Winter weather keeps us inside. Oh, today's bright, sunny skies look great - but looks can be deceiving. The temperature is 5° F which makes it much too cold to do anything productive outside.
Not much "visible" progress this week. I sanded, planed and sanded the birdsmouth test piece and it looks pretty darn (that's d-a-r-n) good.
I haven't gotten back over to my BIL's shop to turn the other piece on the lathe but someday soon…
Ever notice how when looking for a tool or supplies or just about anything, really, information about that tool, supplies or whatever sort of magically appears? Some call it coincidence but it happens much too often to be coincidence. A case in point, last week I brought my epoxy set-up home from my sister's place. The condiment squeeze bottles I use for dispensing resin and hardener needed replacing. Condiment bottles are hard to come by in Michigan in late February… Amazon has bottles (they have everything except decent employment practices) and I made a note to order some. Then - and I do mean right then - I read Bob Easton's blog post about repurposing ketchup and honey bottles to dispense glue. The result? I repurposed a ketchup bottle and a mustard bottle (red duct tape = hardener):
The varnishing of the spars continues, although this may be an exercise in futility (more on this in a bit).
The mizzen boom has been fitted with hardware. Painting of the ends began with the first coat of primer.
We drew scale drawings to compare the GIS sail to the balance lug John Welsford drew up. I am pleased that the two sails are very similar in area and, more importantly, location of the CE. I plan to use Karen Ann's balance lug sail on Gardens - at least for awhile.
I have become so enamored with the prospects of birdsmouth spars that I plan to build a set to replace the original yard and boom built for Karen Ann (the reason why continued varnishing of the boom may be an exercise in futility; and yes, I will have a surplus of spars…). I mentioned this possibility in an earlier post but now I have definitely decided on the new spars. Mik Storer suggested increasing the diameter of the yard (from the plan specs) and gave me an idea for an oval x-section boom.
Those new spars will have to wait until warmer weather. I need to dig out the Volvo wagon to get the 12' lumber home from the lumber yard.
Like I said, not a lot of "visible" progress but it feels like things - odds & ends, bits & pieces -are getting done.
Yesterday I glued up two short spar blanks using epoxy. Here's one of them.
Today I cut the ends of one blank flush and trimmed the corners to get a nice octagonal shape. I used a drum sander to trim the corners - not the quickest way to do it but with my planes in the other shop and cabin fever setting in, I used what I had available. I'll take the second blank to my brother-in-law's shop for turning on a lathe.
I used pieces of a round dowel for plugs, which worked for this experiment but I think I'd want to cut octagonal plugs for the real spars.
Some thoughts and observations from this experiment:
Use a squeeze bag or caulking gun tubed epoxy to facilitate spreading the thickened epoxy.
Use enough epoxy for some (but not a lot) squeeze-out to ensure good glue joins.
Use enough epoxy around the plugs to ensure filling of the spaces between the plugs and the wall of the spars.
Assemble the spar in two halves - glue up two sets of four staves and clamp together but do not glue the two halves together. This makes coating the inside surfaces of the spar with epoxy simpler and less messy (if that is possible with epoxy). It also reduces, by two, the sets of mating surfaces to be coated with neat and thickened epoxy.
Use wax paper or parchment paper underneath the hose clamps.
Have enough hose clamps on hand.
Try not to coat the handle of the screwdriver with epoxy (transferred from squeeze-out to glove to screwdriver)…
Using the Birdsmouth Calculators it occurred to me that by tapering the staves as shown in the illustration, the inside of the spar is tapered as well as the the outside. This creates - in my mind - an obstacle: how does one accurately cut tapered octagonal plugs? Or is this not really an obstacle/issue?
One other factor to take into account is John Welsford's note on the sail-plan drawing: "taper outside not the inside space." I am not visualizing a straight-forward way to taper and notch the staves prior to assembly. Any suggestions on how to do this?
Good question… and another post prompted by a comment. Thanks, Ed.
The Pathfinder plans specify extruded aluminum for spars so there is no taper. But John Welsford states in the plans that wooden spars will work/are acceptable if the wooden spars are 5% larger in diameter than the aluminum spars specified in the plans.
When John drew up a balance lug yawl sail plan for me, he specified a 19'10" wooden main mast with a diameter of 80mm. The mast tapers from 80mm at 5'10" from the foot of the mast to 58mm at the top. He recommended using staves of at least 16mm if using the birdsmouth construction method.
This link provides a lot of information and calculators re birdsmouth construction. About half way down the page is a paragraph and illustration dealing with tapering.
If I am reading that information/illustration correctly, the taper can be cut after the V-notch and before assembly. My thought is to set up a jig and use a flush cut trim bit in the router to cut the taper. I suspect I will experiment with a test sample before dealing with 20+ feet of CVG Douglas fir…
The mizzen mast for the balance lug yawl plan is "as per (original) yawl rig" - in other words, extruded aluminum. I plan to build a wooden mizzen mast using the birdsmouth method but I haven't figured out the taper and I haven't asked John for his recommendation either (I may do that soon).
The main boom and yard offer opportunities to test the milling and assembly sequences for longer spars. I already have a main boom built so I may just experiment - including tapers and, possibly an oval cross-section - with the yard.
Joel's comment asking about how the router worked cutting the V-notch prompted this post.
I am not yet comfortable enough with a table saw to try cutting something like a V-notch in pieces as small as the staves are for the mizzen mast. Yes, I had help - more like I watched - ripping the staves.
Two years ago, in a fit of enthusiasm, I bought a MLCS multi-sided glue joint bit based on encouraging words from another boat-builder. But, once I realized how small the staves are for the size spars we use, my enthusiasm waned and I didn't do anything with the bit. So now, while building Gardens, I decided to experiment with the birds-mouth method.
Having milled the test sample staves to size (16mm x 22mm) and length (914mm), I installed the bit in a Hitachi variable-speed router mounted in a Craftsman bench-top router table with finger boards. Getting the bit height and fence adjusted took a few tries but once it was set up, the routing went very quickly and smoothly. Set on low-speed, this set-up cut each V-notch in a single pass and cut without tear-out. I imagine notching the longer staves will require more help and at least some in-feed and out-feed support. I suspect that notching hardwood might require multiple passes through the router but using fir, spruce or other softwood the single pass eliminates some handling.
Of course, having convinced myself I can make birds-mouth spars, I can see making all of the spars for Gardens using this method. And who knows, maybe, perhaps, going back to make a set of round spars for Karen Ann.
I was finally able to get to the shop to test the birdsmouth technique for building spars. Actually, it wasn't a test of the method so much as a test of my abilities. My first reaction to a new-to-me tool or technique is usually, "Oh, man, there is no way I could do that…" and I dismiss the new-to-me tool/technique without ever trying it as beyond my abilities. Then, with the passage of time (sometimes weeks, sometimes months or, in this case, years), I eventually try the tool/technique to discover that I can, in fact, use it! Such is the case with the birdsmouth technique.
I am happy to say the milling of the staves went without difficulty using a drum sander (to thickness the stock), table saw (to rip the staves to the proper width) and router table (to mill the birdsmouth V-notch).
Gluing the test sample also went without a hitch. The test 'spars' are the same diameter of the mizzen mast and I found the staves to be easy to run on the router table - one of my earlier concerns. Hose clamps worked well for these short sections and, I am sure, would work on the masts - assuming I have enough on hand.
Gluing up two 18" test samples with TiteBond II is probably not an adequate dress rehearsal for gluing up two masts (14' mizzen and 20' main) with epoxy. I think more helpers and a warmer day will make gluing up the masts a relatively painless experience. A gluing party may be in order this spring. Beer may be offered as an enticement…
Two lessons learned in this experiment: One, the birdsmouth technique is not beyond my abilities. And, more importantly, Two, most boatbuilding techniques involve a series of simple steps, which means I can learn most -if not all- of them. I just have to remember that second lesson.
Tom Pamperin is a boatbuilder and sailor. I first "met" Tom by way of the WoodenBoat Forum, where he is a regular contributor. Tom and I attended Sail Oklahoma in October 2011 and I had the privilege of sitting at the table while Tom interviewed John Welsford. Tom and I attended Howard Rice's Small Craft Academy in Mackinaw City, MI in June 2012, where, in addition to the classroom work, lessons and exercises, we shared an enjoyable late afternoon sail from the beach back to the launch ramp.
Tom also teaches English at the high school and college levels (not necessarily at the same time…) and writes - often of small boat adventures. A number of his stories have been published in magazines and on-line. Tom is talented, generous, well-spoken and an all-around good guy.
Tom is now writing - perhaps it is already finished - Jagular Goes Everywhere, (mis)Adventures in a $300 Sailboat. Having researched the publishing options available, he has decided to self-publish his book which is, to me, another great adventure for him. Here is a link to his KickStarter fundraising effort.
KickStarter Campaign For Jagular
Take a look and, if you are so inclined, help him get the book published by making a contribution. The KickStarter fundraiser will close on March 12, 2014.