OK...some of you may have read over on the OC that i have started building a TTE copy style airbox...well as the design is reaching the final stages (I`m kind of designing it as I go) I thought that I would post up on here for any suggestions/comments.
THE TOP BIT
I know you can buy all sorts of ready made airbox type designs or even...if you can find/afford one a TTE airbox,
but as I cant find one nor afford one I will have to make my own...this poised a few problems, the most critical....what to make it from.
Aluminium sheeting was my first thought, but for my amature talentless hands, panel beating alloy sheet into shape was an more or less impossible task, the next option was fibreglass...easy you might say, but as I have never ever fibre glassed anything before it was a steep learning curve.....after many hours of watching “how to fibreglass” clips on you tube I was more or less ready to have a try.
First up was to make what I think they call a blunt which is basically a mock up of what you want to make........problem number two...what to make it from...initially I thought of clay, but its heavy and dosnt hold its shape very long so after a few attempts that idea was binned, after that I thought of expanding spray foam but one unleashed from the can its very uncontrollable. After some help from Dan I was introduced to extruded polystyrene...you can buy this in the form of 8ft sheets from B&Q....you have to peel the alloy foil off of it but your left with a very usable sandable substance that is near perfect for shape forming.
I cut the sheet into squares which covered the area that the airbox would take up and glued 4 or 5 layers together which gives me a foamy cube. After drawing a rough shape on the outside I set about it with a kitchen knife.....this gave me a rough shape of the airbox. Next up some 80 grit sandpaper, the extruded plystyrene sands very well, but gives off alot of dust so a breathing mask is essential (DO NOT DO THIS WITHOUT ONE)
Once I was hapy with the shape I stuck a piece of alloy pipe onto it to size the inlet for the pipework...plus its easier than trying to shape a perfect circle from polystyrene.
After this I covered it in car body filler to make a smoother outside...halfords provided a huge 5 litre tub of easy sand filler (yellow container) which through alot of trial and error is the easiest to work with and sand. After applying it and letting it dry (about half an hour) I started with 80 grit wet n dry and worked my way down to 2000 grit...this leaves a near mirror finish and what I thought would be a perfect blunt.
This is the mk1 which was too angular and never made it past the blunt stage
The mk 2 was similar.
Next step was to make a female mould.....after some discussions with fibreglass direct in Ireland (by far the best and most helpful folk in the UK when it comes to fibreglass supplies) I ordered alot of bits......woven roving, fibreglass matt, polyester resin, polyester gel coat (black), blue pva mould release agent, mould release wax, fibreglass rollers and lots of cheap paint brushes. Make sure the gel coat type matches the resin type or they react and ruin each other.
Woven roving
Next I painted the blunt with blue pvc release agent...about 5 coats (it desolves with water to relase the mould
I coated the blunt in polyester gel coat,
left it to become touch dry...I then started with the layers of fibreglass sheet...you have to dived the blunt into halves (top and bottom) with a shelf type thing...then fibreglass on one side up to this...about 4 layers to start with (maybe too many 2 would be best to leave a small amount of flex in the mould to make it easier to break from the blunt)
Allowing this to dry over night it was time to separate the top half of the mould from the blunt.....a wegde here and there, a lot of hot water and.....
Disaster...the blunt broke into many pieces...not a problem if you don’t need it again, but as I had only done half the mould it was game over for mk2. The problem being that the extruded polystyrene has no strength...I would need to coat it in a layer of fibreglass to give it strength before adding the car body filler.
On the other hand, the mould looked OK though
Mk 4 blunt is currently being sanded, a much smoother flowing design, designed to take a rather large RX8 panel airfilter, the battery will need to be relocated to the boot as it fills a large area of the engine bay...more news soon.
Sorry about the bitty writing style...trying to catch up a bit to where I am today...should be better from now on.
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