Saturday 16 February 2019

Getting Ready To Pour Lead

With everything complete that could be complete on the components of the hull, it was time to progress completion of the keel and the centre board by pouring the lead ballast.

I had purchased sixty kilogrammes of rolled lead at the beginning of the build, intending to use it as weights during panel construction, and very useful it was. But now it was time to start cutting it up for melting.

I bought three old stainless steel saucepans for a quid from a charity shop to use as crucibles, and a good quality pair of metal shears in a DIY store closing down sale.

The old fashioned kitchen scales and a two pound brass weight were used to weigh out the twenty pounds required to pour into the centre board ballast aperture.

This is what twenty pounds of lead offcuts looks like. It fills three saucepans and it's hard to believe that it will all fit into the centre board aperture.

I also bought a propane gas outside cooker burner to do the melting. It looks up to the job and will be handy in the summer for cooking in the garden!

The manual makes it clear that the melting of the lead must be done outdoors because of the toxic fumes, and in dry weather because molten lead and water are a dangerous mixture.

As I write this in February 2019 it is cold and wet, so we are at a halt while we wait for dry weather.

Topside Panels

The topsides are the long narrow panels which when fitted will be the top of the cabin sides and outer wall part of the cockpit sides.

The topside panels were the first ones I worked on after the keel and centre board assembly. They were narrow enough for me to use my work bench as a surface to glue the puzzle joints, like this.

The rolls of lead were in use on the side panels while they were being glued up, so an alternative weight had to be found for gluing the puzzle joints on the topsides.

Bill's wildly tasty fat balls served very well, as you can see.

The topside panels were then stored inside the house until the other panels were finished. They would not be required until much later in the build, whereas the side and bottom panels would be needed immediately the keel is complete to start the construction of the hull, so they were the priority.

By the time I was ready to 'glass the topside panels I had the three tables in place so I had room to process them both at the same time.

Here they are just after the 'glass cloth had been wetted out.

And here they are trimmed and sanded, ready for two more coats of epoxy.

This is the final coat of epoxy, curing slowly in a cold English February.

And finally here are the panels after sanding to a P120 paint-ready finish. Now I need to store them away until they are needed in the build.

Centre Board | Second Cock Up

I started the centre board at the very beginning of the build, while I was constructing the keel. The first step was to glue the two halves together to form a strong 18 millimetre thick board.

Here is the centre board glued up and clamped, and with plenty of lead weights to squeeze the two halves together.

This the board, cured and with the squeeze out cleaned up.

The eagle eyed PocketShip builders out there will see that I had made a simple but important mistake - I had glued the outer faces of the two halves together!

The result was that the designed rebate around the inside of the aperture to retain the poured lead ballast was no longer a rebate. It was now a sort of ledge, like this.

Quite what made me do this I really cannot say. And it wasn't until much later when I put the centre board drawings up on the wall for reference that I realised what I had done! I would need to think of a way to fix this. I could not see how this could retain the lead securely.

Before I tackled the aperture problem I cut a rebate in the leading and trailing edges of the board, as recommended in the manual.

I used my router with a 3/8" two flute cutter. It worked just fine.

Then I filled the rebate with thickened epoxy. This will provide the board with an armoured edge to protect it from damage.

I used pieces of ply covered in sealing tape to hold the epoxy in place while it cured, so it could not run down the vertical part of the rebate.

This was done in two or three stages to fill both leading and trailing edges, with the board clamped to a saw horse.

Finally I sanded the edges flat ready for shaping later, like this.

Then I moved on to the ballast aperture problem. I decided to cut back the 'ledge' to restore a clean, straight inside face to the aperture, and then to cut a rebate in that face. The router would be able to do all this, and a look through the Trend catalogue suggested that a slot cutter would be required to do the latter.

A trip to the nearest Trend stockist confirmed this. A slot cutter consists of three parts. The arbor is the spindle which is held in the chuck of the router; the slot cutter is the rotating blade which goes on to the arbor; and finally there is the bearing which guides the cutter and determines the depth of the slot. The cutter and bearing are separated by spacers and they are all held in place on the arbor with a nut. It looks like this.

Fifty six quid. That'll learn yer.

Here is the finished aperture.

I think it looks pretty good. It will take a bit more lead to fill it but that doesn't matter.

Next I fixed a piece of scrap ply over the aperture on one side of the board, like this.

This is to stop molten lead from leaking out of the underside of the board when it is poured to fill the aperture. I used plenty of temporary drywall screws.

The centre board is now ready to receive its lead ballast!

Bottom Panels

Fabrication of the bottom panels was straightforward. All I needed to do at this stage was to join the two halves of each panel together by gluing the puzzle joints with thickened epoxy. No 'glass is needed here because these panels need to bend quite a lot when constructing the hull and fibreglass cloth would make them inflexible.

Some experimentation with work surfaces soon showed that the saw horses were not suitable as supports for the bottom panels. The panels are simply too long and wide and require a long, flat work surface for support.

So I purchased a third folding collapsible table which when used end to end with the other two tables provides an excellent flat work surface of even height from the front to the back of the workshop, like this.

They easily accommodate the long hull panels and if the puzzle joint is positioned above the strongback where the legs are attached to the table they are stiff enough to take the weight of the lead weights when gluing the joints. They are made by Lifetime and are inexpensive picnic tables from the DIY store. I should have used these in the first place, instead of faffing around with saw horses! Clearly they are only useful for light work such as gluing joints and applying and sanding glass and epoxy, and are no substitute for a workbench.

Here is the first bottom panel glued up and curing.

And here is the second panel laid on top, glued and curing. A sheet of plastic between the panels stops them being glued together by the squeeze out.

I'm getting better at making these puzzle joints. These just needed a light sanding to clean them up.

Here is a finished bottom panel joint. My lovely wife said "Ooh, it's like a jigsaw puzzle, or an Airfix kit". Not amused.

And here are the completed bottom panels, set aside to await hull assembly.

Bulkheads & Floors

While I was working on the side panels I also manufactured the bulkheads and floors.

There are four bulkheads and four floors. The bulkheads are the vertical panels which make the hull rigid and support the deck and the cabin roof, and the floors support the floor boards.

The first task is to glue the cleats in place. The cleats are the horizontal supports to which the deck, roof and floorboards will be fastened. Here we see the cleats glued up and clamped on all the floors and two of the bulkheads.

There is a cleat on both sides of this bulkhead, seen here with one cleat in place. This bulkhead is the forward wall of the cabin. It's quite awkward to work on, being so large. The rolls of lead are clamping down the cleat where clamps cannot be used, and also holding the bulkhead on the bench.

This bulkhead is part of the cockpit structure. Most of this component is just for support and will be cut away when the bulkhead is installed later.

When cured the cleats were trimmed and smoothed, as on these floors.

All of the floors and bulkheads then received three coats of clear epoxy, sanded between coats with P80 grit to get a smooth, matt finish. The third coat received a final sanding with P120 grit to get a paint-ready finish. All this is necessary because these parts will be difficult or impossible to work on once installed in the hull.

This is the Rotex 150 sander at work. It makes short work of the sanding.

When completed the floors and bulkheads were set aside to await hull construction.

Side Panels

I started to make the side panels before I decided to cut out all the parts and store them away. You can still see the sheets of ply on the floor in the background while I worked on these panels.

First I glued the puzzle joint on one side panel, using a saw horse as a strongback to support the joint, weighted down with rolls of lead to keep it nice and flat.

I propped up the ends of the panel with the other saw horse and some offcuts on the two collapsible tables, like this.

I used too much thickened epoxy and made a shocking mess! I used this Bahco scraper and Shinto saw file to clean up the cured joint. I had previously purchased them from Fyne Boats to clean up the squeeze out on the keel and centre board assembly. The saw file in particular is excellent for removing rock hard lumps of epoxy. But as the guys at Fyne Boats said, the best way to get rid of this sort of mess is not to make it in the first place …

Because I don't have enough room or work surfaces to work on two panels at the same time, I then glued the other side panel on top of the first. There is plastic sheeting between the panels so the squeeze out does not weld them together.

Both joints worked out fine.

then I 'glassed the inside face of one side panel. Actually it doesn't matter which side you 'glass, as long as you 'glass its mirror image on the second panel.

I had some teething troubles laying out the glass cloth but got there in the end. The wallpaper brush is a great help when smoothing it out, and I found a decent pair of dressmaker's scissors are perfect for cutting it.

Again I used a disposable roller to wet it out with clear resin, and it worked well on this large area. With the roller I can saturate the cloth but still lay down a thin coat, leaving the weave prominent to fill with two more coats of resin.

I used graduated measuring cups to achieve the 2 to 1 resin to activator mix. I keep the epoxy in an insulated box which I store in the airing cupboard in the house so it is always warm, and I mix it well for at least three minutes before application. It works beautifully and I don't fret about the epoxy any more. And I just move pieces into the house to finish curing. It just takes as long as it takes!

Someone on the PocketShip forum recommended that I use an old credit card to spread the epoxy. I tried it but it was way too small to be effective. But I do now use plastic decorator's scrapers. I trim the edge with a sharp craft knife or my block plane to get a clean straight edge, and they work very well. I can quickly cover a large area with a nice thin coat. Here is the epoxy tool set.

When cured I sanded the panels to a matt finish ready for the next coat. Here I am half way through sanding one of the two 'glassed panels.

It took me nearly six hours to sand both panels, and it was at this point  I realised that the Rotex 90 is just too small for these large areas. So I purchased a Rotex 150, which is intended for large surfaces and is a lot more powerful. It can be switched between random orbital and geared rotary sanding, and it is an awesome piece of kit!

Then I applied two more coats of resin to each side panel, sanding with P80 grit after each coat and finishing off with P120 grit to leave a smooth, matt, paint-ready finish.

The Rotex 150 just ate this up, taking just two hours to do both panels. Here is one side panel, partly sanded.


The keelson is the long, thin, tapered panel which sits on top of the keel and connects it to the bottom panels of the hull.

It is a very simple component and manufacture was a piece of cake after the keel assembly!

Here is the keelson, with the two halves glued and clamped together on a saw horse.

And here is the cured puzzle joint, sanded smooth.

It was then tucked up in the workshop rafters, out of harm's way until required.

Keel & Centre Board Case Assembly | More Drama

This exercise is to create the backbone of the boat, by joining the centre board case to the sides of the keel to form a strong and rigid monocoque casing. I thought it might be tricky, and it was!

I had read one builder's blog where his keel turned out curved. He had to cut it apart down the centreline to realign it. I certainly didn't want that to happen.

I asked for advice on the online PocketShip forum, and as expected I learned that builders use a string stretched between the ends of the keel to make sure that it is true i.e. if everything is straight and true the string will be exactly over the centreline along the entire length of the keel.

This photo shows the dry test assembly of the port keel side and the centre board case. You can see the piece of string stretched between two pins in the centre of the frontmost and rearmost keel blocks.

If the keel is true, the string will exactly bisect the centre board slot and follow the centreline along the length of the keel. Like this, taken during the dry test assembly.

When satisfied that everything was true I started to glue the components together.

The centre board case was glued and clamped in position on the already completed port keel side, with the rear keel blocking and the nose block already glued in place.

The port keel side is underneath the centre board case.

Then the two halves of the starboard keel side were glued and clamped in place on top of the rear keel blocking, the centre board case, and the nose block.

This is when it all got a bit fraught.

I was still relying on the dispenser pumps to measure out the correct mix of resin and activator, and working at speed I was not confident that I was getting it right. I wasted a fair amount of resin because I did not trust it.

On top of that the components refused to slot neatly into place, as they had in the dry assembly. Now they were covered in thickened epoxy glue and they slid around under pressure from the clamps. Eventually I wrestled everything into place, using all the clamps that I possessed at the time to hold it together.

The clamps now fouled the centreline string which had to be removed, so I lost my visual confirmation that the final assembly was still true.

My lovely wife came to visit for a chat half way through this, and was politely told "Not now, darling".

This what it looked like all glued and clamped together.

Note the heavy rolls of lead holding the centre board case down on the bench to counteract the weight of all the clamps, as the keel had to hang over the edge of the bench during assembly to accommodate the clamps. The aft end of the keel is supported on a saw horse.

Also note the blocks inserted in the centre board case slot in way of the clamps to stop the slot collapsing under pressure.

I drew a few conclusions form this experience:
  • I would now abandon the use of dispenser pumps to measure the resin mixture. I would obtain graduated measuring cups to visually confirm the 2 to 1 mix.
  • For the assembly of multiple components I should use temporary drywall screws to hold them in place during gluing, so they can't slide around.
  • Test assembly of the more complex structures must be 100% comprehensive. Losing that centreline string was worrying.
  • If it can be done in two simple stages, then do it in two simple stages. This structure could have been glued up port side first and starboard side later.

Here is the assembly with clamps removed after it had cured.

And here is the stretched string back in place, exactly over the keel centreline. Phew.

I found that the keel sides were not exactly aligned. One side was a couple of millimetres higher than the other towards the front. Thinking about it I could not see that this was material. Such a tiny error would be cancelled out during the hull build with the addition of epoxy fillets, 'glass and resin. So I stopped fretting about it. It's a boat, not a piano.

This is the fully cured assembly.

The next step called for by the manual is the pour of molten lead into the keel (and the centre board aperture) for ballast, and the addition of the keelson to complete the keel assembly. The keel would then be placed in the build cradle ready for the lower hull build.

If I did that next the workshop would become pretty much full and I would not have room to make the big hull panels. So I set the keel aside and moved on to manufacture the panels.

Keel Blocking | First Cock Up

We next moved on to making and fitting the blocking for the keel. That's the royal 'we' - there's only me.

The rear keel tapers gently from the thickness of the centre board trunk to 3/4" at the aft end of the keel. A pattern is provided in the kit to mark this chord onto the timber for the horizontal bottom blocking.

There are two pieces of vertical blocking inside the keel - one which forms the aft vertical trailing edge of the keel, and one which joins the front and rear halves of the keel sides. You have to measure and cut the tapers on these yourself. It's not hard.

Here I have transferred the chord to the bottom blocking and planed it to shape. The pattern is on the bench behind the finished blocking. You can see the taper from the right hand end where it butts up against the centre board case to the end of the keel on the left.

And here we have dry fitted the blocking to the two halves of the port keel panel to check the fit. The vertical block in the middle joins the two halves.

And it was during this test fit that the first real cock up of the build came to light! The steel rule marks the line where the centre board case will reside, glued to the sides of the keel. As you can see the bottom keel blocking is too short. That's because I cut a piece off to conform with the length of the pattern. In other words, the pattern is too short! Much profanity was issued at this point.

The obvious solution would be to glue to glue the piece I had cut off back on to the keel, to fill the gap. No big deal, but very annoying. You know what they say … "Measure it twice, cut it once". Yeah, but you expect a pattern to be true, don't you?!

Here I have glued all the blocking in place, joining the port rear and front keel sides. The collapsible picnic tables are an ideal work surface for such activities.

And here is the missing piece of timber glued back in place. You can just see the pencil line marking the rear edge of the centre board case.

The next step is the assembly of the centre board case with the port and starboard keel sides and the nose block. I thought at the time that this could be challenging, and I was not wrong.