Friday, November 13, 2009

Rackufacture: Karate Monkey Rear Rack, Part 2

Hi. Here's the marathon follow up to Part 1. Exact same warning as last time. (Eric: popcorn time.)

So when you're designing a rack, you have to consider interchangeability and versatility. Or in other words, do you want your rack to be able to fit on more than one bike and do you want it to be able to do a bunch of different things. This rack is on the way far end of both spectrums. It only fits this bike and it only does one thing: carry panniers, and (hopefully) carry them well.

Part of the reason for this is my over-reaction to my frustration with off-the-shelf racks that try to be all things to all bikes and end up doing nothing well, and part of it is driven off of aesthetics and my desire to get away from the boxey, squarish look of every other rear rack. I might still add a removeable, boxey, squarish deck at some point, but for now, I just want something different and clean.

So these are not all, but most of the parts that're gonna go into this thing.



Here's a rough brazed joint. Coupla things: it looks like krap because when you're a newb, you pile brass on like there's no tomorrow and usually end up with way too much and then you have to bust your ass filing it off. Buy it, melt it, turn it to dust. Yay. This looks like something from hell has been gnawing on it because I found that the easiest way to remove a bunch of excess brass is with a wood rasp when the brass is still super hot. / Other thing is that little sleeve. That's gonna get brazed onto the main hoop to keep the panniers from sliding around, but not until the very end. There's four of them and it's a major PITA to keep them in the right section of the hoop while your brazing all the parts on. This one ended up on the wrong side of the brace and I had to cut it and move it, so that's why it has that diagonal joint.



When you're totally freaked on racks and you're in sleep deprivation mode, smooth filleted joints become your addiction. I got a fix here, but it won't last long, it never does. I'm in living hell.



Early attempts at fixturing. I have a lot to learn.



This next part I'm pretty damned proud of. One of the things that this rack has to do is allow me to get to the mounting bolts of the rear disc caliper. Reason for this is that with horizontal droupouts, you have to be able loosen the caliper to remove the wheel. So when I have a flat at twenty below in the dark, I don't want to have to mess around with removing the rack to get to the bolts. It took some goofing but the joints were screamin' tight before brazing (wish I had a pic). I think it came out great.





Here's a fender mount. Started out as the thing sitting on the fender - it's a braze-on you buy from a framebuilders supply house. Rad, if I do say so myself.



First one worked out so well that I decided to do the second one exactly the same way. Which was to take a welding blanket, and wrap it around the joint to protect the fender, tack it in place, then remove the rack and finish brazing.



Except for that this one was a little shorter which means it got a little hotter. Ooops.



Ah well, nothing a little sandpaper and spray paint won't fix. Besides, I think some stainless 29er Berthouds may be in this bike's future. That would be crazy cool.



Here's the fab sequence for the rear light mount . . .













When you're done brazing up your rack, it's covered with flux that has turned harder than glass. It's damn near impossible to sand or file off without destroying all your handiwork. Luckily, it's water-soluble, so you just soak your rack overnight.



You've left vent holes in the rack and water gets into these and dissolves the flux inside, too. So there's some water left inside and you need to get it out. You do that by heating it with a torch and boiling it out. Turns out the satisfaction of watching the steam come out is damned-near beyond words. Closest thing I can think of is ripping off a truly righteous fart when no one else is around. (Probably shared too much there.)



After all this you have a dry and flux-free, but rusty rack. More cleanup work. What's new.



So then I cleaned it up and dropped it off to be powder coated. That was last Friday. Yesterday I got my black rack back:



I've seen lots of powder-coated stuff, but I've never had anything powder coated. I couldn't stop staring. Only thing that came to mind was the childhood experession, "If you love it so much, why don't you marry it."









I had the work done at Powdertech. They were great to work with and the price was super-reasonable. Because it's black. Get your checkbook out if you want your own color.



One other design feature I wanted was rack/fender integration and the ability to quickly remove both as a unit. There are the two mounting points at the canti bosses and two more at the dropout eyelets.



The short post last night was about the fifth mounting point. Here's the fab sequence . . .











The whole deal about this is that I wanna be able to remove the fender/rack without removing the wheel. Doesn't it drive you crazy to have to pull our wheel to get at that last bolt that holds the very end of your fender to your frame???? Okay, maybe it's just me. Anyway, this still needs a little tweaking. That's why it's zip-tied and not brazed. But getting close.



At long last. Doesn't look level, though.



Must be an optical illusion.



Previously floppy fender is super-solid now. Wish I could do away with that last set of stays, but they must stay. At least they fasten to the rack now and have a shorter reach, which stiffens them up. I put 'em inside, so they wouldn't mess with the bags.





Here's the stops for the pannier clips:



Done deal, finally time to ride.



Inevitably, the question will come up as to whether I would ever try to financially run myself into the ground by attempting to sell racks. Please! This is my passion and I have no desire to profit. I am an ARTIST! But I do need to eat. So I would merely like to cover my hours at minimum wage. Please send me a check for $2300 and I'll get started on your rack right away.

12 comments:

John Speare said...

Pat: I'm totally impressed. Great job! Looks great. I can't believe you got it powdercoated for $13. that's f'ing crazy.

Pat S said...

Ya, John, i know. Couldn't believe it either. Need to hurry up and get a bunch more built before they change their prices. ;-)

Hank said...

You called it, Pat. You're an artist. I am blown away.

FBC Spokane said...

Well done!

Alistair said...

Pat, welcome to the world of rack snobbery (I mean that in a good way). It's unlikely that anything off the shelf will be good enough for you now.
I got a laugh out of your $2300 price estimate for a rack, few people will realize (even with your excellent photo sequence) just how much fussy, time consuming work is in these things.
Good point about the highly optimized nature of a custom made and fitted rack. They only do one job, on one bike. To me, that's part of their beauty and appeal. I think that others see it too. All your friends will want one.

Obsessive shaping and finishing of fillets, check.

One last thing. The price you paid for the powder coat is an incredible deal, by Seattle standards. Even with shipping it might be cheaper for me to mail racks to these guys than to get them done locally.
Anyway, nice job.

The Chihweenie said...

That is amazing. Great work!

Travis said...

My eyes are now open to a new world of racks. I've only know multi purpose square blackburn racks. These curvy sexy racks are amazing!

Nate said...

What, no cup holder?

Seriously dude, that's a thing of beauty.

If my medically necessary liposuction and hairplugs weren't already running over $2300, I'd buy one faster than you could say "bling!"

Eric said...

Awesome job Pat!Popcorn finished, have a good supply for further adventures into rackufacture!

Pat S said...

Thanks, guys, for all the positive comments. I really appreciate it.

Alistair, all those hours went by in a flash. I know you know. Time flies when you're having that kind of fun.

Nate, you have to deal with the necessities. I totally understand.

Romney said...

Are you still using this rack? I can't pay your asking price, but if it's just sitting around unused, I would gladly pay what a new rack would go for...

Pat S said...

Romney, still very much using it. It's worked out really well. Sorry.