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Old 08-24-2018   #51
 
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I'm super excited about this part:After reading everything I could get my hands on by master oar-builder Pete Culler, and master dorymaker/riverman Brad Dimock, I decided I wanted dihedral concave faces.

Remembered an article I'd read awhile back about coving wood on the table saw. This was a crazy idea 20 years ago, but is a somewhat common technique today.
https://www.rockler.com/how-to/cutting-coves-table-saw/

Don't tell my dad, but I actually tried this 30 years ago on his table saw when I was trying to make a concave base on an old wooden water ski. 14 year-old me learned that fiberglass is not friendly to table saw blades. I didn't set up a good double fence so the cove on that water ski had some visible kerfs in it. The double fence is the key to keep the wood from wandering.

So I made this sled. The rails in back are 5/8" high so the edges of the blade can ride on them and let the neck/shaft of the oar ride through and not rise up.

(Note that the face taper was already done on these blades with my friend's huge jointer--first pic).
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Old 08-24-2018   #52
 
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I also did a tapered rip on the cedar/spruce blades:


Top of oar will be 5 3/4" and bottom will be 6 1/4" once we add a tapered spacer and ash blade edges
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Old 08-24-2018   #53
 
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If you can't visualize it, here's how the oar sits on the coving sled. Blue is the sled, red are the small blocks to align the oar shaft, green is the saw blade, oar blades are black dashed lines
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Old 08-27-2018   #54
 
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Used my table saw with the blade at 45 and only 3/16" deep to bevel the ends of the square tops. Cleaned them up with a chisel, then they got completely sanded with 60-grit followed by 120-grit.



You don't want to use higher than 120 grit before epoxy, because the finer grits will "burnish" the pores of the wood and epoxy won't soak in. 60-grit is perfect for "structural" work, but you can see the swirl marks under the epoxy so it needs a finer sanding.
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Old 08-27-2018   #55
 
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After sanding, they got epoxied. Cured the first coat overnight, quick sanding, then another flow coat last night. This will cure out, get a quick fine scuff, then ready for varnish.

Tips of the blades still need to be fiberglassed, so varnish is aways off, but I wanted to get the epoxy soaked in to protect the wood from dings.
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Old 08-27-2018   #56
 
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Quote:
Originally Posted by MT4Runner View Post
I started with the depth for the 1 1/4" face but cut on the 1 1/2" face (deeper cut). Fortunately I didn't take a full bite and they're roughed at 1 3/8" x 1 1/4". I think I will glue on a 1/16"+ piece of veneer to take it back up to 1 1/2" before I carve them further.

Fixed my oops. 1/8" thick strips glued on:
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Old 08-27-2018   #57
 
Monument, Colorado
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Thanks for Posting and sharing the Process-Your oars are looking nice!!
Your posts have motivated me to build my own oars after nearly a decade of procrastination.
I just ordered some 10' lengths of CVG from my local supplier today. Ill be doing the square tops as well, but would like to add some carbon fiber fabric to the blades and probably under the rope wraps.
Been reading about some carbon Fiber sleeves....this may be the ticket.

I saw your link to the Fiberglass sleeve...Do you think you'll go this route or stay with the natural wood?
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Old 08-27-2018   #58
 
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Thanks Stelz!


After seeing CBRob's oar snap under his rope wrap, I definitely plan to reinforce it. It appears his rope crushed the outer wood fibers over time, and then being in the oarlock at that single point puts a lot of strain on the wood.





I have a little bit of CF cloth, and a lot of fiberglass; I will probably do a single layer of CF and then 2-3 layers under the rope wrap. I already have the flat cloth, and will just wrap it around the shaft. If I were going to do the full length of the shaft, I'd definitely go with the sleeve, that looks really easy to do.

With 4 oars, I may do two with rope wraps and two with leather collars.


Tips of the blades will definitely get glass. I boat shallow-ish, rocky rivers and my tips do strike bottom. Probably (6) narrow layers x 6oz glass.


Edge - I was thinking of doing a dynel edge bead like Sawyer...but my old oars have gone 14 years with ash edges and no major dings...so I'll probably just epoxy/varnish them.


Face - Both the fir and the jatoba are hard, dense woods. I'm not worried about major dings or delaminations, so I won't glass the entire face of the blades.




My friends' blades have spruce and cedar. They'll get wall to wall glass on the blade faces both for ding protection as well as to hold the laminate together (cedar tears easily), as well as the tips.

I hate to admit it, but I like the look of dings and battle scars, especially if they're superficial. I felt bad about the first dings on my old oars, but now I'm really proud of them 14 years later...they have lots of "patina" and still look nice.
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Old 08-27-2018   #59
 
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Here's another interesting thought. I tried to make curves in the CVG strips cancel each other out, but still ended up with some slight taper.

You can see my centerline pencil marks across the width of the blade. A couple of them ended up off center when I planed off the tip of the curve.



You can also see the glue joint. Notice the glue joint is not centered in the first one on the left? When I was planing the taper into the shafts I noticed a pretty good curvature on that one. I planed away the curve, and the centerline moved....but now I have a very straight oar.
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Old 08-27-2018   #60
 
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Quote:
Originally Posted by stelz View Post
Ill be doing the square tops as well, but would like to add some carbon fiber fabric to the blades and probably under the rope wraps.
Been reading about some carbon Fiber sleeves....this may be the ticket.

I saw your link to the Fiberglass sleeve...Do you think you'll go this route or stay with the natural wood?

Thanks for asking, too. I hadn't quite finalized what I'm doing with the blades and tips. Helpful to have to think about it, and once I've heard myself say it, then I have a decision made.

One of my last decisions is on tip shape. Rectangular tips are more traditional (for rowboats and dories) but rounded tips are what are most common for whitewater oars (Frank's, Sawyer, Smoker, etc.) I've somewhat wanted to go square...but then I look at the damage on my old oars and it really has been ~90% on the blade tips. I think squared corners would invite the most damage....probably will go full round or semi-rounded (big flat oval).
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