Back to Home Page        
  back INDEX next

23a. Bonding shells - fiberglass tape trick

Click on any image to see the full size version

Sanding the salved edge of the fiberglass tape is probably the least pleasant part of the whole kayak building process. The woven edges are rather thick and need to be feathered into the surrounding surface which generates a rather large volume of fiberglass dust.
Furthermore, sanding sometimes makes the weave of the glass visible even after the new filler coat of epoxy is applied on top.

NOTE: This technique is also particularly suitable for stitch and glue kayaks where all joints must be taped and feathered smooth. Ask any plywood kayak builder and they will tell you that achieving a clean transition without sanding into the surrounding fiberglass or plywood is probably the most tedious task of the entire project.

There is a way to minimize all the dust with this little trick:

  • First, mask off the boundary where you want the finished edges of the fiberglass tape to end. Normally I would use 2" tape for bonding the shells, so do the masking 1" (2,5 cm) on either side of the sheerline seam.

  • Now use the next wider tape. Here I am using 3" (or scraps of leftover fabric if you want to save $) so that the salved edges overlap the masking tape by 1/2" or more. Epoxy everything down and let it set until the next day. Slow setting epoxies work really well because the next day the material will be still very pliable. Do not use fast setting hardeners alone for they are too brittle and tend to shatter when bent, scraped or cut.

  • Bend the edges of the tape, together with the masking tape up to the masked boundary as in the picture.
Note that I had used clear masking tape on one side of the seam and a paper painter's tape on the other. The paper tape makes the edge more visible but the clear tape is stronger.
  • Slice (score) the fiberglass tape at an accute angle with a sharp knife, avoiding contact with the underlying fiberglass or wood. It is easier than it looks.
The scored fiberglass will break off very easily and cleanly.

The cut is made exactly at the edge of the masking tape or a little bit towards the sheerline.

Finished seam. Instead of sanding all this stuff off, it has been surgically excised!! Now re-mask and apply an epoxy filler coat. Any subsequent sanding will be cutting more into the hardened epoxy rather than the fiberglass.

Use this technique to trim the abrasion patch of fiberglass on the bottom of the hull as well. This will instantly eliminate any struggle with unraveling edges of the fabric as well as sanding all the mess down.


Home Kayak Designs Kayak Shop Materials Kayak Gallery About us
Building Manual Plans Sandwich Core Wood Kayak Order E-mail
Epoxy Test Abrasion Cloth Rudder Resources Choosing Kayak Guestbook

If you notice any problems with the site (i.e. error links, missing images) please, let me know. Thanks

Vaclav Stejskal
10 Colonial Court apt. 73
Stoneham, MA. 02180
Tel:  781-481-9261


© 1999 - 2020 Copyright Vaclav Stejskal
All rights reserved

Last page update: 11 January 2020