Small Boat, Big problem - Part 3 - Repairing a lapstrake garboard plank with WEST SYSTEM EPOXY

Today we're going to do some intensive surgery on this acorn dinghy. I hope you enjoy it. Howdy folks, I'm Mark Rutin. Welcome to Nomad Boatbuilding. In the last few videos we've been repairing this small dinghy that was built at the Couch and Bay Maritime Centre in British Columbia. This dinghy had quite a bit of damage to both garboard planks. On the port side plank we repaired a crack by installing a dutchman and now on the starboard side our garboard plank is fractured along the full length of its fastenings plus there are several other cracks in the plank. I decided the best solution is to replace about three quarters of the plank from the keel towards the adjacent plank and then we're going to create a joint in the existing plank between a new section and the old section that is essentially like a scarf joint except that it's going to be running the full length of the planking. Sort of a beveled dory lap. Now we didn't replace the entire plank because to do so would be even more work. To remove all the fastenings between the two planks could cause damage to the adjacent plank and replacing all those fastenings when I'm single handed is quite difficult to do. In this episode we're going to steam bend that plank to fit and we're going to make it in two pieces with a scarf in the center. That's just going to make it a little bit easier to fit in this difficult situation and we're going to install this plank with West System Epoxy, the sponsor of this video. So I've got my steam box set up here. I just fired it up. You don't need all of this. If I were starting out from scratch and just needed to start getting into steaming I would just buy a wallpaper steamer. You don't need anything fancy for the box, just a plywood box, anything that doesn't melt under the steam. And sometimes I actually will take a piece of bubble wrap or plastic and staple it on here and just cut a slit into it. Okay here's our plank. Very carefully slip it in here. I always want to wait for your box to be hot before putting the plank in. So we're going to give that, oh I don't know, I think we'll check it in 15 minutes and see how it feels. There's a sort of a limberness to the plank when I pull it out that tells me that it's like prime and ready for bending. You go too far and you dry it out and it'll stiffen back up again. You go too shy and it'll just be too stiff and not bend properly. So there's there's a sweet spot for sure. So I've made up a bunch of little blocks that match the angle of the planking that I'm going to clamp onto the keel here in order to hold the planking down and induce the twist. And while that box is heating up I can knock off all these trunnels as a column. Oh yeah that feels good. That feels very nice. Nice. So there we go. Okay well that sort of works. I'm not quite adding the pressure the way I'd like it but I think that's about the best I can do. I'll have to worry about the rest in a glue-up stage. Okay well mostly things are pretty good. Workable. I'd say they're workable. Not perfect. I knew I wouldn't get perfect. I was hoping I'd get perfect but I knew I wouldn't get perfect. So I'm just going to leave this alone for the rest of the day. Just let it fully cool. I sure wish I could figure out a good way to get this to close up better. I might have to just adjust the bevel. It could be that's all it needs is I need to steepen the bevel on the plank that's hanging. Crawling up inside here this is looking quite good. I mean there's a little overhang for of the existing plank but oh it's looking super clean actually. Yeah that's nice and tight up in here so I think I just need to adjust the bevel perhaps a little bit to get it to fit better. So I'm really happy about that. So I think this will work out okay. As I say this seems a little open down here but if I can shift the whole thing down just a hair to get a closer tight tighter seam here that'll be fine and then we just caulk this joint more heavily which is totally fine. And this guy's a little overhanging here so I've got some room to shave that back to get it to a good fit which is great. That's your ideal. A little bit of a gap back here so somewhere in here this is not able to quite come in. It's probably right around this spot right here. I just need to take a few shaves off of the back edge and the whole thing will shift that way so I'll probably do that before I start playing around with the feathered edge. Okay now what I want to do here is I want to take a little bit of time to just look over how this is sitting and figure out what adjustments I need to make. Looks like it comes down okay over here but not as tight as I would like it to and certainly a bit proud here and then tight over here. So I think looks like in this spot right through here I can stand to come in a little bit. I want to be careful not to go pulling everything off of here before I make my decisions. So if I push down they'll sort of flush up but there's obviously kind of a kind of a large gap there. I'm tempted to bring it down a little. You can caulk in there that's no problem. I think I'd rather caulk in there than have this be too much of a big epoxy filled joint. Yeah that feels like that almost like now it doesn't fit as well down there. So I think it's my bevel's just not quite right between the two. So I think I'll adjust that a little bit and maybe I'll adjust it on the plank as opposed to the boat. So let's see our so right here is where our bevel feels absolutely perfect and then it changes to oversized and undersized. Also oddly our sir mark is not quite on the money. So I'm kind of curious what is going on under here. Maybe we'll just pop this out of the way and have a look. Uh-huh So that was sitting a little hair south of where we wanted it to go. Let's try tapping it up and see what happens. Interesting. Well that's getting better here. And now it's getting tighter or there's more meat here now which is fine because I can remove it but this is improving. Feels like this is all improving a bit so let's keep doing that a bit. About a quarter inch off my sir mark now. I kind of feel like I should try doctoring up the end of this to fit a bit better. Scooch it this way and then I can play around with these bevels. Okay with that little back beveling until now we're here. About there it becomes good. That no longer matters. Okay I'm thinking through here I think I want to take a little off this and a little off that. Give myself a bit of elbow room on both sides. And let's just before I go anywhere let's just redo our sir mark. Little circles just to tell me that that's the new mark. There's the old one. Mark show me where things zero out reasonably well. It's just a tiny bit tight. Tiny bit tight. Then I need to take off more. This is the greatest depth in a larger arrow there. And then we're back to a smaller amount and this is fine from there on in. So sometimes I'll use mark like here's my stopping point and I need to take off stuff that way. I'll do that kind of mark. Whatever you got to come up with. Whatever language helps you remember what you're what you're trying to achieve. Okay I'm ready to install this sort of almost. You do the scarf next. So I think I'm going to park the scarf right over a rib and that way I can use the rib itself to wedge a little backing block up against it and make sure the feather edge of that scarf is closed. It kind of hides where the scarf joint is too. So I'm going to set the the aft piece first and then the forward piece. Go three inches. 12 to 1. Draw that right across. There. That's our cut and that's our scarf. So that was close. There we go. Almost screwed myself there. That was very very close. Okay. All right I've got my parts ready to go on. I added a little shim up here. There's sort of a gap here at the very end that I didn't love. So I thought I would just add that. So what I just want to do is just double check where my scarves start and stop. Make sure they're going to jive up. That's going to slip right up into there. So we'll give ourselves a ser mark on there so it's easier to identify because we're going to put this down first and then this one. So I'm just going to start with a wet out. Put some paper down on the underside of the thwarts and stuff to make sure that they're protected. Thicken up our epoxy. I'm using the 105-206 the slow hardener. A little colloidal silica for thickener and I'd like I want this to be just a little bit a little more body to this filler because I'm a little concerned about if there's voids that I can't really discern very easily. Put a layer on here that's maybe uh I don't know maybe a sixteenth of an inch thick or so or less. Enough that I know I'm going to get good contact between the two halves. Cool good solid contact. I've made a little plastic wrapped backing block for our scarf so after the scarf is laid together I'm going to go underneath there and we'll put some wedges in behind it. It's sitting right over a rib so that it'll press up against the feather edge of the scarf. Help to close it up. So this is the Sikaflex 291 L.O.T. which means long open time which means I've got about three to five hours before it will tack up compared to the regular Sikaflex which will tack up in about one hour. I just want to give myself tons of working time. Well I was a little more generous with the transom. All right now let's make sure we're landing on our center mark up here. Come on. Go. I think I'm pretty much obliged to like start by popping a nail in up here. Start working my way back perhaps and we'll just throw some weights on here and that's the way to go. See right here I'm not getting the squeeze out that I would like to see. Let's see if we can get a little more epoxy in there. There we go. That's better. Okay. Up. There. Drills. So slightly longer nails in the transom. I don't know if we'll use our little blocks along here. So if I were doing a traditional scarf like a traditional scarf and lap strike I use a quite a different technique than you've seen me here. Here I've used the very standard method of just doing a full on flat scarf and the technique I use for doing it traditionally is also flat but there's a slight difference in that the outboard portion of the scarf you leave the trailing edge just a little bit heavy by say a strong 16th and you hollow out the scarf just a tiny little bit so that it's concave the one that's on the boat is just flat and then you plane off the outside of that feather edge down to a feather edge so you've left a little bit heavy at first so it's maybe like a like I say a heavy 16th depending on the size of the boat maybe even up towards an eighth and then you give basically taper you create sort of a rounded off scarf end not grossly rounded but quite fine but the idea being is that it applies extra pressure to that end of that scarf so it doesn't pop open. I suppose one can question whether or not I should be doing this joint with the flexible polyurethane as well and I suppose that's quite possible but I actually have more confidence in using epoxy for this. Okay I'll probably pull this off and for nailing this off but I just wanted in there for this bend I think that's going to be advantageous. So it would grab on like so Okay this was hands down one of the trickiest glue-ups I think I've ever tried. It took me a long time to get through the process and get to where I was sort of done. I'm glad I used the slow hardener that's for sure because it was pretty warm yesterday didn't really feel like it in the shop but I could just tell I could tell the moment I started mixing up that epoxy that it was going to be a fast kickoff day. These little tuning machines using those as a clamp man those worked beautifully my regret is that I didn't make more of them I only have these three sort of junky tuning machines on hand so if I were to get a job like this in the future first thing I'd do is just jump on Amazon and buy myself even maybe even a couple sets of cheap tuning machines to do exactly this and make up a whole bunch of them because they were absolutely the ticket for sucking down this batten. Of course I've got a little hole to fix to accommodate those but that's nothing far simpler and less time consuming than screwing around with these props that's for sure we can break all this down now it's the next day and we'll pull the junk off and we've got a bunch of cleanup to do not a ton though I mean mostly it all looks pretty nice now if I have to do a little fill with some bearing compound or something in here not the end of the world or even if I don't not the end of the world this is this dinghy's been through it and it's got the scars to prove it so I'm not too concerned about leaving evidence of a repair in there and I don't think the owner will be either because she's mostly just concerned about it being functional let's break it down jobs like this are the reminder why you don't get rid of all your scraps having scraps on hand to facilitate these things is important that looks pretty good little gap there perfect perfect scarf is okay could be pushed down a little harder I kind of I kind of forgot about that until the last moment so I probably messed myself up messy messy yeah I don't like how wide that gap was but you know uh what can I say repairs can be less than satisfying from a finicky fitting perspective sometimes you got to take the win that it's structural and it's good enough so all right well we can cut this off all right the last little task is doing that just a bit of touch-up work so I'm just going to start with the west system 105 205 go for the faster cure on this also a bit of junk on the end of this guy all right we're going to use some of the 407 low density filler here I think this is what they refer to as micro balloons I don't use that term so I don't I'm always a little unsure about that I know this stuff has a doesn't prevent sagging very easily so I very often add a tiny bit of colloidal silica to it as well just to make sure if you put it on vertical surfaces it doesn't fall right off on you stuff is like beads that are like real slippery so you got to kind of go slow to get the epoxy to sort of take up on it that's looking pretty good I think I'm going to add some 410 micro light filler as well like this stuff is very um very loose so I'm just trying to make something that'll sand sand out very easily so ideally I want a consistency that's a bit like a you know almost like a putty the micro light on its own is very porous though so you don't really want to use that unless you're going to clear coat over it there we go that'll work it's very thick slumps a little bit but shouldn't slump out of our joints that are slightly vertical all right let's go throw this in okay before I forget about it I've got these little holes that we use to fill our planks I'm going to stuff some of this down there first I'm also going to just put a little cedar trunnel in there on top of it where'd my hole go I'm just going to shove it in break it off and we'll putty it over so it works best for me for doing stuff like this is to have a another trowel as sort of a pallet just trying to lay the bare minimum in there to kind of fill out the joint don't want to sand off a whole lot because it gets laborious just look for wherever that joint kind of finally fills out stop there I'm not going to try and fill out all the nail holes because if you look at the rest of the you can see the nails all over the place so I hit a couple that are looking a bit egregious the danger of having too much on here is the cedar is so soft it's really easy to just when you go to sand something like this to be sanding away at the cedar more than the epoxy itself let's try going this way yeah I'll try that just scrape back the cedar a bunch all right I think that's just about it I don't feel the need at least not for my ego's sake to make this joint completely disappear just want to make it look like I've done a good reasonable job we're not going to mess around with long boards or anything like that just kind of give them the light once over make sure they're sort of fared in so nothing feels proud and chunky saw below the waterline bottom painted areas which never looked any good anyway so not much point putting a lot of effort into it because this is a traditionally built boat you kind of want a minimum of this of epoxy on this thing we don't want like great globs of it faring things out I'd say that looks very reasonable yeah I think I can live with that there might be a couple tiny spots I need to do a little fill on but I think for the most part this is looking just fine just spend I take me about half an hour or something like that to doctor up whatever is there not a lot of sanders that can get down into here one trick that I use is I take my multi master and rather than using the triangular sanding pad which I don't find very effective is I'll put some self-adhesive sandpaper on the back side of just a regular blade I'll just grind off the teeth and then I can get into nooks and crannies I couldn't get into it any other way all right well our bottom is all finished up now it looks pretty good you wouldn't know that we were ever in there exactly what we want repairs as invisible as we can get within reason so I'm happy about that the customers can be happy we came in under budget however they admittedly pushed their budget higher than they were kind of comfortable with so I wanted to come in under if I could of course there's a million things you could still do on this boat because it's an old boat it's had the daylight kicked out of it so my goal is to fix the immediate problems that make it make it usable again and we've done that all right well that was a great little project and we got to try out a few different techniques for repairing fractures in traditional lap strike planking lap strike planking is a great way to build a boat it's fast it's light it's versatile it's quite strong for how light it is the only downside to it is it is trickier to repair than other types of construction so when I looked at this project to start with I took a guess that I was going to take about half a day to fix the port side plank that just had a few fractures and then I figured it would take me at least two days to fix the starboard side plank that had a lot of damage now that's that was just an off-the-cuff guess and at the time I was thinking two days yeah probably but given how much damage there is the difficulty of doing it it could go further it could it could go to a third day quite easily with that in mind we set a budget that would just about cover roughly three to three and a half to four days worth of effort now the job is done it took about 21 to 22 hours for the entire job and I think it still took me about half a day to do the dutchman side that was just the smaller repair once you factor in all the effort getting set up and cutting the dutchman cutting the the whole fort gluing it all in cleaning it all up doing some paint all that sort of stuff and on the starboard side that left about 16 to 18 hours to do that repair which falls right in line with my original estimate so I'm really happy about that it's extremely difficult to look at a job and off the cuff guess how long it's going to take you to do that and not be like way underestimated nor going way over the other line and being ridiculously over the estimate to try and land like within a reasonable power perk of what it actually takes that's extremely tough to do and you really only get to do that through years and a feel for it yeah I'm always jealous of automotive mechanics that have their nice little repair book that tells them exactly how long it's going to take to repair any part on any given car and base an estimate on that that would be just a dream for the wooden boat builder does not exist and never will exist because when it comes to wooden boat building context is everything and every boat is so radically different than the next in so many different little ways that it's really hard to guess what it's going to take to do any given thing all that said I'm really happy that I landed within a pretty reasonable distance of my original guess almost spot on to be honest so the customer is going to be happy about that we can send this boat out the door move on to the next job so I hope you enjoyed these videos if you'd like to see more repair videos please leave a comment below if you'd like to support these videos please consider joining me over on patreon you can find links in the corner or down in the description I want to thank you all for watching and I especially want to thank west system the sponsors of this video so please join me again for another west system video we'll see you later folks