Robvolz 

Day 3: most amazing group of people I’ve ever met.

75% tandems, but singles too. Plus each team was allowed to bring. An individual bike in case say one day that Stalker wanted to stay on the boat and drink margaritas all day, it allowed the captain to still go out and enjoy a ride.

yesterday, we tried all the bikes to the highest point near, Mount Saint Helens, and people barrel down 39 miles in record time to the little town of Castle rock. So far, no injuries, no breakdowns, other than minor tidbit things, 210 participants, and have yet to meet someone I don’t like.



Magnesium tandem?!? Two things: latest Tandem ever. I believe this combination is lighter than my Eddy Merckx racing bike. I wish I could understand the physics behind the ability to weld magnesium.

Hi drive one of the 426 foot box trucks so my view is frequently a little higher than most


This is the cruise ship that everyone sleeps on at night. They wake up with a different port and takeoff for the adventures.

sixtiescycles

Hi, Rob,

I’m the engineer behind the Paketa magnesium tandem. Welding magnesium isn’t easy, but it’s straightforward. Similar to aluminum welding, using MIG (Metal Inert Gas) welding; in this case, magnesium (Mg). There are two main issues. One, you have to choose the right Mg alloy: It has to be weldable as well as extrudable (i.e., able to be shaped into round and oval tubes by extrusion, which you can think of as similar to how a pasta machine works), and have the right mix of mechanical properties for a bicycle frame.

There are, admittedly, very few people who know how to weld magnesium properly. But, they do exist, and good ones can command a contract price of $1000/hr. Compared to welding Al, it’s much trickier as the heat range for producing a good weld is much narrower and must be very carefully controlled. Too low a temperature and the weld isn’t strong; too high and you burn right through the tube and create a lot of white powder (magnesium oxide). It’s an art, for sure. And, because they’re all hand-made, it’s expensive; similar to the price of hand-made custom carbon frames vs mass-produced monocoque (molded) carbon frames.

Where Mg really shines is in a tandem. Why? The mechanical properties of Mg work well enough in a single-bike frame, but are much better suited to a larger frame like a tandem as then the advantages of large tube diameters is apparent: You can use tubes of adequate wall thickness for dent protection (e.g.) but still very light weight and with excellent stiffness and strength. Even in comparison to carbon it’s as good or better on weight and durability, especially for dent/fracture resistance. Magnesium has the same dent resistance as steel with the same tube wall thickness but with less than 1/4 the weight. That makes it especially useful for a travel bike: Much less likely to be damaged during transit, for example.

Glad you all had a great trip!

Robvolz 

wow. Yes, the trip was great. I recommend these trips as well as those who have done 20+ with the Santana gang.

what a treat to ask a question about a frame and get the answer from the actual engineer.

I'm the guy who loaded the trucks each night, and unloaded each morning. It was a treat to pick up your tandem (one hand) and hand it to the ladies who rode it. Anybody who thinks CALFEE is the light way to go, well, you are wrong.

Thanks for reaching out.

Robert

PromptCritical 

Looks like a GREAT trip. We are/were signed up for this year and the cruise line went BK. Fingers crossed we get our $$$ back.

Robvolz 

If you are having issues, send me a message.,