Hello there,

I have been following the forum for some time now and I think it is time to present the idea that I have for my first project:
 I want to produce a corbon fibre bonnet for my cousin´s RS4 (and later on some more parts, obviously )

So far I have watched most of the vidoe tutorials multiple times and I was already trying to transform those ideas over to the RS4 bonnet (which is the standard A4B5 facelift bonnet). The bonnet itself is not of a too complex shape, neither top nor bottom, but it is the part that includes the split grille into  the bonnet that gave me some headache so far. I have seen several of these bonnets made from carbon already, so it surely is possible. But so far I have no idea how to make the mould in that area...
 
The picture shows such a carbon bonnet (disregard the air vents and inlets...). In the front you can see the part of the bonnet that includes the top part of the grille, my current nemesis so to speak. I was thinking about making the top surface a 2-part split mould, on for the actual top surface, demoulding upwards, and one that contains that front part, demoulding to the front. Maybe I can lay up the top layer as usual, and lay up the fron mould in the exact same way, and cure it as one part with vacuum infusion like in the tutorial... Maybe I should close that vast empty space in front with carbon and cut it out later? I am not sure about how well the resin would flow all around this part, have u experts got some ideas to help me out? I´d really love to start this project soon and I think with your help I can finally get going

Best regards from Austria,
Markus

I'd double check visually first but it looks like the leading edge of the bonnet is less than 90 degrees from the main surface so you should be able to make a one piece top mould without any mechanical locking.  I would fill in the grille area for ease of infusion, then cut it out afterwards.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Dear Warren,

I was thinking the same, but there is some kind of seat for the grille in there, maybe u can see it in this picture:

I am not sure if this is really needed but I will check that in the weekend! If not, I think you will be right and a 2-part mould will be sufficient (and I will be much happier). If I need it I can still try to do it as a 2-part mould with adding some kind of flange later on... I´ll report back when I know more about this part

Cheers,
Markus

You might still get it out, but a 2 part would be easier, I agree.  Probably envelope bag it to rule out any leaks through the mould join.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

That is a good idea! I have not seen how to do this in detail but I think it´s just a bigger layer of bag all over the whole part, sticking them together with the gum tape instead of sticking it to the edge of the mould, right?

yes.  A lot of vacuum bags are in fact a lay flat tube so depending on the dimensions, you may get away with just having the two open ends of the tube to seal with gum tape.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Quick Update:
I have met with a friend over the weekend and we had a look at the original bonnet in order to get an idea for the mould making process. I have taken a picture of the area where the grillle is located:
In the picture you can see that area from the left side. The grille is clipped (is that correct english?) in place and for those clips I need the surface that appears a bit dirty in the picture. So it looks like i need to do a 3-piece mould after all (other ideas?). I thought I´ll do it like in the opening post, this way I can make this empty area as a full curved plate and cut it out afterwards.

I have also ordered a hood vent becaue I thought before trying my luck on a huge part like this bonnet I should at leasst try a smaller part before possibly wasting a lot of expensive material on the first try (yeah, I am still a student and hanging on to the bit I got ).

Just waiting for my new credit card to arrive so I can finally order some fancy stuff to get going!