Hey Gary, love watching and learning from your videos. I am a Nacra17 sailor from Canada. We are starting to get to the point where we are putting a lot of time and effort into caring for our foils. I had a couple questions, and was wondering if there was a good way I could contact you, if you would be willing to help us out. Thanks!
What is the brand name of the strong sailmakers double sided tape you use? In Australia, I can easily obtain Kikusui sailmakers double sided tape, but its very weak, but I can't find the tape you use. In the process of repairing many cracks in an IQFoil board. Masking tape doesn't particulary want to stick to the nonskid finish on the board. Thanks for sharing all this information.
Great video thank you! One question: when doing to final fine sanding what is the best sanding movement? Small circles? Big circles? From leading edge to trailing edge? Or lateral from tip to tip? I saw diagonal too. What's the final movement? I am worried that with the wrong method the water might not 'hug' the wing surface properly.. Thanks!
Great DIY footage! thank you. But i have a question do. Why dont you use a epoxy cement? Drilled holes in a layered composiite is detroying the layers. The shrink wrap is a top tip by the way!
Thanks for all the information, i have been experiencing some cracking on my foil mast right below where it goes into the fin box.. any advice on how to fix it?
Hi Dayne, We have seen evidence of this also. Depending on the weight of the rider and how hard you load up the foil determines the durability of the manufacturing process. Without seeing a photo of the crack, I'm assuming it's the outer filler fairing that's cracked. The core carbon bar should be ok. I have repaired this by carefully machining a beveled edge v-shaped along the crack and then filled with a black epoxy bond.
Thanks foillabs for sharing your knowlegde and passion about hydrodynamics and hydrofoils. Beside riding the windfoil i sort of enjoy refining my foils in the garden shed.... 😁 keep up the good work ! greetings from belgium
Thank you very much, Gary! Can you post links (or the names) of the blades and all the other equipment in your Foil Lab? I'm in the USA, but if you provide the NZ brand I can probably find the US equivalent. Thank you sir! Ed
Sir: Thank you for producing such an informative series of videos on foil repair and tuning. I used to enjoy tuning alpine skis at a shop -- and now that I wing foil (in a rocky environment 😵💫) I'm going to invest in proper repair equipment. May I ask, what is the make/model of your touch-up gun? Thanks again! Ed
Hi Vlad, Acetone is a strong solvent that can remove small impurities and grease. It is very viscous and can travel up the fibres of bare carbon, therefore, promoting a breakdown of structure. I only use it to prepare a surface for a new finish. Best to just use warm water and detergent. Much faster.
Awesome videos! Thanks so much for sharing all your knowledge! I would love to see you finish with the durepox and your finishing process once the foil is true and perfected. I've not found much content on the last finishing process once all the imperfections are worked out. Thanks again for your videos!
The product I use is produced by a new Zealand company called Adhesive Technologies NZ Ltd. It is a structural adhesive epoxy resin. 4to 1 mix. Brilliant for repairing scratches. Owner of the company is legend Grant Beck.
Hi thanks for the question. You have used the words fused which infers that the fastenings are stuck together. For me to answer your question could you give me some more detail. Chat soon.
@@foillabs1990 Hello Gary, I have the same question, I think he means: What do you to if the anodized layer on the aluminum has worn off by scratching, sanding, etc. ? If it's down to bare aluminum? Can you leave it as is, or you repaint ?
Thank you for the great videos. Can you post a photo of the failed box before repair? I keep a close eye on my box and often wonder what failure will look like.
Thanks Gary - I was interested in your comment about the direction of force on the box, with the mast pulling down at the back as the foil tries to pivot towards the bow. On my standard windsurfing boards I use a large stainless plate on the deck of my board which I bolt through (it's wider towards the stern) to the tuttle box (essentially huge washers). I have been told this is pointless, but I haven't had any problems so far and think it helps - what's your opinion?
Hi Bruce, Nice to hear from you. In a sense we have inherited construction history from the Formula Boards etc. As a result we continue to see the breakdown of this tuttle design as it was never intended to sustain such massive forces. We have also developed thicker metal plates to mitigate the issue and yes it does help as can spread the load. In the case of IQ we have to work within the class rules and this latest video I have observed a massive increase of carbon layers to make the whole design stronger. The ultimate solution would be to construct an internal framework that gave a skeletal frame to provide strength and rigidity from mast step, foot-straps and foil mast connection. Some of the WingFoil boards get it right but they are not under the same forces as a 100kg rider + 34kgs of kit traveling at 20 knots upwind canted and pushing all that force through a 16mm carbon mast and box cassette. I think we will see a completely new approach soon.
Hi Gary, thanks for the video. While this makes the immediate area of the new box very strong the only thing creating any longitudinal continuity through the length of the board is the glue between the new box and the structures surrounding it. Do the boards have any longitudinal stringers along each side of the original box - or integrated into the original lay and up running fore and aft through the box to take the the loads from the foil, rig and sailor to basically stop the board from cracking off at the front of the box insert or do they solely rely upon the upper and lower laminates of the deck and bottom? Cheers Ian
Thanks Ian, I think my comment above to Bruce deals with my thoughts on historical design concept and the need to completely rethink. Additional to the final strength of this solution if the final depth / thickness of the carbon head in which the mechanical bolts will hold the design firm from any movement. We will be increasing this thickness to at least 15-20mm thereby utilising the carbon walls of the original top section of the box. The IQ boards do not have any longitudinal stringer which would help to withstand the pivot force. Yes its needed.
Hi Doug, The glue mix is quite runny allowing for it to squeeze and fill all the small voids. If you wanted to put a measurement to it it would be 500 microns ( very little to even notice. I make sure the foam porous surfaces are vacuumed and cleaned then sealed. I apply the glue to all surfaces. It is important to do a dry run to identify where the final box will sit. If it's high then something is not right.
Hi Gary, am I correct in understanding the last minute of the video where you talk about the sanding stages as you apply the Durepox, then sand at the finer grit, apply Durepox again, then sand at the next finer grit etc etc?
Hey FoilLabs, great video, very informative! Do you have an example of the polyurethane paint you use for the tracer coat? I'm sure I can probably find something similar here in Aus to use.
In the vids you are focussing on removing material from the trailing edge in particular. But at the end, are you rinsing down the whole foil area to make is faster, or only the trailing edge?
Thanks Gary, for the new material you advised - Durepox. I'll may be try. Good video. But two things... 1 - there is no high pressure (comparing to ambient water pressure) at lower surface of the profile you showed. May be on very low speeds and high AoA only. At normal speed and low AoA, it is low pressure there, just look at its curvature, it is just less low then on upper surface of the profile. 2. If you wanted to apply resin, why did you rub the surface with hand? Skin oils do not help adhesion.
I would not scrape off the bottom side of the rear edge with the blade. One thing is removing just a build up of a finish (lacquer), and another is shaving off actual carbon body. By removing the body you effectively changed camber of the profile at rear edge. Which would be ok if you consciously wanted to modify the profile to reduce, lets say, inductive drag. And you understood that the price will be - reduced lift together with it. It is like you decreased angle of flaps on airplane. So, removing imperfections is one thing and modifying the existing profile is another. I do not think the second was your target. Then why you've done it?
Your comment is just, however if the manufacturing process produces a surface that can be vastly improved then the process only adds to stability and fast flight. In some cases to true up a trailing edge has required taking small amounts of carbon off. The whole finished wing is then finished with Durapox
Hi Qibin, The principles are the same only with Kite Foils the blades are more high aspect ratio to achieve the low drag and higher speeds. I'll keep the suggestion in mind.
Thanks Gary for the great advice. I am following it to do some maintenance on my moses freeride foil and so far I am pretty pleased with how it is coming up. Question for you: What other product would you recommend for spraying other then the durepox? it seems pretty hard to get around here and impossible in small quantities. anything else a beginner could use?
Hi Massimiliano, a good question. The foil that you are working on I assume is composite and epoxy resin? Basically, you are wanting to seal the foil surface with a new boundary layer that is hard and can be finished to a smooth layer. A good two-pot Polyurathan clear coat is good. Where do you live?
Hi Massimlliano, yes the best products are those used in the marine coatings industry. You could go to a local marine shop and ask for a "2 pot polyurethane clear paint. You can buy these in smaller quantities.
Hi Gary, thanks for sharing! Do you have to make de final coat (durapox or 2 parts polyurethane) with pistol and compressor or you can make it by hand?
For the thickener, why high density 404 and not something much softer like 407? I would think you'd want to make sanding those pitting fills easy to avoid messing up nearby enamel.
What a fantastic video!!! In your opinion would fresh versus salt water benefits of a lower grit or higher when compared with salt water ? Thank you very much.
Thanks for the great video, which is helpful for me. There are a number of different epoxy’s available on the market. Which product would you recommend?
Thanks for that Gary, I'm a kite and wing foiler here in Queensland. I find your channel very interesting, it's good to know there is a place I can go if I need to learn about repairs and tuning.
Hi I have a question about the trailing edge of carbon hydrofoil masts. I've noticed on my 2016 lift and now on my 2021 Slingshot Phantasm that over time small Knicks and chips develop. I protect my gear with a padded mast cover all the time and I haven't damaged them at all. Is this a thing you are aware of? Do you have a clip on how to sand/fill/ repair. Cheers Grant
Hi Grant, This is an interesting question as like you all of us in the NZ class buy covers and protect our foils as best we can. I'll poss a theory that foils that are well used develop ware on the leading edge from water friction. So in effect the boundary finished fro the factory has been worn off. Sort of like the rocks in a fast flowing river. Once gone you can observe small pitting as the fibre weave is exposed. Best remedy is to fine wet sand and spay a coat of DuraPox. Then finish with a wet sand to reestablish a smooth boundary layer. Hope this helps.
Finally found someone that pays attention to details! I have a MOSES HAVOK that kept ventilating / cavitating above 47 km/h, so I kept dressing the trailing edges on both the mast and the wings... finally got them below 0.5mm and achieved a marginal improvement (will never by MOSES again). As the edge was so thin and SHARP, I did have the misfortune to sustain a nasty cut on my leg during a crash @ 50 km/h. For the past 3 months I didn't maintain my foil at all, just freeride, but I really admire Your dedication. Keep up the good work!
Thanks for the feedback. We are still learning and much of what I show comes from good sources. I have just finished a 1000 race foil and it is way different. Very quiet but it has a sting.
Thanks Gary, for sharing with us how to improve the foils. One question, you take a lot of time on the trailing edges, I understand that is to reduce the turbulence and imperfections. But what I heard and in one of the videos you said too, is the first third of the blade is super important for the lift, even being this important I haven`t seen you working on the leading edge.
In the video the foil, I was working on needed most of the work done on the trailing edge. Yes, the 1st third is important. Using fairing blocks and hand techniques to achieve laminar flow across this part of the foil is key. Basically from the leading edge to the max cord thickness. High aspect foils require work to sometimes halfway across the section.
Thanks David, Yes your comment is relevant. Our NZ class rules require foilers to ware helmets, and buoyancy vests. Damage to your legs and feet are at risk when you have fallen off, and you kick the foil with your foot or shin when recovering. I always ware a long john wetsuit with shin protection. Some riders ware booties for this reason. It's good to be safety conscience and as coaches we constantly are reminding new riders of the dangers and precautions.
