Sunday, February 28, 2010
Sorry for the delay in updating. It's Boat Show week here in Boston, so things get dicey, schedule-wise.
This is the point in construction where things look the same at the end of the day as they did at the beginning. It can be difficult to keep momentum and focus, but slog through it and it gets better for the next few chunks of work.
As promised, here is a summary of how I deal with broken screws.
One of the great things about Gougeon epoxy is its predictable behavior. The first step in removing screws from epoxied assemblies is to heat the heads with a soldering pen. Epoxy will begin to soften at about 175 degrees. This makes a huge difference in one's ability to remove a fastener in one piece. Occasionally, despite our best efforts, a head will snap off. All is not lost.
The most important part of the tool kit for rectifying this situation is a Rotabroach. It is a set of small hole saws with a spring-loaded center guide. It is primarily used in auto body applications for cutting out the spot welds that join body panels. Fortunately for us woodworkers, the sizes correspond exactly to Fuller bung cutters.
With a center punch, strike a good dimple in the shank of the screw to guide the Rotabroach pilot. Make sure that the drill is turning before the bit hits the surface. This minimizes tear-out. I find that the 1/2" bit is the absolute minimum size that will allow the rest of this process to work. Go deep enough to get a good grip on the shank, but DON"T GO ALL THE WAY THROUGH!!!
Next, carefully clear out the area between the edge of the hole and the screw shank. Another great use for the ice picks. The less you dig at the edge of the hole, the better the bung will fit. Hold your soldering iron against the screw shank and make yourself comfortable for a minute or two. This can take longer than you think, as evidenced by the fact that the screw broke, even after being heated before its initial attempted removal.
Hopefully, you have already set a pair of needle-nosed Vise-Grips to firmly grasp the shank of the screw. Clamp them on and twist the screw out, being careful to not mung up the edge of the hole.
It sounds pretty straight-forward, and it is. Try it out on some scrap if you are nervous about it. For the really recalcitrant screws, you may have to whack at the side of the shanks with your center punch and "wiggle" it from side to side to break the bond. Again, be careful to not do too much collateral damage to the edge of the hole.
I bought my Rotabroach from the Snap-On truck umpteen years ago. It was pricey, but it has saved me numerous times. I have recently learned that it is available through Fastenal for about $80. That's about half of what I paid way back when.
Glue in your bungs, and you are all set. BTW, I use the G-5 "5-Minute" epoxy for bungs. This is not a structural bond, and I don't get a black ring around the bung that's as noticeable as with the regular Gougeon epoxy. G-5 can be thickened with the same additives as the 105/205 epoxy.
I plan to finish the sheer planks bright. I had a 100% success rate in removing the temporary fasteners along the lap and in the stems, so I used the 3/8" Rotabroach to counterbore for the bungs here. A note to those of you considering building this boat: I used #8 x 3/4" stainless truss-head screws for the first couple of glue-ups. I found that if the fits are true enough, 1/2" screws are more than ample for the temporary clamping duties. The difference in removing the 1/2" screws vs. the 3/4" is like night and day.
As far as other work going on: I stained and sealed the sheer planks. I spent a fair bit of time digging through the stack of 10' sheets of plywood, but even the "nice" stuff has a rotary-cut look to it. Staining allows enough of the grain to show through that you can still tell it's really wood, but takes the edge off the heinous grain qualities. I actually considered vacuum-bagging a veneer over the sheer plank stock. I decided that I'd prefer a sharp stick in the eye.
Forward outer stem is laminated, tapered, and fitted. Photos coming forthwith.
This week's kicker: having been on the fence since construction started in earnest, I have now landed squarely on the "sell this boat" side. While this project started as a labor of love, and will continue to be a much-enjoyed process, at this point in my life it makes the most sense to offer her for sale. I won't be broken-hearted if she doesn't sell immediately, but I have student loans and other obligations crying for attention. Who knows? Maybe I can "shake the tree" with this boat and make something long-term happen for my boat building career. Optimally (I really hope my wife doesn't read this), somebody has a TR-6 or an Alfa Spider and some cash. Or maybe an old Land Rover. Or an old Vespa...No, I should just sell her.
There is a solid up side to this decision. I am now absolved of having to make a final decision as to whether or not to build her with Mr. Atkin's skeg. This is a decision that can be made by her new owner, whoever that may be. I don't know what to do about the fact that she has been referred to as "Dark Secret" since construction started. It's supposed to be bad ju-ju top change a boat's name, but I know it's not everybody's cup of tea. She hasn't been christened, yet.
The last image is the ad that is coming out in the mid-March issue of Points East magazine.
I have been reading through some old forums at the WoodenBoat website that cover faerings in general, and some that cover Valgerda specifically. Next posting will cover my response to the "What makes a faering?" question, as well as other eagerly-awaited (yeah, right) philosophical rants. More photos, too.
Friday, February 19, 2010
Here are a few more photos of Dark Secret. She is out of the loft and in the main work bay at the boat yard. Five of my co-workers helped me get her down. She just fit. What a sight she makes sitting on jack stands. She is approximately on her lines.
I left a little meat on the top edge of the sheerplank. I honored the lofted points at the stemheads and the three frames, but I wanted to be able to tweak the sheer line while she is right-side up.
I have built this boat so many times in my head since I first saw her write-up in Boat Design Quarterly #2 back in the early '90s. I had a very detailed mental picture of how she would look. On seeing her in the flesh, I am blown away. First off, she is a lot more boat than I thought she'd be. It was tough to get a realistic picture of her size in the cramped loft. Secondly, her purity of form and rightness of line is a sight to behold. Mr. Atkin truly created a piece of art when he drew her. There are some incredible design nuances that can only be appreciated by building her. I'm going to build a model of her at some point.
I am putting the lofting back down to laminate the outer stems, and I will be taking patterns for the rangs.
I am picking up a couple of small tools tomorrow. I'll go through the broken screw removal process over the weekend.
Wednesday, February 17, 2010
Not much to say here. I finished planking yesterday morning before work. I did some miscellaneous clean-up stuff and dismantled the set-up this afternoon. She's ready to come down from the loft.
Seeing her in the flesh, without all of the bracing and temporary molds made my heart go pitter-pat. What can I say? I get worked up over little things.
As you can see from the photos, she really is a study in simplicity.
WoodenBoat did an article on removing problem fasteners a few issues ago. I was surprised that the method I use was not covered. As those of you who have built boats with epoxy know, screws frequently break during attempted removal. Next posting will cover this in detail.
BTW - I was unable to get all four sheerplank sections out of a single 10' sheet of plywood. I missed by about 1 1/4". Sheet goods tally to plank the hull - 3 sheets @ 4'x8', 2 sheets @ 4'x10'.
She is coming off the set-up and out of the loft a bit before I am truly ready. One of my co-workers has a cold-molded Firefly that needs a new centerboard trunk. I can't hog the loft, so it's down to the main floor for Dark Secret.
In the meantime, I am enjoying a second glass of whiskey. Enjoy the photos.
Saturday, February 6, 2010
Planking continues. Broad strakes are hung. This posting will cover the scarphing process, as well as a couple of other items.
I am a firm believer in scarphing planking stock in place, particularly for lapstrake construction. Scarphing a large panel to length and cutting planks out of it results in much more waste than the method I am using. At $65 per 4x8 sheet, waste adds up. There is also the consideration of edge set. In carvel planking, you can edge set (bend a plank in place after it has been cut to shape) to your heart's content. The frames are generally in place before planking commences, so the fastenings take care of the resulting extra twist. In lapstrake planking one generally fits the frame after planking. This results in the laps getting tweaked out of shape by edge setting them.
Speaking of sheet goods, I have used 2 1/2 sheets of 4x8 to date. I have a sheet of 4x10 for the sheerstrakes. I REALLY hope I can get both sides out of the one sheet, but I anticipate having to buy a partial sheet to wrap it up. I have a significant pile of off-cut 8 foot lengths. There might be enough in the stack to plank the Nutshell Pram I want to build as a tender for Strider.
I talked in the first posting about the "meditative" nature of hand cutting the scarphs with a block plane. What a load of hooey. I confess openly and fully to cheating. I used my 4 1/2" angle grinder to cut the scarph joints. Because the veneers in the plywood serve as a visual guide, careful use of this tool (with an 80 grit disc) gives a perfectly cut 8:1 scarph in about 3 minutes. I do recommend that you cut at least one by hand so that you can appreciate the convenience of the grinder method. I also recommend that you cut a sample scarph with the grinder before diving in to the real deal. I do not, under any circumstance, recommend this method for scarphing solid stock, particularly cedar. Why would one waste the opportunity to make a nice pile of cedar shavings, anyway?
You can see the process in photos. Fit each half of the plank separately. I left a little bit of extra width on each plank section in the area of the scarph joint so that it can be faired through after the glue-up. Mark where the planks intersect. Here is where you need to start paying attention. It doesn't matter whether the scarphs face forward or aft, but do them all the same way so that you don't have to keep track during the process. I am facing all of the scarfs aft, so the end of the forward plank is marked on the aft plank. DO NOT CUT THE AFT PLANK ON THIS LINE!!! Add the length of the scarf (2") to the aft section of plank. Clearly mark which side of the plank is shaved for the scarph before removing them from the boat. This is the most common, and most frustrating, error that is made.
With the plank sections on the bench, stack them so that the scarph lines are butted tight to each other. clamp them firmly in place and make sure that the feather edge of the lower piece is supported. Double check that they are stacked so that the material is removed from the correct side. When you are happy, grind away. wear a respirator and take little bites.
Less than one pop song later (if you want to take it really slow, put on "High-Heeled Boys" just like the classic rock station DJs do when they want to take a lunch break) you will have a nicely cut joint. Use the veneer lines to guide you, and check with a straight edge when you think you are done. A couple of swipes with your block plane will true it up.
Take the sections back to the boat and re-hang them. You'll have to come up with some clamping blocks to put everything where you want it to go. Again, do a dry run to make sure, and don't forget to mask the area around the scarph and your clamping blocks. The final photo in the series shows the scarph joint after sanding the next day. Remove the bulk of the squeeze-out with a scraper and a heat gun. If you try to sand it all off you'll get a wave in the plank from sanding the differing densities of the materials.
The last photo shows the use of a jump stick to pick up the lower edge of the next plank. I used it to determine keel and stem bevels, too.
It appears that I am limited to five photos per post, so I'll end this one here. Next time we meet will be after the planking is complete. I apologize in advance for the delay. I'm sure I'll be nursing a bit of a hangover after the "whiskey plank."
Next post will cover all of the pain-in-the-butt things that have to get done before you can flip the boat and admire your work.