Having survived a perilous afternoon in IKEA yesterday I was keen to get a bit more of the BDN done as I’m away oop north for the rest of the week. So an hour and a half in the garage in the evening saw both of the side panels and the little triangular panel between the seats bonded and riveted on. A quick clean with some petrol to get the excess PU sealant and the job was a good un. There’s also a driver’s footwell floor plate which is screwed on with self tappers so that went on as well. So that’s pretty much completed the work I can get done for now. I might make the seat while the weather’s warm as the polyurethane foam works better.

I spoke to Brian during the day to just check up on wheels then got on the phone to order some. I’d narrowed the choice down to Compomotive CXRs or Team Dynamics Pro Race 1.2s. They both come in the required offsets in 15″x7″ and I like the look of both with the Team Dynamics slightly ahead on that front. The price however made it a no brainer at £66 + VAT each for the Team Dynamics and £120 + VAT for the Compomotives. The factory is about to close for a fortnight so it will probably be the end of August before I get them which is fine.

Unfortunately when I opened the garage doors on Friday some of the polythene sheeting covering the bikes blew and stuck to the roll hoop So first job this morning was to sand that down with some 600 grade wet and dry. I then mixed up some more of the green stuff and finished off painting the chassis. And there’s the end result, of course the camera doesn’t tend to do it full justice, it’s actually brighter than it looks in the photo Here it is basking in the sunshine once it was dry and I could carry it outside.

I could then move on to the aluminium panels. What I’ve decided to do here is just paint the ones visible inside the cockpit with satin black 2-pack. With them all sprayed I left them to dry overnight. I’m happy enough with these but they aren’t perfect as for the first coat I couldn’t get the spray gun working properly and ended up thinning the paint a bit too much. Turned out I was adjusting the compressor pressure the wrong way and when I thought I was raising it I was actually lowering it and it was far too low! On Sunday morning I had to wait till I could get help to turn it back over again to fit the floor. A thin bead of black PU sealant along each rail then I carefully lowered the panel into place trying not to get the horrid black stuff everywhere. Once it was there a few skin pins then I could slap the rivets in place and go round with the air riveter. After a quick clean to get rid of the bits of sealant that oozed through a few of the rivet holes I could turn it right way up again. And very nice it looks too although in the flesh it’s not quite as blurry as this pic makes it look. Sadly that was the end of play for the day as I was IKEAd in the afternoon

After being accused of being a blog post whore (you know who you are!) while at Cadwell I was thinking of playing secret squirrel this week. But I couldn’t bring myself to do it

Four weeks till I should get the next batch of parts, the front and rear sub-frames, wishbones, uprights, suspension links etc. So I’ve been thinking about ordering dampers and wheels. Having raised the question in the RGB Forum we’ve been given a provisional nod on using 7″ rims for next year which makes like much easier, the range of 15×6″ rims available is very small. It’s a bit restricted in 7″ width also due to the offsets required but I’ve found a couple of options. Dampers have proved a bit more of an issue than anticipated due to the fact that they’re mounted horizontally in the BDN. This means that the lower budget dampers will emulsify air with the oil and not work properly. Ideally I need to use gas pressurised units where oil and air/gas are kept separate. The Baldwins have got some from Quantum Racing who do dampers for F3 and Formula Ford etc. While not cheap at over £1200 for four single adjustable units they seem good quality and Brian was very happy with their service. Another option is some BAD dampers supplied by Al Boulton, it seems he can supply some single adjustables for a bit less than the Quantums or a set of triple adjustables for a bit more. Not really having much of a clue what the difference is between single, double and triple adjustable dampers a chat with Al at Cadwell helped me on my way as well as this page on the BAD Suspension website which really gives an excellent illustrated explanation.

In the meantime I have a chassis to paint. I’ve decided to paint it mainly because although it’s less durable paint is easier to touch up when it gets damaged, which it inevitably does on a race car either from stone chips or the general wear and tear due to maintenance etc. I was thinking of powder coating the panels but even once I got my calcs a bit closer on the weight front (probably less than 1 kg) I decided to just paint the bits that are visible within the cockpit. So first job of the day today was turning the garage into a spray booth which meant moving out the Fury and the Dancing Donkey, clearing everything up and making a screen for the workshop end using some tarpaulins. I got the chassis prepped and cleaned off and stuck bits of blutack over the rivnuts etc. to stop the threads getting clogged.

I was finally ready to get some paint on. For the chassis I decided to use the smaller touch-up gun. Once I’d got myself covered and masked up I mixed up the etch primer and hardener and got going. My first experience of etch primer on the fury bodywork was bad, I thinned it too much and made a mess. This time was much better and the touch-up gun worked nicely. I sprayed the underside of the chassis first then after lunch turned it over and did the rest along with some of the aluminium panels. So, here we have a khaki coloured chassis. While that was drying I got the side panels primed.

Later in the afternoon I stuck the chassis back on its side and got going on the final colour. And here it is … RAL 6018, a reasonable approximation to Kawasaki Green. It’s difficult to tell what the colour’s going to look like from colour charts but as soon as I opened the tin I knew it was right Of course there will be those out there who think it’s just plain wrong. I’d forgotten how nicely 2-pack goes on, so much better than the primer, it builds and flattens itself without causing runs and sags too easily. Painting the chassis is actually quite tricky, getting into all the nooks and crannies etc. without catching bits you’ve just done with the air hose. I’ll get it turned right way up tomorrow then I can finish it off.

After writing up the blog last night I realised I’d made a bit of a boo boo. I wasn’t supposed to drill the chassis till I’d done the fuel tank covers. Having said that the reason I’d ended up doing it was because the way the bulkhead panels fit together meant they only fitted in one place anyway. So I was hopeful it wouldn’t be a problem.

The fuel tank on the BDN is a bespoke item hand fabricated from aluminium and sits across the chassis floor immediately behind the bulkhead, so it’s across the bottom of the front of the engine bay, hence the covers. It’s a fairly complex arrangement, and I spent a while studying the 2D drawings as well as the 3D PDF which you can zoom and rotate. I started with the left hand tank cover, the photo to the right shows what it looks like to start with. First job was to do the main fold down the middle then work out the best way of tackling all the edges. SO far as I can see with my limited equipment and lack of ability it’s impossible to do this absolutely perfectly but after the best part of 2 hours I was pretty happy with the result.

The right hand tank cover was next and although this looked slightly simpler it was in fact technically a bit more difficult to get all the folds right. The trouble is as soon as you’ve made a fold you can’t get the pair of angle irons right across for the next fold and have to stop them short and use G cramps. Here’s a pic of this panel before I assaulted it. This took over 2 hours but I finally got there. I then had to fit some clinch nuts and trial fit the panels. This is where life got a bit difficult. My problem was that the fold in the little triangular piece that goes between the bulkhead panels is critical and mine was a mm or so out. This shifted the panels across slightly and even if I hadn’t drilled the chassis already I couldn’t really have corrected it. It wasn’t a major problem and I did get everything to fit although I had to elongate a few holes lightly. They’re behind the seat so really aren’t an issue.

After lunch I downed tools to go on a little shopping spree. First stop was Livermore’s for painty bits – some etch primer, paint for the chassis, RAL code 6018 for that (seems to be a rather bright lime green ), also satin black two-pack. Then on to Machine Mart for a new mask, new spray gun and a couple of other bits and pieces. After that it was Screwfix for a nice 4.5 litre tub of the orange Swarfega and a pump to go on it. I got home, unscrewed the pump to fit it to the lid, bits shot everywhere (large spring involved) then it took me the best part of an hour to solve the puzzle of getting it back together and clear up the resulting Swarfega spatter all over the kitchen!

I did make it back out to the garage to sort out the fuel tank covers. These actually fit together very pleasingly and I was able to mark the chassis for the remaining rivnuts, drill the holes and get them fitted. Getting everything lined up took a couple of remove, fettle panel and refit cycles but by the close of play all the holes were done, all the rivnuts fitted. Getting rivnuts lined up can be tricky and I’ve learned that you need to be patient and get the holes up to the correct size in 1mm increments, i.e. not go straight from a 4mm pilot hole to the final 7mm hole as they tend to drift slightly off centre if you aren’t careful. I also find a 6mm hole in the panel being screwed on works best for 5mm as the extra clearance gives you a bit of wriggle room. Here are a couple of shots of the result of my labours, I’m rather pleased with it. Once I had it all fitted I removed all the panels for final finishing ready for painting and fitting.

The fuel tank will run the full width of the chassis, the taller bit on the left houses the fuel filler neck and in the current race car the filler cap is welded into the large hole you can see in the top panel. Since I want mine to get through IVA this won’t do and we’ll need to route it up and out of the side of the bodywork, Ian’s working on a plan for this.

TNT’s website informed me during the day that my engine had arrived at Brian’s and I had a confirmatory email from Brian so I gave him a ring in the evening. He reports that the engine is looking pristine with no external damage at all. Ian has it set up ready to take all the measurements to do the mounts for it. Brian also thinks there should be sufficient clearance to remove the clutch cover without fitting a removable chassis rail (as they’ve had to do for the ZX12 engine).

Ian has emailed me with a schedule for delivery of the remaining kit, unfortunately Bob at Concept Racing is going on hols so this will put the delivery date for the next batch of parts to mid August. This includes the front and rear sub-frames, wishbones etc. Brian uses Concept Racing for the welding of these parts as they’re designed to quite fine tolerances and the strength and evenness of the welds is critical. He also does the welding of the fabricated aluminium parts like the fuel tank and swirl pot. His welding is really top notch, Brian pointed me at his website to see some examples of his work, including a fuel tank for a Maserati, the parts for which are entirely hand shaped and it’s all riveted with no welding at all! It’s no surprise that he’s a busy bee and has quite a lead time.

Following Tim’s helpful comment about the powder coat (i.e. 70 microns thick rather than 0.5mm) I’m re-evaluating that. Seems total weight on the panels would be less than 1 kg. Painting them myself with two-pack would be significantly cheaper but a bit less scuff resistant.

It didn’t take long to finish off the left hand side panel and the right hand panel was easy enough. This took me on to the tricky bits, the rear bulkheads and fuel tank covers. Once I’d spent a bit of time studying the 3D PDF I started to get my head around what goes where and how. The 2 bulkhead panels both needed a bit of fettling to clear welds but the nibbler made short work of it. The side panels fix to the outside of the chassis and all the welds have been flattened off making life very easy whereas the internal ones impinge on the panels in places which is what I’d expected in the first place. The folds in the panels are all critical to make sure they fit OK so I took my time with them.

My hardware bags contained a load of M4 and M5 stainless buttonhead screws, M4 and M5 rivnuts and some little beasties called clinch nuts that I hadn’t met before. I decided to give Brian a quick ring to get some advice on how to use them. They act as a sort of blind nut and have a knurled rim that gets drawn into the hole you’re fitting them to. Brian suggested making a little piece in the lathe to use with an M5 bolt to pull them into place. So that’s what I did with a small piece of alloy bar, you can see it in the photo to the right along with a loose clinch nut. To the left of the picture you can see one I did earlier as they say. This worked very well and I’m quite impressed with them.

Once I’d got the clinch nuts and rivnuts fitted to the triangular panel that fits in the centre I could position it with the bulkheads in place and get the holes drilled. The bulkheads are removable for access to the front of the engine so they’re secured via M4 screws into rivnuts. I got a lot of the holes drilled and rivnuts fitted but ran out of time as I was playing golf in the afternoon. So, quite a bit of progress today. Tomorrow I can get these finished off and tidy up the edges of the panels where I’ve had to trim them then I can make a start on the fuel tank covers.

The panels are all accurately cut to shape and size, I think they’re done with a water jet, the edges are amazingly smooth with no sharp edges or burrs. The grade of aluminium used is also quite a bit harder than I’m used to and the sheets are quite thin – some are 1.0mm but the floor’s thicker at 1.6mm. Some of them need bending, Brian uses a pair of heavy duty angle irons bolted together, one of which has a 3.5mm radius on its corner – he warned me that because of the grade they’ve used there was a risk of cracking the aluminium without the radius and that bending it wasn’t trivial and would take quite a bit of force. He kindly lent me his angle irons which is one less thing to have to source.

I’d had a look at the panels last night and the arrangement with the rear bulkhead panels and the fuel tank cover is quite complex and how they go together wasn’t clear to me. The panels are all beautifully done with lovely smooth edges, nicely radiused corners and no burrs so require absolutely no work whatsoever. The rivet/screw holes are all done too and are needless to say all perfectly aligned and spaced – when I built the Ultima it took hours trimming the panels to size and shape, filing the edges, marking and drilling holes etc. I checked my email this morning to find an email from Ian with a PDF attached showing how the panels go together. It’s one of his 3D CAD PDFs which is animated so when you click on the ‘Implode’ link the panels all fly into place one by one, brilliant. You can also just select single panels too.

I decided to make a start on the floor panel first. This is obviously the biggest piece of aluminium as it’s all one piece. Fortunately the chassis is light enough that I can manage to manhandle it alone so I turned iy upside down. At each end of the floor panel are 2 tabs that need to be bent 90° to butt against the inside faces of the bulkheads. At first I thought the panel to the base of the tabs looked a bit short but I knew immediately that this couldn’t be the case so spent a bit of time measuring, looking and thinking. The key was the 3.5mm radius on the bend and I worked out that if that radius started exactly at the base of the tabs the outside faces would give me the requisite 2110mm overall length.

The angle iron bending tool was too short to go all the way across the panel so I took one bolt out and used a G-cramp on that end. After lots of checking I finally plucked up courage to take the rubber hammer to it. Brian was of course right and this panel being 1.6mm was indeed quite reluctant to bend but taking my time and working my way along I ended up with a pair of nicely formed tabs. I did the same at the other end of the panel and lo and behold the panel fitted perfectly. You can see the ednd folds tucking in along the edge on the right of this pic.

I then just had to line it up laterally which was easy enough as all the reference points (chassis end plates and bolts) are super accurately placed and provide reliable datum points. With the sheet clamped in place I drilled a couple of holes and fitted the skin pins to keep it accurately located. Then drilled the remaining 180 holes …

With the chassis back the right side up I turned my attention to the footrest panel next. This again was ready cut to size with the notches cut out of it and holes drilled. Unfortunately the notch out of the corner for a chassis tube wasn’t big enough as Brian has reinforced the acute angle with a fillet of steel tube that presumably wasn’t in the original plans. 10 minutes with the air nibbler followed by a little file and it was in place. Clamp, drill, skin pins then more drilling. I needed the air drill for some of these holes as the diagonal bracing tube restricted space somewhat.

I had a look at a side panel next. These are quite large and need a gentle crease to go round the angle in the cockpit, there’s also a tab to bend to locate onto the front bulkhead in the same way as the floor panel. This was easier as it fitted easily into the angle iron. Near the front of the panel there’s a 10mm hole that lines up with a small bracket on the chassis so I used a 10mm bolt fix this in position giving me an accurate location for the panel. I could then mark it for the fold which was again easy with the angle irons. The panel was then a perfect fit onto the chassis tubes, it really is quite remarkable to just offer these panels up and find that they just fit and need nothing doing to them. I was partway through drilling when I had to abandon for the day to go to work.

So, the build’s under way. It seems almost too good to be true – the chassis is actually built to accurate dimensions, it’s absolutely fully symmetrical, every joint is perfectly aligned with no steps and the welds are all perfect. The panels require very little fettling and again simply fit perfectly. If the car ends up anything less than perfect it’s down to me then!

As it happens I’m off work for the following week too. I need to get the Fury prepped for next weekend’s racing at Cadwell but that won’t take long. With any luck I’ll have the chassis ready for all the panels within a day or two and can get on with the paint.

While waiting for Saturday to come round I did a bit of clearing up in the garage, it’s going to be a bit tight until the Ferrari’s sold. I also popped round to see Phil and measure up his Transit to check the chassis would fit in there.

I’ve also been doing some thinking about the chassis. I’ve been undecided whether to spray the chassis or get it powder coated. Spraying it is cheaper and I can do it myself, it also means I don’t need to lug the chassis off somewhere to get it done. On the other hand powder coat gives a good finish and is more durable. The trouble with it though is that it does chip from stones hitting it and as Brian pointed out you’re always wielding spanners around a race car and it gets damaged by this. Once it does get damaged it tends to flake off and rust spreads underneath it. It’s also difficult to touch up whereas normal paint is pretty easy. So at the moment spraying has its nose in front. I still need to decide on a colour though.

I also need to decide what I’m doing with the aluminium panels. On the Fury they’re powder coated black and really do look much better than bare aluminium. Brian was concerned about the weight of powder coating which is of course a factor in a race car. I tried to work out what weight it might add and assuming the powder coat to be 0.5mm think and to weigh about 50% more than water volume for volume I’m estimating it at about 9kg!

Having left the house at 8 we were at Brian’s house well before 10 and the chassis was waiting outside to greet us. First impression is how tiny it is, of course it doesn’t currently have the front and rear sub-frames on there which shortens it somewhat. The bodywork alongside it is the new bodywork which is about 150mm longer than the bodywork that was on the car when Derek was driving it last season.

Not long after we arrived Ian turned up which was nice as I wanted to have a chat with him about IVA issues. His main concern was sorting out a new arrangement for the fuel filler which currently resides in the engine bay, OK on a race car but a no no for IVA. There will of course be lots of other issues including edges within the cockpit, switchgear etc. but they’re relatively minor and shouldn’t be too challenging. He reckons the light height will be OK as they can be mounted quite high up on the front wheel arch. We’re all pretty keen to get the car road legal, for me it’s so I can take it out for shake downs whenever I’ve done any tinkering, for the Baldwins it clearly makes the car more marketable.

One we’d loaded the chassis and aluminium panels into the Transit we headed back and I did a bit of rearranging in the garage to fit the chassis in behind the Fury. And here it is on the trusty old trestles ready to get started on the panels. Initial impressions of the chassis apart from its size are how well triangulated it all looks and how well it’s put together. The welding’s very neat and tidy and it’s clear that only minimal use of the angle grinder’s been required to flatten off the welds.

One of the key features of the chassis design is the front and rear bulkheads. These will be machined aluminium but while fabricating the chassis Brian uses machined MDF which stays in place until the chassis is painted or powder coated. These are bolted onto captive nuts welded into the chassis tubes, they’re what I think are called Philidas nuts which are a form of self-locking nut which have a couple of slots which de-pitch the last couple of threads. They’re very similar to the Binx nuts that were used on the Westfield prop bolts. This photo is of the front corner showing how neatly the tube has been closed off.

I did have a quick look at the aluminium panels and while the side and floor panels are pretty self-explanatory the bulkhead panels fit together with the various fuel tank cover panels which have some quite complex bends in them. Ian gave me a folder with some instructions and drawings in them but I need the main PDF from him which will show me how they all fit together.