all bulkheads were cut for us at swallow boats in cardigan, a bit less than an hour drive from our shed. they balance nicely between well thought, modern and cost effective boat building and classic looking boats made for sailing.
had them cut by a cnc router saved a lot of time and we now have really precise cut bulkheads. all it needed was cleaning up the slightly rough edges and figuring out how the finger joints in the bigger bulkheads would slide together. .. I hope we can trust the computers who did a lot of work for us and everything is fair and in the right place when the bulkheads are set up...
on the three bulkheads you can see on the picture above. i tried out an epoxy system commonly used in surfboard building called resin research and is distributed in the uk by seabase in cornwall. according to their website, the resin has:
· lower toxicity · lower exotherm · longer pot file · shorter set times · lower vapour · better colour · better colour stability (UV stability for brightwork) · better strength · etc.
we still had some leftovers of the widely used and time proven west system resin. so i made a mix of WS as well to compare it with the RR resin. i was interested in ease to work, gelling time, pot life, efficiency, etc.
when we have used the resin a bit more, i will post more details on our experiences. so far i can say that the RR resin is a bit more viscous compared to west system what made it easier to use it with a roller sponge and gave a better finish. it is clearer in colour and doesn't seem to give out a lot of vapours so its smell is much less aggressive than WS epoxy. the RR epoxy had a shorted gelling time than the WS but had a longer pot life and was less exothermic when going of in the mixing cup. it must be said though, that we used the slow hardener on WS and the standard hardener on RR.
styrene stinks! at college today i gelcoated a little shellback dinghy. black bottom and dark green topsides.
we did two coats on the black bottom and the transom first, removed the masking tape and did the topsides. there it didn't matter if we were dripping or painting on the black bottom as it will be covered up by the glass laminate on the inside and shouldn't be seen through the black gelcoat to the outside. tomorrow we're going to prepare the glass, set up vacuum bag, flow medium etc. pipes needed for a resin infusion. we probably will do some test panels to see how quick the resin flows through our laminate stack before we infuse the whole boat.
we started with fixing the short 2"x4" crosspieces you can see to the floor following a centreline we defined with a really tightly pulled dyneema rope.
we used PU-glue to fix the crosspieces to the floor first but to make it a rigid structure we will drill additional long screws into the concrete floor. last thing we want is a moving strongback. the people who poured the concrete floor did a pretty good job so we just needed a few strips of ply to get everything perfectly level.
That's what the seams looked like after the first pouring of the glue. It has already been scraped except the seam of the covering board. You can see little gaps and voids, that are not ideal. They do not look nice and they make it easier for the water to get in. To fill those little cracks and holes, we used a cheap heatgun to melt the glue in the seams and then poured or rather blew some more glue into the affected areas. I just cut open an old metal container and bent it to form a nice nozzle. With the heatgun i then was able to blow the glue more or less precisely wherever i wanted it. Without remelting the glue already in the seams, the new glue wasn't really sticking to it and cracked off quite quickly.
The heatgun was also quite handy when cleaning up after the pouring. In our opinion it was easier to pour more glue into the seams than needed to make sure it is filled. That created a ridge on top of all the seams which needed to be taken off. Just heating it up with the heatgun and then slicing it off with a spatula or an old plane blade worked quite well. It gives a finish like on the picture above on the covering board seam.
And then it's down on your knees and scrape... We used an old 2" plane blade and a bent and sharpened old file I borrowed from a friend. The top surface layer of the teak was a bit worn out and was even easier to scrape off after we poured some hot water over it, which also softened the glue.
Here you can see how it looked after the second pouring using heatgun and the small metal container.
Till i post more pictures of the catamaran project....
I finally finished of a deck today I worked on with colleagues from my boat building college for the last weeks. Most of the deck planking was still in good condition and just a few short planks on the aft deck needed replacing.
After cleaning out the rebates between the planks, we opened up the seams with a wedge shaped caulking iron. It probably has a better name than that... Dumb Iron is probably the right name for it. Then cotton went in the seams. Not a lot because the planks were already pretty tight. We then heated up TBS Deck Seam Glue and payed the seams with that sticky stuff. It is a messy job and after the first few seams we were actually getting a bit worried about this deck being covered in black spots and blobs... Luckily it scrapes of quite easy. especially if you got this:
Our building shed... an old greenhouse on a sunny hill in lower solva, pembrokeshire. all that insulation created a lot of dust but keeps the temperature quite stable. stable temperature+epoxy=good; dust+epoxy=no good the man you can see breaking things is Ysbrand. it is his shed, his idea and he will be sailing that cat.