Saturday, January 18, 2014

Kayak: Flush Deck Fittings

These are the best, strongest, most hassle free deck fittings ever.
(There seems to have been some interest in this so I'll try to improve it. 12 March 2016)

Dan Maroske came up with a method to make flush deck fittings for a kayak by using wire and tubing coated in releasing solution and then slipping on 1/2" fiberglass sleeve. It's a great idea.
I believe I've improved on his method. All the video I've shot so far is awful (In one of them I went fitting to fitting and popped out the mold material--spectacular--except none of it in the frame).
My primary contribution is that I used hot glue sticks for the mold, wrapping them several times with Teflon plumbing tape to keep them from getting stuck after the epoxy has set. Since then I've also used lithium grease as an additonal mold release.
Glue sticks being solid do not kink when you bend them. They are flexible and stretchy. When pulling them out stretching, even a little bit, decreases the diameter. 

The link below connects to the least bad video. If you're interested in making flush deck fittings, it'll be interesting-otherwise not.

My variation solves a couple of problems. 
Problem #1 Kinking. Other method:Using tubing packed with wire. The bend is a tight 1" (25mm) diameter.  Hollow tubing will kink, this is why Dan Maroske packed his tubes with wire.
By using mini hot glue gun sticks, which are flexible and solid--they not only do not kink, but they make a nice smooth bend. (Full size glue sticks will also work, but their diameter is much larger than you'll need.)

Releasing from the mold: Epoxy does stick to glue sticks. (My epoxy skills are not great, I've often had problems with releasing wax and solutions.)  My work around is to wrap two layers of Teflon plumbing seal tape around the glue sticks. There is some adhesion to the epoxy, but it is only to the surface of the top layer of tape. Three layers would probably be even better. This tape is fairly cheap (Harbor Freight), and the glue sticks are still usable--both in your glue gun and as molds. The glue sticks will still retain a lot of the Teflon tape, so you won't have to re-wrap three layers. What you are after is when you pull on the glue stick after the epoxy sets, you want it to slide between the layers of tape. The issue is the mechanical hold of the surface area of your mold against the now solid surface going around a 180 degree bend.
Cutting board with some 'molds' inserted into the holes.

Problem #2 making the loop. I use cheap plastic cutting boards as a base. I drill a 3/8" hole 1 inch apart in the cutting board. Epoxy will stick to the boards, so I coat these with releasing agent (lithium grease).  I've got some delrin plastic (poor man's Teflon sheet) that should work even better. (The cheap plastic cutting board material isn't nearly as slick as delrin or teflon, but it's close and about 1/10th the price--I use it for a lot of things that need to slide).

After I've prepared (wrapped) a handful of sticks, I slide on the 1/2" fiberglass sleeve. When I have the sleeve on a stick, I loosely wrap the (roll) end of the fiberglass tape with blue masking tape. This accomplishes two things. (Fiberglass sleeve can be a bit of a chore opening up the end. I use a pencil. When you're using it for several pieces all the same diameter, once you've got the sleeve over the mold, wrap blue tape once around and then cut through the middle of the tape.)
1. It keeps it from unraveling and
2. It keeps the sleeve open to slide onto the next glue stick mold.
Wrap the tape,  then slide the sleeve off the mold a bit and cut in the middle of the tape. This leaves two taped ends.

Next I just bend them, poke them into the holes in the cutting board and epoxy them. You want to saturate the fiberglass sleeve. Bubbles may appear, use a heat gun to make your epoxy more viscous.
It's best to put on a second layer of epoxy. Tiny holes can remain after only one coating.
After it sets, pop them out of the cutting board. Leave the mold in.

The deck of your kayak should be completely fiberglassed. You don't want to apply a layer of glass over the fittings. You can add more coats of epoxy and varnish, I make little plugs for the holds so the holes don't fill up.

Preparing the deck of your kayak:
I usually drill 7/16 or 1/2 in holes in the deck and then insert the fitting from the inside. You want a gap for thickened epoxy to bond the fitting to the deck. For the extreme bow and stern ends--that I can't reach from the inside. I've drilled larger holes and fed the fittings from the outside. I've also loosely taped them to a stick and reached in from the inside.

When they're all installed, mix up some thickened epoxy, pull them up slightly. Make sure they're coated all the way round.  You already know how to do this.

When the epoxy has set: Next step is to remove the mold material,
Tools to have are a sharp knife and needle nose pliers. Some combination of cutting around the masking tape, the protruding sleeve and pulling on the glue stick with the pliers.
The great thing about the glue sticks is that when they are stretched they become narrower, this loosens them up inside the fittings. I find if I pull and wiggle on each side they will soon become loose.
When they pull out they slowly move and then pop!
This particular fitting I use for the rudder deployment lines. I'm testing it for strength. Next I'll sand it flush with the deck.

Trim anything sticking above the deck, and sand smooth.
Some Teflon tape may be left inside, but it won't show and it won't interfere with inserting line. I've easily pushed through cut but unwicked (frayed) line that is almost as big as the hole. The inside of the fittings using this method are usually very smooth.

There's always something else, but this and my video (the images here are screen captures) should give you all you'll need to know. I will never try to screw a loop to a deck of a kayak again.

For a commercially made kayak that doesn't have a wood core, a fiberglass epoxy 'plate' 2 inches by 1 inch, buttered up with thickened epoxy and inserted from the inside might be a good place to start.

Let me know what you think. Especially after you give it a try. (I got a lot of poopooing about this from guys who clearly hadn't tried it. Maybe I wasn't clear enough.)
Just rediscovered these two videos. Drilling holes, setting up the molds and mixing epoxy. Only interesting if you're going to make these fittings.
Maroske Nettles Deck Fittings.m4v

Maroske Nettles Deck Fittings TWO

 I'd like to do a strength test someday, but not on my kayak. I'm betting the line breaks before the fitting does.
Update: One of my fittings had a slight leak. Nearly impossible to tell exactly where. A light coating of epoxy dripped into the hole, then smeared around and cleaned out with a piece of line took care of the problem.
Has anyone else tried this method? What was your experience?
I always boast that I can learn or figure out 85% of just about anything--which is why I don't skydive. It's also why your thoughts, skills, experience are needed. Thanks. See you on the ocean.

No comments:

Post a Comment