I was told by a very reputable company owner to use marine lithium grease on my foil screws, but what I am finding is sand sticks to the grease and gums up the threads on the screws and in the nuts. I was making it hard for one wing screw to go in, felt like it was cross threading. I was also told a long time ago by Bruno at AFS to use WD-40 on the foil screws and will be going back to that. Note all my screws are A4 stainless steel.

aeroegnr said..
Tefgel is really good stuff

WD-40 won't do much more than clean it, then evaporate

WD-40 is a lubricant and also anti-corrosive after it evaporates, that is more than A4 stainless steel needs IMO.

My concern about Tefgel is based on its name, gel, and since it is a paste would get sand stuck in it too. I do not have a corrosion problem, was just using the lithium grease as a lubricant that did not wash away, but that is the problem!

Grantmac said..
WD-40 doesn't lubricate much at the best of times abs definitely not in water.

You shouldn't need any lube. I never bother with my foil which is disassembled each use.

I agree, did not mean I would spray on WD-40 every time, just once in a while, figure it can not hurt to have a little lubricant and corrosion protection on the screw threads.

Attach and detach in a clean spot.
Once tightened, sand stays out.

A dip in fresh water will do just as much with no environmental impact.

LeeD said..
Attach and detach in a clean spot.
Once tightened, sand stays out.

In 14-20 knots setting up on beach sand gets into everything no matter how careful I am. Do not have a sheltered place to set up gear.

TefGel on bolts covered with couple wraps of teflon plumber's tape. No need to over torque to keep thing tight. Plus easy to remove. I leave the wing and stab attached all season. Sort of Belts and Suspenders overkill. Doesn't take much time to pull off old and apply a fresh tape at the end of the session on the fuse mounting bolts. Supposedly the tape reduces the chance of "vibrations" from loosening the bolts. Seems to work.

TefGel alone. As noted above. Just don't expose it to grit. Any grease will collect sand, dirt...

Ian K said..

OldGuy3 said..
No need to over torque to keep thing tight.

Only yesterday I stumbled across an engineer on the internet talking about torque and loosening of bolts.

The primary purpose of torque is not to prevent them coming loose but to preload the mating surfaces. If an engineer selects M8 bolts then he intended them to be torqued to spec.
www.engineeringtoolbox.com/metric-bolts-maximum-torque-d_2054.html

If the threads are lubricated you knock off ~30%. For M8s it looks like close to 30Nm dry, a bit over 20 if lubricated.

The max torque you can apply with a screwdriver handle is about 10 Nm. Best use a torque wrench to at least calibrate your tightening every now and then. You're not going to get m8 bolts tight enough with just a handle, you'll need some sort of leverage extension.
www.researchgate.net/figure/Maximum-torque-a-person-could-produce-on-a-handle-significantly-varied-for-the-handle_fig3_51698033

Yeah , but keep in mind , those figures are probably for mild steel . Torqueing up a bolt stretches it , keeping the preload of mating surfaces . A lubricated thread will create more tension , not less , on the bolt because you have less friction turning it causing more preload of mating surfaces . A lubricated thread will unwind itself more easily but it would have to be very loose to do that . For a bolt to unwind it would have to be rattly loose . One of two things would have to happen , 1 , the bolt has stretched too much and wont stretch back , or , 2, the thread is wearing , most likely in the hole and is about to pull out . Aluminum is much softer and prone to wear . That's if your screwing into aluminum of course . So if its only 20 nm for lubricated bolts into mild steel , I would think 10 nm lubricated into aluminum would be about right . The same for brass or stainless inserts in carbon parts . I wouldn't overtighten into aluminum or you'll flog out the thread . Also stainless bolts are softer , weaker , stretchier and wont hold tension as steel bolts .
2 cents worth from an engineers point of view .

I can almost guaranteethat if you load up, most of the bolts that come with production foils that are manufactured in China or Thailand, with 30nm they will snap off. I have managed to tear heads off 5 mm bolts with a small Allen key. I doubt most manufacturers have the resources to randomly test the hardware their suppliers provide them with. Just because it says titanium or stainless steel on the bolt doesn't mean that's what they are actually made off.

You don't want to hard-torque screws with tapered heads going into tapered-hole carbon wings. Torque hand tight only. I have seen those carbon tapered holes split from too much torque on the screw. Hand tight is enough for my AFS and SAB wings.

You can torque tapered holes in aluminum, such as SS mast to fuse. Also, you can usually torque any flat fittings with or without a flat washer.

I don't see any of the manufacturers or their reps using a torque wrench in any of their assembly videos.

I believe the torque value is how much the bolt can take, they assume there's enough threads there to hold . One thing for sure you can't just believe the torque figure, I've seen many bolts or components strip before the torque is anywhere close.

the face plate of the that bike stem will go before the bolt does.

Ben1973 said..
I believe the torque value is how much the bolt can take, they assume there's enough threads there to hold . One thing for sure you can't just believe the torque figure, I've seen many bolts or components strip before the torque is anywhere close.

the face plate of the that bike stem will go before the bolt does.

Torque value is not 'how much the bolt can take' it is the quantifiable amount the manufacturer wants you to torque in order to avoid damage to the parts. The breaking strain of the bolt is 'how much the bolt can take' e.g moderate high tensile bolts have 8.8 stamped on the head. If there is nothing on the head assume it's a rubbish soft 'butter bolt'. If it doubt swap out the bolts for quality ones from a quality supplier.

My foil bolts and screws are all A4, I only hand tighten, and what is interesting is the stainless steel screwdrivers I got have different size handles for the Philips #3 (big handle) versus the Torx #30 (small handle), and so the handle size limits how much hand torque I can apply.

The other thing is be observant of the screw tension at the end of the session. If they are loose you either did not tighten enough or something else is loose causing vibration.

AFS included a Torx #30 screwdriver with their foil, the screwdriver handle had rubber ridges running along the grip, I always tightened the screws until my hand started to slip due to those rubber ridges folding over. Never had a wing/stabilizer screw come loose. Unfortunately that screwdriver tip rusted overtime, that is why I got the SS screwdrivers.

airsail said..
If you can, leave your foil assembled, or at least in as few seperate parts as possible. Assemble with Vaseline between all joints and screws, wipe off excess. I've done some testing and normal Vaseline has great anti corrosion properties and easy to use, cheap too.
I leave my Naish foils assembled for months, no corrosion or seized screws. Just give each screw a tweak when you get to the beach.

Well I have to remove the foil from the board, so those two screws are always being inserted/removed, the front wings gets switched back and forth between the F1080 and F770, and so now I just remove the front wing after each session (3 screws), makes it easier to get in/out of the house. So that leaves the stabilizer which I leave attached (2 screws), and those get teflon taped threads which never goes bad.

But good to hear Vaseline works, the issue for me is it will collect sand like any grease or paste, and sand combined with grease turns into an abrasive mess.

I also use Inox MX4 (Lanox) and it seams to work well (no problems so far, 2 users of use).
The Inox product is Aussie made. WD-40 have now copied them with a "specialist" lanolin product.

Well now that I just use WD40 on the foil wing screws they all go in fine, was getting worried since any of the 3 screws would start to cross-thread in the one insert 3 out of 4 times.