Author Topic: Attaching plate mount with through bolts?  (Read 3706 times)

opie

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Attaching plate mount with through bolts?
« on: September 14, 2017, 03:09:50 PM »
My foilmount is delaminating the bottom skin of my board after two sessions, maybe because i punched eight holes in the bottom of my board by using bolts which were too long. :-[

Since I know where I want the foil, I am thinking the easiest option, as I have no skills, will be to just bolt the foil to the board.

 How will I stop the board from collapsing when I tighten the bolts?  Can I just epoxy in four pvc pipes from bottom to top of board?  Maybe put big washers on top to spread the load?

Thanks

Southbay

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Attaching plate mount with through bolts?
« Reply #1 on: September 14, 2017, 03:51:33 PM »
Do you mean put screws all the way through your board?  This will not work. Your board will be destroyed by not only the water but also the force of the foil mast on your unboxed foam. You need a Tuttle box or a mast mount and two large fin boxes installed.


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PonoBill

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Re: Attaching plate mount with through bolts?
« Reply #2 on: September 14, 2017, 08:44:22 PM »
Not so fast there, grasshopper. There is a way to do it--but not PVC. You can use the brass threaded tubes sold in hardware store for making lamps. Drill the holes all the way through the same size as the lamp tubes. put a nut and a fender washer on a tube, coat the inside of the hole and the threaded tube liberally with Gorilla Glue and then spray water on it, shove the tube in the hole, making sure glue gets well distributed. A little more glue on top where the washer will go, spray with water (Gorilla glue won't set unless you spray it with water), put on the washer and nut, and tighten it down enough to compress the fiberglass a little. Let everything set, trim the extra thread tube off flush with the nut, and run your bolts through. It will be stronger than a Tuttle box.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

supuk

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Re: Attaching plate mount with through bolts?
« Reply #3 on: September 15, 2017, 12:09:02 AM »
personally tp do a safe strong and water tight single point  install you will still need some hd foam and going to need epoxy everything in and even then you will probably want some sort of plate on the top to spread the load. If you don't have any skills then seek some one that does as its not something that can really be bodged and you will need to get the de lam fixed now anyway or it will just carry on spreading.

AlexFun

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Re: Attaching plate mount with through bolts?
« Reply #4 on: September 15, 2017, 05:20:33 AM »
Having the same idea like you, but coming from another backround (new to be build custom WindFoilSUP board) i came accross the idea of these guys and think i'll put in something like this for a supfoil in addition to the rear tuttlebox for my windfoil.
Alex
http://foil2board.com/foil2board-idea/

PonoBill

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Re: Attaching plate mount with through bolts?
« Reply #5 on: September 15, 2017, 12:24:04 PM »
A plate on the top would be a fine idea, but the throughbolt approach I describe was what I used initially to mount the geezer foil (GF1) to a fragile and thin-skinned SIC 11'11" so that I could change the foil angle by screwing the attachment nuts up or down. When everyone started yelling about how unsafe it looked I decided to test it for pullout. Tied the board down to my car lift and pulled on the tip of the foil mast with a load cell. Broke the mast at about 180 pounds (hence GF2) but the throughbolts didn't do anything. I used 2" fender washers and two attachment points per side.

I'm not recommeding this, in fact I thought it was stupid when I did it, but if you think about how the forces are applied to the sandwich, it's not absurd, just ugly.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

opie

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Re: Attaching plate mount with through bolts?
« Reply #6 on: September 22, 2017, 02:17:46 PM »
I was going to do the lamp tube idea, but when I got under the delam area I discovered lots of wetness, so I ended up with this.

opie

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Re: Attaching plate mount with through bolts?
« Reply #7 on: September 22, 2017, 02:23:23 PM »
It is a super lightweight board so I am wondering if I should add a layer of fiberglass to the underside of the top skin before I add high density foam.  Then I will glass the 18 oz. on the bottom, drill my holes and use epoxy with filler to seal.  Is it worth an extra layer on the underside of the top or will the high density foam be enough?

opie

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Re: Attaching plate mount with through bolts?
« Reply #8 on: September 22, 2017, 04:41:12 PM »
Surf report looks good so I am continuing with step two:

 


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