For those who have never done a carbon fiber SUP paddle circumcision it can be a scary thing..and painful if you get it wrong.. 
When I cut my new Kialoa paddle last week I took some pictures that might help those who might be a bit worried about taking a saw to their $500 carbon paddle.
Paddles come at a maximum length for those tall bean poles like me..and anyone any shorter will need to cut it to suit themselves..This is important.
I think the best rule of thumb is to flip the paddle upside down..rest the handle on the ground..and where the paddle blade starts to spread from the paddle shaft it should be about eye level..this seems to work much better than the old 6-8" above head hight..or stretch you arm up so the handle is when you arm is slightly bent...btw..Mine are about 12' above my height..I'm about 6'4" tall.
If you're into big chunky boards and mostly flat water you need it longer..and if your are into waves on a sinky board you need it shorter..It's best to be a bit on the long side if anything because you can just paddle deeper..that's better than having to bend over to fully dip the paddle.
Here's a pic taken from the Starboard site...and a pic of me and how mine ended up..Sorry about the stunned mullet look.. ..I took two pics and the other was a real shocker and couldn't hit the delete button quick enough.. 
Once you work out where to cut the paddle shaft I use a hack saw..and also use a saw guide to make sure the cut is at 90 deg..It's no biggie if it's not perfect.
There's no going back now..
All paddles are slightly different with the shaft and style of T grip..The Kialoa has a small foam plug in the T grip..This has to be removed.
I then get a small screwdriver and poke some holes in the foam core of the T grip to let the glue run in the holes to help prevent the chance of it twisting on the shaft.
I use 5 minute Araldite...The good thing about the 5 minute Araldite instead of the full strength Araldite is that it can be un-glued after.
The next thing is to tip the paddle upside down and make sure there's nothing inside to rattle about..and then push that small foam plug into the end of the shaft.
I then run glue into the end to make sure that little sucker seals properly and stops any water getting into the paddle shaft.
I then run glue into the T grip and let it flow into the holes in the foam that I made.
The next step is very important..and you need to act fast..Sometimes they lie about it being 5 minutes..I've seen 5 minute glues go off in less than 1 minute..
Also note that most T grips are not symetrical..Most are shaped to go one way and the more curved side fits into your palm..and the straighter side goes against your fingers..You need to double check this and maybe mark it with some tape so you don't have to worry about which way it goes when you push it one with the glue in it.
Push the T grip on and quickly make sure it's straight..I first lay it down on a flat surface..You can see that what you thought was straight is nowhere near straight.
I don't stop at that..What if the ground is not straight.. ..I rest it on something horizontal and double check by lifting it up and down to check that it's straight.
Once the glue has set..I then like to run a bead of glue around the join..See paddle left without..and paddle right with..It's no big deal to not do this.
I have paddled with a paddle less than an hour after doing this but it's best to leave it over night before using it.
Cutting a paddle and gluing a T grip is no big deal for most people..But for those who are not sure I hope these pics help.
DJ
When i cut my C4 i wrapped tape around where I cut because i got told that the carbon fibre can split off and fray. SO i thought better be safe than sorry.
Good post DJ, and good advice Jake.
Wrap some masking tape around where you make the cut, does two things... Gives a surface you can mark and read if you want to have a line to work from and helps reduce the chance of splintering of the carbon.
When cutting my Starboard paddle I found I could only get a smooth saw stroke in one direction. Taking it slowly and smoothly was the key to avoid hacking it.
I hold the paddle clamped in a work-mate bench thing and well padded in a towel.
To avoid tearing the fibres I would take the cut almost all the way through then flip it over and come in from the other side. Once it's cut a quick lick of sand paper to smooth it out and job's done.
The handle is currently held on with gaffer tape (which works fine). I'll glue it permamently after I have tried it in all conditions.
I took 2 inches off my paddle and I was amazed at how short it felt. I am 6'1" and my paddle is 10" longer than me measured from handle end to blade tip. It felt a bit short at first but it was ok when I got used to the new length and I think it will be perfect for the surf. It's probably a little short for flat water efficiency.
I would suggest around 115% of your height is a good overall length. Start a couple of inches longer and work back inch by inch. Longer is better at first, especially on flat water. The only problem with the paddle being a little too long is it will be a little awkward to swap sides and maintain power.
Glad you cut it DJ.
I use a 6 inches longer than my height on my long thick board and 3 inches on my sinky small board. The shorter the better. Easier to lift over the deck when you change side to side and less shoulder strain.
Nice work DJ, did you test out that lenght on the water before you cut it or is that the lenght that you went for with your naish paddle ?
Hi DJ!
A really helpful post on cutting your paddle to size!
I'm getting a Shaka Pu'u and will be doing the same in a few days.
I've managed to get some 5 min Araldite - how can I "un-glue" it if I need to shorten the shaft later?
Any other last minute advice is welcome!
Happy paddling...
..and it's great to hear that you have chosen a Kialoa..You are going to love the Shaka Pu'u.
Hey DJ,
I'm an expat living in Hong Kong - getting my paddle sent to me from Kialoa in Oregon,USA.
I've heard many good things about Kialoa paddles, so I'm looking forward to getting it on the water.
Only bummer here in Honkers is lots of flat water and not too many waves..oh but for a few good waves!
Will be shortening the shaft this week, so thanks again for a great post!
Later...
Ps.
I'm paddling a Starboard 12'6" Cruiser for the flat water, 6'2" tall...
As one "bean pole" to another, what shaft length would you go for?
I'm guessing a little longer than the standard recommendation of 8"...?
