Thought I'd share a mini project I've been working on this winter.
I've had a couple issues with my fuel pump setup and had to get back into the access panel under the rear carpet to make adjustments.
Doing this got me thinking that it would be really nice to not have to remove the rear carpet, trim, etc to get to the fuel pump.
Also my OEM trunk carpet was alright, but overall it's just very bland and mine is faded worn. I decided I could make the fuel pumps easily serviceable while also sprucing up the trunk area a little bit.
In order to get to the fuel pumps, you have to disassemble almost the entire rear interior, which is extremely annoying for a racecar (which this is obviously). Also, the trunk on the Viper is extremely bland and boring looking, and mine is slightly worn out. Apparently the previous owner used the car to haul stuff in the trunk because the carpet is decently worn.
Here's the stock layout:
You can see some carpet wear on the sharp corners.
Here it is torn down. You can see the access door that is below the carpet.
The plan is to keep the carpet out of the trunk completely, so I can always put it back at any point in time if I desire.
I've been wanting to get into carbon fiber work so I'm going to make a real, carbon fiber covered panel to learn a little bit and see how it goes. I'm making a panel that will cover the top ugly area of the trunk, with a hole for the fuel pump access in the center. On the door cover, I am 3D printing a big 3D viper logo to fancy it up and be the center focal point in the center of the CF panel.
It will be laid out like this.
The carbon fiber and epoxy gets here next week. First things first, I designed the cover I will put on the fuel access panel.
Hard to see, but the two outside rings are at different heights, so when the top is painted red, it should give a bit of 3D effect with some depth change.
This will be epoxied/glued onto the current factory door, with some nice black hardware and cleaner holes drilled out. Then the whole thing will be primered to smooth out the texture the 3D printing leaves. Then i'll paint the viper logo and outside rings red like my concept picture above.
2008 SRT10 Coupe- Black w/ Silver stripes - Sold
1997 Viper GTS- Front Mount Single Turbo
Cut out the carpet on the top surface, and leave the molded carpeted edge on the corner and the front surface.
2 things I didn't like about that.
1) I would have to cut up and ruin the OEM molded carpet. Doubt I would ever care, but on a 20 year old car, it's hard to do in case I ever wanted to put it back.
2) the sharp edges on the carpet are rather worn, and the overall color of the carpet isn't a nice clean black becuase it's old. I'd rather not have it in there uglying things up.
With that being said, I plan to make a piece that is flat on the top, but then has a 1-2" lip hanging down over the front surface to make it look clean. This means I'll have to wrap the part around those surfaces, so it'll be harder than a perfectly flat piece, but I don't think it's a showstopper.
Ended up coming up with this design, with a little Fast and the Furious inspired joke for some fun. The nice thing about 3D printing is that if I get bored with something, I can just print another one that says somethinge else and change it out.
First, I printed half of the outside trim ring to see how it would turn out. The reflecting light really makes these pieces look rougher in pictures then they are. I was really impressed with the quality of this piece.
I still needed to print the other two pieces of the design before gluing them all together and finishing it.
Here's the final design I came up with.
center plate design
You can see the small dome I added. Instead of making the snake on top of the dome, I made it sunken in with the tops at the same height. It's subtle but I think it will look nice.
I printed another piece for 6 hours and my roll of ABS ran out with 20 minutes to go
I messed around with the design a little more to see if I could use the 3D printer to print the front "lip" geometry instead of trying to make something myself. It's 50" wide, so I would have to print it in 5 pieces and attach them together, but if i wrap it in CF afterwards it shouldn't matter.
Use your imagination that this gray pattern is CF. It was the best thing I could find in CREO on short order.
This is what happens when you start a print and go to bed and find out it failed in the morning.
This is because I'm printing ABS. ABS loves to warp and shrink when it cools. I extrude the ABS at 240 C (464 deg F) and the printer bed is at a toasty 120 C (248 deg F).
Basically, my printer is open to the ambient air, so the farther vertically your print goes, you are extruding 240 C plastic and it's cooling instantaneously in the ambient air a few inches above the print bed. This causes serious issues of warping.
Also, the more solid you make your part (read: structural), the greater difference in cooling rate you have from inside to out which causes warping as well. This was causing the corners of my parts to peel up. Well, when you are printing layer after layer of material on top of itself, and something peels up, you get the instance you saw above.
did a trial print yesterday to test a way to prevent this. I added some "puddles" to the corner of my parts where the peeling was occurring. This would give better adhesion to the printing bed, and I figured I could just cut off the excess after.
You can still see I'm getting some de-lamination between layers as the print gets higher off the bed, so i'm going to experiment with enclosing the printer in a big cardboard box to keep the ambient air hotter which should help keep it from warping as badly.
Did a test fit in the trunk of my trial piece.
When I print these for real, i will do it in 10" sections. It will take 5 pieces connected together to make the entire trunk border.
These 5 pieces will get pieced together, sanded, filled (if any holes/flaws at the seams) and then the whole thing will get wrapped in carbon fiber and epoxied.
Next I got all the pieces finished to make the fuel access cover. The main middle section came out a little rougher than normal. No clue why. It took over 24 hours to print so I'm going to make it work and smooth it out with some primer/filler or something.
Here's all the pieces laid together. A total of 4 pieces. I'll attach them together and then start smoothing it out in preparation for paint.
I messed around with some more printer settings, and came up with a fancy enclosure to go over the printer to keep some of the heat in.
Between the updated printer settings, the puddles I added on the corners to keep them from peeling, and the fancy enclosure, it seemed to do the trick on my first 10" full size print last night.
I also decided to add some keys that I can superglue into their positions and tie the pieces together better until i wrap it in CF. These will be on the underside of the part in the free space so no worries of interference or seeing them.
Well, I printed the next part for the trunk border and it failed miserably, even with the box over the top and all the same settings. No clue why but I'm sick of wasting material and time so I ordered a roll of PLA filament and am going to try it instead of ABS. PLA is not as heat resistant and is much more brittle than ABS but it doesn't warp, and since this piece will be painted and protected, and not structural, it shouldn't be an issue using it.
In the meantime, I continued to work on the access panel.
First I laid down a plastic primer to get paint to stick to it. Second I laid down a couple coats of filler primer to try and fill some of the texture from the 3d printing. It wasn't near enough to cover the imperfections. Also, the rounded portion around the logo ended up being extremely stair-stepped. It looked stupid and I decided I had to try and fix it.
Here's what it looked like after a couple coats of filler primer.
So on to Plan B. I busted out the Bondo Glaze. Glaze, if you've never done body work is simply a more refined version of body filler. it's the final coat you use to smooth things out after you do the major filling. It's much finer and you can sand it down without leaving a transition edge.
Round 1 of Glaze. I was able to bridge the "stair-stepped" portion of the rounded area with bondo to make it look stepless.
Hit it again with primer and saw more uneven spots and a few pinholes.
Fail. Round 2 of Glaze.
Hit it with primer again. Fail, still some rough spots I wasn't happy with.
Buuuuttttt.... I got pissed at how long this was taking and shot some black on it and told myself it was good enough. The black only made the situation worse. The gloss made the imperfections really visible.
So... sanded it back down and did a 3rd layer of Glaze.
After glaze, hit it again with 3 coats of filler primer, sanding it with 600 grit between each layer to level the surface.
Starting to look pretty good. I decided to leave the background of the center portion with the 3d printed texture. I think it looks kinda cool, and it would have been really hard to glaze in that area around the snake.
Also decided to shoot the final black color in flat black paint, as opposed to satin which was pretty glossy and showed every tiny imperfection. Black paint should go on tonight, and then I'll paint the snake, bordering, and lettering red and it should be done!
Now that I was printing with PLA, I was able to crank out all 5 trunk border pieces with zero issues.
I also printed the "keys" for assembly.
Assembling the pieces with the keys.
Testfitting the first 3 assembled center pieces
Testfitting with all 5 pieces assembled.
Re-testing my cardboard template with the border and access panel
Next step is to sand the border pieces and make sure the transition lines are seamless so I can paint or wrap it in CF. I still haven't decided which would look better. I also need to transfer my cardboard template onto the real material so I can cut it out and start working on skinning it with the carbon fiber.
I blew a fuse in the circuit board on my 3d printer, so I'm out of business until I can get a new one. Can't be bought in stores, but already found it and ordered, so hopefully it will be fixed by the end of the week!
Anyways, still moving slowly along on my trunk project when I get little bits of time.
First things first, I needed to use my carboard template and transfer it to the 1/8" plywood I'm actually using to cover in carbon fiber.
Original template in cardboard
template transferred and cut out in 1/8" plywood
Once I verified fitment, I sanded all the edges so they were smooth and wouldn't catch or tear the carbon fiber. Now it was time to start preparing and laying out the carbon fiber for skinning.
First step was to layout the carbon fiber and cut a piece slightly larger than the plywood I am covering.
Laid down a painter's tape line so I could cut the fabric without it fraying.
Next I needed to prepare the plywood before laying the carbon fiber.
I bought all my materials in a kit since it was my first time doing this and I wanted to ensure compatibility. Bought the Composite Envisions kit. Came with carbon fiber, epoxy, hardener, black dye, gloves, brushes, stirs, etc.
In my preparation for this, I had bought a kitchen scale for accurately mixing the epoxy and hardener as well.
First step was to mix the first layer of epoxy. This is the layer the carbon fiber will adhere to so it needs to be black since it acts as a background and carbon fiber is transparent enough that if the background isn't black, you would notice.
Weighing out the epoxy, hardener, and black dye in correct proportions.
Next, time to coat my working piece with the black layer of epoxy.
Once the epoxy is laid, you wait for a few hours until it starts to dry and get tacky (think wet paint that is drying). It took mine about 5 hours to stop being wet and actually turn tacky.
After it had some tack, it was time to transfer the carbon fiber onto the first epoxy layer.
I took special care to make sure I kept the strands square and all flowing parallel.
Now it's time to wait a day for it to dry, and I'll start adding clear epoxy layers on top of the carbon fiber!
Also have cleaned up the border I 3d printed to look more "factory".
I used the same procedure as I did with the fuel pump access cover.
plastic primer, followed by heavy build primer, followed by bondo, followed by lots of sanding and smoothing. followed by more primer, and then my finish coats.
First layer of bondo to hide all the transitions and layer texture from the 3d printing.
All finished up in a matte black that will hopefully match the other interior trim pretty well.
Very cool project. I don't know what everyone else does when they need to get to the fuel pump, but all I usually do is grab the top section of the carpet and pull it back. Roll the carpet back being carefully not to crease it any matter. When I'm finshed, lift the edges of the interior pieces and slide the carpet back. You shouldn't need to remove any of the interior panels to do this.
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