Some Real Progress At Last!

The next step is fiberglassing the hull floor.  The rear (transom) compartment and the storage compartment are not quite ready yet, I have to sand the fillets some more, so I am making paper templates for all the floor sections.

Rear Cabin Template

 Here is the first template in place.  I have made all the cabin floor templates and the next step is to use them to make two fiberglass panels each, one for the port side and one for the starboard side of the cabin.

Cabin Floor Templates

Here's a shot of all the cabin floor templates in place.

Port Side 'Glassed

I have laid in all the fiberglass panels for the port side of the cabin floor and added the wetting-out epoxy coat.

The first starboard side fiberglass panel is in place but not epoxied as yet.  As you can see, the panels overlap about four inches over the keelson and from front to back.  They also go up three or four inches on all the bulkheads and floors and the side panels.

First Wetting-Out Coat Applied to Both Sides

 I have glassed and wetted-out the fiberglass panels on both the port and starboard sides of the cabin floor.  In an hour or so I'll go out and add the second (fill) coat of epoxy.

More Fillet Work & Getting Ready to 'Glass Inside of Hull

About all I have been able to get done since building the rudder is sanding, sanding, and sanding the fillets.  They are starting to look pretty good--I don't have any pictures, but the newer fillets don't look much different than the earlier ones.  The fillets in the rear compartment were acceptable, but I felt they needed some smoothing.  There were quite a few low spots, but they were so shallow I'm not sure they would have caused any problems.  However, once that compartment is sealed up I will never be able to see in there again and if a delamination or something else catastrophic were to occur I would not even know about it.  So after much sanding I added another layer of fillet material and got it smoothed out pretty well as you can see here:

Rear Compartment Fillets

Rear Compartment Fillets

Hull 'Glass Template

After finishing that job I decided to begin making templates for the fiberglass that will cover the bottom-inside of the hull.  Only one template is done so far.  As you can see, the fiberglass will lap up onto the sides and the bulkheads.  There will be an overlap of about 6" over the keelson at the bottom-center.  This will add a lot of strength--that section will have a double layer.  The fiberglass will also be overlapped above the floorboard joists.

The manual doesn't mention anything about making the templates, but I can't think of any better way to get the fiberglass cut to fit.  Laying it in there and cutting it would be much harder and would probably damage the cloth here and there.  The two sides of the hull are mirror images, so I will only have to make templates for one side, and then use them for both.

More Work on the Rudder

Last week I glued the rudder "cheeks" in place.  The cheeks reinforce the rudder at the point where the tiller will be applying side forces.  You can see the slot for the tiller--wish I could add an arrow pointing to it, but I think it's obvious.

Rudder and Tiller

Here's a shot of the rudder with the tiller in its slot.  I have done most of the sanding on the rudder--a little more and the fiberglassing can begin.  Fiberglass will be applied below the cheeks and down the rudder sides, and then curve out onto the bottom plate.

Bottom Plate Fillet

In this closer shot of the fillet you can see a few lighter areas where I added fairing compound to any low spots.  This joint will be under a lot of pressure under sail and I want to make sure the fiberglass has an even, smoothly-curved surface to adhere to.  It is suggested in the manual that the bottom plate can be used as a step for boarding the boat, but I'm a little leery of that idea.

Wetting-out Coat, Side One

This morning I added fiberglass cloth to one side of the rudder and applied the "wetting-out" epoxy coat.  The wetting-out coat is to make sure that all the cloth is evenly "wetted" and that there are no spots that are starved for epoxy or that have too much epoxy.  I stood the rudder up temporarily to apply epoxy to the bottom plate.

I absolutely have to apply the next coat (fill coat) before the wetting-out coat has a chance to harden.  It can no longer be sticky, but must still be "rubbery."  This will happen in about eight hours or so.  The fill coat must be applied at that time to ensure a good chemical bond.  Chemical bonding is best, but a mechanical bond can also be achieved by sanding first.  In this case, though, sanding would damage the fiberglass cloth, which is barely below the surface of the epoxy. So it is imperative that I apply the fill coat at the proper time.   The third (gloss) coat can be applied after the fill coat cures (with sanding) but to get the best possible adhesion I will also try to apply it when I can still get a chemical bond.

It's hard to tell from this shot, but on what is at the moment the upper left corner of the bottom plate, the fiberglass cloth does not quite reach the corner, so I added a little patch.  I'll correct the template before I cut the 'glass for the other side.  Also you can see some black streaks where I got Magic Marker ink on the cloth that was applied to rudder.  I'll have to be more careful about that in future, but it does not matter here because I do not plan on a "bright finish," i.e., it will be painted instead of varnished.

Fillets Fixed, Building Rudder

I retired Oct. 10 so am finding more time to get some work done on the boat.  I finished chiseling and sanding the bad fillets and have now covered them over with new fillets.

You may remember from my previous post that I had applied the fillets when it was too warm and I was unable to smooth them out before they set.  I chipped and sanded out the bad spots and re-covered the fillets--this is a huge improvement--not as good as some I have seen in other blogs, but they will serve the purpose of both strengthening the joint and allowing the fiberglass cloth, to be applied later, a smooth curve to bend around.

Yesterday I began building the rudder, which seems fairly simple, except that it is tapered from the front to the back, but not at the top where the tiller will slot in.

The rudder consists of two sheets of plywood with wood "blocking" separating them.  The wider blocking at the top of the picture is 3/4" thick; the bottom blocking (to the left) tapers from 3/4" at the front to 1/4" thick at the rear of the rudder.  The  vertical blocking is tapered from 3/8" to 1/4" all along its length.  The more complicated part is the "triangular" block, which has a compound taper from 1/4" to 3/4", so that it is supposed to be a full 3/4" thick all along the edge that butts to the wide blocking.  I was a little over-zealous with my sanding so the triangular block is a little too thin at the bottom edge.  So it does not make good contact with the plywood there, but only for less than 1/2", and I am filling the gap with thickened epoxy so I don't think it will cause a problem.

Here the blocks are glued and clamped (the wider block at the top was glued yesterday).

And here is a closer shot of the compound-taper area clamping on the triangular block.  You can see the gap, but again it is very narrow and I am going to fill it. The block is in full contact with the plywood from the less than 1/2" to the top.   I clamped blocks of wood on the outside top and bottom to keep the triangular blocking in place and help the plywood conform to the curve.  At the top right you can barely make out the slot where the tiller will fit.  Another sheet of plywood will be glued to the top after these parts cure.

A "Not So Fun" Job

In an earlier post I talked about the weather being relatively cool and deciding to do some filleting work, which was a disaster.  More about that later.  The fillets are thickened epoxy used to round or soften any corners in the hull so the fiberglass cloth has a smooth curve to bend around.  It will not adhere well at all to sharp corners.  These fillets have to be as smooth as possible, not only for appearances, but because any bumps or voids will leave a "bubble" under the fiberglass causing a weak spot.  Weak spots, especially in boat hulls that are going to be bouncing around on a trailer, can be disastrous.

On some of the fillets I was at least able to do the initial smoothing and today I chiseled away some of the roughest areas on those.  After filling in a few low areas I should be able to sand them smooth enough at this point.

A not too bad fillet with the worst areas chiseled off--ready for sanding

There were one or two particularly bad areas where the epoxy started hardening before I could even start to smooth it out.

Very bad fillet, most of which has been chiseled away

 It is hard to tell from the picture, but in this case I have chipped most of the fillet away.  It will be sanded and a new fillet put in its place.  I'll post the results when I am able to get the job done.

The way the fillets are supposed to be done is the thickened epoxy is laid in, then smoothed and sculpted with a flat, rounded stick to get it as close as possible to the finished shape.  Then any spills and excess material are cleaned up with a putty knife.   After an hour or two, depending on the temperature, the fillet has started to gel, but is still malleable.  At this point the final smoothing and shaping is done with a gloved finger dipped in alcohol.  This can be done very nicely if the temperature is anywhere between 60 and 77 or so degrees F.

According to the epoxy manufacturer's literature, at 77 degrees the pot life of their resin, using slow hardener, is 23 minutes.  That's how long you have to spread the epoxy before it becomes unworkable.  What they refer to as "thin film set," where the epoxy feels fully hardened but is not yet cured is 5 hours at 77 degrees.  Full cure at this temperature takes 5 days.  So, at that temperature it is best to wait about two hours before the final smoothing.

Again according to manufacturer literature, at 86 degrees the pot life is about 17 minutes, thin film set (TFS) occurs at about 3 hours, 45 minutes, and full cure takes 3.75 days.  At 95 degrees pot life is 11 1/2 minutes and TFS is at 2 1/2 hours.

So to me this means I should have had at least an hour to an hour and a half before the epoxy became unworkable.  That tuned out not to be the case.  As I said, most of the fillets from that "pot" only gave me time for initial smoothing and the last fillets didn't even give me time for that.  I would estimate the actual pot life at about 5 or 6 minutes and the TFS time at the end of pot life at about one more minute.  The temperature when I started the project was 85 and I don't think it climbed above 87 before I was finished.

So what went wrong?  One possibility is that I accidentally added too much hardener.  But according to the manufacturer, this does not make the epoxy cure any faster, but can make it weaker.  As I learned today when chipping away at it, it was definitely not any weaker!  So I don't think that was it.

One response to my previous post was that epoxy starts to become unpredictable above 80 or so degrees, meaning I guess I can't trust the literature completely.  So, one more lesson learned the hard way.  If I remember all these lessons my next boat will be perfect!

Gluing Up the Mast

It was finally cool enough (70s) this weekend to glue the mast together.

Here I am cleaning up some of the squeeze-out after epoxying three sides of the mast together.  I didn't get pictures, but there is a 32" piece of 2x2 inside the base of the mast and a 16" piece of 1x1 tapered to fit in the tip-top end of the mast.  A pivot will be inserted through the mast near the top end of the 32" piece so the mast can be lowered for trailering and storage.  Several pieces of hardware will be installed near the top and bottom of the mast, so the the 16- and 32-inch plugs will strengthen those areas for that purpose.

The fourth side has been added and glued in place.  I used every clamp I could find that was large enough to fit.  Even so, I'm not sure I used enough.  The instructions are not clear on this but I think you are supposed to glue all sides at the same time.  I didn't have nearly enough clamps for that, so glued three sides and the plugs yesterday and added side four today.

Odds and Ends

Sanding Bowsprit

Not a lot going on with the boat--too hot for epoxy work and there are tons of other outside jobs to keep up with during the summer.  I did find time to work on some of the spars.  Rounding over and sanding the gaff, then filling in tiny gaps where the two parts are glued together.  Then chamfering and rounding over on the bowsprit, and sanding both.

Sanding Bowsprit

Here I am sanding the bowsprit.  The gaff (spar that lifts the upper part of the sail) is lying beside it.  If you click on one of the photos it should become quite a bit larger and you can just make out some of the chamfering about a foot back from the small end.  All that means is that I have used a 45-degree router bit to bevel the corners.  This gives it a nicer look, but more importantly lowers the weight a little.  There are several parts of the boat where measures have been taken to lower the weight, especially higher up where there is more moment-arm.  Ballast is added at the very bottom and weight reduced higher up, so maybe the thing     will stay upright.

I hope to start again in earnest when the weather cools, and then devote much more time to it after I retire in October.  The plan is to get it on the water by sometime next summer.