Monday, 11 November 2019

Floorboards | Finishing With Danish Oil

The floor boards were all complete and awaiting a finish. I decided to use Danish oil, purely because that is what the builder in the manual used and I figured that if it is good enough for a professional then it must be good enough for me.

Danish oil is apparently a blend of Tung oil and solvents. This is the brand I selected, having read good reviews of it.

And I decided to try foam brushes out for the first time, again having read great things about them when used for varnish. Here they are.

They are excellent, allowing fast, easy and accurate coverage with no mess.

I used just under a litre of the oil to apply four coats to both sides of the floorboards. That should take care of them.

When the odour had disappeared I moved them into the house to harden off completely before being set aside to await final and permanent installation.

This is the TV lounge currently.

We are getting there! My next job is to tidy up the interior of the hull and paint it before refitting the floorboards for the very last time.

Floorboards | Making The Lift Out Sections

With all the floorboards rounded over and sanded smooth it was time to make the lift out sections, which of course entails the nerve wracking business of cutting full length floorboards into three pieces.

So I measured twice, and cut once. The results were excellent. I used the mitre saw to ensure that the cuts were accurate and clean , as below.

The pieces of the lift outs were then joined together by three cleats made from scrap Ash. Here they are, glued up and fastened with temporary dry wall screws.

It remained for me to drill the finger holes. These had to be quite large at 25mm and perfectly vertical, with a very clean cut and crisp edges.

I experimented with the router and a plunge cutter, but it was a failure. A hole saw would probably work but I could not be sure of drilling true vertical holes with a drill and I was not sure of the quality of the cut.

What was really needed was a Forstner bit, which is specifically intended for this sort of job. Forstner bits though are for use in pillar drills. In the sure knowledge that I would face this problem again in the build I decided to invest in one.

I looked at the pillar drills in my preferred tool store. The biggest craft and hobby model was too toy-like for the job, and their entry level trade model was enormous and immovable.

I needed something in between that would be good enough to drill stainless steel tubing when the time came, as well as hardwood floorboards now.

I found another tool store online which sells a vast range of pillar drills and called them to ask for advice. They were very helpful and recommended a model between their craft/hobby and trade ranges which can satisfy my requirements but is small and light enough to store in a corner when not in use.

So I visited the store and bought one. I also  purchased a set of top quality Forstner bits by Fisk. Here are the bits.

And here is the drill, set up to drill the first finger hole with a 25mm bit.

Here is a close up showing the drill clamp which I purchased with the bits to hold work down firmly on the drill table.

It was set to a slow speed for drilling hard material, and after a few tests I drilled the finger holes. It worked brilliantly! Here is one of the holes after drilling.

The temporary screws were removed and replaced with silicon bronze wood screws, and the lift out sections were ready for finishing.

That was good fun! I love my new drill ...

Floorboards | Levelling The Planks

During the whole exercise of fitting the floorboards it became obvious that some tuning of the height of the floors would be required to get them to sit level and fit nicely.  So out they all came again!

Shims were required on bulkhead 2 and floor 3, and I also decided to increase the width of the sister cleat on bulkhead 2 because I didn't think there was enough material for the screws to securely hold the floorboards. I made the shims from plywood scrap, tapered to make the floors level. Here are the modifications being glued up.

I also fitted an insert to the port side of the cleat on bulkhead 8 because it was not long enough to securely fasten down P4. Here it is.

I made and fitted mini cleats to floors 4 and 6 to support the lift out floorboards because the floor by itself was not wide enough for the job, as here.

Lastly all the floorboards were refitted (for third time!) to check for levelness.

All was well! Finally all the floorboards were taken out (again!) and rounded over with a 3/8" bearing guided router bit, and sanded smooth.

Floorboards | Fairing The Planks

Marking in a fair curve to the floorboards requires a long, flexible strip of some kind. I used a length of wooden edging.

Here is the batten held in place by spring clamps against nails pushed between the floorboards.

When the curve was marked to my satisfaction I removed the boards one by one to do the final trimming with the jack plane, and then replaced them to check the final fit.

Here are the trimmed boards, all in place.

Now I can stand in and move around the boat with ease. Hooray!!!

Floorboards | Fitting The Curved Planks

With the easy-to-fit full length floorboards in place I now faced the challenge of making the shorter boards with curved ends, and in the case of the outermost boards entirely curved sides.

I must say that in common with some other builders I felt somewhat abandoned by the build manual at this point. It devotes just three pages and five photographs to what is actually a really big project. You can tell that the writer of the manual was not the builder of the boat!

My first question was how to shape the edges of the floorboards where they meet the sides of the hull. Should the edges be perpendicular to the top of the boards, with vertical edges, or should they be chamfered to lie flat against the hull sides? The manual offers no clues, and I could find examples of both approaches in builders' blogs.

However, common sense prevailed when I realised that a chamfered edge would require the planks to be longer and wider than they are designed to be. So that was easily answered.

My next question was how do I mark up the curved ends and edges on the floorboards? It was easy to see how the final fairing would be done, using a batten on the fitted boards, but how do I cut the boards to shape without removing too much or too little waste for them to fit?

I tried making a pattern but that didn't work. Then I tried spiling from the side of the hull onto stock, but all that did was mark in the curve that would be required if the boards were chamfered.

In the end I figured it out from other builder blogs.

First you need to mark where the full width floorboard first touches the side of the hull at both ends. This point is where the curve begins. In the pic below, X marks the spot where the full width of P5 meets the hull at the bow.

Mark this on the floorboard, then draw a straight line to a point at the end of the board which removes enough stock to allow the board to be fitted but leaves enough for the final curve to be faired in. Like this.

Here is P5 fitted in place. You can see the gauge being used to mark the position of pilot screw holes on floor 4, and the spacers to hold the planks 1/8" apart. I held the boards lightly in place with bar clamps, just to stop them from moving while I was marking up. 

Not all the floorboards had perfectly straight sides, unsurprisingly, so needed a bit of trimming to make them sit neatly alongside each other.

Here P5 is being trimmed with a big Lie Nielsen panel plane which I bought ages ago for just such a job. The jack plane isn't long enough to do this.

You don't need a plane like this very often, but when you do it really is the only way of getting a true straight edge.

So that's how I fitted the curved floorboards ready for final fairing. It's a bit hit and miss and is not very scientific, but it works.

Here are all the floorboards fitted, looking aft.

You can see in the picture below that the curve will flow between the points where each side of the board meets it's neighbour. The trick is to leave enough waste in place to scribe in the curve.

The next step is to fair in the outline of the floorboards.

Floorboards | Fitting The Rest Of The Full Length Planks.

There are eight full length floorboards running from bulkhead 2 at the front to bulkhead 8 at the rear of the hull - four on each side of the centre board case.

I refer to them as either port (P) or starboard (S) and by number, going from the centre board case outwards to the side of the hull.  Thus P1 to P4, and S1 to S4

Fitting them does not require a lot of work, other than making sure that they are the required 1/8" apart.

However, it does require focused attention and bearing in mind our mantra mentioned in the previous post ("measure it twice, and cut it once") I immediately made a silly mistake when marking up and drilling the countersunk screw holes.

There are lift out sections in the floorboards, two boards wide and on both sides of the boat. They run between floors 4 and 6, meaning that the lift out boards do not require to be fastened down to floor  5.

The first plank I marked up and drilled was P2, and of course I forgot that the lift out does not require screw holes.

So I cut and fitted ash plugs to fill the holes, hoping that they would not be noticeable. They are ... at the time I considered it to be a big deal but on reflection it is a purely cosmetic issue, so I downgraded the incident from Cock Up to Silly Mistake.

Here are P2 and P3 being test fitted. You can just make out the bungs in P2!

I used a countersink drill bit in the plunge router to bore all the screw holes. Here it is.

Before each plank is fitted pilot holes have to be carefully drilled in the support floor or bulkhead cleat.

The planks were fastened down with temporary dry wall screws, which will be replaced with silicon bronze wood screws when the planks are permanently installed later in the build.

Here is S4 in the process of being fitted. A drill driver makes short work of the very many screws, and a piece of stiff wire is useful in aligning the floorboard with the pilot holes.

There is insufficient room for a drill to be used below bulkhead 7 and below the cleat for the cockpit sole on bulkhead 8, so a new tool had to be purchased.

This right angle drive made it easy to drill pilot holes and drive screws in tight corners. An excellent piece of kit!

Here we see all eight full length floorboards fitted. Note the unusual pattern and colouration in the grain in P4 at the rear. I don't think it is very attractive but as with the plugs it is a purely cosmetic issue, so I placed that plank where it will be hidden under the cockpit decking - out of sight and out of mind!

The next step is to fit the curved floorboards, which had me scratching my head for a bit ...

Floorboards | Marking Up And Fitting The Central Planks

At last the time had come to make and fit the floorboards! I had really been looking forward to working with some real wood again, and setting the epoxy resin aside for a while.

Now, the Ash provided to make the floorboards is beautiful wood and it would be a crying shame (as well as expensive) to waste any of it by careless working. So the mantra for this phase of the build would very much be ... "measure it twice, and cut it once".

Bearing this in mind, the first task is to fit the two central planks which run along either side of the centre board case. This requires a section to be cut out of each plank to accommodate the case.

Rather than directly mark up and cut the planks themselves, I made a pattern to be sure the fit was correct before any wood was cut. I wanted to be sure that the width of the cut out would ensure that the two central planks would sit 1/8" apart when fitted, and that the curved front end would sit nicely around the case.

Here is the pattern, slid into place. This is how I wanted the planks to fit.

When the fit was correct I used the pattern to mark out the waste section on both boards, like this. 

Only when I was completely confident did I get out the saw, planes, chisels and rasps.

Lastly I test fitted them, as here.

So far, so good. I have floorboards!

Thursday, 19 September 2019

Getting Ready To Fit Floorboards | Spacers & Marking Gauge

While I pondered how to begin actually fitting floorboards into the boat it became clear that accurate positioning of boards and screw fastenings would be critical. Any discrepancy would be very visible and unsightly.

To start with, the boards have to be uniformly 1/8" apart. To achieve this I made some spacers, using nails which are exactly that in diameter fitted into holders made of scrap ply. Here are the spacers.

They look a bit lethal, don't they?

And to ensure that the screw holes are always in the same place on every board, I made a marking gauge. Here is it is.

The idea is to slide it along the edge of the board until the upper and lower pencil lines exactly align with the floor, and then use a bradawl to mark the screw holes through the two holes drilled on the centre line.

Tests show that they both work well.

I can't claim any original thought here. I copied these tools from another builder's blog. Thanks Ron!!!

Getting Ready To Fit Floorboards | Making Rebates

As recounted in the previous post, I had to sister the cleat on bulkhead 2 to compensate for it being attached 1/2" too high.

The floorboards are 3/4" thick, so I would have to cut a 1/2" rebate in the face of the forward end of the affected boards for them to sit snugly against the bulkhead.

I decided to use the router and a 1" two flute cutter, with the fence attached.

I also made a jig to hold the boards securely in the correct position, and to provide a long and even face for the router fence to move against.

Here is the set up with a board in place before the rebate has been cut.

And here is a board with the rebate cut, nice and clean.

Eight boards in total butt against the bulkhead, so I selected eight lengths of Ash and chose which face to be uppermost, and cut the rebates.

It has been a lot of extra work to remedy the unexplained error, but I am confident that the outcome will be satisfactory.

Getting Ready To Fit Floorboards | Fourth Cock Up

When the deck and cockpit support cleats were all fitted I was very excited to break out the timber for the floorboards and to start preparations for making and fitting them.

I had long been aware that floor 3 was a fraction lower than the other floors, but I wasn't worried about that because a thin shim would be easy to fit - if indeed it was even required .

So to check out how level the floors were I laid my newly acquired long level across the floors, and immediately discovered that I had a hitherto undetected and serious problem.

The cleat on bulkhead 2 where the forward end of the floorboards land is 1/2" too high. Not just a few millimetres, which I could probably understand and live with, but a big fat half of an inch. Here is the level with a steel rule attached showing the actual as opposed to the required level of the top of the cleat.

How did that happen? I still can't work out what went wrong.

Initially I thought that bulkhead 2 must be too high in the boat, but it isn't. It is correctly positioned and the cleat is exactly where the drawings say to fix it, so I am at a loss to understand it.

I didn't immediately panic and do anything rash, and I posted on the CLC PocketShip forum asking for advice. It seems that this has happened to other builders, at least one of which hacked out the cleat and fitted another one. There was no way that I would do that … so after a bit of thought I decided to sister the cleat i.e. fit another piece onto it but at the correct height, with another piece behind it to butt up against the bulkhead.

I liked this idea because it would give the floorboards more of a ledge to land on and allow the fastenings to be a reasonable distance from the bulkhead, rather than right up close to it as designed.

So I made the sister cleat and dry fitted it, as here.

It worked very well, and I was so pleased with it that I decided to sister the cleat on bulkhead 8 as well, where the aft end of the floorboards land, to give more room for the fastenings.

Here are the two cleats which I made.

 The one at the top is the cleat for bulkhead 2. You can see the backing piece fitted to its rear face which sits under the original cleat and butts up against the bulkhead, making one single solid fixture.

Here is the extra cleat fitted to bulkhead 8, held in place with temporary screws.

And here is the additional cleat glued up on bulkhead 2.

The floorboards will require a rebate to be cut in the front face to fit over the original cleat, hiding the sister cleat from view. That's the next job.

Fitting Deck And Cockpit Cleats

Now that the finish of the hull interior surface was complete, it was time to fit cleats to support the rear deck and cockpit. This promised to be quite a big job, and required some careful thought and planning to make sure that the cleats go in the correct location.

I started by dry fitting cleats to bulkheads 7 and 8. Their location is obvious and fitting is straightforward.

Here is bulkhead 7.

And here is bulkhead 8.

The location of the cleats on the transom is marked out by extending a straight edge from the bulkheads back to the transom itself, like this.

I taped a steel rule to a builders level to achieve this. I initially tried to use a short level which I already had, but it didn't work very well and after wasting some time getting inaccurate results I just went out and bought a good long level. Problem solved instantly!

The same technique is used to mark out the location of the long cleats on the inside of the hull, as here.

And here.

The long inside cleats are held in place with temporary screws through the hull, like this.

Here are the transom cleats, held in place with temporary screws.

I found that I had to mark out and cut slots for the deck frames in bulkhead 8 myself, as here.

There are no pre-cut slots and the manual offers no guidance on positioning, so I just deduced it from the drawings and by lining up with the slot in bulkhead 7 and the cleats on the transom.

I hope I've got it right! The hull hardware package should arrive soon so I can check where the cockpit deck hatches will go before I deck over the frames, just in case remedial action is required.

Here are the rear deck frames, dry fitted.

When I was satisfied that everything fitted properly I profiled the exposed and visible edges of the appropriate cleats, using a router and a 3/8" roundover bit.

For this job I set up the router table, as above. The table is attached to a piece of kitchen benchtop so it is portable. I ran all the cleats through the table in no time at all.

Then I glued the cleats in place, with plenty of clamps. Like this.

When gluing the long port side cleat in place I immediately found that I had not used enough temporary screws. Friction holds the cleat when it is dry fitted, sprung into position with just three screws, but when glued up it slides out of position. I had to quickly drill for and fit more screws. Nine fastenings are required on each side to hold the cleats in place.

Here are the transom cleats glued in place.

While working on the footwell support cleats I also attached cleats to the footwell sides and test fitted them, as here, to make sure everything is in the right place. It all seems to fit nicely!

The final thing I did was to glue the rear deck frames in place. In the above photo they are simply dry fitted.

Now that the cleats are all done it seems incredible that the next job is to fit the floorboards before we deck the boat!