Hiya,
Apologies for putting this in the Windsurfing forum, but I thought there would be more years of experience fixing stuff here.
I have had a look at these previous threads (below) and have a general idea of what I need to do, but I would like a few suggestions as to:
(i) how far to go with the cutting back (how wide, past the ends) and
(ii) epoxy the insert holes, some of which look cracked at the edge, at least one of which might have been poked through the bottom.
The board is on Day 3 of stuffing a rag in the drain hole (I've removed the Goretex plug) and it's already seeped out quite a bit of water. I had it in the sun for a while and then at night in a room with a dehumidifer.
This is for a Wing Foil Board, bought second hand, seems pretty brittle TBH (as Mark_Australia often says about early foilboards) and I have already had to glass over a few dings, cracking glass (mostly at the nose). It was nice and light but it just got heavier and heavier so I peeled back some of the EVA Pad and sure enough, water was seeping out from both (a) the footstrap holes and (b) from around them (see photos).
At least one of the holes seems cracked, at the end holes (they are a 5-hole insert set); the glass near the end holes is where most of the cracks appear.
I don't actually use footstraps ATM, (but might at some stage) and really want to avoid having to replace EIGHT five-hole inserts and, especially given the fact the thing might need other ongoing repairs, I don't want to make a silk purse out of a sow's ear either i.e. minimum to make it watertight (which was originally just bung a few layers of epoxy/glass over the top, but I gave up on that idea due to possible future use of the insert holes).
So, my plan was to cut out (feather the edges with a Dremel) the fibreglass in a 'box' I marked around the current inserts, clean up the tops of the inserts and put down 3 layers of new glass. In case I don't quite get it right, I don't really care if the glass sits slightly proud of the current board level, I just want it to stop taking water. I was also just going to try and squirt some warmed-up epoxy into the leaky end holes and abandon them, leaving 3 of 5 usable. It's a 99L board, so can possibly move the foil mast to match the available footstrap positions in future.
Would really appreciate any comments on the plan!
Reference Links for Repairs:
www.seabreeze.com.au/forums/Windsurfing/General/Leaking-foot-strap-insert?page=1 (2018)
www.seabreeze.com.au/forums/Windsurfing/General/Footstrap-repair?page=1 (2021)
www.seabreeze.com.au/forums/Windsurfing/General/Replacing-inserts--found-water-in-core--Suggestions-?page=1 (2020)
www.seabreeze.com.au/forums/Windsurfing/General/F2-foot-plug-repair?page=1 (2015)
www.seabreeze.com.au/forums/Windsurfing/General/Installing-footstrap-inserts?page=1 (2012)
Might save u some grief
how many are leaking and can u get it warm enough to bubble out if applying soapy water
whatever you do, don't put the goretex vent back! Once water is in the board, it will no longer breath!
You need to use a standard screw up bung now.
Select to expand quoteMark _australia said..
Might save u some grief
how many are leaking and can u get it warm enough to bubble out if applying soapy water
Probably about 5 of them, I think (I say that as it is standing up ATM might be it is coming out of one hole (the upper one) and being sucked into the lower ones through skin tension of the water drips). I have just laid it on its tum, holes down as it was standing up draining out the plug for a while.
I can leave it in the sun, it's touching 30 deg in the daytime (Celsius not those awful Fahrenheit things they have in NA... 
). Will let you know, it's not hot enough right now, back end of the afternoon and the soap suds weren't showing anything useful.
It looks like the fellow put (too large? too long) screws in the end-holes (at least); and put heaps of stress on them.
But there are some pretty ordinary cracks around the inserts, I am pretty sure at least one of these leaks through the glass fibre.
Select to expand quotedecrepit said..
whatever you do, don't put the goretex vent back! Once water is in the board, it will no longer breath!
You need to use a standard screw up bung now.
Oh bugger. Haven't yet but I am hoping to dry the thing as much as possible. I'll have to source a new bung then... it just gets worse 
...
Normally I would suggest routing out the failed inserts and replacing them with new set into higher density foam cassettes.
But... if you don't use straps and the inserts are under the pads and the foam is dry and not crumbling... you could just glass them over and get back to sailing.
Select to expand quotejdfoils said..
Normally I would suggest routing out the failed inserts and replacing them with new set into higher density foam cassettes.
But... if you don't use straps and the inserts are under the pads and the foam is dry and not crumbling... you could just glass them over and get back to sailing.
Haven't actually seen the foam yet TBH, I think it's OK, will know when (if) I cut it out. I say "if" as your idea to "glass them over and get back to sailing" is definitely an attractive option here. It rankles a bit in terms of 'not doing the job properly' but my other (more visible) repairs on the nose aren't beautiful either.
If I cut out the existing fibreglass and reuse the current inserts, how hard is it to remove the fibrelass from the tops of the inserts left IN the board, without destroying them or the surrounding foam? Or should I grind them down to the original profile with a dremel?
If I use a router, what's the normal process, just run around the outside of the plastic insert, so the hole slot is maybe the width of the router each side of the insert, plus the insert width? I'd probably end up using Q-Cell (still have some) to epoxy them back in, but it seems like it will use... quite a lot.
btw Aliexpress has quite a few of these inserts and other websites selling Chinook ones all look identical to the Aliexpress ones; and hollow between the holes. www.aliexpress.com/item/1005005875742745.html
Are there any recommendations for these if I decide to buy some, they seem as cheap all get up on Aliexpress ... and hilarious showing FCS fins on the same set of pics as footstrap inserts ... plus the ubiquitous note that they can 'withstand water pressure' ... )
btw what are those ones with threads in them? www.aliexpress.com/item/1005005453689345.html
I am thinking if it's only five, fI'll them with resin
suck on the breather hole with a very SMALL amount of vacuum to help ingress
them redrill to 4.5mm and 22mm deep
check again and maybe no leaks.
then glass over to be safe
but if you do go router, nowhere near that big .. Width of the bit .. Like maybe 3/8" all round.
Select to expand quoteMark _australia said..
I am thinking if it's only five, fI'll them with resin
suck on the breather hole with a very SMALL amount of vacuum to help ingress
them redrill to 4.5mm and 22mm deep
check again and maybe no leaks.
then glass over to be safe
but if you do go router, nowhere near that big .. Width of the bit .. Like maybe 3/8" all round.
Cheers, sounds like a plan, thank you.
- So one layer of mat over the top and no cutting back to glass over the cracks/edge of the inserts? I think it's 6 Oz mat (see pic; hard to get board repair stuff here...)
- Should I use the sizes I show pencilled for the mat extent, about right? Its about 1.5cm to 2cm outside the edge of the insert.
- Should I use the Q-Cells microballoon filler for the single layer of mat?
If you are going for the quick and cheesy repair:
Sand off all paint, down to resin/glass in repair area
Fill insert holes with a mix of chopped fiber (or cabosil)and resin
Glass over the top- I would go all of the way to the rail, if you stop near the inserts as marked above, you risk further cracking at the edges of the stiffer repaired area. At the least go 50mm beyond the damage area and feather back the edges after curing. I would use 4oz but 6 will be fine.
GO SAIL!
Select to expand quotejdfoils said..
If you are going for the quick and cheesy repair:
I'm going to try Mark's suggestion for the holes in the hope I can salvage their usage, but will also go for the cheesy glass-over to try and seal / strengthen around the inserts.
Point taken about introducing stress at the interface between the thickened part and the original and thanks for all the pointers, much appreciated.
OK, so here's a bit of feedback...
1. I tried Mark's suggestion first and it is difficult to know if it worked or not, even with my high-tech vacuum pump with "adjustable pressure regulator"... I have a vacuum pump but there's no regulator on it yet so I did not use it as it's either full-on-robo-chubby or ... off.
2. I drilled out the filled holes using a hand drill (recommended) and an idea from another thread for a depth stopper (see pic). However... probably because the quantities were small, my guesstimate of 5:1 (in my clearly marked 5, 10, 15, 20ml plastic medicine thimble) was probably a bit out especially as it was 15ml (5x3) + 3ml hardener, the resultant epoxy was a bit soft. I let it go off long enough. Anyway I drilled them all out.
ONE THING OF NOTE, Mark mentioned to ream out to a 4.5m x 22mm hole, but the holes (measured before I epoxied them, were not a 4.5mm x 22mm hole; I tried most of the 50 holes and a 4.5mm shank of the drill bit would NOT go in; and they are shallow, just 20mm. They actually seem to be 4mm x 20mm holes.
I looked at our 3 windsurfing boards (RRD 96L FSW, RRD 84L FSW and JP110 110L FSW) and they all have bigger holes. So do our JP Freefoils (115 and 130). So I reckon someone split the holes at the either the sides (what I saw, end holes) or bottom, due to using (too big) Windsurf screws in the foil board insert holes. Wasn't me btw.
chinooksailing.com/products/5-hole-footstrap-insert say 4mm. So seems about right, seems to be what I have.
3. Anyway I made another batch of epoxy and used jdfoils chopped up glass idea and stuffed them in.
4. I then glassed a rectangular area around the inserts as it was definitely leaking from cracks in the fibreglass deck around the holes, especially the end holes.
5. I didn't have any peel-ply so I looked up alternatives and was reading, Taffeta, Dress Linings and the like; Nylon a must. Anyway I got something that I 'thought' was like a dress lining, all stretchy and didn't look to be cotton, a bit like stockings. Placed that carefully over the top and put a plank on it and some weights.
All good... or so I thought... then doubts started to creep in about my Peel-Ply alternative (yep, what do I know about Taffeta...)... so I started peeling them off and what a cluster... two came off OK, one pulled bits of mat with it, but one was so stuck to the epoxy, it wasn't going anywhere (see photo). I tried sanding, a razor blade, a wire brush... incredible stuff, it was like a very fine fibreglass mesh, embedded in the epoxy, but impossible to sand or remove. Anyway I left it, it is going nowhere and it is hidden under the deck pads. Lesson learned, get proper Peel Ply (or don't use it at all...).
I think (hope) it's (more) water tight than it was, it's certainly stronger. I will drill out the centre (2 or 3) holes as I think they are still OK on most of the inserts, leave the end ones as is, full of epoxy.
Thanks for all the help once again... learned a lot ... mostly due to stuffing things up. It ain't pretty, so thank goodness for the deck pads, feel like a Doctor, bury my mistakes :-).
btw the ugly black mound at the back that looks like a blob of tar, was just a trial with chopped up carbon to see how it behaves. I put in over one of the leaking glass next to one of the holes, as a second layer ..."too much glass".
k.
The standard M6 footstrap screw has a minor diameter (core) of 4mm so they will split
that's why I said to drill to 4.5
factory inserts were drilled to 4.2mm previously (imperial throwback) so M6 worked great.
chinook now are now larger than 4.5 which is wonderful . Now I know it's a Konrad ..! ..
if those are only 20 deep they were set high and sanded back down I bet
Konrad are bloody hopeless TBH do have a good look at the tracks too before you spend too much time on it
got one here I will look at shortly
Yeah just looked at one
can't even get a 4mm bit to jam it in there so they're smaller than anything I've seen before
20mm deep
gotta love manufacturing whereby early adopters of a new sport who just go make whatever 
Up to my last boards i only find same straps inserts with 4mm holes. I had many repairs like this to do... Last plugs, called micro adjustables, have 5mm holes with less space between, seems better.
Lesson: wind foils boards need sandwich build at least under feet even more if strapped. Same with kite boards.
Select to expand quoteMark _australia said..
. so they will split
. that's why I said to drill to 4.5
... Now I know it's a Konrad ..! ..
.
Konrad are bloody hopeless TBH do have a good look at the tracks too before you spend too much time on it, got one here I will look at shortly
Yeah the skin is like an eggshell, thin and brittle as hell. Already glassed nose and the underside near the nose once. You have me worried about the tracks .
If the holes are 4mm you still think I should drill out to 4.5mm (and keep 20 deep)?
ta
k.
Nah change my mind now I know all this. I would check the tracks realllyyy well for and cracking
feel inside with a bent paperclip for cracks etc
look really well
Then look for tracks lifting by using oblique lighting.
if it's good then to the inserts. I say fill completely and never use them - or replace completely with chinook ones with the fat hole
sorry for my previous advice it was for normal ones.
Select to expand quoteMark _australia said..
Nah change my mind now I know all this. I would check the tracks realllyyy well for and cracking
feel inside with a bent paperclip for cracks etc
look really well
Then look for tracks lifting by using oblique lighting.
if it's good then to the inserts. I say fill completely and never use them - or replace completely with chinook ones with the fat hole
sorry for my previous advice it was for normal ones.
Cheers thanks Mark. As above, you're right about those early Wingfoil boards and this one is a disappointing example.
Cheers
k.
