Lots of things went wrong this weekend, now beer

So, the cunning plan was to get the short engine built this weekend, and I wasn’t far away until I had a mild issue that turned into a disaster. Well, a recoverable disaster, but not without effort and maybe cost.

I have been time slicing between getting the printer working how I want it, and doing the jobs on the engine. The major job this weekend was getting the head on, with the ARP studs set. The head had been modified and professionally built for me, but you can’t put it on the block with the cams in place – they obscure the head-bolts.

So, off came the cams, and in went the studs (threads lube’d of course) and on went the gasket and head (including the two small dollops of gasket). All the threads were painstakingly painted with the correct graphite paste and done so with an artist’s toothbrush. I’ve learned there’s no use really caking it on – it just squeezes out.

All the pressure washers went on, and as I was putting the last bolt in to hand tighten it before the torquing sequence, I fumbled it and it went down an oil gallery. Mildly frustrating I thought, but no big deal – just take the sump off (only finger tight on three bolts) and it should have dropped down. I turned the engine over on the stand, and this is where it all went arse. Four of the cam buckets fell off on to the floor. I managed to turn the engine over before more did.

Each cam-follower-bucket-type-of-thing is separately chosen for the correct valve clearance, and you guessed it, they’re all different. So, I don’t have a record of which is on which valve, and I’m just hoping my engine builders did keep a record. If not, I will have to take it back to them to be reset. Not a major deal, but hours wasted.

Then I went to do just a simple job – put the cam-chain guides on. The supplied bolts are socket-headed cap screws (my favourite of all the bolts) and they are to be torqued to 9.75Nm. No problem there – I have small torque wrench just for this, and it’s a 1/4 square. Arse. I have step-down from 1/2″ to 1/4, but no step up. By then it was 5pm and Halfords was of course closed. Then I went to my magnificent box of shiny bolts, and found a pair of flanged bolts that were the right size, and shiny. Did I mention how pretty they looked?



Resin to cloth ratio by weight

IMG_2088.JPGIMG_2087.JPGSo, here are the two sample pieces, as mentioned previously in this post. They’re rough and ready, and not pretty to look at. What’s more, I had an infusion issue so there’s more air in the part than I would want.

However, it’s worth looking at the following dry weight calculations:

Part Final Weight Dry Weight Diff % Resin
with Veil [1] 136 103 33 24.26%
No Veil 144 110 34 23.61%

So, the lesson is that the part absorbed about 24% resin, excluding that retained in the infusion mesh, pipework, etc. It is also very important to note that the 10mm core is cross-drilled every square inch with a 2mm hole and has resin channels scored in the underside to allow rising to flow over the other side of the core. this will have absorbed some resin as well, which won’t be there if a core isn’t used.

Next post, I’ll get these under the microscope and you can see what the bubbles look like. If I can find a text-book infusion part then I’ll compare against that to see what gets left behind when the job’s done properly.

[1]The veil part is an experiment I ran with a piece of polyester veil under the facing layer to see if it acted as an air-removal medium to make the facing layer more cosmetically pleasing. Due to me cocking up and getting air in the infusion, I have no idea if it would have worked. It certainly didn’t work for me as a backing layer (as advertised). it absorbed far too much resin, was a pig to wet out and didn’t easily go into corners, leaving bubbles behind the gel-coat which have to be repaired.

Notes on applying Meguiar’s No 16 Wax

So, again, thanks to Vic, I’ve started applying wax to the transmission tunnel in order to both give it a decent shine and put a layer of release in there. The wax won’t be the only release agent I will use – i will also spray a healthy coat of PVA on there as well. When the whole thing is blue, it’s safe 🙂

The wax is Meguiar’s No16 paste wax, and is great stuff. It’s a lot thinner than the mould release wax I have used in the past, which took some polishing off with a micro-fibre cloth. This time, I have started using a red polishing head on my rotary polisher, and that’s making light work of buffing it. It should do considering it’s on a nice large flat surface.

Lessons Learned

  • Put it on thinly – if you clag it on you just spend more time polishing it off, wasting wax. A nice thin coat means the polisher can whiz over it and bring out the shine all the quicker
  • speed setting on the polisher is between 3 and 4
  • it takes a while to dry and glaze over – I left it overnight which isn’t the norm at all, and it was 5C in the garage. This, I think, is a reflection on my operating conditions rather than the wax

Fuel tank – ready for high-build

So, we’re moving further along with the fuel tank. The last post I did on this was more or less finished, but then I’ve done a little more.

Firstly I decided that the recess for the fuel-senser was a little tight (potentially tight) so i modified it, thus:

IMG_0062 It’s a nice shaped curve, feels organic and now there’s loads, loads of room (I tells ya) to get the sensor in there.

The black disk is cut from a piece of carbon sheet I had made and then changed direction. It was lying around.


If the bits of bog on there leave me with a surface that’s not flat enough to work with a rubber gasket (which I doubt) then I can also cut another disk and bond it on – the epoxy glue can go on as thick as I need and it’ll leave me with a good sealing surface. Similarly if the angle on the black disk isn’t quite right and the sensor doesn’t go where I need it I can adjust it a little with adhesive. I’ve spent a lot of time trying to get that disk in the right place, so here’s hoping.

IMG_0061Here’s the final tank.




So, the last things that have been done have been to paint a little resin over the wood to lift the grain. This is necessary so I don’t end up with the grain lifting when I spray it. Once the resin has set, the grain is lifted and a quick once-over with 120 paper on a sanding block did it.

Lessons Learned

  • Paint the resin on carefully with an artists brush. I used a small paint-brush (it was late and I wanted the job done). I ended up with the odd run. I’ve sanded back what I can, but if I’d used an artists brush and taken my time, I’d have had less runs.
  • When you’re mixing resin, get the quantities right. The last time I was mixing this stuff, I was mixing it one to two litres at a time. I had a little measuring jug from lakeland for cooking. This time I mixed 100g of resin, and added 20g of catalyst. It should have been 2g. It bubbles and boils and then weirdly doesn’t go off for ages. It ends up looking like cinder toffee. Of course, it also has zero structural integrity.
  • Forming compound curves is difficult.

Proud father of a … transmission tunnel buck

imageSo, I managed to get the wet-lay done last night. It took a couple of hours and about 4 litres of resin. The stuff I was using was simple non Lloyds approved resin from Leeds Fibreglass Supplies which worked well. I mixed it at 2% catalyst and in 2L batches. It only started to gel-off right at the end of the tub, which was a success. Also, the resin was pink not blue, and turned gray as the catalyst started to activate.

imageThe part came out of the mould in about 90 minutes which was a fair fight. I’m really glad I used PVA again because it’s water soluble. You just get a thin wedge in (I used a plastic bog-spreader) and spray some water down. It slowly starts the separation and all is well. Keeping forth the birth metaphor, you can see the birthing remains stuck to the part. PVA is like a skin (rather than EasyLease which is a chemical barrier).

imageHere’s a nice shot down the top of the tunnel, or chute, or birth canal, if it were. What you can’t see is the quality of the surface finish. It’s actually quite shiny but there’s little sunlight to reflect off it (cloudy overcast day).



It’s not all perfect though – no matter how much resin I poured on and how manic I got with the bubble-buster (i.e. special wet-lay roller) I just couldn’t sort some of the white patches and it’s come through the mould. There’s the odd bubble between the layers (which I will live with – this is the master buck, not the part) but there’s also some dry patches of glass on the face.

Next steps are to dress the surface issues and then seal for a part … can’t wait.

Lessons Learned

  • Making a master part from the failed mould was the right thing to do. Not only am I confident I have a good part but it was a step forward after the frustrations of the mould not working due to bad mould material choices.
  • Thoroughly wet through the first layer. Don’t get resin on most of it and then try and catch up later. If I’d done this, even though I may still have had bubbles, I wouldn’t have had dry spots.
  • Filleting wax is great.
  • I rushed this a bit because I was concerned resin would be gelling off. Not so.
  • 2% catalyst was right for this part in these temparatures. I was working with “winter catalyst” which is more aggressive.
  • Laying large (300mm) strips down the side into the middle with lots of overhang into space means the glass is balanced on top of the part and doesn’t fall down into the mould. Once set, the overhang can be cut off and reused in smaller bits.
  • Having lots of supplies (i.e. spare glass and resin) means you’re not fretting about running out (which I did last time) which meant rushing.
  • Styrene stinks, and gets through the brick-work from the garage into the house. I need to think about what to do here.

something old, something new, something borrowed, something blue

This post is basically a lessons learned post. Thankfully the first thing I did meant all the other lessons learned have ultimately only caused harm to my wallet and my schedule.

After failing to get a seal on my mould, and in discussions with Warren, the best way forward with this tunnel is to take a fibre-glass part from it which won’t need a vacuum. It can just be laid in. This means I can crack out a quick part, ensure excellent surface finish, and then make a mould from that using a full mould making system.

photoThe first thing to do is apply release agent to the mould, and I went for spraying in PVA (to make it all blue).




PVA Spraying Lessons Learned

  • advice – not a lesson because i didn’t make this mistake – use a clean airline, not one that goes through an inline oiler.
  • make sure you attach your airline fully to your spray gun, else it may fire free, hit the deck and spray dust and crap onto your mould
  • you want a light mist each pass – anything heavier and you may get runs
  • when you’re spraying near the bottom, you may blow crap from the floor onto the part
  • because the mould is very smooth and well finished, you don’t need to spray loads of PVA in to go blue, you can do it with a wipe of the cloth. meh – that was plenty of time wasted, but at least I now know how to put it down in such a way that i can take a part off concrete.
  • Spraying a mould this size to get that much blue meant I used nearly a litre of PVA.

Laying in fibreglass lessons learned

  • for three layers of 450gsm chopped strand mat, your remaining last litre of resin isn’t enough. Not nearly, nearly enough.
  • trying to put the glass in in 6 big pieces just means it all falls down
  • don’t try to fit the glass to the mould and flange – let it hang way down each side – that way the weight of the glass stops it falling into the mould.
  • OR, cut yourself lots and lots of 6″ strips of glass and lay them in – it’s not a competition to get the smoothest inside of a part – that comes later with the proper infusion part.
  • it’s handy having a skip outside to throw away the glass that has only some resin on.

Starting again

  • it was sensible to cut my losses when I did
  • I’m really relieved that I used PVA release agent – it’s water soluable
  • I will pull what I can out of the mould, wash the release agent out (from where I manked it up with grit from the garage floor)
  • Blast it with the power hose and start again
  • I’ll wipe in the PVA this time
  • I now have a 25 litre drum of resin and the right amount of catalyst – no chance this will happen to me again.