1st Build, DK touring Canoe questions

[Dan0]

Background: I am a Displaced Texan, in a remote province in the Philippines, North latitude 13.8. Building supplies and equipment are not readily available. Shipping cost and time quickly make the the price or time frame of things prohibitive. I have to improvise a lot. I had to special order 1/4" Marine plywood from another island. Delivery took 4 months due to the factory schedule. This type (5 ply, no voids) is for export only but the factory owner added my order (10 sheets) to the order of a local building supply store.

I spent this time reviewing the plans and perusing the site (Introduction, Questions and Comments (12 pages), tips and tricks, miscellaneous and the build logs)). You have a fantastic site.

Now my problems:

When Mixing epoxy and catalyst I am using plastic cups marked for 2 to 1 mixture but since the epoxy is so thick (like Karo syrup) the ratio is not exact when I combine parts A & B in a larger shallow container. I do this because I seem to recall that the resin curs more quickly if in a deep container. My mix seems to cur slowly even though temperatures are generally in the 90s or 100s. Any suggestions other than add more hardner?

Initial stitches are to be loosely done. At what point should they be tightened?

The instructions state that the internal tangent radius in the seams should equal the thickness of the panels (1/4" in my case), but the spacer recommendation is to use Popsicle sticks or tongue depressors which are only 1/16"! Is this not a conflict? I have cut small pieces of plywood scrap and drilled a stitch hole in them to maintain the radius.

Unshielded copper wire is not that common here so I am using Aluminum wire about 1mm in diameter cut from a 7 strand cable.

I am at the point of installing the frames, but other than the location and taping the corners, there is no detail on how to attach them. The instructions state that frames may fall out when the boat is turned over. I think this means they are not stitched or glued. The mid panels tend to push the frames away from the bottom panel, are my loose stitches to tight already? Sheet 12 of the instructions show the frames being squared up before the upper panels are installed. I found no information on how to stabilize the frames in the proper position.

Instruction sheet 3.1 shows 4 triangles. I found no reference to these pieces. Are they salvage to lighten what appear to be temporary frames cut from the center of the permanent frames shown on sheet 3.2? But, then why lighten temporary parts?

I seem to recall some mention of temporary frames in the instructions but will have to reread to be sure.

Any assistance will be greatly appreciated

[jem]

When Mixing epoxy and catalyst I am using plastic cups marked for 2 to 1 mixture but since the epoxy is so thick (like Karo syrup) the ratio is not exact when I combine parts A & B in a larger shallow container. I do this because I seem to recall that the resin curs more quickly if in a deep container. My mix seems to cur slowly even though temperatures are generally in the 90s or 100s. Any suggestions other than add more hardner?

Resin cures faster if it's confined more because as it cures, heat builds, makes the remaining resin cure faster, compound effect. I'd say don't mix until you're absolutely ready. You could store the parts in the fridge until you're ready to go.

Initial stitches are to be loosely done. At what point should they be tightened?

After all panels are stitched.

The instructions state that the internal tangent radius in the seams should equal the thickness of the panels (1/4" in my case), but the spacer recommendation is to use Popsicle sticks or tongue depressors which are only 1/16"! Is this not a conflict? I have cut small pieces of plywood scrap and drilled a stitch hole in them to maintain the radius.

Radius of the fillet and space between the panel are two different measures. The measurements are a guideline, not an absolute.

The mid panels tend to push the frames away from the bottom panel, are my loose stitches to tight already?

No. you just have push them into place and stitch to the frame. The reference to the frames falling out is further in the process than stitching.

Sheet 12 of the instructions show the frames being squared up before the upper panels are installed. I found no information on how to stabilize the frames in the proper position.

Stitch to the hull.

Instruction sheet 3.1 shows 4 triangles. I found no reference to these pieces. Are they salvage to lighten what appear to be temporary frames cut from the center of the permanent frames shown on sheet 3.2? But, then why lighten temporary parts?

Decks

[Dan0]

Matt, Thanks for your comments.

I think I will try mixing my epoxy in the measured cup before pouring it in to the shallower pan. I think this will yield a more accurate mix. I never mix until I am ready to apply the mixture.

Now to give you a chuckle or make you roll on the floor with laughter.
This is still very much a learning process. After rereading the instructions for the Nth time, I see that it stated the frames may fall out after the stitches are removed. DUH! I probably should not mention this but I have no pride. I managed to attach the top panels in the mid panel position. I then installed the mid panels as top panels to better Alaine the frames. Then I noticed that the frames did not match up with the panels and at first thought I had lofted the frames incorrectly because the boat, even though screwed up, was looking pretty good to me. Taking another look at the drawings, I discovered I had confused the mid and top panels. It only took me a half day to unstitch the panels and restitch mid panel. Since I had failed to mark the frame locations on the side panels, I positioned them on the bottom panel and used a framing square to mark the mid panels after insuring that the bottom panel was flat for the full length of the square. Will wonders never cease, I managed to get the butt blocks on the inside of the boat! I had just stitched the frames to the mid panel when I came in to check for advise/comments from you pros.

I will now go stitch the top panel to the mid panel. Hey the stitch holes are already drilled!

Two more questions: Should the frame to hull joints/stitches have a gap or is wood to wood OK ?

The only reference to deck that I recall stated it should be made of 1/2" material so how do the triangles fit in?

Thanks again
Dan0

[OnkaBob]

My mix seems to cur slowly even though temperatures are generally in the 90s or 100s. Any suggestions other than add more hardner?

Dano, don't add extra hardener!

You need to remember that epoxy is not like polyester resin where you have a peroxide hardener that is added at rates of something like 0.5% to 2.5% depending on temperature/batch size etc. Think of the epoxy as being like 2 resins that react together. There are various ratio systems you can buy but they are different because of the chemical composition and varying the mix ratio can seriously affect joint strength. The way to change the cure rate is buy "slow" or "fast" hardeners but I gather you are having trouble obtaining any sort of epoxy at all let alone different speed components.

If it is as thick as I imagine from your description then you may have trouble wetting out the glass. Mixing smallish batches may help because even though cure is slow the mix often starts to thicken fairly quickly.

Hope the rest goes well.

[Dan0]

Thanks Bob, I had to go to Manila for the epoxy and glass cloth, a 12 hr. trip each way by bus or car, 45 minutes by air but we only have 2 flights a day so an overnight stay is required if I have to spend time searching for stuff.

To date I have only been mixing about 3 to 4 oz. of resin to 1.5 to 2 oz. hardener for the butt joint blocks and fiberglass butt joints in the bottom. the epoxy without hardener is thick. The hardener thins it some and it has a pot life of just under 30 minutes (which is good for me) before it starts to thicken/harden. The cloth has wet out very well but I over did the epoxy on the glass splices then covered it with plastic sheeting without flattening it well. The resulted was a very thick and rough surface that I had to spend the better part of a day sanding down to a smooth finish. I cut out two canoes at the same time by doubling the sheets of wood and have made up all the panels for both. I did use a squeegee to spread the epoxy on all of the side panels but because I only have room to work one panel at a time there is still a lot of sanding to remove the blush. I do this as I prepare to assemble the boat.

I should be ready to start filleting the 1st boat tomorrow. Since I used 1/4 " spacers it will require a lot more flour for the seams. Will the wider joints make the seams stronger or weaker? I am thinking that since the seams will be taped inside and out, and the whole exterior sheathed with cloth and epoxy it will make no difference except to add weight. Right or wrong?

I plan to use both boats as sailing canoes for coastal sailing or line of sight trips between islands. The water is very flat in my area so it is not at all like sailing in the open ocean.

I am thinking I will test the 1st. boat after taping the seams and applying a couple of coats of epoxy before glassing the exterior. Is this advisable or not?

Thanks again for your input

[jem]

Gap or no gap for the seams on the frames. Some gap would be more advisable if it were a power boat but for a paddle boat, no gap is ok.

The 2 triangles make one deck piece. Wasn't enough room on the ply to draw as one solid piece.

[OnkaBob]

I am thinking I will test the 1st. boat after taping the seams and applying a couple of coats of epoxy before glassing the exterior. Is this advisable or not?

I'm not too familiar with this design but I would think that you need to glass the hull before adding the gunwales and I wouldn't risk taking it out without the gunwales on. Depends on what the designer thinks on this one.

Personally I also would not take it out before glassing the hull because it will never be quite as clean as while it is still in the build shop. I always thought that you taped the seams after glassing the hull if doing both but then I've only built 1 boat.

Just out of curiosity what epoxy are you using - is it a name brand or an unknown?

[Dan0]

Thanks to you both Matt & Bob.
The frames: I was thinking that since they will be faired into the hull it would not matter, good to have it confirmed.

I am using Polymer Products Laminating Epoxy. I do not know if it is made here or imported. The only info. that was included was the mix ratio marked on the part "A" cans (no pumps just pour and eyeball it to marked cups).

As for taping, everything I have read stated the joints should be taped and faired before applying the cloth followed with at least 2 coats of epoxy.

I plan to bolt the gunwales over the glass a I expect I will have to replace externals periodically.

I will use 1/2" ply for the decks and extend them 24" to 30" to incorporate a mast step. It will be similar to a cat boat with maybe a lug rig. I have plans for a lea board and rudder.

Well back to work, I have to level up my horses and secure the boat.

[Dan0]

When taping the exterior mid to upper panels seam, should the hull remain upside down or can I turn it on the sides? If on the side, do I tape the frames back in? I have cut strips of cloth since no tape was available. The bottom to lower panel went great but I am concerned about the cloth staying in place if the hull in upside down which makes the seam more or less vertical.

[jem]

Once you've tack-welded the seams and the epoxy-filler mixture has fully cured, you can carefully rotate the hull anyway you like.