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Insolent Gnome

LANpak - Scratch Build

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The idea behind this one came to me last year on my way to Omaha for the NETWAR LAN. It was a pretty nice day and I was cruising up in my truck with my rig and I thought, "Man, this would be a great day to be on a motorcycle! It'd be nice to toss everything on the bike and blast the 5 hours up to Omaha." But how to transport my rig? 

I could go small. Get a SFF case and a small monitor so that I could toss stuff in my saddle bags. Or ship the thing beforehand and just figure out how to get it from the hotel to the LAN. 

Shipping it just wasn't a good option at all and SFF cases are cool, but I want some area to mod. Tiny case, tiny mods and a whole lot of figuring out how to stick things in a small box. 

Another option that popped into my head was a backpack. Just strap the computer to my back and hop on the bike. That sounds like fun!

Now I know that there have been backpacks before, but I thought I could give it my own flavor. First off, it needs to be slick and aerodynamic. I want it too look good and I really don't feel like wearing a sail on my back running down the highway at 70(hahahahahahaha, as if). Also I don't want some weak little system. If I wanted to game on a mobile chip, I'd take a laptop, I want a real screamer of a system. And finally, I don't want to have to figure out how to also strap a monitor to my bike(even though I totally could) or have another backpack for my keyboard and headset and all of that. One pack...everything.

First, I need to set some parameters for the build. Obviously mITX because space is at a premium. Watercooling would be nice. A hard shell is a definite. I want protection and I'd also like to not have my fans eat my case. Waterproof, because rain does happen. And as light as I can get it, cause...well...

So lets get a hardware layout going, something backpack sized.

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MITX, SFX-L PSU, and 2x240mm rads. You know, the basics, LOL! I'm not sure that I'll water cool the GPU, but I want the space because it's better to have it and not need it rather than the other way around. M.2 for the storage so I don't need to worry about finding a spot for a drive. I'm not really sure about the res, I may have to figure something else out for a res/pump. But it's a start and the size is good.

For the exterior, I figured fiberglass because it's rigid, tough, relatively light and with some gelcoat, water resistant(think boat). I can mount stuff to it if I need to, which I will, and I can form any shape with it. It doesn't hurt that it's my business these days. So let's get a shape.

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I knocked something out in SketchUp just to get an idea on measurements. I'm going to have a much more rounded look, but this gives me some good references.

Now for some physical work. I cut down a box so I could see IRL the size that I'm working with. This represents the space for the hardware and a storage compartment below it.

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Not too far off from the size of a work backpack.

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You'll notice my assistant in the background. He was helping me with getting a feel for the size of the backpack.

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With my box for my minimum dimensions, I surrounded it with foam so I could carve out the mold of the shell to lay my fiberglass on.

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A little bit of glue and some weight, and we wait.

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After a little bit of cleaning up the edges with a rasp, I'm ready to start carving out my form.

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Thanks for checking my project out! [IMG]

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To get an idea of how to start carving this thing, I wanted to see the areas I needed to work around, so I drew out my minimum space requirements on the outside of the foam.

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Now I can layout some of the parts that need to line up with the shell of the case, like the fans.

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It's hard to explain but I think the best way to describe what I'm wanting to do is that the fans will sit at the bottom of a pocket. The shell will dive into a flat spot and that's where the fans and rads will mount. That's not very clear, but basically, I need a hole where these fans are. I marked out the fans and then gave myself an extra 5mm for fiberglass and corners and what not.

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Then the fun part, I took a router and starting with a straight cut bit, I cut out the pocket.

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I'm not sure this is the final depth, but it's good for now. Note that the fans will be on the other side of the pocket when it's all said and done, mounted inside the shell.

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Hey look, pink snow!

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To combat the blizzard of pink snow in my shop, I decided to try my hand at making a hot cutting wire setup for some of the basic shaping. I started off with some 1/2" MDF and some 19 ga. steel wire.

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The plan is to use the MDF to hold the wire so I don't electrocute or burn myself and I'm cool with that. First I notched the board.

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Then with some screw and brads as guides, I strung the wire between the ends. Now this is janky as f**k, but it's more quick proof of concept than long term shop tool. I want to see if it works for me and if I need to, I'll make a better version.

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I screwed the contraption to the end of my work table so that I could use it like a band saw, with the table being a good surface to move my workpiece around on and keep things sort of square. And then I hooked it up to a battery charger. Yeah, this looks totally safe.

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But you know what? It worked!

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I did have one question about my specific case though. I used wood glue to stick my foam together and it can get hard, can the wire cut through it?

Yep!

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And now I'm in business. Now, I'd never suggest using 1/2" MDF for something like this and I wouldn't have except I had the piece on hand and it was a perfect size. I'm thinking a 3/4" plywood or something along those lines would be better, maybe even some standard boards since you're really stressing the edge of the board with the wire. And speaking of wire, mine worked but I've seen videos using guitar wire and a tuning peg to tighten the wire as it expands. Needless to say, I've got those goodies on the way but this contraption should get me going for now.

Thanks for following along! [IMG]

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So I decided I didn't want to wait for the parts for my 'enhanced' hot wire cutter to arrive and tried out my rigged up trial version...And it did ok. It had a definite lean to it, but with some effort I got a majority of the outside cut down without the blizzard. First up, I made a template to make sure I got my sides even. Hopeful thinking, but hey, positive attitude!

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And then I marked out my cuts.

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They were mainly for bulk removal, figuring I'd snazz it up with some final shaping. And it worked...

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Rough, but with a rasp I could knock down the bigger bumps. Side note: a sheetrock rasp makes quick work of XPS foam, but it' rough.

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After the rasp to even out the shape, I turned to 220 grit sandpaper to slick it up.

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It was looking a bit boring so I tried to add some creases...still boring.

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It wound up looking like a piece of luggage. Instead of a LAN, it looks like I'm going on holiday. Call Samsonite, I've reinvented their bags.

Welp, I think I'll re-think this direction.

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After mulling over my luggage, I decided to go back to the drawing board. I needed to change things up a bit. Number one, the exterior needed to follow the hardware a bit closer, to give it more of a cut up feel and to cut down some size. Number two was to revamp the layout a bit to slim it up. The previous design reminded me too much of a mid tower. Granted it's a system plus peripherals, but I wanted it to look sleek, not like you strapped a case to your back. A bit of time 'researching' on a motorcycle accessory site, and I was ready to give it another go.

First up, the layout. To thin the design up a bit, I decided to tilt the radiators and instead of mounting them at the bottom of a well, I'd mount them directly to the side of the case and figure out some waterproof covers for transport. I also ditched the res and pump for now. I'll add them back in later, but I'll either find a spot for a off the shelf unit or make something custom. I just don't want my design dictated by the res/pump.

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Then I worked my design around the shape of the hardware. Leaving a bit of play room but following the contours and going with a very angled design.

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Rather than try to hand sculpt it, or sit down and figure out all the measurements for each facet, I threw the design in Pepakura and let it make templates for me.

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And then it was cut out paper, transfer it to cardboard, and assembly.

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On all the pieces for the sides I added 2" extra. I'm going to use this as a plug for a fiberglass mold and that two inches gives me an edge that I can just cut off later. Also, I'm not sure how much room I'll need for figuring in a monitor, so I've got some room to play with.

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Mmmm...puzzles.

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Assembly was with hot glue. I threw in some braces to help keep things squared up and a little stronger till I get this glassed up.

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Assembly was pretty simple since I usually had 2 edges to give me my angles and attach too.

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And done.

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I really like the shape better and it's not huge. Currently bout as deep as a decent laptop backpack and runs from my shoulders to my belt. It's a little wide as I clip my arms on it moving them around, but it is a computer shoved in a backpack so...

Next up is playing with some polyester resin to start turning this into a plug.

Thanks for following along! [IMG]

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Now it's time to turn my cardboard creation into a plug. A plug is just the basis for a mold. The process goes like this: make a plug which is the shape that I want my shell to be, then make a mold off of the plug, and then I can layup my composite layers in the mold for my final product. It's a lot of work, but I'll be left with a mold so if I screw something up or want to try something different with the shell I can make another copy. 

To start, I need to stiffen my cardboard up a bit. For this I'll be using chopped strand fiberglass and polyester resin. The chopped strand is easy to work with and wrap around curves and the polyester is a cheaper resin but will work perfect for this. Well, mostly perfect. I had some Bondo resin laying around it works fine as a resin and it's cheap and available, but it's more of a patch resin. It works well in one coat. 

The funny thing about polyester resins(and others) that I work with is that they don't cure in air like say a paint. They don't cure by a solvent evaporating, but rather a reaction in the resin and air kills that reaction. Sucks if you're trying to put a finish coat on something, but for laying multiple layers, this is great because each layer bonds with the one before. The way to get layer to fully cure is to coat it with another material. Another layer of resin, some plastic sheeting, or very commonly, a wax. I'm pretty sure the Bondo resin has a wax additive that helps with this last layer curing which doesn't really make it ideal for laminating layers. 

Long story short, I had to move fast to make sure all the layers bonded to each other. And don't worry, I won't be using bondo in the final shell, it just worked for my plug and I had it.

The first thing in layering this up was to fill all my gaps so the strand wasn't bridging across a void. I did this by mixing the resin with a material called Cab-o-sil. It's a super light silica for thickening up resin.

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Mix that with some resin and you wind up with some goo.

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I slathered that in all the gaps and tried to keep it as clean as possible. Any random glob will stand out under the glass.

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Next, get a good base coat of resin to soak into the cardboard and help with the wet out of the glass...

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But then thought about how fast this stuff cures up and got right to the glass.

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Tearing this stuff vs. cutting it gives you edges you can feather out better.

I'd provide more pictures of the during, but like I said, it was a time crunch. In a cup, the the resin gets hot and cures faster so I had about 20 minutes of pot life to get the glass down and all the air bubbles out before that batch was useless. On the plug, the resin takes anywhere from 30 to 45 minutes to cure so once I got one layer down...

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It was time for the next.

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I probably wound up with about 3 layers overall with all the overlap from the pieces of chopped strand. It's pretty tough now and ready to sand. I wanted to get a lot of the stranding out and knock down any high spots. Also to provide a surface with some tooth for the next layer.

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And cleaned up. Still pretty rough, but that's why they make filler.

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This is a standard polyester filler that I use in tub repair. Low shrinkage, sands easy, and white with white hardener so it doesn't stand out under thin gelcoat and you have no idea if you've mixed it up well at all.

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First of a few coats.

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And after some sanding.

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It's very important that this plug be as perfect as I can get it. Every little detail on this plug will wind up on the mold, which then transfers directly to the final product. So the better the plug is, the less work I'll have to do cleaning the final shell. After two passes of filler, I've still got a few spots to touch up, and then I'm still not done, but more on that next time!

Thanks for following along!

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To pick up where I left off, I've got the plug sanded pretty smooth and cleaned off.

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Now to smooth it up even more with some epoxy primer. This will fill in any small holes and I can use it to find any dips or high spots.

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Since I'm planning on sanding the crap out of it, I went ahead and just applied it with a brush.

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And then more sanding. Anyone else starting to see a trend here?

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After doing another epoxy coat and spot filling the most stubborn spots, I was ready to be done sanding. Now to waxing. Uggghhh.

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The mold release wax is just for that, filling in all the little pores and letting the mold pop off easier. 3-5 coats (I went for 5), wax on, wax off. After that much waxing, I can give Daniel-san a run for his money. The plug does look slick though. And is slick. It's hard to hold on to that bad boy after 5 coats of wax!

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Next up, I finally started the molding process..sort of. I need to split the mold otherwise I'd never get what I molded out. My first idea was a 4 part mold with breaks on the sharper corners, since they hide mold marks better and that should make getting the part out afterword very easy. After procrastinating because that seemed very complicated (some of the 2 month delay) I decided to just go with a 2 piece mold, right down the middle. The mold line will show, but I'm pretty sure there's gonna be some cleanup anyways and I can take care of that. Maybe a little more difficult to demold my part, but it's a lot simpler for the first mold I'm making.

First up, I need a divider that will give me my flange for the first side of the mold. I'm using corrugated plastic sheeting...or like I described it to the Home Depot guy, plastic cardboard.

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It's tough, easy to cut and gelcoat doesn't stick to it too bad.

So I made a template out of cardboard and used a neat little trick I saw in a YouTube video about mold making. I cut my template big and then used tape to fine tune it.

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Then transferred that to the corrugated plastic.

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With a little bit of work, it fit like a glove.

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To make it stay in place while I'm putting gelcoat and fiberglass on it, I hot glued it to the plug and used stir sticks as braces.

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Before putting the gelcoat down, I went ahead and waxed the plastic to make it come apart easier and filled any gaps with wax as well, to keep the gelcoat in check.

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And since I want some registration marks in the mold so that it all lines up like it's supposed to I tried hot glue since I didn't have anything else that really stuck to the plastic very well. It's not perfect, but I can clean it up when I get the other side ready.

Next up, gelcoat and fiberglass.

Thanks for following along! :)

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And now the fun stuff, making the mold. I'm starting off with a few layers of gelcoat. 

Gelcoat is a polyester resin, like the resins for fiberglass, used for the outer coat. It's durable, finishes up nice, and works great with fiberglass resins since it has a lot of the same properties, like not curing in air, allowing follow up applications of gelcoat or fiberglass to bond chemically with the previous layer. If you've got a fiberglass reinforced tub in your house, gelcoat is most likely what your seeing, backed by layers of fiberglass. In fact, a lot of tubs are made very similarly to how I'm going to make this mold, by applying a thin layer of gelcoat on a mold and then backing that up with fiberglass.

And here's what I'm using, plain white gelcoat but I'm gonna dye it blue. Normally you'd use a tooling gelcoat for a mold, which is harder and more resistant to damage, but I'm not planning on making 100 shells a day so regular gelcoat should work and that's what I have on hand. The dyeing it blue is to help with casting the shell. If I'm casting with gelcoat, I can see thin spots in my coat, but more than likely I'll be using CF or a similar composite and the blue will let me see spots where I might have a gap.

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I'm going for two layers of gelcoat, about half a pint for each should give me coverage.

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After brushing it on. You could spray it, but it's not necessary since the finished side depends on the plug and not what the exposed surface looks like.

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I gave each coat about a half hour to an hour to set up before the next coat. After the gelcoat was down, it was time for the fiberglass backing. This is the resin I'm using, polyester layering resin. It doesn't include a wax so that the outer skin of a coat doesn't set up and the next layer can bond with it.

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For the first layer, I'm using chopped strand fiberglass. It doesn't have the woven look because this is just strands of fiberglass laid in a sheet and held together with a binder that the polyester resin dissolves. 

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And laying up the first layer.

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Next layer I did woven fiberglass because I had a roll laying around that wasn't being used up.

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And a last layer with more chopped strand. There's no real reason to have mixed the layers or what order they are in. Chopped strand takes up a lot of resin and adds bulk and strength quickly whereas woven cloth is thinner and uses less resin. Since I'm looking for bulk and strength, the chopped strand is more what I want. Woven cloth for the whole mold would work fine as well, it would just take a lot more cloth.

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And with everything all cured up, things got a little meh...

I pulled my divider off and realized that I had a lot of void spots and just an all around bad finish. I blame this on not getting all the wax off the divider and the gelcoat being able to pull off while curing. Also, my registration glue dots, not the best.

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But it's what I've got so lets start by cleaning up the edge.

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It just so happens that my new job and company is fiberglass and gelcoat repair so this shouldn't be a problem. I started the fix by grinding out all the rough spots.

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Then after some sanding to make sure the patches had something to bite onto, I layered in some gelcoat, leaving some dips for my registration.

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And then sanded it out.

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It's not perfect but I figure any imperfections are just extra registration. And it could be a problem that my patches are only mechanically bonded to the mold instead of chemically bonded, but that should only be a problem while making the second half of the mold, and I've got an idea about that.

And last time I said something about a sponsor...check out this beast.

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I want to thank GeForce Garage for sponsoring a RTX 2080Ti for the build and for being great to work with all around. They're always helping me out if they can and getting me in on cool projects. This will definitely go a long ways towards making this the fastest thing at a LAN.

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Thanks for following along, more to come soon! :)

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Continuing with the mold making, after getting my edge sorted out, it was more wax in case I rubbed through a spot somewhere and since the flange had never been waxed.

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To be honest, I tried to pull the first side off so it would be easier to fix and that was a non-starter, so I wanted to make sure this side was at least easier to pull off. Not only did I use the mold release wax, but I put on a coat of PVA wax as well. This will dry to a thin film and washes up with water. Should make everything come apart easy.

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And then it was the same as last time, couple layers of gelcoat followed by fiberglass.

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Once I had that all laid up, before popping anything apart, I drilled my holes for the bolts to hold the mold together.

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I'm kinda guessing on the bolts so I went overkill. Just a few 5/16" bolts.

Then it was time to see how all this came out. The second side, the one with the PVA came off pretty easy with a little wedge application between the flanges. It's almost perfect, though it does have a few imperfections I'll have to fix.

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The first side...well...

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It didn't seem to want to let go. Obviously the PVA was a very good idea on the other side. The gelcoat managed to grab on and pop some of the filler and epoxy off with it. It took 3/4 of a box of paint stir sticks to wedge in to get it to finally let go.

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So lesson learned, just waxing isn't enough especially if the plug isn't polished to a mirror finish. Luckily a lot of the filler comes off with a razor blade. It's stuck, but it's not STUCK.

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So after a lot of razor blade on mold action and some sanding, I got the side cleaned up.

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It's got a 120 grit sanding on it, which will have to get a lot finer, but first I need to fix any imperfections. So bring on the dremel to grind out any voids and then I'll patch it back with some gelcoat and sand it nice and slick.

Once again, thanks to GeForce Garage for sponsoring this madness!

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Thanks for following along and I'll see you next time!

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And I'm back! I mean, I didn't go anywhere, but I'm back working on this mod. It's nice enough weather now that things will actually cure in my basement so, let's make up for lost time.

When I left off last time, I was cleaning up the mold from my de-molding the mold process. Totally doing that differently if I do that again. But, I got the sides cleaned up and filled any holes with some gelcoat and sanded it all nice and smooth.

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Then I was ready to try my layup. First things first, wax and plenty of PVA to make sure this thing comes out easier than last time.

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And what am I laying up you ask. I'm starting with a layer of 3K carbon twill, then two layers of Kevlar twill and then a layer of carbon fiber veil. 

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Why this mix? Why Kevlar? What the heck is veil??? Well this is a deep rabbit hole with a lot of interesting stuff, but lets just go for the overview. Ok, lets start at the CF twill. We all know CF is light and stiff which makes it good for this shell, unfortunately it doesn't do so well with impacts. Hit it with a hammer, run it into a car at 40mph, it breaks. That's kind of a problem, and that's where the Kevlar comes in. Bullet proof vest right? Yep, and that's sort of the reason I'm using it. It is super tough and resists impacts. Not that it won't break, the epoxy in the matrix will break apart but the Kevlar is stupid tough and will hold it all together. Think safety glass, it shatters and breaks, but it doesn't go flying everywhere. So if something bad were to happen with the shell, it would break, but you wouldn't wind up with chunks of carbon fiber flying around being all stabby. Kind of important. And then there is the veil, it's a super thin weave that doesn't really add to the structure, but holds epoxy. This makes it a good sanding layer over my Kevlar since Kevlar is a PIA to cut and sand and just frays anytime you get into it.

I would have prefered to do the layup with another layer of CF instead of the veil, but I shorted myself on materials. Being able to sand the veil, I can go back and add a layer later.

Starting off with the CF. 

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Then the Kevlar.

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I didn't get a shot of the veil because at this point I was in a hurry. I decided to try vacuum bagging the layup, which is exactly like it sounds. Put it in a bag and suck the air out. This helps to compress the layers, pull out any bubbles, and pull out any extra epoxy, so you wind up with the lightest and strongest part possible. And since it was my first time trying this, well let's just say next time will be a lot smoother.

So in the bag you go with a layer of material that is permeable and doesn't stick to the epoxy, and a layer of fill that lets the air flow out and sucks up the extra epoxy. 

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Then, in my case, spend 30 minutes reworking your vacuum pump to work with this set up and another 45 finding all the leaks in the seals, and suck all the air out.

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I never did get that thing totally sealed, but it turned out pretty good for a first try.

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The inside was a bit rough with the veil giving me some folds and pockets, but I'll take care of that next update. Thanks for following along and thanks to my sponsor:

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Keeping going on the shell, I got my order of CF so I could add the final layers. I sanded it all down, inside and out.

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And then made a slurry mix of epoxy and Cab-O-Sil to fill in any air pockets and smooth the corners out to make the next layer of CF lay a bit better.

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I got the piece for the inside cut out and figured out how I was going to weave it all together.

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Then epoxied it all up.

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Same with the outside but a little different method. I cut pieces that fit a little better and leave nice seams but still overlapped and stuck them in place with a little Super 77 adhesive to keep them from moving around.

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It's such a complex shape that you'd never get one piece to lay nice over it and seams are necessary. Still trying to figure out the best way to pull them off, but it turned out alright for the first time.

Then epoxy.

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After the fact I kinda figured that the best way to seam it would have been to cut that center piece wider, epoxy it and just not work the sides down. That way I could just sand it back giving myself a cleaner seam. As it was, I cut it close and wound up with strands hanging over instead of weaved material.

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All in all, it worked but it wasn't the cleanest seam.

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The whole thing was sanded to get most of the bleed through of the weave out.

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It could be better, but it's still pretty cool. I'm gonna hit it with a medium scuff pad and then put another thin coat of epoxy on it to even the surface and then with some sanding it'll be ready for paint. Yeah, I'm covering up all this CF. It looks cool, but it's not perfect and I'm looking for perfect. Plus, that's a lot of CF in one spot, I'd rather have some carbon accent pieces than everything carbon.

Thanks for following along and thanks to my sponsor on this build:

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