Interference Fit
Nurburgring
- Joined
- 7 Apr 2024
- Messages
- 459
Having recently explored the cost of replacement front lip spoilers for the 996 aerokit as per the below.....
I saw myself coming backwards when I learned that a curved plastic moulding was now circa £500+ , which out of sheer principal, I couldn't justify for what is effectively an almost sacrificial part.
I considered a nearly new one for sale which was still hundreds, but was too far away to collect, and not being particularly impressed with any of the aftermarket items, I thought it might be a fun project to see if I could build an exact replica myself.
For a prototype, I chose polycarbonate as it it very tough, very flexible and easy to work with, so I bought a suitable sized sheet and laid it out over the (removed) front bumper so I could perfectly replicate the mounting holes.
To ensure I found the perfect centre of the holes, I 3D printed little guide bosses that were a snug fit to enable accurate pilot holes to be drilled. That's what the little green bits are in the mounting holes.
With the holes now in position, I could make the base plate. This took a very long time to scan all the multiple images on line of factory parts to work out the correct dimensions of width, depth, thickness and profile, which other than the thickness, none were uniform. Much to my delight, my measurements were very close, confirmed by very slight witness marks in the paint where the original had been, permitting a perfect dimensional copy.
Next up was to create the vertical piece, which is a tricky piece to get right as whilst it appears to be at a right angle to the mounting surface, it isn't. When mounted, the mating surface slopes upwards as it goes forwards toward the front of the bumper, yet the front face is in the perfect vertical plane, making the angle between the two surfaces one of constantly varying acuteness as it curves round toward the ends. This took a lot of messing around with jigs to get right, but I got there in the end.
Following this was then the usual hours or fit, refine, refit, refine etc, etc until I was happy it fitted correctly. I also wanted to make sure that the internal blend between the two surface planes was the correct radius and uniform along its length as per the original. Once I was happy with the final level of fit and prep, I applied primer and paint to leave me with a master prototype which in itself is perfectly serviceable, however my initial goal was to take a master silicone mould from this so I can then produce (cast) many more in the correct polyurethane material as the closest replica part I am capable of. Not sure when I'll do this as it's been an investment of many days work to get to this stage, but the option remains if I get the urge.
All in all I'm satisfied with the outcome.
I saw myself coming backwards when I learned that a curved plastic moulding was now circa £500+ , which out of sheer principal, I couldn't justify for what is effectively an almost sacrificial part.
I considered a nearly new one for sale which was still hundreds, but was too far away to collect, and not being particularly impressed with any of the aftermarket items, I thought it might be a fun project to see if I could build an exact replica myself.
For a prototype, I chose polycarbonate as it it very tough, very flexible and easy to work with, so I bought a suitable sized sheet and laid it out over the (removed) front bumper so I could perfectly replicate the mounting holes.
To ensure I found the perfect centre of the holes, I 3D printed little guide bosses that were a snug fit to enable accurate pilot holes to be drilled. That's what the little green bits are in the mounting holes.
With the holes now in position, I could make the base plate. This took a very long time to scan all the multiple images on line of factory parts to work out the correct dimensions of width, depth, thickness and profile, which other than the thickness, none were uniform. Much to my delight, my measurements were very close, confirmed by very slight witness marks in the paint where the original had been, permitting a perfect dimensional copy.
Next up was to create the vertical piece, which is a tricky piece to get right as whilst it appears to be at a right angle to the mounting surface, it isn't. When mounted, the mating surface slopes upwards as it goes forwards toward the front of the bumper, yet the front face is in the perfect vertical plane, making the angle between the two surfaces one of constantly varying acuteness as it curves round toward the ends. This took a lot of messing around with jigs to get right, but I got there in the end.
Following this was then the usual hours or fit, refine, refit, refine etc, etc until I was happy it fitted correctly. I also wanted to make sure that the internal blend between the two surface planes was the correct radius and uniform along its length as per the original. Once I was happy with the final level of fit and prep, I applied primer and paint to leave me with a master prototype which in itself is perfectly serviceable, however my initial goal was to take a master silicone mould from this so I can then produce (cast) many more in the correct polyurethane material as the closest replica part I am capable of. Not sure when I'll do this as it's been an investment of many days work to get to this stage, but the option remains if I get the urge.
All in all I'm satisfied with the outcome.
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