[MT4Runner]

Buddy wanted a set, so I told him I'd help. Then two more guys wanted oars. We're now up to four sets of 3 oars.

Bought some gorgeous cvg Doug for at RBM lumber in Columbia Falls, MT, along with some spruce and cedar for blades.

8/4 x 6" x 10', and a couple of 8/4 x 8" x 10'.
I can easily get three shafts out of the 8" wide boards; probably 2 each with rips for blades or to laminate into an additional shaft in the 6" boards.

Not entirely sure what I'll do on the square top...probably 3" square, which will require a 1/2" ripper glued to each face of the 2" board above the rope wrap.

Running out of attachment space, so I resized these pics

 

[whee]

I hope you continue to post build pics. I'd like try building a set of oars but I'm not sure how the layers go together.

 

[CB Rob]

Time for me to make another pair.
Broke one trying to squeeze the 16ft cat down the right side of skull.
Noticed that 22 years of rowing had really affected the surface grain under the rope wrap, should have replaced the rope at the 10 year mark

 

[CB Rob]

The embarrassing incident
https://youtu.be/59Ngla1qcH0

 

[MT4Runner]

I hope you continue to post build pics. I'd like try building a set of oars but I'm not sure how the layers go together.

Thanks for asking! I wasn't sure if I was posting too much without enough info as I didn't get many responses. Finally got started last Thursday night.


I had originally wanted to make them all out of 2x2 solid stock, but while the grain was straight, there was some curvature in the boards. We ripped the boards to 1 1/16" x 2", and then planed them down to 1"x2". Laminating them--even with only one joint--will make them much straighter and stronger. A side benefit of ripping 1x2's is that we ended up with a couple pieces with knots that we will discard or use for raft paddles, and will be able to build 2 total extra oars.



With all the wood ripped, we started swapping boards around to come up with sets that would all be the same weight. (One heavy board/one light strip, or two medium-density strips.)
Also flipped the strips end-for-end or upside down to make sure that any grain runout was canceled by straight grain or opposite runout in its mating piece. Grain runout is when the grain runs off the side of the board instead off the end of the board (which is ideal straight grain).



If you have a grain line that runs all the way across the board, it's going to break there. If the grain runs across the board in less than a foot, it's going to break right away. If it runs across the board in 4' or more, there's probably enough strength in the board to not ever break. So, if we had some grain that ran from upper left to lower right, we'd mate it with straight grain wood, or a board that that had runout going to lower left to upper right--counteracting the stress on the runout and minimizing the chance the oar could break from wood splitting.


The wood is all sorted and sitting on sawhorses with big 2" x 8" hardwood strongbacks that will clamp all the oar blanks perfectly straight while the glue cures.



We ran out of beer and it was 11:30pm, so we called it a night. Hopefully gluing tomorrow night. I'm epoxying mine; Jeff plans to use Gorilla Glue on his.

 

[MT4Runner]

Time for me to make another pair.
Broke one trying to squeeze the 16ft cat down the right side of skull.
Noticed that 22 years of rowing had really affected the surface grain under the rope wrap, should have replaced the rope at the 10 year mark

Ouch!


I really appreciate you giving us the update and a pic of the failure mode. Do you think it was due to water intrusion or just the pressure of the oarlock? Would it be worthwhile to do an epoxy/fiberglass wrap under the rope wraps to prevent this on future oars.

Edit: it sucks to break an oar, but it's going to look magnificent hanging on your wall.

 

[CB Rob]

I think the failure was all due to getting slammed against the rock, and that any oar would have snapped.
It did allow me to get a look at the inside of the oar, and I could see that the repeated stress of being pushed against the oarlock had damaged the surface grain, as well as allowed water intrusion.
There was a thick layer of epoxy under the rope wrap but years later it was all broken down.
I had resealed the rest of the oar 5 or 6 times, but never pulled off the rope to seal under it.

 

[MT4Runner]

Thanks again.

I had my original oars' ropes off 7 years ago when they got a complete sanding/re-varnishing. Those wraps haven't been off at all since, nor the v2 7yo oars. I'll give them some more attention later this summer/early fall when the new squaretops get done and wrapped.

I plan to build a serving mallet per the Marlinspike Sailor (as shared on the Shoelessmusings blog)

 

[MT4Runner]

It did allow me to get a look at the inside of the oar, and I could see that the repeated stress of being pushed against the oarlock had damaged the surface grain, as well as allowed water intrusion.
There was a thick layer of epoxy under the rope wrap but years later it was all broken down.

I may add a tube of glass under the wrap--or maybe all the way to the throat of the oar.

https://www.ebay.com/itm/Braided-Fi...-fiber-Glass-PER-10-FOOT-section/142384220991

 

[kengore]

I am really enjoying your posts. Please add as much detail as you can, I am considering making a pair for my drift boat.

 

[codycleve]

Following... love my oars but love building things myself... does anyone know the size of the square on an actual squaretop.... i run pro locks and they make a plastic sleeve to slip over the top.

Sent from my SM-G920V using Mountain Buzz mobile app

 

[MT4Runner]

I am really enjoying your posts. Please add as much detail as you can, I am considering making a pair for my drift boat.

Thanks! We're gluing the blanks tonight. I'll post more pics tomorrow.

does anyone know the size of the square on an actual squaretop.... i run pro locks and they make a plastic sleeve to slip over the top.

Interestingly, they're not all that big! 2" at the square top, about 1 15/16-1 7/8" under the rope wrap, and only 1 9/16" down at the throat.

I'm planning to make mine 2" square all the way through. I'll laminate on some exotic hardwood scraps (harder and also a color contrast) for the square tops to make them 2 3/8" square. Hopefully 2" under the ropes if I don't sand them down too much, and then down to 1 5/8"+ at the throat. Shooting for slightly more weight inside the oarlocks than Sawyers--and I can always sand mine down more--difficult to add weight!

 

[whee]

What epoxy are you using? We used to make laminated cutting boards using gorilla glue wood glue and don’t think it is the right stuff for this application.

I’ve used T88 epoxy in another application and think it might work well for oars.

 

[MT4Runner]

US Composites 3:1 medium cure

Last ones were Raka. I liked Raka but they got up near West Systems for price

 

[whee]

Thanks! I’ll check them out.

 

[MT4Runner]

http://www.uscomposites.com/epoxy.html
635 Thin Hardener with 3:1 medium hardener.



We just used 16 ounces to wet out and 16 more ounces mixed with wood flour to laminate 10 oars.

I figure 1oz ea for square tops, 1oz to laminate blades, 1oz to glass tips and blades, and 1oz to saturate the exposed surfaces before varnish.

7oz total per oar with good epoxy techniques (minimal waste)

You could do 2 oars with a pint kit or 3 easily with a quart epoxy kit.




Golf club parts suppliers sell 1oz mixing cups. For this big batch, I mixed 16oz at a time in 32oz paint mixing cups from Home Depot.

 

[MT4Runner]

Flopped the pairs open, confirmed we liked the grain direction.


Coated each mating face with unthickened epoxy.


Then coated each mating face with epoxy thickened with wood flour (from the belt sander bag--it was a dark hardwood so the thickened epoxy is dark). I often use regular household wheat baking flour as it makes the epoxy a nice honey gold.

It is important to not clamp an epoxy joint too tightly. You need it tight enough for the boards to be in alignment, but if you clamp it too tight, you will squeeze out the glue and have a "starved" joint.

Protip: a lot of boatbuilding epoxy is the consistency of honey. It doesn't spread or mix easily. You can carefully warm it in the microwave and it will be the consistency of cream...but it also significantly cuts down your "pot life" and it will turn into a hot smoking mixing cup of goo if you're not careful. Epoxy is a thermoset plastic and cures with an exothermic reaction...warming it up speeds up the polymerization.



I nuked the 16oz of epoxy for 30sec in a ~900watt microwave. It went from about 80ºF ambient to slightly more than lukewarm (say 100°)

We dumped it immediately on the wood and started spreading it. This medium cure epoxy has a pot life of 15-20 minutes at 80°F ambient temp. By microwaving it, that same 16oz of epoxy will maybe have 5-10 minutes of pot life. It will also start curing faster. Should be hard by tomorrow night instead of by Thursday night. Fun with chemistry (but be careful!)

 

[MT4Runner]

Also flipped the strips end-for-end or upside down to make sure that any grain runout was canceled by straight grain or opposite runout in its mating piece. Grain runout is when the grain runs off the side of the board instead off the end of the board (which is ideal straight grain).

If you have a grain line that runs all the way across the board, it's going to break there. If the grain runs across the board in less than a foot, it's going to break right away. If it runs across the board in 4' or more, there's probably enough strength in the board to not ever break. So, if we had some grain that ran from upper left to lower right, we'd mate it with straight grain wood, or a board that that had runout going to lower left to upper right--counteracting the stress on the runout and minimizing the chance the oar could break from wood splitting.

I thought some more about this--figured a sketch would be helpful.


Let's talk about grain runout. Ideally, we want straight grain, where the grain in the wood runs out each end. If your grain is very tight and straight, you can have a few grain lines that run off the side of the board, but in general, the grain should be very parallel to the length of the board. (See first two examples). If the wood for your oar shaft looks like this, you probably don't even have to laminate it--you can use it solid.

Then we see really bad wood (second two examples). The first one is wavy and will break where the grain runs convex off the board. It also has enough wave that it might break across the board. The second one has really bad runout across the board and a knot that might be above your blade or under your oarlock--REALLY BAD high stress locations. You can use this stuff for blades (if you fiberglass them) or for firewood.



Then we have "maybe" wood (3rd pair). If you have a straight board with tight grain, but some runout that crosses the entire board maybe over the course of 4-5', you can laminate it to another board and mostly have their runout cancel each other. Knots are also not as big of a concern if they are near the end...they may not look as good aesthetically, but you can bury them lower in the blade where there is less stress, or up in the handle--both areas also get a LOT of grain removed, so they may get cut away entirely.



To laminate this wood, let's look at two examples using the "maybe" boards from the 3rd pair. You do not want the grain runout parallel--it can break just like the bad runout wood. You want the grain runout to cross with the other board so the fracture lines cancel each other. This makes a very strong shaft.


So...we had a couple of planks that had runout over a span of 7-8', so really strong wood, but we still wanted to hedge our bets and make sure we had "lifetime" oars and not something we'd worry about breaking the second time out.

 

[MT4Runner]

This is a big shout-out to CB Rob. Using a roundover bit on the shaft is mf'ing BRILLIANT!

Used a 2in router bit for the shaft.

My first oars were made round with a table saw, a jack plane, and a block plane, followed by copious sanding.

Second set were built with a table saw and hand power plane, followed by copious sanding.


I bought a 1" roundover bit online for $21. Worth every penny--especially spread out over 14 oars. My buddy Jeff chucked it in his shaper and we went to work. Rounded them from the bottom of the squaretop to the top of the blade. These took maybe 5 minutes per shaft, and will take minimal sanding. Thank you CB Rob for the protip!

 

[MT4Runner]

The top will remain square. The top right now is 32" long. I will carve out a 6" handle, and the squaretop will be about 26" long where it will then taper down into the rope wrap section.

The bottom is square for now. It's also 32" long. The blades will be 30" long. The bottom square will get tapered down to 1/2" at the tip on the front and back faces of the blade, the sides will stay parallel and then I'll glue the blades on.


It was easiest at this time to leave both ends square for 32" and be open to the last-minute decision on which end becomes the loom and which end becomes the blade.