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Epoxy tip....

Discussion in 'Paddles and Paddle Making' started by JPembleton, Oct 27, 2008.

  1. JPembleton

    JPembleton Chest Nut

    Simple question....

    What do you use to tint epoxy tips on paddles? I plan to try doing an epoxy tip but am not sure on what to use to get the proper color....

    Thanks

    Jamie
     
  2. Rob Stevens

    Rob Stevens Wooden Canoes are in the Blood

    Saw dust from the paddle being protected.
     
  3. OP
    OP
    JPembleton

    JPembleton Chest Nut

    Hmmm... I was thinking more of the dark brown color that would contrast with the natural lighter color of the wood.





     
  4. pklonowski

    pklonowski Unrepentant Canoeist

    Use a darker sawdust, like walnut.

    I don't know if aniline dyes, or maybe artists' pigments, would work in epoxy. Might be worth a try, and please report back here!
     
  5. OP
    OP
    JPembleton

    JPembleton Chest Nut

    Thanks guys.... I just assumed there must be some dye available that everyone uses, assumed wrong :) .

    I had planned to use silica powder to thicken the epoxy but now that I wil likely be using saw dust, is there any reason to bother with the silica?


    Thanks

    Jamie
     
  6. MikeCav

    MikeCav Restorer/Videographer

    A friend who carves greenland style kayak paddles uses an off-white acrylic paint mixed in with the epoxy to simulate the look of the bone that was traditionally used. I assume any color would work.
     
  7. Todd Bradshaw

    Todd Bradshaw Sailmaker

    Sawdust mixed with epoxy will be darker by quite a bit than the wood it came from because sawdust is similar to end-grain. Mahogany will often go very dark brown, walnut almost black and even light woods like birch and maple will turn out medium to dark brown.

    The problem with dye is that it doesn't provide any strength to the epoxy. Some sort of particles (graphite powder, wood dust, milled cotton fibers, milled glass fibers, etc.) in a fairly high concentration will generally make a tip that is less prone to shattering.
     
  8. Douglas Ingram

    Douglas Ingram Red River Canoe & Paddle

    I use resin pigments. You can buy them in small tubes or bottles from a place that sells epoxies, or boat repair materials. Lots of colours available

    In the past I used dry tempra paint powder. It worked OK.

    I add in some colloidal silica to thicken the epoxy slightly. You don't want to add too much, or maybe you do. I've been experimenting with the viscosity to lessen the amount of trapped air bubbles. Expect to do some touch up.

    Some fillers allow the pigmented resin to wick up the end grain of the paddle wood. The silica seems to be the one to not do this. Cotton fiber allows for it big time. Don't use cotton fiber.
     
  9. Todd Bradshaw

    Todd Bradshaw Sailmaker

    Time for a little bit of basic wood/epoxy technology. Your paddle's tip is end grain. If you expect the paddle to last and you are applying an epoxy tip, you had better hope the resin wicks up into the wood - just as far as it can go -because if it doesn't, water eventually will! I don't think I need to tell you all what that leads to.

    If you are using a filler that makes the resin so thick that it doesn't wick well up into the end grain, then it's not doing a proper job of sealing out water (or bonding) and you're just asking for trouble. Wood/epoxy technology does not revolve around the principle of "sort of" sealing the wood to prevent water intrusion, it relies on doing everything possible to completely seal the wood.

    Thick hunks of resin and/or resin containing tints or pigments look nice, but are quite brittle if they happen to be attached to something that occasionally gets bounced off of rocks. In order to temper that brittleness and drastically increase durability, you can mix the resin with a high amount of various types of filler particles or fibers. These will thicken the mixture and as mentioned, reduce penetration into the wood. In the process, you greatly reduce both the strength of the bond between the wood and the resin tip and the amount that the resin can seal the end of the raw wood.

    The way to take advantage of the strength and durability boost offered by the filler/fiber mix and to still get maximum sealing power (and without wicking colored resin up into the wood) is to pre-coat the wood in the bonding area with several coats of unfilled, unpigmented epoxy. Mix some resin and hardener together and brush a coat on the raw tip wood. Give it a few minutes and do it again, if that seems to soak in and disappear, do it again. You should see the resin absorption stop or slow to a crawl before you ever even think twice about moving on to adding filler or pigments and forming the tip.

    Whenever you are bonding epoxy resin to wood the absolute last thing you want to do is anything that will reduce the epoxy's ability to penetrate, seal and get a really good, deep grip on the wood. This is why any spot where you use heavily-thickened, filled resin on a boat should always be well coated first with unthickened resin. If it's thin, it flows in...if it's thick it won't stick.
     
  10. pklonowski

    pklonowski Unrepentant Canoeist

    I've done the first step of Todd's procedure on a couple of paddle tips, and the unthickened epoxy really soaks in nicely. I didn't follow up with the tinted/thickened epoxy step... the paddles held up well so far,though they've had a pretty easy existence, relative to my normal paddles.

    I'd suggest masking off the faces of the blade, so you don't drip any epoxy onto them. It saves cleanup time. Also, after the epoxy stopped soaking in, I added just enough more to create a slightly rounded tip (the wood was cut flat & square to the faces), which essentially became the resin tip.
     
  11. Andy Hutyera

    Andy Hutyera The Red Canoe Guy

    I'm fairly new to putting epoxy tips on my paddles. In the past, I've done ok by just keeping spar varnish on my paddles. At this Summer's Assembly, a West rep showed up and demonstrated their G'Flex Epoxy. He recommended it for paddle tips. It's a thick goo that's formulated for underwater repairs on boats. I found that it makes a very nice paddle tip. It can be smoothed with a wet gloved finger and has practically no sag as it slowly dries. I would imagine that it would work quite well after sealing the tip as Todd suggests. Unfortunately, I can't offer any info on coloring the the stuff as I just applied it as mixed. It set up with no bubbles and was easy to work once it had hardened. It is really tough stuff and does a good job of protecting the tip from rocks and abuse.
     
  12. Douglas Ingram

    Douglas Ingram Red River Canoe & Paddle

    What Todd says goes without saying, and I apparently I did go without saying it.

    I also omitted saying that when I do an epoxy tip on the paddles, after the tip is cast and cured, I cut a cross paddle tip slot through the epoxy tip and well into the wood. Into this slot I insert and bond with epoxy, a fiberglass plate that is 4 layers of 6 oz glass. It holds the whole thing together extremely well.
     
  13. Rob Stevens

    Rob Stevens Wooden Canoes are in the Blood

    Douglas' comment about inserting a fibreglass spline reminded me that a hardwood spline can also be inserted in a slot across the tip of the paddle.
     
  14. Douglas Ingram

    Douglas Ingram Red River Canoe & Paddle

    True, but if you're doing an epoxy tip, why use wood now?

    I did use wood on my first few epoxy tips, but then had to deal with that question and found that I couldn't reconcile myself to a wood spline.

    Making the fiberglass plates is easy enough to do. I make a panel about 18" x 24", exact size doesn't really matter. After its cured I can cut it into 2" strips with scissors, then down into 5-6" pieces. Makes enough for 20-30 paddles at a time. Its also important to properly prepare the surface for future bonding.

    OK, so I realize that most hobby builders won't be making 20-30 paddles very quickly, but its as easy to do more than just the one, and then you're set.
     
  15. pklonowski

    pklonowski Unrepentant Canoeist

    If you're going to do Doug's 'glass spline, wouldn't it be easier to cut the slot into the wood, install the spline, and then cast the epoxy tip around it? Or am I missing something... again?
    :eek:
     
  16. Douglas Ingram

    Douglas Ingram Red River Canoe & Paddle

    Paul,

    I tried it that way when I started doing tips this way. It works, but you have to be VERY careful about shaping the blade so as not to go through your paddle wood and into the spline.

    I do the rough taper on the blade, then do the tip, then do all the shaping of the paddle blade.

    Putting it in after you do all the shaping ensures that you get it centered.

    Each approach has its own merits and detractions, you just choose which are important to you. Putting in the spline after means that now I have to cut the slot through all that epoxy, but it means that I don't shape the blade and risk showing the spline. Been there, done that, can't sell a paddle that looks like that.
     
  17. pklonowski

    pklonowski Unrepentant Canoeist

    Good point, Doug. Think if I did that, it'd be firewood.

    I guess I was thinking the blade would be mostly carved before cutting the slot to let the spline in? That still leaves a bit to chance.
     
  18. Douglas Ingram

    Douglas Ingram Red River Canoe & Paddle

    Yes, its mostly carved by the time that you put the spline in but consider how thick the blade wood is on either side of the spline.

    Just to illustrate the situation:

    Theoretically, if the spline is perfectly centered, you can do it. I know that you know how the blade wood moves as you work the wood down to final dimension. Can you guarantee that you will get the spline in perfectly +/- 1mm prior? I can't. Easier and safer by far, to shape the blade to just before sanding, then get the spline in.
     
  19. pklonowski

    pklonowski Unrepentant Canoeist

    Good point...

    Especially when I consider the time delays that I inevitably encounter. I've taken weeks to get one paddle from the board to the finish line, and a lot can happen to it in between. I've had to steam a shaft so I could straighten it out...and it's still not quite straight.

    Of course, we've hijacked this thread....;)

    Think the epoxy manufacturers would have some idea how to color their products?
     

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