Smooth surface on new passive rock protection reduces how well it sets?

So I've noticed as I've practiced placement with my DMM Wallnuts and Torque Nuts at the base of the cliff that it almost appears as if they seem to set easier, better, and stay in place after the anodized surface has been scratched up a bit.

Am I imagining this? Or is this just that I'm getting better at placement as I practice?

I've heard of this from my mentors when I first learned climbing. It makes alot of sense. The extra texture improves friction and reduces the chance the nut will pop out from rope movement. Obviously this is unlikely to directly improve holding strength.

I've heard the exact same story applies to new climbing rubber on shoes too, which I think is true.

Anodized aluminum alloy has a much higher surface hardness than raw aluminum alloy. This gives rock a much better chance of "biting" into raw aluminum protection pieces than anodized ones.

So, yes, anodized aluminum nuts (and cams) can slip out of a placement easier than their non-anodized counterparts.

Generally, this would not affect their ability to hold a fall, just their chances of falling out due to rope movements etc.

That said, it would make sense that cams with brand new anodized lobes also have slightly increased risk of pulling out in a fall than those with raw aluminum alloy lobes (particularly when placed in relatively smooth rock). That is why Totem for example does not anodize their cam lobes.

In all cases, the anodized layer is short-lived so it's nothing to loose too much sleep over.

Climb for joy wrote:why even bother?

Because it looks better in the store and most people don't know what difference it might make anyway, so it sells better.

That said, I like the color coding aspect, but again it wears off nuts so quickly that it is not very useful anyway.

On cams, it wears off from the contact surface quickly but remains just about for ever everywhere else, so the color coding advantage is real.

Eric and Lucie wrote:Anodized aluminum alloy has a much higher surface hardness than raw aluminum alloy.

It's also basically sapphire. But it's also on the order of 0.0005" - 0.001" thick and on top of a much softer base, so it no practical difference in terms of grip on the rock since any texture on the rock is likely an order of magnitude larger than the thickness of the hard anodized layer. Which is exactly why it wears away so fast....

Climb for joy wrote:Or perhaps a partial anodized pro on the non-contact surface where the wires or slings enter the device for size and color recognition?

Easy answer: anodizing the whole thing is cheap and easy. Partially anodizing it involves tedious handwork masking the surfaces not to be anodized and then removing the mask afterwards. Which makes it a PITA and expensive. Another option would to be anodize and then remachine various surfaces to remove it, but that's more handling and machine work, which means a PITA and more expensive.

Far easier to simply let it wear off since it really doesn't make a difference anyway.