:13 AM
You can just glue the two-bys face to face or you can rip them in two and juggle the 4 billets end for end to make certain that every knot is buttressed by a clear section of the neighboring billet. I took it one step farther and trimmed the inner corner off each billet to create a hollow mast.
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