Audi S2 trunk.
As I got the order for two hoods I also got two trunks ordered.
The part I got to mould from was far from perfect finnish wise.
Audi makes them in plastic for no obvious reason.
Not for weight reasons thats for sure.
This item without glass weight about 17kg.
First I had to polish the surface and add edges for the mould.
I covered the hole from the window. Not that its neccessary since I wont use it,
but it ads strength to the mould if I include it.
Fibre glass all over the place and then strengthening.
I use spray foam which I cover in plastic.
The only issue is that the first cast have to harden before I can add the spray foam.
Next thing is that the spray foam have to harden completely before I can surround it with polyester.
The foam does not like polyester in wet state.
The foam itself does not add any strength at all.
Its the fibre glass surrounding the foam that makes the strength.
The day after its time to change page in the book.
In the first pictures you can see the plates I casted against in the first step.
They have to all be removed since the next part is to be casted against the first part.
The shape is quite complicated so I had to make a 3 piece mould.
There was a deep ditch between the wing and the end of the trunk.
I tried to delete it with some electrical tape.
Looked good at first but the gelcoat released the glue and caused allot of fixing later on.
Allot of planning and thinking is required when making such complicated moulds.
There were allot of obstacles on the inside.
Place for rear wiper, locks and various things not needed in a light weight application.
I taped or covered the largest holes with aluminium plates.
Positive stuff was filled in the mould later on.
Gelcoat, polyester and fibre glass.
The inside had so much shapes that I didnt need any additional strengthening.
As all parts are cured I trimmed of all hairy edges
and drilled holes between all the parts before I progress demolding.
Since the release agent is water soluble a place for washing cars comes handy.
Here you can see I should have waited longer before I added polyester and fibre glass
since it went thru the gelcoat layer. Its tricky with all 2K things.
Even if its fully hardened in the mix pot, it might not have cured at all on the thin layer on the mould surface.
Hardening and drying out is two completely different things.
It got a fairly shining surface so its good enough.
Bolting two of the parts together and preparing.
The shape of the wing inside out and upside down was a quite complicated shape.
It was surely no picnic to get one piece of fibre 150x200cm into all corners,
but it turned out fairly ok in the end even though I had my doubts.
A couple of hours later, peelply, release film, breather and bag in place.
One can really see the power of vacuum around the bolt heads.
I use a pretty slow hardener so I have to wait 30 hours prior de moulding.
The feeling removing the peelply is still like christmas.
It turned out I got the first (visible) layer fairly okay.
Not Koeningsegg perfection but well okay for the application.
How about the weight?
Impossible to say since it was too weak to stand it on the scales in this state without the inside...
...the inside.
There were more work on the inside due to all holes and different things that required grinding or filling.
Finnish was not a priority here. Only function and weight.
Both parts ready all I needed to do was to glue them together.
I left the outside as it came out of the mould. Bolted it to the mould to make it stable.
The inside was grinded and sanded to fit fairly perfect in the outer part.
I glued them together with regular quick epoxy glue.
For extra strength I also laminated the upper and lower parts together.
One of the insides looked too terrible so I wet sanded it and painted it in full with more epoxy.
Also laminated in my logo here and there.
What about the weight?
2,5kg! I am really satisfied with that.
One can have opinions about finnish. Some strays occur and the pattern sometimes is'nt perfect,
but the weight and fittment is absolute top notch. I was promised they should be painted
but little surprisingly at least one was only clear coated.
One boot has already ben tested on the tracks.
It well works.
