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Canoe Stuff! And Other Projects
Aug. 21st, 2010 06:25 pmYesterday I got out the longboard, with 80 grit sandpaper, and began sanding the canoe.
When I built Patience I tried to do this job with the random orbital sander, but I was not happy with the results. It is just too easy to sand into the fiberglass, which I don't like doing, except at the edges of a patch where it has to be sanded down fair with the rest of the boat. I thought the longboard would give me more control and it did. It is also harder work; that's the price you pay. It's still not a big deal though, I did most of the sanding in two and a half hours or so. And it was blessedly cool yesterday morning--only 78 degrees, if humid.
However the longboard is so good at fairing down the lumps and runs (not that I had many runs--go me!) precisely because it doesn't get down into all the little valleys. And my epoxy is not yet thick enough that I am confident I can make everything as low as the valleys without sanding through the epoxy in places. And... if the epoxy has cured enough that you can't get a chemical bond with the next layer, which I suspect it has, you need to scratch up the surface to get a good mechanical bond--which means scratching up the surface in the valleys too.
The answer? Scotch Brite pads. NOT the no-scratch ones, for obvious reasons. They don't clog up as fast as sandpaper, and they easily press down into the valleys. A package of three will about do one canoe-I did mine in about an hour this morning. The book says you can rinse them out and reuse them, but in my experience they stop being sharp after a while--when it doesn't look like they're scratching--they're probably not scratching. And rubbing a canoe is hard work so you might as well get the scratches you want.
I have patched the two little bubbles down stem, and one deep bubble I hadn't spotted last time I wrote. For the deep bubble I actually bought a syringe at the feed store (you'd be amazed what you can buy at the feed store) cut the top of the bubble off with a sharp knife, mixed up some of the epoxy-silica-sawdust mix and stuck it in the syringe, and injected it into the bubble. I only needed a little tiny bit for that operation so mixing 4 ml of resin with 2 ml of hardener gave good results. The teeny plastic cups that 2 quarts of drink powder comes in? Make great mixing cups for tiny bits of epoxy. I've been going through the ice tea like water and it's nice to have something I can do with them besides throw them in the recycle.
For the patches I mixed 20 ml resin with 10 mi of hardner to get approx 1 fluid ounce of epoxy. That was a little more than I needed but I didn't want to run out in the middle. I'm glad Randwolf suggested the syringes for measuring; I'm running low on the epoxy and don't want to have to buy more; it's expensive stuff. So far I'm out about $150 for wood and $100 for fiberglass--but using the epoxy left over from Patience has saved me easily another $100. The hardener has gone a bit yellow, so the epoxy is a bit yellow, but for the price I can't complain. Apparently Raka Epoxy, though it is comparatively inexpensive, gives reliable results, doesn't blush, and stands up to years of use, does tend to yellow.
I tried to sand the patches an hour or so ago but the epoxy is still too rubbery. I will try again in a bit. Though maybe I will put the second stem layer on tomorrow. It will take me some time to build the cradles/slings that the boat will sit in when I'm working on the inside; maybe I can do that tomorrow too.
One thing I did notice this morning is that the heavy duty castors I got to build the canoe lifter have worked excellently well. I haven't had a single one fail and need to be replaced. Last time I must have replaced three or four of them. Heavy-duty is the way to go. I built this canoe lifter in such a way that I could take it apart and save it, and I think I will be doing that--aside from a couple minor glitches I'm quite happy with how it works.
And the other project is the wax tablets for Kip. Kip wanted me to put "CAT ME FECIT" on them. (I used capital letters because I know how to draw them all and I know they're right for Latin--Uncial letters would also be okay but I don't know exactly what they look like and besides curves are harder to carve than straight lines.) The best tool ended up being an exacto knife. I measured out a space for each letter and space, drew the letters in pencil, and cut straight down along the pencil lines. Then I made an angled cut on each side of the pencil line, aiming to meet in the middle. It could be neater, but for a first attempt I think it's not bad.
Kip and I talked about finishes. I was inclined to just warm the boards in the oven and paint the (liquified in a double boiler) beeswax on with a paintbrush and call that the finish, but Kip was worried about the outside of the diptych being sticky if it got hot and spoke up for varnish. I had some varnish left over from the great Pre-Quetico Varnishing, so I pulled that out and used it. I'm varnishing the edges of the recessed wax-bed, because I'm planning to tint the wax and don't want it bleeding into the wood along the grain. But I'm not varnishing the bottom, in the hope that the wax will stick better. The down side of varnishing means several coats, sanding, time to dry, yadda yadda. But Kip doesn't actually need the tablets until the end of next week so there should be time.
When I built Patience I tried to do this job with the random orbital sander, but I was not happy with the results. It is just too easy to sand into the fiberglass, which I don't like doing, except at the edges of a patch where it has to be sanded down fair with the rest of the boat. I thought the longboard would give me more control and it did. It is also harder work; that's the price you pay. It's still not a big deal though, I did most of the sanding in two and a half hours or so. And it was blessedly cool yesterday morning--only 78 degrees, if humid.
However the longboard is so good at fairing down the lumps and runs (not that I had many runs--go me!) precisely because it doesn't get down into all the little valleys. And my epoxy is not yet thick enough that I am confident I can make everything as low as the valleys without sanding through the epoxy in places. And... if the epoxy has cured enough that you can't get a chemical bond with the next layer, which I suspect it has, you need to scratch up the surface to get a good mechanical bond--which means scratching up the surface in the valleys too.
The answer? Scotch Brite pads. NOT the no-scratch ones, for obvious reasons. They don't clog up as fast as sandpaper, and they easily press down into the valleys. A package of three will about do one canoe-I did mine in about an hour this morning. The book says you can rinse them out and reuse them, but in my experience they stop being sharp after a while--when it doesn't look like they're scratching--they're probably not scratching. And rubbing a canoe is hard work so you might as well get the scratches you want.
I have patched the two little bubbles down stem, and one deep bubble I hadn't spotted last time I wrote. For the deep bubble I actually bought a syringe at the feed store (you'd be amazed what you can buy at the feed store) cut the top of the bubble off with a sharp knife, mixed up some of the epoxy-silica-sawdust mix and stuck it in the syringe, and injected it into the bubble. I only needed a little tiny bit for that operation so mixing 4 ml of resin with 2 ml of hardener gave good results. The teeny plastic cups that 2 quarts of drink powder comes in? Make great mixing cups for tiny bits of epoxy. I've been going through the ice tea like water and it's nice to have something I can do with them besides throw them in the recycle.
For the patches I mixed 20 ml resin with 10 mi of hardner to get approx 1 fluid ounce of epoxy. That was a little more than I needed but I didn't want to run out in the middle. I'm glad Randwolf suggested the syringes for measuring; I'm running low on the epoxy and don't want to have to buy more; it's expensive stuff. So far I'm out about $150 for wood and $100 for fiberglass--but using the epoxy left over from Patience has saved me easily another $100. The hardener has gone a bit yellow, so the epoxy is a bit yellow, but for the price I can't complain. Apparently Raka Epoxy, though it is comparatively inexpensive, gives reliable results, doesn't blush, and stands up to years of use, does tend to yellow.
I tried to sand the patches an hour or so ago but the epoxy is still too rubbery. I will try again in a bit. Though maybe I will put the second stem layer on tomorrow. It will take me some time to build the cradles/slings that the boat will sit in when I'm working on the inside; maybe I can do that tomorrow too.
One thing I did notice this morning is that the heavy duty castors I got to build the canoe lifter have worked excellently well. I haven't had a single one fail and need to be replaced. Last time I must have replaced three or four of them. Heavy-duty is the way to go. I built this canoe lifter in such a way that I could take it apart and save it, and I think I will be doing that--aside from a couple minor glitches I'm quite happy with how it works.
And the other project is the wax tablets for Kip. Kip wanted me to put "CAT ME FECIT" on them. (I used capital letters because I know how to draw them all and I know they're right for Latin--Uncial letters would also be okay but I don't know exactly what they look like and besides curves are harder to carve than straight lines.) The best tool ended up being an exacto knife. I measured out a space for each letter and space, drew the letters in pencil, and cut straight down along the pencil lines. Then I made an angled cut on each side of the pencil line, aiming to meet in the middle. It could be neater, but for a first attempt I think it's not bad.
Kip and I talked about finishes. I was inclined to just warm the boards in the oven and paint the (liquified in a double boiler) beeswax on with a paintbrush and call that the finish, but Kip was worried about the outside of the diptych being sticky if it got hot and spoke up for varnish. I had some varnish left over from the great Pre-Quetico Varnishing, so I pulled that out and used it. I'm varnishing the edges of the recessed wax-bed, because I'm planning to tint the wax and don't want it bleeding into the wood along the grain. But I'm not varnishing the bottom, in the hope that the wax will stick better. The down side of varnishing means several coats, sanding, time to dry, yadda yadda. But Kip doesn't actually need the tablets until the end of next week so there should be time.
