Plywood blades

[RobC]

Here's some pictures of my plywood blades. They were made from 1/2 inch Baltic birch plywood. This plywood is very good quality with almost no voids. The 2 main layers were slotted for the 1 inch shafts. Then I went over the top of the shafts with 2 more pieces of ply to hold the bolts. And one more thing I used a lot of  polyurethane type glue on these blades.  The blades are 5 ft long with a constant 5 degree angle. I don't recommend this type of blade for a high tsr however. Anyway for what its worth have a look RobC

[Chagrin]

Poly glue is awfully expensive for that many laminations, not to mention it was probably a mess to work with. I'd recommend a glue like Titebond II or III in the future -- I can imagine you might be hesitant to do that but I can guarantee that either glue would work fantastically, speaking from the experience of having built a sailboat rudder, two oars, and a paddle with Titebond II.

[pepa]

very nice work RobC, it would easy to put the proper twist in your next set by clamping the plywood in a jig while the glue dried. i glue a few 1/2" dowels thriugh the blades at different stations along the blade length to hold the twist and bond the plywood better. this is a method that i have used for years to form curved handrails and other special millwork in my millwork shops. make sure that you seal the pores in the wood and add a good weather proof finish to the blades when finished. this type of blade should be inspected and refinished on a regular basis as you know but they are nice to look at and very strong with proper care. pepa.

[RobC]

 Actually the glue is your common off the self type polyurethane either elmers brand or Gorilla glue.  The nice thing about the glue is that it swells and fill gaps and its cheap.

[Chagrin]

Sure, I know the glue you're talking about and how it works, I've just never heard of anyone that enjoyed working with it or described it as being "cheap"

[RobC]

Thanks for comment Pepa I may  build a set with twist one of these days if I have time.

[RobC]

Yes Chagrin I agree You could just as easily build these Blades with titebond II or III in fact I keep a gallon around just for laminating projects. RobC

[Warrior]

Nice work Rob

How come you don't recommend for high TSR?

Tks,

Warrior

[RobC]

Thanks Warrior, I haven't tried it myself so even though it might work great for a high Tsr I can't recommend it. The main reason I posted about these blades is because they have had a lot of hard wind for over a year and they still look good. Hopefully more people who can't find good wood in their area  will find this post useful. RobC