There is also a 2.5" Lip around the entire mould to allow a lot more surface to attach the aluminum undertray to. This undertray will be fabricated up by Wayne Yeates of Way's Performance Services.
I removed the 3 support ribs that were in the fron of the original version. I figured that since there are support rods those should not be required.
This time I used Adobe Illustrator to create the template that I would be using to cut out the mould. I made very precise measurements from the bumper, instead of just tracing around the bumper like I did the previous version.
I printed up the template, and layed the bumper over it and adjusted as needed. I also, had to remember that ABS has a shrink rate of 3-8% so I averaged it out and brought down the template 5%.
Once the template was finalized I used a scroll saw to cut 3 layers of 3/4" MDF(Medium Density Fibreboard). I screwed and PL Premiumed each layer so this thing is completely solid and should be around for hundreds of pulls. This solid piece was then sanded to make 1-2 degrees of negative draft so it could be extracted easily from the ABS form.
The large horizontal splitter was cut using 1/4" HDF(High Density Fibreboard) and was only screwed into the Main MDF body with 4 screws. I plan on this being replaceable as it is a thin piece and could snap when trying to eject it from the ABS.
During the test pull there were a couple of issues. A vaccuum leak prevented the left and right rear corners to get completely sucked onto the mould. This was a minor leak and everywhere else sucked nicely to the mould. It looked pretty good other than that, almost like a final working piece. Even the test fit to the bumper cover was almost perfect.
Also, releasing the mould was a very painful experience as it took about 15 minutes of banging on the finished test piece. the MDF body cracked a bit and will have to be repaired.
After examining the mould we discovered that their was actually a very slight positive draft on a couple of inches of the mould, which prevented it from being released from the the formed piece. That will have to be sanded down to create some negative draft.
Also, after this last test, I am going to add alot more draft to the inside of the mould where you won't even see it when installed. I will add 5-10 degrees just so it will be a very simple process of extracting the mould from the ABS final piece.
Spraying the mould also with sandable primer on the next revision will be sanded sound to a "baby's bottom" smoothness level. We couldn't use silicone spray on this mould since it was bare MDF and it would have just absorbed the silicone and caused it to swell or warp slightly. So using the primer will seal the MDF and allow us to use the silicone spray which will create slippery surface so extraction will be even easier.
If only this test piece worked out, because, by accident, we used a piece of scrap ABS, thinking at first it was polystyrene. Only after the test pull was complete we could smell that it was ABS. Ah well.
Test Pull Rear-So Pretty.
Test Pull front
Test Fit Front-Perfect Fit!
Test Fit Rear
Also, I had to build some custom brackets that will hold the support rods from the splitter to the bumper. U-Brackets are hard to find so I had to cut a Flat T-Bracket, and use a brake press to make the U-Brackets I needed. It turned out pretty well. The rest of the hardware will be from Brafasco as they have everything I need. I've never been there and I'm quite excited aboutfoing to a showroom full of hardware.
So, hopefully, this coming week I will make all the revisions and repairs required on the mould and do 1 final test pull on the vacuum former. Then it should be ready for the final piece with white 1/8" ABS. Yes, I said white because the suppplier only had white and really, I could really care less what colour this thing is. As long as it's functional, I will be super happy. I can paint it black easily enough.
That's it from my end. I'll update soon with the next version of this splitter.
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