tag:blogger.com,1999:blog-3580987459140037495.post6092940617482641917..comments2024-03-18T10:29:20.125-08:00Comments on TriloBoat Talk: Piecing the Bottom Together: A New ApproachDave Zhttp://www.blogger.com/profile/13241033623115158564noreply@blogger.comBlogger13125tag:blogger.com,1999:blog-3580987459140037495.post-57480069277244226852014-03-30T09:53:46.450-08:002014-03-30T09:53:46.450-08:00Hi John,
I've wondered that myself.
Traditio...Hi John,<br /><br />I've wondered that myself.<br /><br />Traditionally a wood hull was finished with 'black varnish' (recipe seems to have been lost... today, some use mix of turpentine, pine tar and Japan drier... I might throw in some tung oil), and covered with Irish felt (heavy wool or flax felt saturated in tar). Some slather tar before and/or after the felt. Then copper.<br /><br />My guess is that this waterproofs the hull and gaskets the fasteners for the copper. Certainly the MIMI (100+ year old schooner we saw recoppered) looked dry and bright when her old copper/felt came off (no sign of either black varnish or tar, other than a bit from the felt).<br /><br />We've used gluey polyurethane paint, before, which seemed to work out okay. But it's expensive, and takes a lot to make the gasket.<br /><br />While shopping for Irish felt (which has become rare and expensive) a boatwright friend suggested self-adhesive roofing underlayment, which is apparently the current, professional gasketing material between timbers, for mounting hardware and such.<br /><br />A scrap was lying around, so we tried it... it's in its third week hanging in the drink, still with good adhesion. Seemed nice and easy to apply and relatively cheap.<br /><br />The brand we're ordering is Grace Ice and Heat Shield.<br /><br />Here's hoping!<br /><br />Dave ZDave Zhttps://www.blogger.com/profile/13241033623115158564noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-65844986115403215002014-03-30T09:39:33.985-08:002014-03-30T09:39:33.985-08:00Luckily, DIY is therapy, of sorts... may help stav...Luckily, DIY is therapy, of sorts... may help stave off that walker!<br /><br />8)<br /><br />Dave ZDave Zhttps://www.blogger.com/profile/13241033623115158564noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-12676015725993985812014-03-30T09:37:53.234-08:002014-03-30T09:37:53.234-08:00[Posted on behalf of JOHN]:
Hello Dave,
What is ...[Posted on behalf of JOHN]:<br /><br />Hello Dave,<br /><br />What is the purpose of the "underlayment (for Copper)" that you have listed in your bill of materials?<br /><br />JohnDave Zhttps://www.blogger.com/profile/13241033623115158564noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-45377164565250795012014-03-15T14:06:54.909-08:002014-03-15T14:06:54.909-08:00Yes it does get tedious. I'd quite like to get...Yes it does get tedious. I'd quite like to get to enjoy this boat before I start having to shuffle around with a zimmer frame!Joelhttps://www.blogger.com/profile/10844967794207697583noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-86211111784924995602014-03-15T10:23:03.521-08:002014-03-15T10:23:03.521-08:00Hey Joel,
Thanks for the info on Gorilla Glue usa...Hey Joel,<br /><br />Thanks for the info on Gorilla Glue usage! That squares with my memory.<br /><br />We get GG in 36oz and 18oz (or less, but not cost effective). 400ml comes out to about 14oz.<br /><br /><i>So, a bit less than half a liter or 36oz per panel of ply laminat.</i><br /><br />Good info on the overbending, too.<br /><br />And it does get tedious, dunnit?<br /><br />DaveDave Zhttps://www.blogger.com/profile/13241033623115158564noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-13815576714130885522014-03-14T23:36:19.133-08:002014-03-14T23:36:19.133-08:00The computer has benn playing up last few days...M...The computer has benn playing up last few days...My glue comes in litre bottles, I think it was working out at about 400ml ish, per panels.<br />The curved panels at the front end did straighten up a bit, but i had givrn thrm a bit more curve to start with, I think it was an extra 3/4"inch on the 8' lengths. I glued them up on top of the athwarship beams, (the beams are parallel sided) and added the 3/4" at one end to give the extra curve to account for the straightening up. I just got another 3 panels to make soon to finish the bottom of the boat...groan! Joelhttps://www.blogger.com/profile/10844967794207697583noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-12117579625679668972014-03-07T18:40:37.217-09:002014-03-07T18:40:37.217-09:00Hi Joel,
Question for your follow-up... How many ...Hi Joel,<br /><br />Question for your follow-up... How many ounces of Gorilla Glue are you using per sheet? I seem to recall an 18oz bottle with a little left over... that close?<br /><br />Dave ZDave Zhttps://www.blogger.com/profile/13241033623115158564noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-6784182018918111352014-03-07T10:31:17.023-09:002014-03-07T10:31:17.023-09:00This is pretty much how I built the bottom panels ...This is pretty much how I built the bottom panels on my boat. Two layers of 3/4" marine ply glued and screwed together. Used stainless screws. I used gorilla glue. Maybe not the strongest of glue, nevertheless I consider strong enough because there is a huge glueing area and little stress. The panels, are 10" x 4" , 1 1/2" thick. The screws are 30mm long, slightly counter sank. I drew a grid on the sheets 6" apart, a and put a screw at each intersection. Also drilled screws holes along the edges where the panels were going g to be glued and screwed to the sides of the hull, also to be able to screw and glue panels to each other....a bit more to follow in a moment...Joelhttps://www.blogger.com/profile/10844967794207697583noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-987439013986905652014-03-06T22:58:02.810-09:002014-03-06T22:58:02.810-09:00That, or my run-on answers buried it in all the bl...That, or my run-on answers buried it in all the blah-be-dah! 8)<br /><br />DaveDave Zhttps://www.blogger.com/profile/13241033623115158564noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-33685652040002086862014-03-06T20:22:41.676-09:002014-03-06T20:22:41.676-09:00Whoops! I just noticed somebody said that. For som...Whoops! I just noticed somebody said that. For some reason the make-a-comment box loaded before the existing comments.Peterhttps://www.blogger.com/profile/09074125801234414010noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-17185028192191801202014-03-06T20:20:09.130-09:002014-03-06T20:20:09.130-09:00You may find, Dave, that the curved fore and aft l...You may find, Dave, that the curved fore and aft laminated sections, once taken off the molds for them (if I understand your plan aright) will want to "spring out" somewhat from the curve you've set in the jigs (in other words form less of a curve than they did when on the jigs). This may not matter, of course, for several reasons, but it's good to know stubborn wood sometimes does this sort of thing.Peterhttps://www.blogger.com/profile/09074125801234414010noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-32102474640429318302014-03-02T15:43:51.858-09:002014-03-02T15:43:51.858-09:00[...Continued]
John: Finally, how will you assemb...[...Continued]<br /><br />John: Finally, how will you assemble, then remove the plywood from the curved templates? If you screw (my assumption) the inner layer to the template pieces, then glue outer plywood to the inner plywood, how will then unscrew the inner plywood? I'm sure you've got some clever idea worked out, but those curved ends will definitely be trickier than the deadflat portion.<br /><br /><br />Dave: Well, not <i>too</i> tricky... a very few, smooth nails (easily pulled) to tack down the kerfed piece, then longer, temporary screws through both layers and into the nailers. We'll be using some heavy lag screws, later in the project, which would make good candidates.<br /><br />Finish up by prying the assembled section off the nailers, nip the nail ends and grind flush. Plug and glue holes with red cedar, of which we have plenty of off-cuts, to make good stopwaters.<br /><br />One point to note, one lap will extend proud... it can be strongly fastened with screws and leverage applied against those... the nails only have to keep the gains long enough to get the second layer in position.<br /><br />*** NEWS FLASH ***<br /><br />Anke just came by (with pie) and read what I just wrote. She asks, "Why remove them from the nailers?"<br /><br />"Well," I pontificate, "you can't do that because... ah... um... why, indeed?"<br /><br />So simpler answer: leave them on. No spring-back, no temporary fasteners or holes. Just flip the whole shebang, and when the time comes, position and fasten the nailers (inset by side panel thickness) to the sides!<br /><br />Need I say, she's the brains of our operation?<br /><br />BTW, the mid-curves of the jig don't need fasteners... they're just there to keep the ply honest (prevent saddling).<br /><br />******<br /><br />So there's our latest evolution. Stay tuned for results!<br /><br />Dave ZDave Zhttps://www.blogger.com/profile/13241033623115158564noreply@blogger.comtag:blogger.com,1999:blog-3580987459140037495.post-10145295449333315982014-03-02T15:43:00.500-09:002014-03-02T15:43:00.500-09:00[Response to an eMail from JOHN]
Hi John,
Good q...[Response to an eMail from JOHN]<br /><br />Hi John,<br /><br />Good questions all! I called them the 'finnicky details' in the post. My answers, here, are just one way among many that others have figured out.<br /><br />John: I was thinking about how you might pre-shape the curved pieces for the ends of the hull using the final curved side pieces as a template. I'm thinking that even though the inner and outer pieces of plywood will be glued together, they most likely will spring to a flatter arc when released from the "mold". If that happens, will that be a problem for whatever method you use to attach the copper?<br /><br /><br />Dave: I'm guessing that there will be a little play... meaning that the copper (screwed, in our case) will allow a little flex-to-fit.<br /><br />Still, we'll 'overbend' the ply, slightly to stay as close to true shape as possible. As I recall, we added about an eight of an inch every 4ft, using shims above the true curve at mid-span. I'm going to research this further, but as I recall, it's what we've used before for laminating arcs.<br /><br />(See below... this answer has been superseded).<br /><br /><br />John: I'm also thinking that the two layers of plywood, at least 8'x8', plus the copper, could result in a pretty heavy piece. How will you move and position that heavy of a component.<br /><br /><br />Dave: Yep. Depending on our set-up options, we may just do 4ft x 4ft sections, plus overlaps, to keep weight low. But even if it's 8ft x 8ft, flipping them is easy compared to a hull!<br /><br />Two layers of 3/4in ply weigh about 150lbs, and a 4ft x 8ft x 1/8in plate of copper weigh about 185lbs, for a total of about 235lbs. The end curves, joined, would come to about 375lbs... not too bad.<br /><br />We'll build the deadflat components on the two-beam jig, flipping each (around one edge, so half the weight to lift), and joining.<br /><br />Now we've got a big, flat workspace. Build the nailer jigs, then each panel. Flip, and scoot to their ends where the wait until the sides are up. Position with glue and lift the outboard end while fastening from inboard.<br /><br />The tricky ones, if we do 4ft components, will be the very ends, since their inboard ends are above the deadflat (supported) level. Thus we'd need a tricky scaffolding-like arrangement. Argues for 8ft x 8ft and taking our medicine in a heavy but straightforward flip job.<br /> <br />[Continued, next comment...]<br /><br />Dave Zhttps://www.blogger.com/profile/13241033623115158564noreply@blogger.com