DIY square top oars - Page 4 - Mountain Buzz
 



Reply
 
Thread Tools Display Modes
 
Old 07-23-2018   #31
 
codycleve's Avatar
 
salmon, Idaho
Paddling Since: 2004
Join Date: Mar 2012
Posts: 1,079
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

codycleve is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 07-24-2018   #32
 
MT4Runner's Avatar
 
Kalispell, Montana
Paddling Since: 1997
Join Date: Apr 2012
Posts: 2,296
Quote:
Originally Posted by kengore View Post
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.




Quote:
Originally Posted by codycleve View Post
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!
MT4Runner is offline   Reply With Quote
Old 07-24-2018   #33
 
idaho falls, Idaho
Join Date: Jul 2011
Posts: 47
What epoxy are you using? We used to make laminated cutting boards using gorilla glue wood glue and dont think it is the right stuff for this application.

Ive used T88 epoxy in another application and think it might work well for oars.
whee is online now   Reply With Quote
Sponsored Links
Advertisement
 
Old 07-24-2018   #34
 
MT4Runner's Avatar
 
Kalispell, Montana
Paddling Since: 1997
Join Date: Apr 2012
Posts: 2,296
US Composites 3:1 medium cure

Last ones were Raka. I liked Raka but they got up near West Systems for price
MT4Runner is offline   Reply With Quote
Old 07-24-2018   #35
 
idaho falls, Idaho
Join Date: Jul 2011
Posts: 47
Thanks! Ill check them out.
whee is online now   Reply With Quote
Old 07-24-2018   #36
 
MT4Runner's Avatar
 
Kalispell, Montana
Paddling Since: 1997
Join Date: Apr 2012
Posts: 2,296
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 is offline   Reply With Quote
Old 07-24-2018   #37
 
MT4Runner's Avatar
 
Kalispell, Montana
Paddling Since: 1997
Join Date: Apr 2012
Posts: 2,296
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 80F 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 80F 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!)
Attached Thumbnails
Click image for larger version

Name:	IMG_5191.JPG
Views:	100
Size:	172.8 KB
ID:	31405   Click image for larger version

Name:	IMG_5192.JPG
Views:	128
Size:	169.0 KB
ID:	31407  

Click image for larger version

Name:	IMG_5193.JPG
Views:	132
Size:	192.1 KB
ID:	31409  
MT4Runner is offline   Reply With Quote
Old 07-25-2018   #38
 
MT4Runner's Avatar
 
Kalispell, Montana
Paddling Since: 1997
Join Date: Apr 2012
Posts: 2,296
Quote:
Originally Posted by MT4Runner View Post
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.
Attached Thumbnails
Click image for larger version

Name:	runout1.jpg
Views:	104
Size:	202.4 KB
ID:	31413  
MT4Runner is offline   Reply With Quote
Old 07-27-2018   #39
 
MT4Runner's Avatar
 
Kalispell, Montana
Paddling Since: 1997
Join Date: Apr 2012
Posts: 2,296
This is a big shout-out to CB Rob. Using a roundover bit on the shaft is mf'ing BRILLIANT!


Quote:
Originally Posted by CB Rob View Post
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!
Attached Thumbnails
Click image for larger version

Name:	IMG_5203.JPG
Views:	143
Size:	325.4 KB
ID:	31459   Click image for larger version

Name:	IMG_5206.JPG
Views:	85
Size:	568.5 KB
ID:	31461  

Click image for larger version

Name:	IMG_5208.JPG
Views:	124
Size:	360.9 KB
ID:	31463   Click image for larger version

Name:	IMG_5210.JPG
Views:	139
Size:	348.1 KB
ID:	31465  

MT4Runner is offline   Reply With Quote
Old 07-27-2018   #40
 
MT4Runner's Avatar
 
Kalispell, Montana
Paddling Since: 1997
Join Date: Apr 2012
Posts: 2,296
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.
Attached Thumbnails
Click image for larger version

Name:	IMG_5212.JPG
Views:	126
Size:	412.2 KB
ID:	31467  
MT4Runner is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Topic Thread Starter Forum Replies Last Post
Sawyer square top oar Tether ring? Treswright3 Whitewater Rafting 10 06-15-2017 11:56 AM
Sawyer Square Top Refinishing Mtflygiy26 Rafting | Gear Talk 1 05-21-2017 08:43 PM
Dry top, semi-dry top, or spray top? heyguys Kayaking | Gear Talk 7 11-29-2010 12:40 PM
Paddlers meet at 10. 30 am today at South Main Square in BV Park for CBS 4 Denver pc bvwp1 Whitewater Kayaking 1 04-22-2010 10:05 AM
Oars, oars, oars Randaddy Whitewater Kayaking 13 04-26-2008 01:53 PM

» Classified Ads
Powered by vBadvanced CMPS v3.2.3

All times are GMT -6. The time now is 02:46 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.