Worth mentioning, trucks are finger tight with two bolts. I admittingly took out a mm more than was needed in the back. The removal for the majority of the front cavity is pretty negligible. And they were pretty flexy to start with, like touching the ground in the center flexy
I am planning to FG the entire bottom of the deck and I still have a full layer of maple to add to the top of the deck planned. I havent decided how to finish this deck off just yet, so I may use the nice piece of carbon fiber I have. By the time the bottom gets FG and the top gets a layer of maple, the enclosure gets bolted on, it’ll stiffen a lot from here. ( you can just spot the last layer of maple I have in the roarockit box under the couch)
Battery will be flexy of course.
As much as I like carbon fiber and I dislike fiberglass, I honestly think fiberglass is a lot better for esk8 usage. It’s transparent to radio waves. This is very important.
Can you use radio devices inside a carbon cavity? Maybe. But why? If your life depends on stuff working, I’d give it every chance to work as best it can, and one way is by using fiberglass instead of carbon fiber. Unfortunately.
Everything prepped, final layup on the bottom was today. Unfortunately this was a mess- the dog must have walked on the vac bag (normal vac bagging film) and punctured it somewhere. After doubling up the butyl tape seals on both ends and not being able to hold a vacuum I had to switch bags and make a new one quickly in real time. I was definitely past the working time of the 206 hardener by the time I got a consistent vacuum.
This is using the roarockit pump to create a static vacuum so there’s not concern for dry areas since I wet it out by hand. It may mean that most of the excess epoxy was left behind and worse case, the FG wasn’t held well to the surfaces or the curves in the pocket I cut. We will have to wait and see
Layup was 4 ounce weave from tail to 1/3 length of the board. Then just the drop down to 1/4 length. Then a layer of 2 ounce weave over the whole deck end to end. Peel ply and then breather
I left it outside on the hood of my car in the shade for the first 3 hours or so. It’s ambient about 90* today and it’s 69* in my apartment. Hence the writing
After the vacuum failure on the FG the other day I realized I was stuck because I was out of bagging film. I did a dry layup in the Roarockit vacuum bag which couldn’t bend enough to pull the mat tight in the cutout and I would’ve wound up with the same result again. So while I waited for supplies from Fiberglast.com I got the upper veneer prepped. I soaked the veneer in some warm water in the bath tub to soften it and into the Roarockit bag it went with the board. I left it wet for the first 4 hours and then I added a bath towel inside the bag behind the new veneer to soak up the moisture and dry the veneer out while its being pulled to shape in the vacuum bag. If you wet a veneer and just let it dry, it will substantially warp. This way of pre-forming it and drying it out is the best way I’ve found to meet these complex contours during the glue-up.
Also received some stainless m5 threaded EZLOK inserts which ill be installing. Once this is pre-formed ill fiberglass the bottom, then install the upper final veneer.
Getting closer! The BMS that the USPS lost finally showed up. Thank you to @thisguyhere. Once I was able to check clearances Im ready to finish pouring the urethane. I didnt want it to be the same depth around the unity because I have other items like the remote receiver and BT for the BMS to create a spot for as well. To accomplish this, I 3D printed a part to attach to the heat sink (which made sure it was square) and I used some clay to fill the gaps around it. This will be the sport for the main negative and positive P groups. Tooth picks were just to gap the battery plug away equal distance
I have some of that stretchlon 200 as well, may try it. I think the standard film can make the curves just fine I just lost vacuum pressure while the epoxy was setting.
Also from @DerelictRobot these 4p 21700 PCBs, only because I had the space for them. As recommended, they were spot welded and soldered to the nickel strip. The substrate on the PCB is pretty thin so I spot welded them about 10 times per side to make sure the nickel was held to it in many locations and tightly bent against it. My malectrics spot welder was set to half of what I normally weld 0.2 nickel to cells at
For a flexy pack, I also like that these take the connection points off the nickel. Depending on how much flex exists, the moving series connections will transfer some of that flex to the nickel to cell connection, and this eliminates that. To finish them off ill add a touch of glue under the edge of the PCB essentially locking the cell, nickel, pcb into one unit. They’re pretty cheap so buy yourself an extra to practice on and get a tear test done with the nickel you’re using
It’s a tight fit for sure! This damn heatsink made this all a lot more difficult
Now that the last battery section has been poured with urethane the next step is to figure out how I’m handling the tail section where the wires will come through to the rear motors. Likely going to cut some of the MK3 channels back.
Then I’ll paint the enclosure with a textured bed liner
Oh no, everything’s being built to work out. It’s been a lot of fun working through these problems and not limiting myself on solutions. A lot of time, sweat and money has gone into this but I’m excited to see the finished product.
I could’ve cheated with a thick gasket and used a D140 and gotten away with it I think. Still would’ve been tough with the heatsink.
Getting some ideas about motor phase wire routing. Too much length on the maytech motor sensor wires so I’ll shorten them
Figuring out if I can mold MR60s into a tail gasket to seal off these channels. This would have the motor phase wires plugging in from the outside, although the distance is really short so they may have a tendency to get tugged out
It’s gonna be a tough area to form and pour this urethane or epoxy too because it’s pretty runny. Might get some of the brushable stuff they sell which is much thicker. Don’t really wanna make a whole mold for this and then glue it in.
There’s a rate of return on all of these products that’s rapidly diminishing. Like a $40 bottle of urethane to make the gasket is getting excessive.
I’m also considering fiberglassing an end cap with the MR60 plugs sticking through for a lot less effort and cost then making a big urethane plug for the tail.
Rather than a whole rubber plug, I’m going to fiberglass an end cap on the tail cable channel which I’ve cut down quite a bit now.
Worth going to a GX12 or something similar for sensor wires or should I stick with a grommet for those? I’ve seen the haggy plugs, but the overall connection gets pretty long
I’ve been following this with great interest Bwah! There are many new techniques that I haven’t seen anyone do before here, potting the batteries with urethane, fucking genius! Looking to essentially build something very similar with the Sportster and this has been an extremely valuable writeup <3
