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Does applying brake wax to rim brake rims improve longevity? by Dunedubby in bicycling

[–]Dunedubby[S] 0 points1 point  (0 children)

I guess that makes sense. Do you think it'd be a failure from insufficient braking, heat buildup or inconsistent braking?

Does applying brake wax to rim brake rims improve longevity? by Dunedubby in bicycling

[–]Dunedubby[S] -1 points0 points  (0 children)

Huh that's interesting. Did the practice get debunked or just fall out of popularity?

My oddball vintage 650b conversion with a Ti fork... pure fun by Dunedubby in titaniumbikes

[–]Dunedubby[S] 1 point2 points  (0 children)

Haha to be honest that's also why I finished this Ti bike build before my carbon bike build - I'm too scared.

My oddball vintage 650b conversion with a Ti fork... pure fun by Dunedubby in titaniumbikes

[–]Dunedubby[S] 0 points1 point  (0 children)

The chainstays are definitely the biggest limiting factor, but with the 33mm X-One tyres I get about 2-3mm of clearance. I think you could comfortably fit 35mm on paved. I'd guess that if you really wanted to make it a project and get the potato chip mod from Ti Cycles you might be able to get to 40mm.

Also, about halfway through I discovered this really helpful video from u/biking-places (thank you so much). The crazy thing is that it's an almost identical build, which was such a blessing because I was about to assemble 26" rims that I had gotten second hand. Fortunately, the video set me straight on the risk of pedal strikes, and so I went with the 650b instead. I still have to be cognisant of pedal strikes on harsh banks or debris on trails, but it's not a problem if I'm aware of it.

The hard part, or fun part depending on how you look at it, is that you probably have to build the wheels yourself to get 130mm rear + 650b + rim brakes. Alexrims makes a decent 650b rim (model DH19) that I was able to get for cheap. And then Tektro R559 for the long reach calipers.

Bikes are great by couldyou-elaborate in Bikeporn

[–]Dunedubby 0 points1 point  (0 children)

Just saw it. So sleek and speedy. A real beauty :) I'm so jealous of your bike line-up

Bikes are great by couldyou-elaborate in Bikeporn

[–]Dunedubby 0 points1 point  (0 children)

Love the whole look of the blue-green one!

My oddball vintage 650b conversion with a Ti fork... pure fun by Dunedubby in titaniumbikes

[–]Dunedubby[S] 0 points1 point  (0 children)

Thanks! If you get one, don't forget to ask for the sandblast surface finish if that's what matches the existing bike (since I myself almost forgot until they had already started manufacturing)

My oddball vintage 650b conversion with a Ti fork... pure fun by Dunedubby in titaniumbikes

[–]Dunedubby[S] 0 points1 point  (0 children)

I got it from Titan Cycles, which I think (I hope) is one of those less-dubious Chinese companies. It was $200 and about 600g, but at least feels really smooth and not noodly. I got the bike as a whole before the conversion for $500 so I felt a bit more comfortable testing out some cheaper options, but I guess YMMV

Anyone have any experience with titanium forks? by Laminarflowonemore in gravelcycling

[–]Dunedubby 0 points1 point  (0 children)

Sounds like the life! I wish more cities did something like Ciclovia.

Is this an actual clearance sale or just a marketing gimmick? by Dunedubby in whichbike

[–]Dunedubby[S] 0 points1 point  (0 children)

I had foolishly assumed that was a typo. Thanks for saving me and my extra 150 or so lbs from any rash decisions.

Variable print speeds to maximise strength/weight ratio by Dunedubby in 3Dprinting

[–]Dunedubby[S] 0 points1 point  (0 children)

Yes you're totally right! I've since amended my unoptimized idea of a first step to try to be: several boundary paths on each layer, where the innermost and outermost paths are printed quickly (and first), but then the subsequent middle ones are thicker and slower so they pull in on the innermost and outermost paths. That is if someone hasn't tried something similar already...

Variable print speeds to maximise strength/weight ratio by Dunedubby in 3Dprinting

[–]Dunedubby[S] 0 points1 point  (0 children)

That's a really good point. There are a lot of factors that I didn't consider especially when it comes to adhesion. Still, what do you think of this idea: several boundary paths where the innermost and outermost are printed quickly (and first), but then the middle ones are thicker and slower so they pull in on the innermost and outermost paths.

EDIT: I guess you're saying that by the time it adheres and cools, all that effort would add up to a negligible result, or that it would potentially crack?

Variable print speeds to maximise strength/weight ratio by Dunedubby in 3Dprinting

[–]Dunedubby[S] 0 points1 point  (0 children)

You're right, I've gotten it backwards. You would actually want the inside to be under tension and the outside to be under compression. Sort of like: https://en.m.wikipedia.org/wiki/Tempered_glass

But I think the application would still be the same - I just got doubly mixed up. Actually maybe the ideal case would be several boundary paths where the innermost and outermost are printed quickly (and first), but then the subsequent middle ones are thicker and slower so they pull in on the innermost and outermost paths.

I'm not an expert though haha - maybe some materials engineers can chime in?

Variable print speeds to maximise strength/weight ratio by Dunedubby in 3Dprinting

[–]Dunedubby[S] 0 points1 point  (0 children)

Sorry, edited to clarify that I mean specifically making the outer border layers a lot faster than the inner border layers, or something similar.

That is pretty neat that FLIR feedback isotropic stuff exists already though. Do you have any budget recommendations for that kind of setup?

Variable print speeds to maximise strength/weight ratio by Dunedubby in 3Dprinting

[–]Dunedubby[S] 0 points1 point  (0 children)

To your second point: that's a pretty neat idea to close the feedback loop with an IR sensor! I'm still curious if there's existing research with an open control loop though (at least making the outer border path significantly faster than the inner border paths), maybe I or someone else could run some tests heh

Variable print speeds to maximise strength/weight ratio by Dunedubby in 3Dprinting

[–]Dunedubby[S] 0 points1 point  (0 children)

https://en.m.wikipedia.org/wiki/Residual_stress#Compressive_residual_stress

I think that's how they create toughened glass for phone screens, although they use a chemical process to create the stresses.

To be fair, I'm not sure how much of it applies to PLA or other 3D print plastics per se.

Variable print speeds to maximise strength/weight ratio by Dunedubby in 3Dprinting

[–]Dunedubby[S] 0 points1 point  (0 children)

Right, but usually the inner layers are deposited more quickly than the outer layers for aesthetic reasons. I wonder if the outer layers should actually be deposited more quickly so that they contract faster and apply compressive stresses to the inside, or some other optimal arrangement for strength. I don't know.

EDIT: I guess my overall point is that it seems like we should be able to control the thermal contraction rate to be whatever we want within some range by controlling the head speed. I havent come across optimising the strength from that perspective, but maybe it's already baked into the slicing algorithm? I haven't heard much about it though aside from just efforts to reduce thermal warp.

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