So, here is everything laid up as a reminder of where this started. I think it’s a good reminder of how far the tub has come, but at the same time it’s also making me think the duratec is photobombing everything in my garage.
Now, here it is in the car:
It’s pretty close to where I want it now, and I’m doing the final fettling. I made this with a positive mould, which has meant the outer surface (that fits to the chassis) isn’t perfectly flat. I’ve had to take it back a little at a time with the flap disk in the appropriate areas to be sure it fits. I developed a methodology to do this after I’d removed the obvious obstructions.
I go around the gap with a feeler gauge set to 0.7m, and look for areas it traps. When I find a trapped area, I set the gauge to 0.05 mm and see if that still sticks, and anywhere it does, I mark with tape (hence the packing tape on the tub at the back top) and take it back about 1mm with a flap disk. I deliberately only mark the jamming points rather than the tight points so I can avoid making gaps unnecessarily larger than they need to be.
Once everything is marked, I lift the tub out (it’s only 13kg, so two adults can easily lift it with fingertips) and do the sanding. When it goes back in it fits a little better. Everywhere is pretty much where I want it, apart from the back where it’s still a little high. Everytime I advance the fit, the back lowers down a bit. I have about 3-4mm left before it’s flush and I’m happy.
This one is a little more difficult to wrap your head around, but it’s the mating surface between the tub (carbon on the right, starting in the top right corner) and the chassis rail. As you can see, the gap is pretty uniform now, and I’m aiming for between 1 and 2mm.
It unfortunately means I’m doing to have to remove some of the powder coat with a flap disk.
Here is the birds eye view. You can just see the lip at the back. I don’t want to just sand it off – I think I can make the tub a better fir before I have to do that.
Then the final act before bonding it in is to have it lacquered and cured. Then I will have an awesome finished product.