If you got access to lantor coremat, this would be a really easy way. Two layers of reinforcement like 450csm, 5mm coremat followed by 2 layers of reinforcement gives a thickness of around 10mm, and is lighter and cheaper than building up thickness just with csm.

You don't need a better spray gun, you just need to practise using the one you've got. A top quality spray gun makes the difference in the hands of a top quality spray painter, but if you don't have much experience with spray painting then you wouldn't notice the difference between a job laid down with a $50 gun or a $750 gun.

As oekmont suggested, coremat works ok for building thickness. Personally I prefer not to use it in moulds as it isn't as good as a monolithic laminate, but for a one off it will certainly do the job. Alternatively, pieces of timber bonded or glassed to the back of the mould are a common way to form a rigid backing structure. Timber is a good option because it doesn't shrink like composite resins do, so a well designed timber backing structure will ensure your mould remains dimensionally accurate. A mould made with coremat will twist if it doesn't have the geometry to resist, which your roof doesn't. But again, you're doing this for a one off, so coremat is easier and will do the job. 

If I can make the mold to last for making more roofs later I think will be nice.. Who knows.. the car can get vandalised or i can sell one if they came out nice.. 

Hanaldo:

Timber.. Is that pices of wood? To me that is what you cut down with a chain saw..

Last time I used the old mold I hade heater fans under the roof mold to give the curing process some heat. I imagine that the sun can make the roof pretty hot during sunny summer days. I guess maybe I got the mold to about 40-50 deg.
So if I do some kind of wooden struckture I dont want it to distort the mold.

If you mean like wood planks I guess I would do a frame with 4" x 1" standing planks and a cross in the middle so you can lay the curved mold with the wood structure on a flat flore. 
Will that be a good way you think?

I never got issues with either delamination nor twisting. And I even made a counter mold for a glass plate. There is not a single mm twist over one metre. Wood works fine too, but it has to be dry, and fully enclosed by glass fibre afterwards, because otherwise it might take up water, and expands

Alright.. I have sold my older Kemppi ac/dc tig welder to get some funds to order some carbon fiber stuff. I still have my newer Kemppi ac/dc tig left so no wurries..

I want to learn this and make alot of stuff in the future so it will be a pretty large order to get all the equipment.. I have some stuff as vacuum bags and some stuff to make wet layups but I need degassing and catchpots etc..

What I am wondering or debating about is what to use as backing material in the layup..
I will use 200g twill as first and last layer but what is a good and economical material in between? I do want a material that will be easy to get in the corners of the mold I posted earlier..
About 1000g total should be enough thickness I think.. What do you think about that looking at the pictures I posted earlier..?

What I am looking at now for adding thickness between the two 200g twill  is ether 3 layers of this 200g second grade twill:
https://www.easycomposites.co.uk/200g-black-stuff-22-twill-3k-carbon-fibre-cloth

or two layers of this 380g twill:
https://www.easycomposites.co.uk/surplus-carbon-fibre-8hs-satin-weave-3k-366g

or 2 layers of this:
https://www.easycomposites.co.uk/surplus-carbon-fibre-8hs-satin-weave-3k-366g

Or maybe two layers of this:
https://www.easycomposites.co.uk/wholesale-offers/Incredible-Discounted-Carbon-Fibre-Biaxial-300g-1m-Wide.html

One more thing.. 

What do you think is the best way of setting up the epoxy inlet , vacuum port and spiral looking at the mold I posted in page 1?
I plan on using infusion resin IN2 slow.

Hi Frederik,

In terms of backing materials, any of those will work fine.  To be honest, even a "chunky" 650gsm cloth would get into the corners of a roof mould no problem.  Just choose the best value for money option based on building your thickness up.

For a simple mould like that, a U shape of spiral for the resin feed, all around the bottom edge and 2/3rds up the sides of the part is fine.  The vacuum port then goes centrally  at the top of the U shape.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Thank you.

You don't need a degassing chamber, there's no need to degass for resin infusion - it just complicates the process and increases the opportunity for things to go wrong. Just follow the EC video tutorials.