Gestalt asked : got me thinking whether brass screws for the brass inserts would be strong enough.
By experience, answer is no.
One of the local sailors who knew absolutely nothing about the technical aspects of windsurf boards (but could sell pastries as his normal job), used brass screws on one of his boards after a SS screw failure and they failed under load almost immediately.
Select to expand quoteWindmanV said..
Gestalt asked : got me thinking whether brass screws for the brass inserts would be strong enough.
By experience, answer is no.
One of the local sailors who knew absolutely nothing about the technical aspects of windsurf boards (but could sell pastries as his normal job), used brass screws on one of his boards after a SS screw failure and they failed under load almost immediately.
Thx
Good to know..
Select to expand quotelemat said..Gestalt said..AI.Dave said..
corrosion and stuck/broken screws with the finer threads and metal to metal contact?
It depends on the type of stainless steel screw being used with the brass. both brass (sanded) and titanium (Flikka) are excellent in saltwater environments. I specify lights for coastal architecture and use a local company that specialises in brass fittings which offer good warranty.everything else just falls off the buildings.
titanium is even better..
the issue is galvanic corrosion between the stainless steel and brass insert.. marine grade 316 is ok but the brass will corrode over time. I think Flikka uses all titanium so that's not going to experience galvanic corrosion. You don't want to use titanium with brass. Flikka also use titanium because it's light.
got me thinking whether brass screws for the brass inserts would be strong enough.
Edit..looks like m6 brass screws are available with hex head. Maybe with deox r81 anti seize.
I done some insert with A4 (marine grade) stainless claw nuts set in forex plate and laminate both side. With A4 screws no problems. Brass insert should work too, it work with fins. With a little neutral grease on screw before set even better. Galvanic corrosion is a far bigger problem with aluminium.
I wouldn't mind trying something like this or the big head fittings but the cost is steep compared to the sanded inserts. FWIW the sanded type inserts are also available eBay for about $3 per plug.
Select to expand quoteGestalt said..lemat said..Gestalt said..AI.Dave said..
corrosion and stuck/broken screws with the finer threads and metal to metal contact?
It depends on the type of stainless steel screw being used with the brass. both brass (sanded) and titanium (Flikka) are excellent in saltwater environments. I specify lights for coastal architecture and use a local company that specialises in brass fittings which offer good warranty.everything else just falls off the buildings.
titanium is even better..
the issue is galvanic corrosion between the stainless steel and brass insert.. marine grade 316 is ok but the brass will corrode over time. I think Flikka uses all titanium so that's not going to experience galvanic corrosion. You don't want to use titanium with brass. Flikka also use titanium because it's light.
got me thinking whether brass screws for the brass inserts would be strong enough.
Edit..looks like m6 brass screws are available with hex head. Maybe with deox r81 anti seize.
I done some insert with A4 (marine grade) stainless claw nuts set in forex plate and laminate both side. With A4 screws no problems. Brass insert should work too, it work with fins. With a little neutral grease on screw before set even better. Galvanic corrosion is a far bigger problem with aluminium.
I wouldn't mid trying something like this or the big head fittings but the cost is steep compared to the sanded inserts. FWIW the sanded type inserts are also available eBay for about $3 per plug.
For me those plugs looks good. At least better than chinook plastic one's.
Whether the footstrap plug is metal or plastic or something else, isn't the main question -> what matters is how well the plug bonds to the substrate.
- If there is a significant difference in stiffness between two adjacent materials, it will have a natural-fracture-boundary.
- If the surface preparation of the plug is not suitable for structural-adhesion, then it will have a likely-fracture-boundary.
- _all metals_ have some form of rust - if there is any water or air contact to that surface, will cause it to rust to some degree. Rust increases the thickness of the surface which creates a stress point, which results in possible-fracture-boundary. **
** Aluminium and other metals are said to not-rust because the surface layers create a natural ceramic. That ceramic is still an oxidation of the Al metal. Same for Zinc, titanium, etc. It is still rust, just labelled differently.
Big boats have marine-grade stainless steel cleats and fittings. Generally speaking those dont fail, while still being bonded into fibreglass/carbon hulls. So it is possible to do the bonding/embedding with sufficient strength. But big boats aren't weight-constrained so they can use suitable construction techniques.
Windsurf gear is extremely weight-constrained, which limits what we can do to have effective bonding.
I'm not saying it would be the lightest but I've often thought about using something like a US box track for footstraps. Very fine adjustment and you can replace the threaded component easily.
Select to expand quoteGrantmac said..
I'm not saying it would be the lightest but I've often thought about using something like a US box track for footstraps. Very fine adjustment and you can replace the threaded component easily.
I see a DIY wingfoil board with something like that, small US box like plugs so the guy can adjust straps, a problem for wingfoiler when they start using strap for jump after long time strapless. If i remenber well he build is plug with 3D printer.
Keeping with foot strap inserts and interesting using tracks 
Specifically metal inserts, Agree use stainless 316 grade.
A long time ago, I built a couple of wave boards (with offset back inserts).
Used furniture inserts into H80 foam then glassed over, a bit of mucking around to stop resin into threads but worked well and so easy to change compared to conventional inserts.
No problem with jumping but 3 years later the corrosion issue!
I like the furniture insert idea and the track concept.. fwiw I use silicon to fill boxes and plugs to prevent resin getting in.. front straps specifically on a track is really interesting.. as with all this stuff every decision comes with weight penalties.
stainless is not the best for marine environments. best is titanium, by a long shot. then brass.. i get stainless is stronger than brass but it's also heavier and it rusts.. if you do a deep dive into stainless in marine environments you will see it has a very hectic cleaning schedule or it rusts, tea stains etc. titanium unfortunately is very expensive..
I'm going to try brass inserts direct into hd blocks on my next build.. super light and cheap
psmfasteners.com/product/inserts-for-plastics-m6-x-16-sonic-lok-brass-0-size-16mm-psm8600060x16-slbm6-os-16mm/
www.wkooa.com/product/brass-insert-nuts-for-plastic-blind-knurled/?srsltid=AfmBOordZFQjHGXd-fR_vpBuAIr9v0c5DaSJSQhL-tzPlZS8eZG7AHlW
Select to expand quoteGestalt said..
I like the furniture insert idea and the track concept.. fwiw I use silicon to fill boxes and plugs to prevent resin getting in.. front straps specifically on a track is really interesting.. as with all this stuff every decision comes with weight penalties.
stainless is not the best for marine environments. best is titanium, by a long shot. then brass.. i get stainless is stronger than brass but it's also heavier and it rusts.. if you do a deep dive into stainless in marine environments you will see it has a very hectic cleaning schedule or it rusts, tea stains etc. titanium unfortunately is very expensive..
I'm going to try brass inserts direct into hd blocks on my next build.. super light and cheap
psmfasteners.com/product/inserts-for-plastics-m6-x-16-sonic-lok-brass-0-size-16mm-psm8600060x16-slbm6-os-16mm/
www.wkooa.com/product/brass-insert-nuts-for-plastic-blind-knurled/?srsltid=AfmBOordZFQjHGXd-fR_vpBuAIr9v0c5DaSJSQhL-tzPlZS8eZG7AHlW
Brass work well it's easy to find and to work with hand tools. For no rust problems stainless steel must be 316L grade, A4 for screws and must be work with dedicated tools. I see corrosion problems came from use of same tools for working stainless steel and standard steel. Using protective grease for screws is a good habit, even simple vaseline work for that.
