Yeah, I’m getting a real workshop! My brother stopped by for more than a week and we got all the stud walls up. I’ve since put up a lot of insulation since then.
And the garage is full of tongue and groove pine, and I don’t want to work in there and spill something. But, I need to take a break, the electrician is booked out about a month so there will be some downtime, I’ll find a space to finish up.
I did sand some of it down and it worked pretty well. I should get back to that. And I just realized I have some video that I shot weeks ago, I need to process that and publish!
That’s a real good point! I think I have a 32 minute working time, which is awesome.
Respirator, yup!
This is where I failed, I had tons of lumps. They just didn’t want to dissolve!
And I have a 24 hour cure time. I think I was turning the paddle for several hours, I set a 15 minute timer…
Especially given how tricky it is to mix it in.
I got the tint from Raka. Very easy to work with. I think I put too much in, but I guess that that’s ok.
There’s a big difference between the cure time and the time until the epoxy “kicks”, which is when it pretty suddenly thickens to the point that it won’t flow anymore. It’s similar to the “working time”, but probably a few minutes longer. After that point, there’s not much you can do with it. It becomes rubbery, but continues to cure and eventually become hard. Based on what you’ve said, you shouldn’t have to turn the paddle for more than 45 - 60 minutes, but it varies with the temperature. The warmer it is, the faster it cures and the shorter the working time.
This is the 22nd episode in my series on making a Greenland kayak paddle entirely with hand tools, but really, start with #11. In this episode I attempt to tint the tip with epoxy resin and pretty much botch it up!
I actually recorded this on July 9th, I’m just so behind in processing…
If you have a Dremel (rotary) tool, you could potentially grind very carefully. A very sharp chisel would work if you are careful, but the risk of pushing into the wood is great. Paint a contrasting stripe? Those are some brainstorming ideas I have…
Paul, I’ve never seen clumps in fumed silica like that. I’ve been using West Systems Cabosil and it mixes in beautifully. Somehow or other, you need to break up the clumps before adding it to the epoxy. I think you hit on the right idea when you mentioned sifting but you’d need to do it inside a plastic bag so it doesn’t blow all over the place. Another option would be pouring it into a blender or food processor, but you must take precautions (a tight lid) to avoid a huge mess. Either way, a respirator is mandatory. Fumed silica is not toxic, but you don’t want to inhale it!
FWIW, I have seen lumps like that when testing glass microfibers, which is why I don’t use them.
Always wear gloves when working with epoxy! I thought you had already learned that lesson.
I cringed when I saw you using edged tools on epoxy containing fumed silica. It’s made from sand, so it’s the last thing you want to push a blade into! The saving grace for you was that the epoxy was still soft; if it was fully cured you would surely have ruined the edges on your tools.
Rasping or sanding is the best way to smooth those areas. You need to start with pretty coarse sandpaper, like 80 grit, and the epoxy needs to be fully cured, or it will just clog the sandpaper. I also recommend wet sanding over dry, to reduce dust and clogging. I start with 80-grit on a hard sanding block, then switch to 150-grit on soft block once I have the shape I want (the sanding sponges you have are essentially the same thing). As for the lip of the epoxy, just wrap a couple of layers of painter’s tape around the wood and carefully wet sand it until it’s a uniform thickness. Having an edge there is not a problem. Remember, the epoxy is a sacrificial layer meant to protect the wood. It does that job better if it’s proud of the wood surface.
Wild, I thought I was doing something wrong. Maybe it is a bad batch? It certainly made my life miserable.
I wear them in the next episode! :- )
It worked really, really well. The chisel was amazing. As for ruining the edges? That’s what sharpening stones are for. I have a set of 4 DMT diamond stones, love them. 2 Veritas honing guides. I can fix any blade up, ok, most blades up, in decent time. I actually enjoy sharpening.
I really like the fine control I got with the blade. Wait until you see the next episode. I actually don’t show more chisel work, but I used lots of epoxy resin on the tips and had to shave away tons of it.
Good to know. Since my epoxy was till somewhat soft the dust just fell to the floor.
I’m scared to try that. This paddle is essentially done!
Proud isn’t a problem with you are holding at the ends? Hmmm, I rarely hold that far out, but it just seems wrong.
The whole epoxy thing has really turned me off of epoxied tips. I’m considering learning better joinery so I can just use oak or something. But still, that white looks really fine!
I’m not sure what’s going on with the fumed silica, but it’s not your fault.
I don’t mind sharpening either and I have a ridiculous amount of sharpening equipment, but I tend to be protective of the edges of my tools. The first time you chip an edge and have to remove a lot of material from an expensive tool to fix it, you’ll understand why. I do have some cheaper tools that I designate for work that I know is going to damage the edges. They’re the equivalent to have a “beater” car for the winter. Note that this is only an issue if you have fillers like fumed silica or glass microfibers mixed in. If you’re just using tinted epoxy, it’s no problem as long as it’s not fully cured.
When you sand epoxy that’s not fully cured and hard, it doesn’t produce dust per se, it’s really just peeling off little chucks, which is what you saw.
There’s nothing mandatory about sanding the tips as I suggested. As long as you’re happy with them, don’t do anything that you don’t find comfortable. However, if you go slow, you can sand it quite precisely. I’ve never even noticed the edges of the epoxy tips when paddling, so I don’t think it will be an issue for you.
It’s too bad that you had to deal with all this unnecessary grief with the fumed silica. Epoxy coating tips it not typically such an ordeal. Typically, it’s one coat of clear epoxy to seal the wood and one coat of tinted, thickened epoxy over that, which self-levels enough that minimal sanding is required, if any.
I had the pleasure of attending a sharpening class at the water powered Chase Mill in Alstead NH. I asked the instructor, how do I know when my irons are dull? He asked, what was I working with. “Cedar” I answered. He said, “They’re dull.” It turns out that cedar has a high silica content.
So, I guess the moral is, we gotta keep sharpening!
I’m so happy you said that. I’ll be contacting System Three and seeing what’s up. And I won’t, yet, be making plans for hardwood or Corian tips!
This is the 23rd episode in my series on making a Greenland kayak paddle entirely with hand tools, but really, start with #11. In this episode repair the botched epoxy tips! Is the paddle ready? Actually yes, as I type this it has been paddled, but you need to wait for Episode 24 for the click-baity almost finale.
There’s a couple of things I want to mention about sanding epoxy:
Wear a respirator! The dust from epoxy is not something that you want to breathe, especially if it’s not fully cured.
Unlike wood, epoxy doesn’t have grain, so there’s no reason to sand in only one direction. To reduce the ridges at the start of the tips, it makes more sense to sand across the width of the tips, as you can control it better. It’s also a good time to use a hard block that will keep the sandpaper proud of the wood surface. I generally use a hard block for the initial shaping, then switch to a soft block with the finer grits.
Nice tips, and, Doh, of course! I’ve recently applied another coat of BLO and got some on the tips, will need to sand again probably, will use that trick, it might even help with the lip!
Note that this is only an issue if you have fillers like fumed silica or glass microfibers mixed in. If you’re just using tinted epoxy, it’s no problem as long as it’s not fully cured.
