forcasted 25 degrees. not great for wet-lay

I am pushing to finish the fuel tank moulds today. It’s all wet-lay all the way, and at 25 Centigrade is going to mean a couple of things:

  • hot and sweaty work – I wonder if I can do it outside
  • You can’t mix more than 500ml of resin before it starts to gel off

So, lots of mixing and swearing and sweating. At least cure times will be quick.

Footwell Fettling for Friend’s feet, Part 3 – Finished

footwell part 11

Right, so, you’ve seen the video about laying up, and here is the final layup ready for the vacuum bagging stack. It also shows extra corner bracing and there are similar reinforced corners underneath in aramid.



The stack I have gone for is as follows:

  • 6 layers of mould release wax to ensure a good barrier and a shiny finish
  • one layer of GC50 clear gel-coat to give it a good shiny finish and UV protection (which it won’t need under the bonnet)
  • three layers of chemical release agent
  • 2x 350gsm CF, for the initial outer facing layers
  • 1x 250gsm Aramid for intrusion protection
  • 1x 200gsm e-glass for a little bit of flexibility in the part
  • 1x 3mm soric for the core
  • 400g of infusion epoxy mixed with 120g of catalyst (slow)

footwell part 12Rather than go for a standard side-to-side infusion I went for a circular infusion down to the centre. This stuck me as better because going edge to edge would require the resin to also climb back up the vertical slope and could spend time infusing into the corners. The vacuum will drag it up eventually, but it could be a pain. Furthermore, if there is a long wait as it gets into the final corner, you end up with the situation where resin is going into the catch-pot and the part isn’t yet fully infused (which is money down the drain). At least this way the infusion is relatively uniform, and gravity is acting on my side.

Once infused, I baked it at 50C for 12 hours in the oven, and then pulled the infusion stack off. Following is the video of me using the air-line lazy method for getting the first part of the stack off (the vacuum bag). I also used a new kind of peel-ply (knitted rather than the standard spikey flat stuff). It’s great for this kind of infusion because it will pull under vacuum into all the difficult corners. However, it remains a little stretchy after infusion, so it requires more effort to tug/haul/swear out.


Once the entire infusion consumable stack is removed, the part is left in the mould and the second stack is laid upon it in reverse order (without the GC50). The mould performed well and managed to split without too much trouble and about 50-75g wasted resin. I know Warren (who manufactures parts at volume) has a much more refined process for managing resin amounts – he writes the amount a part needs on the back of the mould. My parts are one-offs, so there’s no need to stress about that.


footwell part 14Once I had split the mould, and got the first half off, the second gave up the ghost really easily and I had a part! This was a hell of a moment because it’s the first time I’ve gone from idea to composite part in 3 dimensions. On the part you can see the extra shiny side, which was incredibly easy to get to. I washed the chemical release agent off with warm soapy water (didn’t seem to make much of a difference, to be honest) and then I put a little Farcela 300 Polishing compound on to a cloth and gave it a bit of a rub – no real application of elbow grease required and this is the result.

footwell part 15 The part has been partially trimmed (dremmel with a steel slitting disk, P3 safety mask) and offered up and it’s a great fit. You can just see the deliberate fitting gap between part and chassis, which should be between 1 and 2mm for the adhesive to work well.



footwell part 17This time the view is slightly different in order to show the clearance a little more between the part and the chassis. I had deliberately left a min of 5mm to allow for some absorption in a side-ways impact. I could have taken the footwell deeper if I hadn’t welded in the extra strengthing bar you see there to complete the cradle around the engine.


footwell part 18Sorry about the crap qualitty of the photo, but this is where you shove your feet. It has been sized to take size 11 trainers so most normal feet will fit fine. For final fitting, I’ll trim that remaining lip off, and bond the part of the contacting edges only. If I decide to go belt-and-braces, I will make some 90 degree angle and bond that onto the chassis and wrap it around on to the part.

Stronger than steel, far better shape, and I’ve not yet made a weight for weight comparison with the steel I cut out. I’m proper thrilled.

Footwell fettling for friends feet – part 2

So, it’s time I completed the write-up of the carbon-fibre footwell, lest alliteration break out o’er the land.

In Footwell Fettling Part 1, I go through how I make the part, and you can find the other footwell posts which are tagged with the footwell tag. I didn’t ever say I was original.

Following on from the sharp-edged part, I then rounded off all the edges using quadrant beading and prepped it for spraying. The process for cutting back and adding the quadrant beading has been gone into at some length in the composite fuel tank section, so I won’t labour it here again.

footwell part 1Here is the part, flatted back, polished and waxed. I waxed it because the wax serves two purposes: performs as a release agent, and gives a shiny surface, filling in all the tiny micro-scratches that come from polishing.

What I’m learning is that you need to add shine on every part of the process in order to get a reasonable shine out of it without major effort at the end.


footwell part 2.jpgHere is the part offered up to the fluted sign-board flange. I’ve tried all sorts of methods to get a good straight cut and have settled on a tile shape transferring thingy, and a steady hand with a fresh Stanley knife blade. I’ve tried cutting along steel rules with the Stanley knife, and have found that I get better results with just simply cutting by hand and eye. You can see the green breaker-tape sealing the flanges to each other; resins can’t stick to the tape, so you get a simple seal and don’t have to worry about release agents. Similarly, you can see the moulding wax filling the gaps between the parts and the sign board.


footwell part 3.5A word of note here – sign-board is far too flimsy on its own to be a flange material, so it needs to be backed up with some form of stiffer board (I use 6mm ply), glued together with hot-glue. Similarly, the ply needs to be glued to the base and part using triangular gussets. Here you can see the whole thing set back at a distance, and get an appreciation of context.


footwell part 4It puts the gel-coat on its skin or it gets the hose again. What you don’t see is me spraying the whole affair with a couple of coats of PVA release agent first. Again,that’s been covered against the footwell tag.



footwell part 5Three layers of 450g CSM backed up and set in poly-resin. You can see how I’ve taped the thermocouple to the part in the oven to avoid over-heating. The part can easily exotherm to 40,50C and if the oven doesn’t sense that, it can add more heat than is needed and the part will over-heat and be trashed. This is also both halves of the mound made together and going in for the final bake.


footwell part 6I’ve split the moulds and you can see a few things. Firstly, the finish looks matte, and this is due to me also adding a chemical release agent on top of the wax to be super sure it was going to come out. From a seasoned mould, this isn’t a problem, but for a green mould that’s a one-off, belt-and-braces is what you need. The arrowed part is where the mould took some of the body-filler from the part with it, so even with all this extra releasing, I still had a mild sticker.




footwell part 8Here are the two mould-halves re-attached to each other. The flanges have been drilled and cross-bolted (M8, because they were handy). The shiny side has been polished by hand quite quickly with Farcela compound, just to demonstrate the difference between the ‘out of the part’ finish, and the final polish before a part gets pulled.


footwell part 9Here is the whole mould backed in breather cloth. Because I’ve split and then reattached the splits, it won’t be easy to get a vacuum tight seal for a pleated bag, so I’ve got to go for an envelope bag. Breather fabric is just a soft, cheap, disposable cloth designed to absorb resin. The red circle shows a part of a corner I didn’t notice wasn’t properly wrapped and this caused a punctured bag. Click here to see a close-up and to see how easy it is to puncture a bag.

I’ve already made the post about laying up the cloth in this youtube video, and next will be the removal and fitting to the car. Believe, me, it’s f’excellent.

Fitting an Electric Handbrake #2

In which, i go through some of my reasoning behind my design, and tease you with how hard unidirectional CF is to work with.

estop sizeHere, you can see the E-Stop actuator sat next to the layer of soric I’ve cut out and marked up to show where it sits, and where the cut-outs will eventually need to be for where it bolts through.

You may notice the tapered shape of the soric, and that’s because it’s the shape of the bottom of the transmission tunnel. As such, I’m going to be able to mount this at the very bottom of the transmission tunnel under the gearbox selector bit. This is fantastic because it means I’m getting 2.2 kg of mass right down there at the same level as my arse, and right on the center line, to give the lowest polar moment of inertia possible. What’s more, it definitely means nothing needs to be cut through the transmission tunnel.

Mounting it this way at the bottom of the transmission tunnel means I have the option to add extra strength. If I had welded tabs onto the transmission tunnel bottom and bolted the actuator to that, I would have mechanically coupled the bottom of the tunnel together adding strength (yeayy) but would have done so using the actuator housing which may not be designed for that (boo). It could end up an expensive mistake.

So, I needed a plate that did the coupling and added the strength whilst at the same time weighing more or less nothing. This is a job for … unidirectional carbon fibre. What’s more, the plate needed to be blind-ending for attachment. As in, it needed to be bolted in from below without having to grow an extra fistful of knuckles to put the bolts in place. Thankfully, I’d found these big-head fasteners which do the job.

You sit them on the finished part and bond them in. They’re not designed to be part of the infusion which is both a bummer because that would be a neat solution and also great, because it’s a far more simple manufacturing solution. I used East Coast Fibreglass Supplies to source these.


20140629-134234-49354453.jpgHere you can see them offered up on some 3mm closed-cell core material to give an idea of where they will fit and where they will clash with the necessary mounting holes for the actuator. For the most part, all is hunkeydorey apart from where the tunnel narrows. In the case where it does, I’m going to cut the hard-point own to size.


In the next installment, you can see how I laid up the cloth, and how it totally failed to infuse as a part. As I said, unidirectional is a difficult cloth to work with.

Fitting an Electric Handbrake #1

This is going to be an interesting set of posts taking you through  how I fitted my electric handbrake. It’s not been an easy ride (ahem).

In this post, I debated the various options I was thinking about whilst wanting to move away from the conventional handbrake solutions for an actuator with control. I went for the Speedway Motors E-Stop kit and I must say, Speedway were a very efficient outfit to order from. Their international sales team were quick to confirm the international shipping rules with me, and it arrived 5 days later, which is excellent from the States. HM Customs then stuck me in the eye for £90 duty though. I wasn’t pleased about this.

Following is a 3 minute video they’ve done which shows how it fits and how it works. The only major difference between their video and my circumstances is that this shows the e-Stop kit working on a gert big american chassis, and I’m going to squeeze it into my tiny Fury.