Started off with the deck. 5 layers of 3mm baltic birch ply, glued up in a vacuum press with an inch of camber:getting it in the bag with wet glue everywhere was a total birch
Cut to size with the jigsaw:this girthy deck is 36 inches schlong
Had a minor panic attack here and started checking myself for injuries. Luckily I found the real culprit and it turned out I was being dumb in a different way than usualturns out I was dyeing instead of dying, I’m so disappointed
A quick jump test before proceeding:
not sure yet if it’s a trampaline or an MBSline
I could have gotten the 13" I need from a continuous plywood sheet but I would have needed to buy 2 packs of 15" instead of one 12", so I decided to make like I was a ~fancy furniture boy~ and put hardwood edges on it:the ‘hardwood’ joke for this caption is left as an exercise for the reader
In and out of the vac bag again for a 400gsm layer of +/-45deg carbon fiber
this part of the process really a-peels to me
This wasn’t supposed to change the flex very much since the fibers are on the bias, it’s more for torsional stiffness and waterproofing. The deck is flat when I stand on it, which means my math was correct for once.
jumping carbon and carboff
I made some 4 layer plywood by the same process as before, cut them with a jigsaw, and used the duct tape method to hold them in the zigzag shape needed for the rear arms during glue-up. There’s a platform made from a cereal box under the high side, to keep it parallel to the table and at the correct offset.did you this plywood contains 87000% of your daily recommended fiber intake?
Then I cut a slot through the middle section to increase vertical compliance, and rounded all the edges over. The inside corners also got a big fillet with thixo so that the joints are hopefully not the weakest link in the system.the bare slot is not pictured here for the sake of decency
The carbonized versions, fresh off the vacuum presses. The stray fibers will get cleaned up with sanding before installation, and they’ll be varnished after the chassis is put together.
Same procedure for the front arms, except these need to articulate to create a 4 bar linkage. I’ll need some heavy duty hinges for that. But where can I get extremely strong hinges with next to no friction?same old jigsaw-ng and dance
OH SHIT @jack.luis GAVE ME A 3D PRINTER FOR THE BOTY CONTEST, THAT’S WHERE. I’ll just set Cura to vase mode and let it rip.and you should, that dowel is trying its best
For real though these are PETG compression molds for making forged carbon parts, with 4 walls and 70% infill. The layup direction that gave the right fiber orientation was perpendicular to the direction the parts needed to de-mold from, so the molds have 4 parts. 5 if you count the dowel.
The molds get thoroughly waxed up and bolted into pairs, then packed with chopped carbon tow. Like 20% overfilled seems to work alright because air gets squeezed out, the excess just needs to be tucked in before closing the molds.acheiving this EXACT level of messiness is CRITICAL
Step 27(b): Imprison the molds in THE FORTRESS OF MANY CLAMPS. If it oozes a bit you’re doing it right.you fuckers will take that sentence out of context, won’t you
The chamfers in the mold blocks let me pry it apart with a putty knife and some pliers.fresh and crispy
After deburring, I made a foam jig to keep the pivot lines parallel and correctly spaced during glue-up.it was legally required that I cut the slots out with a jigsaw, smh
THIXO is a high strength filler epoxy that lets me create bevels to back up the hinge blocks. It also lets me get up, and get down with the thickness
OOH AH AH AH AH
The hinge blocks get an overwrap of carbon tow around their lower halves, so that tension doesn’t rip them off the wood, while the middle section gets more of the same to reinforce the flex cutouts.TO SHOW YOU THE POWER OF DECK FLEX, I SAWED THIS CRITICAL STRUCTURAL MEMBER IN HALF
With tension/compression handled by the UD, the arms get 45deg biax cloth vacuumed on to handle shear loads. Yes, the middle links are wrinkly, it was crazy hard to get the vac bag to sit right.that’ll buff out
With the hinge blocks reamed out to seat the bushings, the linkages can be clamped to the front wheel and aligned to the deck.that’s not wood glue bonding the parts together, that’s pure elbow grease
And now the front wheel is floppy:
leaning can’t turn the wheel past the point where the outside linkage straightens out, which is a useful and totally intentional feature to avoid steering lock at high lean angles
A flat fiberglass plate acts as a compression spring here to provide some centering force for the front wheel. An analog test ride showed that this noticeably helps controllability at low speeds.the test ride was an analog for how the board rides when it’s acoustic
These dowels prevent the arms from flexing outward under load, and as a good place to pick up the board from. The arms also get big fillets of chopped fiberglass/carbon between them and the deck, and the whole structure gets a nice shiny clear coat
Fillets and 3DP edge protectors on the outside too, and this shit’s DONE.even my fillets have fillets over them
Ok well i changed out the threaded inserts for M8 steel hex, because the brass ones from Lowe’s were BS. But NOW it’s done.