Silent Maids rig is built in the same manner as Elf's with one major exception, the inside of the spars are lined with carbon fiber. The staves are scarphed together, birds mouthed and tapered just as Elf's were but before the staves are assembled carbon fiber cloth and rod is vacuum bagged to the inside face. This means a very stiff spar of a smaller diameter, wall thickness and weight can be built. In this case the carbon is in the form of a woven layer, a 1/4" rod set in a groove down the middle of the stave, and a layer of unidirectional cloth. In effect the wood is now a matrix for the carbon fiber which is doing the real work. All of this depends on a good bond between the carbon and wood as well as keeping the amount of epoxy to a minimum, hence the use use of a vacuum bag.

The first step is to set up a group of staves so they are perfectly straight inside the vacuum bag. We joined plywood panels with strips of wood hot glued to their top face then hot glued spacers to that base to hold the staves in place. The simple jigs pictured to the right were used to align the staves. After the alignment was complete the staves were lifted and a sheet of thin plastic placed over the ply and spacers kept the staves from being glued to the set up. All faces of the stave that are not to be covered with carbon are sealed with packing tape to make the epoxy cleanup as easy as possible.

Once the carbon and all the necessary layers have been cut out the glue up commences. Speed counts here so things have to be well organized. The mastic that seals the envelope is in place with its backing left on until it is needed. Four staves are done at a time to keep the job from getting to big and on the forty foot mast four people are very busy. The glue is rolled out , the first layer of cloth is and the rod is wetted out, then the final layer of carbon is stretched out and stapled taut. Staples hold the rod in the groove every six feet or so.

After the carbon the first layer that is not part of the finished spar is the release fabric. This soaks up excess epoxy and can be peeled off the finished composite easily. Then a layer of plastic to keep the glue out of the breather fabric. The breather allows to vacuum pumps to pull evenly on the entire bag. There are two pumps one for each half of the bag. The air is drawn out through nylon tubing with the ends sealed and small hole drilled in it. The tubes are taped to a batten and care is taken to keep the tubes in contact with the breather fabric over the length of the spar.

The Workshop has a large compressor so two Venturi type pumps are used to draw a vacuum. They draw this 40' long bag to 9 lbs of pressure per square inch and the compressor is up to the task of maintaining this pressure overnight. A close inspection for leaks is the last step in the process. These usually occur where the hoses enter the bag or where there are folds in the bag. Since everything is sucked into the bag these are easily plugged with mastic.

The staves remain under pressure overnight. Then the task of peeling the tape and trimming the carbon is taken on. The overhanging carbon is trimmed with a pattern makers bit set up in a router table with ecxcellent dust collection. This is important as are the dust masks that are worn no matter how good the dust collection. A hand plane takes care od the details before the mast is assembled. That task is best viewed as a movie.