cast & drill . . .

[hokeyhydro]

That is Graham's recommendation for a rudder installation on the Dive kayak. Do an end pour and then drill a 3/8" hole for the rudder post. Right. My freehand perfectly vertical drilling skill is suspect, and I figured blocking and leveling the kayak under my drill press would be a major PITA, so on Diva #123 I went with the bolt on SS gudgeon. (see pic).

On Diva #125 I decided to do the pour. But not the drilling. I glued in a small wedge of wood with a forstner bit 3/8" dead end hole about 3" down, used a 3/8" dowel to establish vertical, glued on a strip of scrap ply to form a vertical dam, and then installed my drill cheater = a 3/8" shank bolt with the threaded part cut off. Then I did the filled epoxy pour. When cured I fired up the blue tip wrench, heated the bolt and removed it, leaving a nice vertical 3/8" hole! (see pic of bolt and hole)

I'm liking this method and may use it again, say for centerboard & case drilling.

[Garry]

Thanks for the info. Keep us posted on the finished setup. I'm not sure I fully understand it yet but I may want to do something similar on mine.

[PAR]

A trick I've used when I can't drag something under a drill press for a true bore, is to carefully cut a perpendicular through a square or round length of polystyrene. This is placed in the oversize hole and usually a dot of hot melt glue, to hold it upright. Epoxy is poured around the foam and when it cures, acetone is used to melt the foam out of the hole, leaving a perfect hole for a pivot bolt or whatever. Naturally it is handy to size the foam to the finished bore diameter, but an under size foam blank will permit a centered pilot hole, to be finial sized after the casting.

[hokeyhydro]

Thanks for the info. Keep us posted on the finished setup. I'm not sure I fully understand it yet but I may want to do something similar on mine.

If you look at pic #1 on the left you'll see the SS gudgeon I mounted on the kayak tail to receive the rudder post. That method leaves a 2 1/4" gap between the kayak stern and leading edge of the rudder.

In pic #2 on the right the rudder post will go into the hole and I'll have to shave about 1/8" off the kayak tail to provide clearance for the rudder. A nice snug fit. The epoxy pour saves weight over the SS gudgeon, and saves $$.

The end pour method is good for pointy tail kayaks, might not work on blunt tail kayaks since the steering bar part of the rudder assembly is about 3" wide and would need to be set back far enough to clear the transom.

[hokeyhydro]

A trick I've used when I can't drag something under a drill press for a true bore, is to carefully cut a perpendicular through a square or round length of polystyrene. This is placed in the oversize hole and usually a dot of hot melt glue, to hold it upright. Epoxy is poured around the foam and when it cures, acetone is used to melt the foam out of the hole, leaving a perfect hole for a pivot bolt or whatever. Naturally it is handy to size the foam to the finished bore diameter, but an under size foam blank will permit a centered pilot hole, to be finial sized after the casting.

I used that trick to make one-off test hulls for R/C model racing yachts back in the 70s. I would shape a hull out of foam, tightly drape it with cling wrap to keep the old school polyester resin from attacking the foam, and lay up a hull. No acetone needed, although I usually had a 5 gallon pail working in the shop, as gasoline worked just dandy to melt the foam away, and back then gas was kinda cheap.

[PAR]

I've used gasoline and several other chemicals too, usually whatever was handy at the time.