Friday, 28 November 2014

Lead keel pour

After hiding from it, procrastinating and being down right scared of it the time had come to pour the keel.  I had previously purchased some lead, and bought another couple of hundred kilograms of ingot and about 200kg of lead flashing, dive weights for a total of about 934kgs.

Mold calculation was for 800kg plus 20mm oversize on top (120kg) to allow for final finish of the keel.  This meant a total of about 920kg's in the mold.  I had a kind offer to borrow one from someone on the woodenboat forum (Thanks Peter, Coopers Pale Ale on the way!) and this would be the four or fifth keel melted in it.  Also bought some antimony to harden it a little bit, should end up about 3% of the total.

Got the Tradesman organised (my Dad), and it was on.  A few nights before I started having trouble sleeping.  The first dream was I was melting it in an old steel boat (don't ask me why) which had holes in it and all the lead just ran out on the ground.  Then the night before I woke up three hours early thinking about it.

My wife asked me what my confidence level was.  I said 80%.  I knew the melting pot could hold the amount of lead (about 77 litres when melted) as one of the previous keels was 1.2 or 1.4 tonne.  My 20% concern was sealing the outlet.  The outlet underneath was a 90 degree elbow, with the inside vertical entry blocked by an internal pipe with holes cut in the side, also with a metal cone like piece on steel reo that fitted into the pipe to block it.  This was to be sealed with clay.

In short it was my fault.  I was too worried about not getting the clay off and went too thin on the covering.  We lit the fire and Dad and I left to get some course sand to line the hole we had dug for the mold.  We did not put the mold in the ground the day before the melt as we didn't want it to get wet from rain or dew, or to absorb moisture from the ground.  Part way home I got a message from my wife, lead was leaking out of the elbow on the pot onto the metal u-channel used to transfer from the pot to the mold.

Mild panic attack on arrival, although the lead was not gushing out.  We didn't add any wood to the fire, got a palm sized ball of clay, a rounded off piece of wood and jammed them into the outlet of the elbow.  We then packed more clay all around it and prayed.  No more lead came out!

Stoked up the fire, put some sand in the bottom of the hole,stuck the mold into the ground and piled up the sand around it.  Then we got into our protective gear (overalls, respirators, hard boots and welding gloves) and the fun started.  Once the ingots were melted and the rubbish skimmed off we added the lead flashing keeping aside some dive weights and pieces for after the pour.

Once it was all melted we used a petrol powered leaf blower, via a long metal pipe, to force air into the fire.  Unbelievable how hot it got, we could only run the blower on idle!  Once the antimony was melted (around 640 degrees I believe) we let it go.

A picture paints a thousand words, hopefully a few more answered below.  Still have to take it out and clean it up but the beers we had after the pour never tasted better......

Tuesday, 4 November 2014

Cabin sides and roof on

I have a cabin, and it is really starting to look like a boat!  At least the front two thirds anyway.....

Last post I had just put on the cabin front and the supports for the roof.  I continued with the air boxes/lockers each side putting the fronts in place, with generous epoxy fillets.  Below shows the fronts on, and the insides where it steps back for the mast tabernacle.

From overhead showing the insides of the vent boxes:

And a close up from the sides.  It is hard to make out but air comes in on the left where the round hole is, is forced down by the first ply (there is a gap underneath but it doesn't look like it), travels up over the top of the second ply and continues into the cabin through the right side second hole.

The cabin sides are two layers of 9mm ply, screwed on 100mm centres into the bottom and top carlines (I think they are called) and into the frames where extra wood has been added.  Sorry for the poor focus, this is the starboard side epoxied and screwed in place.  You can just make out the screws along the botttom.

The laminated curve beam needed a curved knee.  The plan called for making it out of laminated strips and cutting it to shape.  I decided that I would match the other existing knees which were two pieces of 20mm thick hoop pine.  I made the knee first, the forward one below and notched it into an existing space I had accidentally left (I had used a short piece of lamination on the bottom of the curved beam).  The knee sits underneath the beam supporting it.

I started to make a second identical knee which would continue up to the top of the beam and be epoxied to both,  As I was about to cut it out I decided it would make a perfect place for a grab point, and also match the ones near the galley.  So I cut out a hand hold and left it.  When I attached the sides I put three screws into each part of the knee from the outside of the cabin side and screwed the top down into it as well.

Below is the port side of the cabin screwed, epoxied and filleted in place, with clamps as well looking aft.  If you look closely along the bottom edge, just back from the front you will see a drain hole from the deck locker/air vents to allow water to drain over the side.  The camber of the deck should assist nicely.

And looking forward a bit closer showing the screws and fillets.  Vertical screws at the rear are off set to they don't hit the ones on the rear of the cabin.  Part way down you can just make out the six screws into the knees, and all the way forward the vertical screw lines into the frames and deck box front supports.

Then it was time to close in the roof, for me a very exciting progression.  The roof is two layers of 6mm ply.  Below is the middle section of the first layer epoxied and screwed in place.  Clamps only at the rear, more on that later.

The cabin was too wide at the rear for a single sheet, so I decided to have the first layer in three pieces so the final layer I could have two larger pieces joined down the middle.  This means no overlapping joins, and I can fibreglass tape the join on the final layer as well.  It appears the designer has taught me something from the hull and deck as this seemed very familiar.

Once that was done, out came the trusty electric plane and belt sander for a "minor finesse" of the cabin sides to match the existing slope on the solid wood.  Below is looking forward on the starboard side.

Then I cut out, drilled and countersunk the pieces for each side and stuck them on.

I thought I'd taken a photo of the first layer in place but couldn't find it.  Looks the same as the ones of the second layer anyway.  Below is looking aft, the cut out at the rear is for an access hatch into the cabin  Note the join down the centreline which will be taped later.  All screw holes are also filled with left over epoxy.

A slightly closer look, forward space between the vent holes is where the mast tabernacle goes as I said before.

And a shot looking forward.  I put screws all around the hatch space on the final layer, I have to build the hatch so wanted to leave plenty of space between them for screwing into for that.  Had to move my fluorescent light inside, it's getting darker in there!

I've borrowed a pot to melt my lead in for the keel cast, while I sort out the remainder of the lead and psych up I will look at maybe taping the hull/deck, cabin/deck, cabin sides/top and cabin centreline joins.