foam corks at each side of the hole (just keep 5 to 10mm more than the center hole diameter) drill only one side ...
I’d go for 25-30mm each side if I did this.
Also might add extra wraps of carbon or glass around outside near hole. Both would help to take beatings from safety releases, stress concentrations from the hole etc...
I made a second bar with 25*22mm carbon tube. 60 cm bar with 3D printed bar ends. I messed up the position of the 22*20 carbon tube center reinforcement. So I took some uni D CF and cut a 60cm long, 100mm wide, tapering to 50mm wide. With uni running along 100mm width. Then I wet it out and simply rolled it around outside at center. Dropped in into vbag. Thus added 2-3 mm thickness at center. Then I cleaned it up, drilled it out and filled center area with epoxy and fumed silica puddy. Then smoothed out hole. I tested flex before and after. It is very strong.
After adding eva 2mm foam to whole bar it has a nice gradual bulge on center.
It was really easy and what I would continue to do.
Another two sessions today, and be on 9m and one on 5.5m cloud, foiling in gusty winds. Having extra throw to instantly depower makes foiling in nasty winds so much more comfortable. A few crashes where letting go of bar meant it snapped up against stopper ring but no damage or issue. Single skin 22x20 tube with 4cm nylon plug in center and thin discs at ends to seal and for leader holes. Pic below. 27m 500# Jerry brown lines. Diaper for scale.
Thanks for your contributon, you replied to a question I was wondering, I guess we are all basically too scared to see the barre breaking around the center hole due to weakened area.
So even with a only 1mm thick tube no need to reenforce by second skin (beside making our mind comfortable). I could procure a 22x18 carbon bar (so 2mm thick) to make a 70cm long bar version, so I will go very confident with it whithout any further renforcement beside pooring a mix of Epoxi / Graphite powder.
In parallel I will also work on my mountain bike bar, I should be even more confident since it is a 2,5mm thick with enlarged center !
In order to absorbe the potential hiting shoks on the stoppers you may insert a plomber rubber sealing (I found that made on a serial bar from the market)
where did you procure the stainless teel pin of your quick release ? ( is that the one you took from your cloud original bar ?)
I don’t have a CCS. While my bar has a white stopper ball that is its only function. I’m using an old Flysurfer leash Quick release. Here is an old pic, but I have since reversed it so it stays attached to harness, not the bar, when activated. Yes that means line has to be under tension, but this is acceptable to me.
I’m cutting a lot of safety corners compared to regular bar/chicken loops but I have my reasons. I’ll let you know if I have any issues.
Looking for suggestion on the smallest depower line I can use somewhat safely.
I made a couple of center lines out of 1/8 Amsteel doubled up per this process linked below, but I also want to try using the smallest single line I can buy at a marine store. Have any of you tried to use line that is smaller that typical factory depower lines?
For the depower line, basically a single 3mm diameter spectra/dyneema should be robust enough (950 daN !!!) but our main issue is the wear - so alternatively you can cover/protect with heat shrink tube (from electric's goods suppliers) here below an example - this is not as thick and rigid as usual PU tube and it is just enough to prevent line wear, I have applied it to the safety line, it is easy to install and gives nice and effective results, not yet on the main depower line but will apply asap. https://fr.aliexpress.com/item/10Meter- ... 61794.html
Just a heads up. My single skin bar cracked at the hole. Oddly the crack started at the top not the bottom. I plan to epoxy some carbon around it for a fix.
In the mean time, i’ve been using my first carbon bar with offset hole made from low friction ring lashed to bar and I actually like it a LOT. Once I got used to the feel, I find it much easier to ride one handed than a normal bar since I can hold the bar easily in the center without rubbing the center line with fingers. Plus, it feels stiffer, so maybe other bar did have some flex after all.