A couple new members in the club have now started to scratch build 36/600's and I thought it would nice to write an article on how to construct a rudder. By no means is this the only way but at least it is a start to other ideas.
Once I have the design for the rudder, I first start with a 1/8th rod of brass. Be sure when you get your brass rod, get a brass tub of the diameter of 5/32th, in which the brass rod will slide up into, (the tub is used to get the rudder's rod into the boat). Measure a two inch length from the end, and file a flat side to the depth of 1/32th. Next, turn the bar over and file that side flat too to the depth of 1/32 of an inch. Once done you should now have a two inch filed bar up from the end of the brass rod.
While filing, be sure the two filed sides are parallel in thickness to each other and straight down the shaft with out any twist. If not done right start over or your rudder won't be straight. When done, you will want to round the filed bar's edges a little so the they will match the rudder's curved sides when placed on.
The last step is to solder a 1/8th by 3/4 inch bar on the bottom of the filed bar. When soldering, make the solder connection three quarters of the length of the 'T' bar. Once done taper the 'T' bar at both ends so when the sides of the rudder are placed on, the 'T' bar will march the curve of the rudder's sides.
To continue the building of a rudder, I use 1/32 inch birch 3 ply plywood for the rudder's blades. One of the comments which I have received from a club member was, when using the same type of thin 3 ply wood, it had a little warp in the rudder's blade after he build one. To remedy the problem, after tracing two outlines of the rudder on to the birch plywood and after cutting out the two blades, I dampen both sides of each blade and pressed them in a large book for a hour or two. For me, this solved the problem of warping.
After marking the rudder's brass shaft placement line inside both blanks, attach the shaft to the inside of the rudder by useing fast setting CA glue. This is very important, be sure you glue the 'T' bar shortest end pointing toward the leading edge of the rudder. If you don't, you will end up with a rudder with a shape problem.
Apply the CA glue one drop to every 1/4 inch; too much and it takes longer to set-up and your fingers may become part of the rudder. Put the shaft down on the glue line, (again with the shorter 'T' bar pointing toward the leading edge) and hold it in place until the CA sets. Once done apply the CA glue as before to the other side of the exposed brass shaft and carefully, (and quickly) place the other inside blank on the brass shaft and hold in place.
After the glue has set and dried, now comes the "welding" of the two halves together. This is done simply by applying CA glue to the one side all along the outside edge. Note, don't glue too much at once, just lay down an inch around the edge and press the two blade blanks together. It is very important to have both blanks glued together all the way around with no holes.
Well, the third and last part of building a rudder which will hold up to the demands of sailing a 36/600. Now that the rudder's two sides have been "welded" together, the next step is to inject strength to the inside of the rudder itself.
This is done by injecting polyester resin into the hollow space between the two halfs. The best and easiest way is to use a Glu-Plicator syringe. With a syringe, all that is needed is to mix up the resin, draw it up in the syringe and at the top of the rudder on either side of the brass rod, inject the resin into the rudder. The amount of resin injected is around 1/4 of a ounce, so the weight is very miminal.
After 24 hours to allow the inside resin to harden, the next step is to shape the rudder's blade before you fiberglass the outside. This is done by sanding the blade's entire edge to a knife-like edge. This allows the rudder to pass through the water with little resistence.
Once the rudder's edge has been sanded, all that is needed is to fiberglass it's outside. Since everyone knows how this is done there is no need to explan this task other than the merits of outside strength and water proofing. After the fiberglassing, it is a matter sanding and painting it to your desired color.
Well, I hope these rudder building articles has help you or has given you some ideas for your own rudder and I am looking forward to seeing your ideas on the water!