Saturday, March 31, 2007

Fairing and closing holes

I'm now working on both floats. When one is curing up I can do work on the other. My plan is to laminate the outer layer this easter. ( Yes, I got a 10 days holiday.) So to do this I need to fair the outside.

I am a little in doubt here, since some of my foam is scallop which means that a single sheet of foam hollows from edge to edge as much as 2-3 mm. This has to to with hot forming foam. I found in the end of the process that each piece of foam has a curved shape so by placing this to the outside and heating from both sides some of the scallop can be overcome. I could fill this before i laminate or after, or both. So I settle on the latter, bought a 50 m roll of good quality 40 grit sanding paper, and made up a 1 m longboard from 6 mm plywood.

Also bought 10x 0.3 kg of microballons as this disappears fast from the stores, so I hope I got enough of this expensive stuff.

I then faired one side of a float to see how it worked. Use a thin batten to see if hull is fair. After filling lows i sanded with longboard for about one hour, then sanded all with the orbit sander with my vacuum cleaner attached. I just worry to fill to much as it adds weight but I do need to fair the hull some way or another. Maybe I sand the foam more roughly before filling next half.

Tips: When filling with bog (here, microballons and epoxy) I found that the bog gets more and more dry as you work it on and of the foam, this is because the epoxy gets squeezed out. So i just have a little cup with some fresh epoxy, I add a squirt and mix with the remains. This way the consistency remains the same. To dry bog is very hard to work with: it rolls of the foam and is almost impossible to level with the trowel. I use 3 sorts of filling knifes/trowels, a small for use in the bucket and two wider ones for spreading.

I use a router to fit high density foam. I think this is a easier way than doing it while still in foam frames.

I close all holes to make vacuum bagging more easy, except the big hatch which is already glassed. The bag will seal around the edge of this. Also stern and bow is now closed. I fit a bumper to the bow later so hull is kept watertight if a front collision should appear.

I close the bow with a pregassed sheet ( a cutof from a hatch). Later a bumber piece well form the bowprofile.

End of this fine day. I start now to take a shot from this corner to see the how things change from a bigger perspective. The grey stuff on the nearest float is S-fill a twopart epoxy filler ready to mix and apply. I bought it for fairing outside after glassing so this is just a test to see how it is to apply and sand. Very easy to apply, easier than my homemade filler.

Sunday, March 25, 2007

Inside floats

It's been awhile, but I am back in blogging business. So what happened?? First I got the joined hulls away from the floor so I could remove the strong back, after care full making the position on the floor for reuse for the main hull. Then I sanded the floor to give it two coats of 2part varnish I was generously given by Jorn Bagger (see ealier blog: the guy in the grey work suit, a great friend of mine). This makes cleaning much easier, since glass fibre stick to anything, so a smooth floor makes it easy to sweep.

I then started taping the half floats together:
First a fillet of glass bubbles and epoxy is spread with a bakers bag, and smooth of with a stick.

A glass tape is saturated with epoxy using a plastic sqeegee. I use this plate with a vacuum tape edge, and a plastic sheet. Then I can easily change the plastic, the next day. The plate can be moved around as well.

This is a bit tricky to reach all areas, so a stick to place the tape is handy, as well as a long brush. Peel ply is used to help create a smooth surface, this I found out during the fitting of bulkheads. I cut a 10 cm roll out of the big one I got so it is easy to apply a strip to the glass tape.

The gusset between stringers ready to glass in place. Gusset is foam, glasssheated.

The finished chainplate with carbon and glass on top

I fitted a high density foam in after i fitted the chainplate to see what i was doing inside. The big mistake here is that I should have fitted the chainplate before i joined the hulls, much easyer and better. Chainplate testfitting.

A selection of the tools I used so far, including nailboard in middle to perforate bulkheads before vacuumbagging. Japanese saw is great for trimming foam with only one side glassed, since it cuts when pulled so glass is not forced away from foam but against. This is not all the tools I used but most.

Saturday, March 3, 2007

Preparing float for joining

Elevated top half with a stack of insulation plates. I can lift the half with one arm and push the plates under bulkhead to support while cutting holes. This is lightweight building. I am used to heavy oak wood so it is quite a relieve to work with these materials.

End of float need a little adjustment but these half's fits very well, within millimeters.

Checking where to put battens before gluing so edges match up. It is like edges pops out of shape when released from mold, but easy to match with lower half, and once glued they stay in place. Note that I still wear ear protection, my wife is present.... ;-) Sorry but that was just the only stupid comment I could think of now.