Thursday, 8 July 2021

Upper Hull | Sanding & Third Clear Coat

I left the second clear coat to cure for a couple of days before sanding it to a P80 finish.

Here I am nearly through sanding the port half of the boat.


The Rotex 90 sander fitted with a medium soft sanding head is ideal for this, allowing small and curved areas to be neatly sanded to a matt finish.

I finished the cockpit deck and had just started on the starboard topsides, reflecting on how well this sander stands up to continuous use, when with no warning it abruptly stopped working. Totally dead.

This was something of a setback.

Fortunately I had the second sander to fall back on. It's Rotex 150 and is a much bigger and more aggressive beast, so not ideal for this task, but I completed the starboard half of the boat with it.

The third and final coat of clear resin was then applied.

Here is the cockpit viewed from port at the stern.


And here is a view of the forward starboard topsides.


Luckily there is a Festool dealership close by so I was able to put the sander in for repair on the day it failed.

I can't finish-sand the third coat until it comes back from Festool which will hopefully be next week, so I'm taking a break from PocketShip until then.


Upper Hull | Second Clear Coat

There are two more significant activities to carry out on the boat before we flip it over to finish the bottom hull - clear coating the upper hull with epoxy resin, and painting the interior of the cabin.

There are a few minor activities to finish also, such as drilling the footwell drain holes. But they can be done at any stage.

I decided to do the clear coating first.

The entire upper hull was covered with fibreglass cloth in November last year, with the exception of the forward deck and inside topsides which were already finished.

The upper hull had been sanded to a P80 finish and was ready for resin, so thankfully no big sanding job was required.

In a previous post I said that I had problems gluing the mast because the resin had crystallised without me noticing until it became too 'gloopy' to pump and failed to cure properly.

The cure for this is to put the resin container in boiling water and warm it until the resin flows freely again. I did this for all three resin containers which I currently posses and it was completely effective, although it does take 20 to 30 minutes and a lot of hot water to restore a 4 or 5kg container.

But now I was ready for clear coating and had no problems rolling out a thin coat over the exterior of the upper hull. It took several hours, reminding me yet again that this is a big small boat!

Here we see the port forward topsides and roof.


And here we see the cockpit viewed from starboard.


Lastly, here is view from starboard of the forward topsides and cabin roof.


Clear coating is always fun because it covers large areas really quickly!


Friday, 2 July 2021

More Clear Coating

Some parts of the boat still remained uncoated with resin so I gave them a first coat.

This is the slot in the transom for the tiller.


And here are the tabernacle backing plate and the drop board flange in the cabin.


In the above pic the mast has just received its third and final clear coat in situ on the boat..

Cabin Interior | Sanding The Fairing

Some time ago I applied fairing compound to all the seams in the cabin interior, to hide any unattractive joins or gaps.

They now needed to be cleaned up and sanded smooth.

Here is the finished article on the starboard side of the cabin.


And here is the forward cabin wall, with the backing plate nicely faired in.


Sanding these seams was a horrible job. It had to be done by hand and created a lot of dust.

Here is a top tip for sanding right into tight seams. Use an old plastic card and a folded piece of sandpaper, like this.


The card is hard and rigid, but slightly flexible, so you can sand right up to the seam or join and get a neat, clean edge.

Time to think about painting the interior. The manual says to do this when the boat is upside down but I can't see how that would be easier than doing it now.

I'm looking forward to that!

Air Bubbles & Patches

Way, way back when I 'glassed the upper hull I managed to get a few small air bubbles underneath the cloth.

I marked them with a bit of blue tape so I wouldn't forget where they were.

Here is one on the forward cabin wall, in the forward deck well.


This one I created myself when I used the hot air gun to remove a temporary screw. The heat must have forced some air out of the wood.

I will sand out the bubbles and apply fibreglass cloth patches before I clear coat the upper hull.

Building Flip Cradles

We can't realistically flip the boat yet to finish the bottom. There are still too many pandemic restrictions in place for me to comfortably ask people to help me turn it over.

However, with the time available I can do everything that remains to be done before the flip.

When upside down the boat will need to rest on a support of some kind at bow and stern, and the supports will need to be on wheels to allow the boat to be moved.

After some experimentation and measurement I devised this cradle for the bow.


It is actually a dolly rather than a cradle, made from cheap studding timber and fitted with braked casters.

And here are both dollies outside.


The bow dolly is 30" wide and will need to be chocked up to a total height of 10 1/4" when in use.

The stern dolly is 72" wide and will need to be chocked up to 17".

They were set aside to await deployment when feasible.

I will need to find a way of providing a flat surface on the driveway to roll the boat out of the garage. The driveway is coarse gravel and impossible to navigate for anything with small wheels.

But it's good to know that the dollies are ready and waiting! 

Mast | Clear Coating

The mast received the first of three clear coats of epoxy resin in situ on the boat.


I put a piece of plastic sheeting under the mast where it rests on the boat, and in this way was able to cover all four sides at once.

Mast | Rounding Over & Sanding

It was time to finish the mast in readiness for clear coating with resin, so outside it went for rounding over the edges.

Routing edges makes a lot of mess so I always do it outside, like this.


This was done with a bearing guided 1/2" round over cutter in the router.


The bottom 30" are left square, where the mast resides in the tabernacle. Here you see the small shoulder where the round over stops.


The tape told me where to stop routing.

And here is the top of the mast, rounded over with a rasp and sandpaper.


 Then the mast was taken inside and sanded smooth, as here.


Here is the sanded shoulder, looking nice.


Lastly it was stowed back on the boat to await clear coating.


We're getting there!

Mast | Trimming & Cleaning Up

When the front face of the mast had well and truly cured I took it outside and sanded the seams smooth.


The seams aren't all as tight as I would have liked, but they look fine and are certainly good enough.

Then I trimmed the excess material off the ends. Here is the masthead.


And here is the foot.


Finally (and with some relief) I stowed the completed mast on top of the boat to await finishing.


All is well that ends well!

Ship's Cat!

The household welcomed a new feline resident at Christmas. She has recently started to visit me in the workshop and has even shown some interest in the boat.

Here she is, checking out my workmanship on the upper breast hook.


She is actually a very sweet and pretty cat, although she looks rather demonic in this pic!

Mast | Gluing In The Front Stave

The front of the mast was ready to be glued in place, so I made sure all the clamps used for the test fit were to hand. As here.


Glue was applied and the front piece fitted and clamped and left to cure, like this.


Fingers crossed that it turns out well this time! It should do, and like the rudder I actually think the mast is a bit better structurally for a partial rebuild.

Mast | Test Fitting The Front Stave

When the mast's front face was correctly marked up I cut it out and carefully trimmed it to obtain a snug fit in the mast itself. 

Here it is, dropped into the mast rebate and test clamped.


That's not looking too bad!

Mast | Marking Up The Front Stave & More Drama

As with the original front stave I marked up the front piece by measuring from both edges at each of the 9 stations on the drawing, where station 0 is the foot and station 9 is the top of the mast.

It immediately became obvious that something was not right. The taper was not correct at the top of the mast. On reflection this could only be due to the stave not being exactly straight, and sure enough on examination it proved to be very slightly curved i.e. the scarf joint was not exactly true.

The only way to mark up the front piece was to draw a centre line on one of the two pieces which formed the stave, and extrapolate it along the second piece to get a true centre line for the front face along  the full length of the stave.

I did this and marked up the centre line.

This is what the centre line looked like at station 9 i.e. the top of the mast.


This shows that the extrapolated centre line is some way off the centre of the stave.

Luckily the curve was slight enough to still allow the front piece to be made. This is what the stave looked like at station 9 after the front piece had been marked up.


There was still plenty of wood from which to cut the front face, so all was still well.

Now I know why the scarfs on the pieces supplied in the timber package are all cut edge-to-edge. They require a lot more wood to make them but you can't go wrong when gluing them up. As long as they are clamped tightly to a flat surface they will be correctly aligned.

I learned something here. From now on edge-to-edge scarf joints will be my norm on wider stock.

Mast | Clear Coating The Interior

Having cleaned up the interior of the mast I thought it would a good idea to give it another clear coat of resin to fully seal it.

Here is the mast with its clear coat in the workshop.


I left it to cure while I made the front piece.

Mast | Cutting Out The Old Front Stave

I now faced the tricky problem of removing the front of the mast. I could see no option other than cutting it out. 

So I set the circular saw very carefully to cut the exact depth of the rebate in the side staves and ran it repeatedly along the length of the mast while adjusting the fence to effectively excavate the front stave.

This technique worked well. I didn't take any pics - I imagine I was too preoccupied with not wrecking the mast to bother with the camera!

This was the outcome. In this pic I am cleaning up the rebates and hacking out the excessive squeezed out resin.


Chisels and an abrasive wheel did the trick.

This is the interior of the mast, close up.


And this is the interior at the foot of the mast.


One good outcome of this is that I was able to see that the rest of the mast was soundly made.

Next is making the new front piece!

Mast | Making A New Front Stave

Clearly there were only two options available to fix the problem of an uncured seam in the mast - replace the front stave or build a new mast.

I seriously considered the latter but decided that too much work and wood had gone into the mast to merely scrap it, and in any case it was 75% sound.

So I decided to replace the front stave, and purchased enough Douglas Fir to make a new one.

The other staves were made by joining two or three pieces of wood with scarf joints to make 16' lengths.

These scarfs came pre cut, which was great but I noted at the time that the scarfs were cut edge-to-edge rather than-face-to face.

A scarf joint needs to be 10 times longer than the thickness of the timber, so edge-to-edge joins on 3" x 3/4" boards are over 30" long as to opposed to 7 1/2" for a face-to-face join.

I therefore expected the new timber to be cut for edge-to-edge scarfs, but it wasn't.

When it arrived I measured the two pieces and there was enough to make a 16' stave using a face-to-face scarf, so that's what I did.

Here I am marking up the scarf on the first piece.


A stiff steel rule clamped firmly in place and a marking knife make this easy.

The scarfs were cut with the jack plane and test fitted, as here.


It looked good so I went ahead and glued the joint, like this.


I clamped the join to a piece of straight timber to make sure that the two halves of the stave were aligned, as here.


The the joint was left to cure while I tackled the old front piece in the mast.

Mast | Resin Woes & Tenth Cock Up

I left the mast to cure for a couple of days and then sanded off the squeezed out epoxy resin, leaving nice clean joints.

The following day I was dismayed to find that sticky glue had oozed out of the whole length of one seam on the forward face of the mast, meaning obviously that it had not cured - and never would.

This is what it looked like.


You can see that the seam on the left has fully cured, whereas that on the right is still soft and sticky.

This was a real problem. It was not as if the mast is a small or simple component which could be easily remade. Many hours and a lot of wood had gone into building it.

Clearly I had done something wrong when mixing the resin and gluing up the front stave.

Then I remembered that towards the end of the gluing session my resin suddenly became very thick and gloopy, and refused to pump easily. I switched the pump to a new container of resin which improved but did not eliminate the problem. The uncured glue must be connected to that.

I asked the supplier what had gone wrong and they explained that the resin will sometimes crystallise if the ambient temperature varies a lot. If crystallised resin had been used it would not cure properly.

So that was it. Something similar had happened when I glued the companionway sill in place and I had also been mystified then.

So I now had to decide what to do. Definitely a complete Cock Up!