Fibreglass bonnet and infusion

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#1

I am making a mold over this coming weekend of a bonnet it will be used fOr carbon fibreglass production.

Never infused with fibreglass before and i will be using woven glass not csm. Will be using epoxy gelcoat probably Infused with my normal resin. The fibreglass will be twill weave.

The bonnet is a single skin item and i wamt to use a closed cell foam core when infusing (3mm or 5mm)?? Has anyone used this core?? I want to cut it in a simalr pattern to the oem frame underneath. Id like to create a top quality grp hood that would be lighter and very strong.

I have a seibon carbon hood for the car that i will compare it to weight wise and inc weight sving removing the hinges and catch

Any advice on a layup im thinking

Epoxy gelcoat
Woven fabric
Woven fabric
Core
Woven fabric
Woven fabric

Also is it ok to ad a pigemnt to the resin ??

Thanks in advance

#2

not having to have a hood latch or hinge mounts is nice easy lay up.

#3

With out a doubt i have also made bonnet pin recesses to infuse so the bonnet pins sit in a nice recces :slight_smile:

Any other things you would like to ad have you worked with foam core (closed cell)

#4

Nobody got anything to add?

#5

Is the core Lantor Soric? http://www.lantor.nl/index.php/id_structuur/10599/soric.html
Soric does a good job on body panels another local infuses VE, 2-3 layers CF, Soric, and 2-3 more layers. The panels are plenty strong, not the lightest (Soric really holds alot of resin), but good enough for the people racing around Road America. Divinycell would be a good choice of core if weight/strength are a big concern. http://www.diabgroup.com/europe/products/e_prods_2.html

Check with the manf. or who ever sold you the epoxy about adding pigment. It never hurts to do test panels tho and then you’ll get the answer you want. Plus when doing test panels you can get crazy with painters tape and get practice making graphics with the colors just like prof. boat builders do with their gel coats. When I make swim platforms I will tape off the name of the boat in painters tape, apply the surface coat, and peel off the text tape before the IMC starts to kick leaving a nice clean edge. Once tacky you can lay carbon or what ever in and start infusing. The finished part looks nice color matched to the boat with the name showing threw in carbon text.

Hope this somewhat helps.

#6

On thin lay ups you will probably see the perimeter of the core and also the perforations in the foam (if they are too big) It will look fine in the work shop and you’ve polished it beautifully but wait till you put it in the sun.
We only use epoxy and in cored areas we only use honeycomb. We infuse the entire skin and cook the hell out of it then de-bag it and bond the honeycomb and inner skin in the second step. This way the outer skin is completly inert and does not print.

#7

My choice of core was going to be closed cell foam core, with little resin uptake i thought this would be best??

My glass of choice is eglass in a 2/2 twill

#8

I’m not sure that just 4 layers of glass for something like a hood is going to be enough if the core is going to be in the shape of the OEM support structure. For just 4 layers you would want the core over a much greater total area of the hood. The core will give it the stiffness that you need for such a large item. There can be some cosmetic issues around the perimeter of the core so be strategic about that. I’ve used Divinycell and Soric but I would suggest you make some test panels first to get an idea of the cosmetics and stiffness of each before making the part. Soric LRC in that thickness would conform pretty well.

Brad has some real good points about shrinkage and print through; you should spend some time thinking about. In general good materials and process can go a long way to prevent this.

#9

I must have missed that you wanted to cut the core in the shape of the OEM support structure. I was talking about using the core for the entire panel which I have done with good results. For SURE they are right about print threw with such few layers and a core cut in such an odd shape. The local did a entire body out of CF/Soric for SEMA and you could see print threw of the core perimeter on the rear quarter and bumper, you had to look for it but it was there. He didn’t take the core to the edges on that car and it showed.

#10

Well it was a idea ide like to test. But not set in concreate hence why i asked for advice on the layup.

The material in question 2/2 twill 390g (sorry i work in metric) i can easily go more layers and loose the core due to print through. But i will be using an epoxy gel coat and epoxy resin.

Can anyone suggest a strong layupif i was to loose the core?? And i will be infuseing so i will be getting good resin to fabric ratio. Maybe put in a layer of kevlar? Between 3 layers of glas each side??

Open to suggestions