[fortythirtyfive]

This has been in the works ever since I had to cut a hole in my last GTS hood (back in late 2021) .. long story and it still pains me today so don't ask

Anyway since then I've been rocking an aluminium hood and finally I've begun the road to getting it how I want.

Thought I would document the process with updates as and when I get around to doing more work.

FTR the only area with exposed carbon will be in the middle of the hood, the sides and middle power dome will be painted body colour. Previously I left the entirety of the middle exposed and it felt too much, at least for a non M car because of the skinnier body. I have a rough mockup which I made in photoshop:





Sanded the paint off including an excess perimeter for the bodyshop to blend with filler when they repaint the entire thing



First few layers of base coat to separate the aluminium from the carbon fabric itself, this is required to stop galvanic corrosion. Typically a layer of fiberglass would be used to create a barrier, however as it's cosmetic piece resin will do just fine providing it's left to cure before starting work on top



Base coat levelled



Attempt to fix the notorious issue with these aftermarket / aluminium GTS hoods. The top and bottom layers aren't stuck down entirely, just the edges. This leaves room for air to creep in and build up pressure specifically around the vent, you can actually pull them apart if you wedge a tool between them.

To fix this I prepped the openings and filled/sealed them with betalink from BMW. I will be getting the underside repainted too so ignore the mess haha.



Next I tackled another issue, these hoods flexing real bad. Whilst the previous mod above will fix any potential rattling/shuffling around of the hood; there's still an issue that there's hardly any internal support to stop them bending.

I won't go into too much detail but basically this is my second attempt at wrapping the hood from this stage onwards. The first attempt failed due to the resin system curing too fast and the fabric curing with ripples, the biggest issue though was due to the hood being inadequately supported internally, the vacuum pressure actually managed to invert the entire thing when I hooked it up

To complete the flex issue I bought professional grade (closed cell) rigid expanding foam. You have to mix this stuff and man is it nasty. It ruins clothes, sticks to your skin for days and the curing gasses are toxic. I poured a large batch in via a few holes and rolled the hood around to help spread it. I plan on blocking all excess holes when it gets painted so you won't be able to tell.



Next I imported 3 meters of v-style weave from the US. Due to Brexit and import charges I had to spend over £200 on just fabric before they would consider shipping anything to the UK, in total I had to spend £200 on fabric, £60 on shipping and then taxes on both the product and shipping costs. Sadly nobody else in the world appears to produce 2x2 twill v-style weave in a length more than 0.8m.



Final prep - the expanding foam actually added a tiny bump on the power dome.. oh the irony. I fixed this with some dolphin glaze (stays elastable up to 180 degrees before cracking).



First epoxy coat down, this will act as a binding layer for the fabric



After 2 hours waiting for it to go slightly tacky I laid the fabric, pulled the vacuum bag over the top and left it to debulk for 45 minutes - this consists of the fabric being pulled down extremely tight under a near perfect vacuum, it helps the fabric conform to the design but most importantly it flattens most of the weave so that you don't have to level it too much.

Even though I had backfilled the hood with rigid foam for extra structure I still couldn't risk it inverting again, I added a secondary valve on the other side letting a tiny air leak engage, this allowed me to completely control the internal pressure.

I'm 99% sure it wouldn't have inverted for a second time but I couldn't take the pain of starting everything again.



45 minutes later I debagged it all, you'll notice there's some minor marks and ripples, these are purely just resin marks, under vacuum some of the resin manages to soak through the fabric and stick to the bag. These will disappear in the next step when I wet everything out.



First coat of epoxy poured, otherwise known as a wet out. It took 600g of resin just to do the first coat. The fabric is only 197gsm but seemed to drink like it had a bad habit! I'm now letting this cure for 24-48 hours before I lightly sand/key it in preparation for some thicker epoxy coats.

[Oksamit78]

Amazing work.

Would not it be easier to wrap the whole hood and then have it painted to the pattern you'd like? Or the width the V weave fabric is not available in the size to cover the whole hood?

I'd love to do something like this to my F34, but with stock hood since there is no offerings of GTS style hoods for my car.

[fortythirtyfive]

Originally Posted by Oksamit78

Amazing work.

Would not it be easier to wrap the whole hood and then have it painted to the pattern you'd like? Or the width the V weave fabric is not available in the size to cover the whole hood?

I'd love to do something like this to my F34, but with stock hood since there is no offerings of GTS style hoods for my car.

Exactly that, the fabric width unfortunately isn't long enough. It's around 1.58m and the entire hood needs at least 2m, I don't believe I know of any consumer grade supplier that has any style of fabric in that width either.

Does the F34 not share the F30/F32 hood? Because if so you could just use one of those.

Slight update too, I went to sand the first epoxy layer today and noticed the piece of fabric I used had a tiny fold line which even though it's laid flat; the reflections make it look otherwise.

You may notice it on the left side of this photo, it looks like a bright vertical line. Unfortunately due to the way carbon strands reflect light this will only become more visible with extra resin.



This was the last piece on the first roll I had sent, I do have another 3m which I know is flawless however I was hoping to save this. My plan now is to level the fabric ever so slightly in preparation for another piece of fabric to go on top.

Just need my delivery of extra resin to arrive on Tuesday

[Oksamit78]

Originally Posted by fortythirtyfive

Does the F34 not share the F30/F32 hood? Because if so you could just use one of those.

F34 has unique hood/headlights/bumper cover/fenders combination that is not interchangeable with any FX car of the same generation. The flow lines between hood and A-pillars are of different design shape than F30/31/32 etc..

Originally Posted by fortythirtyfive

Slight update too, I went to sand the first epoxy layer today and noticed the piece of fabric I used had a tiny fold line which even though it's laid flat; the reflections make it look otherwise.
...
This was the last piece on the first roll I had sent, I do have another 3m which I know is flawless however I was hoping to save this. My plan now is to level the fabric ever so slightly in preparation for another piece of fabric to go on top.

I can only imagine the frustration... The first approximation of the result already looks amazing. Good luck with the second layer.

[fortythirtyfive]

Originally Posted by Oksamit78

F34 has unique hood/headlights/bumper cover/fenders combination that is not interchangeable with any FX car of the same generation. The flow lines between hood and A-pillars are of different design shape than F30/31/32 etc..



I can only imagine the frustration... The first approximation of the result already looks amazing. Good luck with the second layer.

Ahh damn! That's unfortunate.

[fortythirtyfive]

Added a fresh layer of fabric tonight, I lightly levelled the entire surface in preparation before laying it down, I also sanded some edges into all of the body lines to try and emphasise them, I was worried another layer of fabric might begin to loose them otherwise.



Spotted one tiny shadow in this roll too sadly, I resolved it by rolling it flat out on the floor, heated the area up with a heatgun and then smoothed it out gently. I'm going to guess that these issues are purely down to the fact that I have a weblock backing applied. Any creases or slight folds leave a memory behind in the fabric. As weblock is a tacking adhesive heat softens it so I managed to kinda "reactivate" it to smooth the areas out.

Gotta leave it debulking for 8 hours again so I'll post more updates when I get to wetting out the fabric again.

[toxik]

nice vanquish

[fortythirtyfive]

Been slacking a little due to holidays away but mainly because there's nothing crazy different to report.

Slowly built up layers of resin, I haven't really documented this bit as its very repetitive and looks exactly the same each time.

This was after around 4-5 layers of resin:




I applied one thin coat of resin after to decide how it looked wet, this gave me an opportunity to stick it out in the sun and really inspect the panel for any defects inside of the resin after.

Sadly the mixture must have been out by a gram or so because it never fully cured, the surface went slightly milky due to moisture and "cured" rubbery. I had to sand this pretty harshly to remove the resin I had painted on.

I did however spot some small white pockets deep in the resin so I had to drill those out and refill the areas with resin - this brings me up to where I am now.. the surface looks a bit mottled but that's just because I had used my stippling roller to pop any trapped air in the resin.



I am hoping to sand this flat next and providing I get a perfectly flat surface without any low spots (due to drilling) I'll do one last coat so that it's glossy before sending it off to be baked in an oven for post curing. Once post cured I'll most likely have to do a light sand again to remove ripples, these appear when the resin softens up again during baking and sinks a little.

[fortythirtyfive]

Slight update.. fitted the hood to get it on the car and inspected by my local bodyshop.




I was really hoping to use them (The Motorist bodyshop) as they're a 3 minute drive from my house, not only that but the place is immaculate, had a huge investment is a lot more than just a bodyshop. They also seemed very confident about working on the project. Here's why I said "was" though.. their quote for using an oven/booth to warm up and post cure, paint the front bumper/hood and blend into the wings is £4000 with a good chance of it rising depending on the labour involved.

I want the best job possible and I don't want to sound cheap, but £4000 is a lot for two full panels painting and some blending. Plus I'll have PPF on top of this. It just isn't feasible to me considering the car has a max value of £15-16k.

[Oksamit78]

Looks awesome.