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Frequently asked questions

After a couple of years, I've been consistently getting a few questions which I hope to reply below.

  1. How much epoxy is needed for the construction?
  2. It takes forever for the epoxy to harden. What's wrong?
  3. How much fiberglass do I need?
  4. Where are the plans of the kayak?
  5. Could you send me pricing of epoxy (or fiberglass, or wood...)?
  6. Ok, so where can I get the epoxy/fiberglass then?
  7. How do you apply color to the resin...?

  1. How much epoxy is needed for the construction?
    This is a difficult question - which is why I didn't specify it in the actual pages. The exact quantity depends very much on a number of factors, such as the care of the builder, the thickness of the fiberglass cloth used, the absorption of the wood, if you decide to put some cloth inside the kayak (like I did) etc.

    That said, I think you will need a minimum of about 5 liters (1.5 gallons) of epoxy plus its accelerant.

  2. It takes forever for the epoxy to harden. What's wrong?
    Provided you did add the accelerant in the prescribed quantity, there are two principal causes for the delay.

    First, you didn't mix well. A good indicator is that after the normal hardening time, the leftovers in the cup don't come out or remain sticky.

    It's not that easy to mix well, particularly if you mix in small disposable cups. Use a flat object - a 'squeegy' - one of those wooden popsicle sticks - is very handy and effective.

    The other motive is temperature. Calculate that hardening time doubles for each 10 degrees less temperature. If the specs say an hour at 25C, then it takes 2 hours at 15C, 4 hours at 5C, etc. Don't worry - it'll harden eventually. Unlike polyester, epoxy always hardens - the accelerant just hurries it to a bearable time.

  3. How much fiberglass do I need?
    Again, this is difficult to predict. Go to your source first and ask for the width of the cloth you need. There doesn't seem to be a standard for this.

    Then draw scale forms of the two large pieces of cloth you will need (deck and bottom), and try to fit them as efficiently as possible. You can incline the forms slightly to make better use of the width. This will not be noticeable in the final result.

    The unused material will probably be sufficient to make all the strips to join and reinforce the stichings.

  4. Where are the plans of the kayak?
    There are no drawn plans for the kayak. I've found (and several others confirmed it), that it is nearly impossible to print/plot the plans for this kayak. The strips for the sides are over 5 meters long and only about 10 cm wide. It's just too easy to distort such unwieldly strips of paper.

    Instead, a table is privided (see the links left). It takes some work, but the results are much more reliable that paper plans!

  5. Could you send me pricing of epoxy (or fiberglass, or wood...)?
    No, I cannot. This is just a passtime for me. If you need software for some controller or industrial project, or develop some webpages, do e-mail me, but not for building materials ;-)
  6. Ok, so where can I get the epoxy/fiberglass then?
    Basically, look in the commercial telephone guide in your zone (yellow pages or whatever). It's normally better to buy personally from a reputable shop than mail-ordering. Check the shop's credentials. Particularly check if the owner knows the difference between polyester and epoxy... I know it sounds stupid...

    Check the lot dates on the containers. The accelerant tends to attract humidity which translates into problems later. Ask for mixing ratios and hardening times. Ask what happens if you change the ratios.

    For locals I've included a link to my provider on the links page.

  7. How do you apply color to the resin...?
    I'm assuming you are talking about polyester (not epoxy). Generally colorants are not added to the resin directly, as this may influence on the mechanical properties. Colors for boats and other projects, are assigned to the outer - special - layer, called gelcoat (This is normally the first layer applied to the mold). This coat has several special properties, such as accepting colorants and filter UV light for protection of the actual resin. I haven't worked a lot with gelcoats - please consult your provider.

(c) John Coppens ON6JC/LW3HAZ mail