Titanium vs Stainless steel

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Titanium vs Stainless steel

They test several materials, not just carbon and titanium.
I’ll stick with stainless steel.

Alan

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Re: Titanium vs Stainless steel
moredownhaul wrote:

They test several materials, not just carbon and titanium. I’ll stick with stainless steel.

I've seen what kind of bike you ride... Lol Steel is great for some things, not others. I can't imagine a stainless steel windsurf mast or hydrofoil. CF was pretty easily crushed but if you put the carbon in a different form, it's much harder. As long as we don't build highway bridges out of PVC, we're good.

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Re: Titanium vs Stainless steel

Sorry I forgot to mention I was referring to fin/foil screws and hardware. I was actually researching a stronger/stiffer form of carbon fiber layup (Graphene) when I came across that video.

Yeah I don’t think I’d like a stainless steel mast or boom.?

Here’s a video about graphene, kinda long but very interesting if you’re into that sorta stuff. Go 42 mins in if you just want to see how much stiffer it is.

Alan

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Re: Titanium vs Stainless steel

What's being measured in the video is compressive strength (ends being pushed together) which isn't really the problem for fin/foil screws. Those depend on tensile strength (ends being pulled apart) which can vary a lot depending on the grade of the steel. Carbon steel comes in various grades (2, 5 and eight) and the better grades are stronger than stainless steel. The reason to use stainless is for the corrosion resistance in water. It can seize up which is why we need tefgel or marine grease to prevent it.

https://www.boltdepot.com/fastener-information/Materials-and-Grades/Materials.aspx

"It is a common misconception that stainless steel is stronger than regular steel. In fact, due to their low carbon content, many stainless steel alloys cannot be hardened through heat treatment. Therefore, when compared to regular steel, the stainless alloys used in bolts are slightly stronger than an un-hardened (grade 2) steel but significantly weaker than hardened steel fasteners. Unless great care is taken, stainless fasteners are susceptible to seizing up during installation, a phenomenon known as galling."

For fins and foils it is hard to imagine the screw breaking off, seems like the fin/foil box or the fin/foil itself would be more likely to give no matter what screw is being used material.Or as we know the board might just break in half.....Stainless steel prevents rust so that's what I use, but I've used the best regular steel I can find locally in a pinch until I can get stainless. (For salt water, stainless is a necessity.)

Grade 2 has no marks on the head, while grade 5 has 3 marks and grade 8 has five. This chart show the relative strength of various types of screws and identifying marks.

https://www.boltdepot.com/fastener-information/Materials-and-Grades/Bolt-Grade-Chart.aspx

As for titanium, its' high strength to weight ratio is useful many things including aerospace applications. It is about as strong as low grade steel but much lighter. I recall the Slingshot titanium bolt debacle - it may have been caused by the poor quality of the product used rather than weakness of the material. Pretty clear that Slingshot didn't need titanium bolts and the M10 bolts they used for Tuttle head foils were overkill as well. Nobody uses them now.

Well - that's probably more than anyone cares to know about steel etc.....

What happens in a black hole stays in a black hole.

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Re: Titanium vs Stainless steel

So after talking to someone earlier today about this, it seems that all the slingshots that found a watery grave were more likely due to using the wrong bolts in the wrong holes. I was always under the impression that the bolts snapped under pressure. Good to hear those aren’t in use anymore.

I remember when my Horue head broke, one the stainless steel screw was still attached to the unbroken part of the head and bent about 80 degrees but never broke.

Not sure how accurate this chart is but it still shows 304 stainless having more tensile strength than Ti.
I guess if it’ll save my foil the extra 10grams is worth it.

Alan

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Re: Titanium vs Stainless steel
moredownhaul wrote:

So after talking to someone earlier today about this, it seems that all the slingshots that found a watery grave were more likely due to using the wrong bolts in the wrong holes. I was always under the impression that the bolts snapped under pressure. Good to hear those aren’t in use anymore.

I remember when my Horue head broke, one the stainless steel screw was still attached to the unbroken part of the head and bent about 80 degrees but never broke.

No, proper length bolts did snap. Really two separate issues: 1) the confusion over the proper length screws to use for the top of the mast - the plate adapter and tuttle adapter were similar in lengths. They were close enough that "it looks like it should work" ™ Not only did Jim C have this happen but saw it down at Fred Howard, too. Lucky for them, they had the fuse turned backwards so there wasn't enough pressure on the kit before we noticed the issue. 2) the screws for the fuse/mast connection. There are only two and unlike almost every other mast/fuse connection, it's just a butt joint so there's no sort of socketing to support and stabilize it. The fuse rocks back and forth if things (and even if they are) tight, enough to fatigue the heads of the screws. If one goes, the whole thing goes. It was a bigger deal with the i76 because the wing wasn't big enough for it's buoyancy to float the rest of the fuse/stab. The i99 would so at least there was something floating that could be recovered.

The solution to the second issue is to use high quality A4/316 stainless screws. The "titanium" screws were prone to cracking. Titanium can be brittle. It's advantage is it resists corrosion. Stainless will corrode eventually but is much stronger.

The definitive thread below. Also, there is a claim which I tend to believe that the titanium screws are just titanium coated. NP's screws are explicitly said to be that - coated. Titanium is pretty pricey and titanium alloys which are a lot stronger are even more pricey.

https://www.seabreeze.com.au/forums/Windsurfing/Foiling/Slingshot-titanium-bolt-failure?page=1

Edit: just saw your post, Randy. I don't know a lot about steel but enough after a lifetime of riding steel bike frames. Stainless was always hyped by people outside of the industry for frames because of the corrosion resistance but tradtional chrome and mangesium molybdenum alloys (essentially 4130 series and closely related steels) are so much stronger and newer alloys which are heat treated even more so (which allows for thinner tube walls). I think some of the newest alloys might include some stainless types but the vast majority of high strength steels aren't. 4130 steels are also commonly used in aircraft and racecar roll cages, etc.

The reason that carbon fiber has supplanted steel isnt really about weight but more that you can fine tune the shape of a cf frame better and, by altering the fabric layup, create a frame that can be strong in one direction but compliant in another. Steel is unidirectional so much harder to do this. Still today, some very high end steel frames are being made, mostly at the custom end of the market.

The shiny bits here are not chrome but polished steel.

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Re: Titanium vs Stainless steel

That one of your bikes William?
That’s a piece of art.

Alan

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Re: Titanium vs Stainless steel
moredownhaul wrote:

That one of your bikes William? That’s a piece of art.

Heavens, no. I've been lusting over that guy's frames for years. He posts build pics on a forum I used to spend a lot of time at. (Used to is more accurate. Hope all is well with him.) I did have a nice bike built for me in my youth which I baby too much. I need to ride it more.

Let's just say if I had $42 billion to blow on a vanity project, I think I'd just hire this guy or one of his peers to set up shop in my garage and build my friends and me bikes. Lol That way, I'd end up with 41.9 billion and a bunch of really fun bikes to adventure on.

https://www.velocipedesalon.com/forum/showthread.php?t=18350&p=952989#post952989

a couple pages earlier in that thread you can see how he polishes up the lugs, etc.

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Re: Titanium vs Stainless steel

I think the stock phantasm mast (AL) to mast adapter to the fuse are Ti bolts. They feel very different to me to torque than the stainless screws, like I am going to break them. I think I'll eventually swap them out with SS after thoroughly coating them, as the SS to AL joints on my starboard and slingshot foils were just fine with a line of tefgel after a couple of years.

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