Our carbon fiber props are all hand-made. They start from an original prop from which we make a mold. If we desire to make changes to the original, we try to make the mold to accommodate the changes. Each prop is hand laid up in the mold using continuous strands of carbon fiber and epoxy.

As a new prop comes out of the mold, it will have flashing around the edges. It will contain all of the flaws that were in the original prop, plus those we added as we made the mold. The majority of the work will be on the "face" of the prop. The "back" of our props are very accurate as the come from the mold and you should not have any work there. We try to make the mold as good as possible, but perfection is not possible. (The "face" is the side of the prop that faces forward when mounted on the model.)

All this means that the raw, unfinished prop needs to be "worked up" before it can be used.

There are several steps to finishing a CF prop.

Deflashing:
The thin flashing of epoxy and carbon around the edges of the prop must be carefully removed. Use a sanding block and some 80-100 grit paper. Carefully sand the "outside" of the flash, bending it back over the surface of the prop as you sand. As you thin the flash, it will fall off the edge of the prop when you have sanded it through.Be careful when deflashing. It is easy to sand too hard and eat into the edges of the prop or leave big sanding grooves.

The area around the hub needs special attention. There is usually flash around the edges of the hub which should be sanded off, leaving the back of the hub clean and flat. Be careful when you sand the back of the hub since that surface controls the pitch and tracking of the blades. The flash that leads from the leading edge of the blade along the side of the hub needs to be carefully sanded off. (A round stick wrapped in sand paper or a round rat-tail file is useful here.)The front of the hub should be sanded flat and clean.

Finishing the tips:
The tips of our props are purposely "crude" as they come from the mold. This allow you to make the prop that suits your needs. The tips must be finished, i.e., sanded to shape and thickness.

Cut the tips to give you the length of prop you desire. Use a small needle file and file through the prop about 1/16" beyond the desired diameter, then sand the tips to the exact length. Be careful since you can split the tips. (A little CA will usually handle minor problems if you do.)

Shape the tip to your desired shape by sanding the leading and trailing edges. Typically, the general outline of the rest of the blade is carried to the tip, with the actual tip shape (e.g., square, raked, etc.) as you desire.

Sand the face of the tips to blend the blade surface to the tip. The front surface of the tips will usually be somewhat rough, reflecting the "working" of the mold as we adjust it to give the desired raw propeller. The tips come from the mold pretty close, but will purposely have extra thickness: you need to make sure they are thin and continuous with the remainder of the blade. Make sure that the leading edge of the tip is properly radiused to match the rest of the blade and that the trailing edge is thin and fairly sharp.

Balancing:
Use your favorite balancer. We typically use the TopFlite Magnetic balancer, although it is a bit of a pain to use on the larger props. Sand the face of the heavy blade making sure that you maintain the airfoil. Remember that a small amount of material taken off a long way from the hub changes the balance more than that taken off close to the hub.

Once you have the blade-to-blade balance correct, you may still see some hub imbalance. Typically, this is so small as to be ignored, but you can sand on the hub some to try and get rid of it. An alternative is to add material on the light side of the hub. I have seen some use coats of CA on the light side of the hub. I also have seen suggestions of drilling small holes on the light side and adding small lead pellets, but I worry about potentially weakening the hub by drilling holes in it.