Cheating way to insert bolt into light carbon laminate & polystyrene foam

[Jethrow]

Hi all

I have a clear finish carbon & foam wingfoil board that I need to put some kind of carry handle in the bottom. As it will only see maybe 10kg's of load I didn't want to carve big holes in the bottom and then try and finish all pretty again. I've done some carbon reinforcing of the foil boxes that is maybe 2mm thick (3 layers of 200g uni's in a fan pattern). Yes, I should have done a handle while doing this.

My thought was to use a 3mm dyneema line with eye splices each end and insert small bolts with cup washers at each end. To preserve the finished look I was going to drill small holes for the bolts and tap a thread into it, use a small spike to dig out the foam from inside to create a cylinder, lube up the bolts so they can be removed, and then fill the holes with a slightly thickened epoxy and screw the bolts into the hole before the epoxy kicks.

My thought is that this will leave the smallest disruption to the boards finish if it doesn't work, while giving me a functional, lowish drag handle that is watertight.

Another option I though was using one of the glue on padeyes with the dyneema loop but this isn't as clean or removable as I would like.

 

[Zonker]

Ha. As I was reading this I was thinking "glue on padeye etc" till I got to your last paragraph.

Your idea sounds reasonable if the top laminate has any thickness to it. Usually foam boards are made of pretty light foam with almost no strength so you can't rely on the foam doing much.

Use a small allen key or a bent nail in a drill to chew up the foam

 

[El Borracho]

Sounds like screws not bolts ;^) Threaded hardware is so 20th century. Figure out a way to use a piece of hi-tech line. For only 10kg working load the line can be really tiny. Epoxy tiny loops into drilled holes? A pair of laminated recessed padeyes?

 

[Zonker]

This is the BOTTOM of the board. He doesn't want a piece of string hanging from it when using it. The string gets threaded in when the handle is used.

(Why not put the handle string on the top of the board permanently?)

 

[Jethrow]

Yeah, I should have added that the handle is in the bottom of the board so it's draggy until up and foiling.

It doesn't work in the deck as the weight of the foil has too much leverage. Think carrying a surfboard tucked under your arm but the width is too much to reach the other side, therefore the need for a handle in the middle.

Also, this is my beginner board so i don't want to butcher it too much as I'll need to sell it sometime in the next year and upgrade.

 

[Jethrow]

Why not put the handle string on the top of the board permanently?

Actually Zonker, I could attach something to the deck that just wrapped under the bottom rail and reached up the other side. It would then just trail out the back a bit when sailing...

 

[Zonker]

Also, this is my beginner board so i don't want to butcher it too much as I'll need to sell it sometime in the next year and upgrade.

Oh, then use some VHB tape to affix something and accept the extra drag until foil borne

 

[cyclone]

A hole through both sides could be lined with bonded carbon tubing or G10 tubing. Thread line through from bottom, tie stopper knot.

 

[Hansel]

Surfboard leash plugs would be a starting point. Classic longboards use the ones cyclone mentioned. You can also make a glasson leash loop from ud rowing, it could be very tiny so not so much added drag.

 

[SimonGH]

One way is to drill a small hole in the location where you want them through the first skin. Then as zonker said, use an allen key in a drill to carve out the foam between the laminates from that hole. Then fill with thickened epoxy and let cure.
Then you can come back and drill through the same hole all the way through and use the line with a stopper knot, or drill partially through and glue in a threaded insert...

 

[IStream]

Maybe I don't fully understand what you're trying to achieve but why not just wrap a couple of loops of line around the board to use as a sling? When you need to use the board, just remove the sling. You could make the loops as large soft shackles made out of thin dyneema.

No permanent changes necessary.

 

[Jethrow]

Maybe I don't fully understand what you're trying to achieve but why not just wrap a couple of loops of line around the board to use as a sling? When you need to use the board, just remove the sling. You could make the loops as large soft shackles made out of thin dyneema.

No permanent changes necessary.

Hi IStream, you mainly need the handle in the bottom because launching you have the wing in one hand to leeward and the board under the other arm with the foil pointing out to windward. Where I launch from it is pretty rocky at low tide and a small choppy shore break so you can't carry the board in and go back for the wing.

Removing a temporary handle isn't really on the cards and a shoulder loop might be a bit unmanageable.

All the newer boards have the handle in the bottom but mine was from the season before they figured this out.

 

[Jethrow]

Surfboard leash plugs would be a starting point. Classic longboards use the ones cyclone mentioned. You can also make a glasson leash loop from ud rowing, it could be very tiny so not so much added drag.

Hi Hansel, I was trying not to use the leash plugs as they'd look a bit daggy cut into my nice carbon reinforcement job.

I had considered the UD carbon loop/saddle method and might have to revisit using this as the cleanest way.

 

[casc27]

Use a small allen key or a bent nail in a drill to chew up the foam

Don't do this. It'll work but it's the ugliest way to get that job done. If you have access to a Dremel type tool the 115 bits are perfect for evacuating core material in situations like this. Much easier to control and you end up with a much cleaner result.

 

[Zonker]

Yeah, I've used those bits myself for exposed edge core. But he wants the smallest possible hole...

 

[Jethrow]

Yes, I have a collection of sharpened allen keys for doing this on yacht cores but will need to create a new one for the small scale of this fix.

 

[Haligonian Winterr]

Hi all

I have a clear finish carbon & foam wingfoil board that I need to put some kind of carry handle in the bottom. As it will only see maybe 10kg's of load I didn't want to carve big holes in the bottom and then try and finish all pretty again. I've done some carbon reinforcing of the foil boxes that is maybe 2mm thick (3 layers of 200g uni's in a fan pattern). Yes, I should have done a handle while doing this.

My thought was to use a 3mm dyneema line with eye splices each end and insert small bolts with cup washers at each end. To preserve the finished look I was going to drill small holes for the bolts and tap a thread into it, use a small spike to dig out the foam from inside to create a cylinder, lube up the bolts so they can be removed, and then fill the holes with a slightly thickened epoxy and screw the bolts into the hole before the epoxy kicks.

My thought is that this will leave the smallest disruption to the boards finish if it doesn't work, while giving me a functional, lowish drag handle that is watertight.

Another option I though was using one of the glue on padeyes with the dyneema loop but this isn't as clean or removable as I would like.

This is the way. As Zinker said make sure you get a bent spike to carve out some foam right at the underside of the carbon.

Also be wary of the allen key trick with thin laminates and dense-ish foam, as sometimes the laminate is not strong enough to keep the key centred and you wind up marring the shit out of the pretty hole you just drilled.