Wednesday, January 30, 2008

Another lesson learned on infusion. Unfortunately, I don't know which one.

After applying today's layer of fairing compound I continued the preparations for resin infusion of the beam bulkheads. When doing resin infusion you never stop having surprises. My approach to this technique is to read Henny's starter kit instructions and then try to anticipate what happens with a certain setup using common sense and what I remember from school in addition to Henny's tips.

The principles are after all very basic: Place your fabric, core and other elements of wish in the desired configuration, wrap in plastic, suck out all the air, then let the atmospheric pressure fill up all the empty spaces with resin. The hard part is to anticipate how the resin flows under different circumstances and in different distribution media.

Until today, I have infused all flat panels using inlet in one end and outlet in the other end. Today's part, however, had a non-rectangular shape and thus not ideal for this approach. I use a core with pre-drilled holes and 0° - 90° grooves for resin distribution. I place the grooves facing down. This works fine with my regular setup as the grooves distributes the resin very effectively. I decided to use one central inlet and outlet in the perimeter on this part and I did not anticipate any problems with this configuration. The picture below shows the setup just prior to infusion start:

So, based on my previous experience on the same core, fabric, peel ply etc I expected this part to be totally impregnated in 10 -15 minutes. I was quite surprised to see the extremely slow migration of the resin. Here after nine minutes:

And after half an hour of infusion:

This is what I suspect is the explanation: When doing the regular inlet one side outlet one side infusions, the inlet tube is at the end of the core. The resin migrates directly to the end of the grooves and distributes further along the part.
With this setup, however, the resin had to pass through the release film, the peel ply, then two layers of carbon fabric, through the holes in the core and THEN being distributed. I suspect the way from the inlet to the grooves were the bottleneck slowing the process down.

Anyway, after one and a half hour of speculations, most of the part was impregnated, the bucket of resin was finally empty and I left the building:

Final results will be reported when available.

Tuesday, January 29, 2008

More fairing and bulkheads

I do a light sanding between the layers of fairing compound. Making sure to do it before it is fully cured, the next layer can be applied without fairing the whole surface. At the same time letting the compound cure for a while makes it possible to sand down the high spots and the small unevenness from the previous layer. The paper gets clogged quite soon, though.

Here the second layer lightly sanded and the third layer on it's way:

After some fairing of the third layer, fully cured before sanding this time. Guess the sander had to take a break and it felt reasonable to utilize this time documenting progress... By the time I had sanded this side down until I met the hard spots the surface felt very even. I have decided I will hire a professional to do the final coating and I will not go any further in the finishing at this stage. I had a visit from a professional car body painter tonight and he confirmed my suspicion about the quality of the surface.

Doing the candy bag routine on the other side. Using an air driven cartridge gun makes it easy to apply these lines of fairing compound:

This next picture illustrates the point with this method. A low spot along the keel line, after fairing the ridges with the long board the fairing compound can be added very precisely and a lot of time sanding down wrongly positioned compound is saved.

Between the sanding I have started the preparations for the beam bulkheads:

Laying out the two layers of 200g carbon fabric each side, 0° - 90° and then 45° - 45°

The plans says no overlaps, but as this fabric only comes in one meter rolls that is not possible....

Temporarily fixed to the foam with 3M #77, a technique that I piced up at the resin infusion composite lab at the Norwegian University of Science and Technology (NTNU) in Trondheim. Ready to receive the peel ply, release film, tubing and vacuum film.

Saturday, January 19, 2008


After doing the candy bag routine the other day the fairing compound had now cured enough for fairing. It seems the float is very even and the ridges left after fairing is almost negligible most of the surface.

There are however some low areas and I started filling between the ridges today. Experience from the deck fairing have made me decide I will do this three times within the curing time of the fairing compound in order to compensate for the shrinkage of the compound, then fair. Here the area in front of fwd beam covered.

All these fairing pictures may not be very interesting, but I am very happy with the way the workshop turned out after my "redecorating". When comparing pictures I regret I didn't do all this before I started building. But it is done now, and I will probably pick up with the progress quite soon due to much better working conditions and better cleanliness.

My new vacuum cleaner also visible, the old one burned during a concrete-dust vacuuming session around Christmas after a damage to the stuffed filter and then dust in the motor. This one has an automatic filter cleaning function where it blows air in reverse through the filter every 15 seconds and this is very convenient when vacuuming fairing dust.

Float after first layer of fairing compound.

I have a very tight working schedule the next few days, hopefully I will have the energy needed to put a new layer on the next two days. If not, I will have to fair everything down between each application in order to secure a good bond.

Thursday, January 17, 2008

Building boat!

Finally! I have not been able keep steady progress since early September, and have not built anything on the boat since November 11th.

It felt wonderful to do the candy bag routine on the inner side of the starboard float today.

The plan is to finish the float fairing while making panels for the main hull. And then....

Wednesday, January 09, 2008

Nice items arrives by mail

I received Plan Book 2 from Ian Farrier the other day, new exciting information such as a confirmation that the trailer I bought is way over kill :-). Actually I knew when I bought it and I don't think it is a problem, on the contrary it probably will be very comfortable on the road.

I also received an item that I spent a lot of time trying to find out if actually existed when I rebuilt the interior of Frimann some years ago. At the time I never found evidence that such a product was available on the market. I am talking about a two burner kerosene stove for marine use. I ended up buying a Wallas (two plate model) for Frimann, it is nice when you have plenty of currency to light it up as there are no fumes inside the boat, moderate (but adequate) effect, and a disaster when you really need that cup of hot soup on a cold and rainy day with winds in the thirties (knots, that is) and it won't start because the battery is not top charged.

During the Holidays my brother in law, knowing my preferences for kerosene heaters, evolved during my years in the armed forces experiencing the Optimus 111 as the best friend a man in a tent with -20 °C and a meter of snow can get, did some skillful internet searches and returned this link. I ordered momentarily and it arrived today. He came over and we made a nice cup of coffee on it.

This is allegedly a model that has never been available on the open market, made in 1991 especially for the Swedish Navy. It has a 1,5 liter tank, two burners of 2.400W each, consumption of 0,5l/hour with both burners on full effect. It was delivered with a spare burner and a comprehensive spare parts box. A wonderful piece of KISS machinery!

The model is called Optimus 155W, I found an interesting homepage about this burner, probably on the subject maintenance although I was not able to interpret the content. It seems as it is also available in Germany at a ridiculously low price!

To the right in the picture you can see the Swedish "Tre kronor" (also the name of the Swedish National hockey team).

I also painted the third and last epoxy coat on the workshop floor today, now moving in ASAP!