Hi.. I am pretty new to this and I need guidance and help walking me through this process..

I have done some wet layups but never infusion parts and I know I am taking a chance making a big part  like this the first time.. But I need to learn the process for future parts too and hopefuly with help from this forum I will make it.. I might be able to try some small stuff first though. Rear side panels maybe.

The car is a -91 Honda civic hatch that I have been working on now and then for over 15 years and will be something of a time attack/street car.  The roof is about 1,5mx1m in size. I have made a mold of the stock roof and after that the car has been painted without a roof. The skeleton structure that the stock roof sheet are glued to are left on the car.

I made a nice wet layup in my mold of 2 layers of 200g twill. I used peel ply, perforated release film and breather and with vacuum to that the part came out pretty nice but way to thin..  I put the part back in the mold and added 2 more layers of 200g and pulled vacuum again and it was a big fail.. The surface was not straight at all and it was deformed.. I then got tired of it and took my polyester mold to a professional that would make a part for me using my mold with a autoclave and pre preg. I told those guys that they need to make sure the mold can take the heat and pressures.. I had no Idea if it could handle it.. They said they would be careful and try it in the autoclave before laying up the part.. It was a disaster.. I should have known but I trusted them..  Every little small air bubble were pulled through several layers of 600g fiberglass and gel coat. I later discovered it was slightly deformed too. I was disappointed to say the least.. I just put everything away for almost 2 years before I now began to deal with it again.

So.. Looking at a lot of youtube tutorials and videos it seems that infusion is the way to go..  I am ordering a lot of stuff from easy composites but I need help choosing everything before ordering.. I live in Sweden so I would like to save some shipping cost ordering as few times as I can..

I am debating on fixing the mold or make a new one.. Making a new one involves finding a good roof to make a mold of and get some more chemicals and consumables for it. I might even need to have that roof fixed from dents and painted before making a good mold.   It is time consuming and kind of expensive.. I have sanded the old mold straight but all of maybe 100 holes of different size needs to be filled and I was thinking of using regular polyester bodywork filler and then have the mold painted by a professional car body painter. Whats your thoughts on this..

If I am in need of making a new mold I would like to have it done so it can handle a autoclave.. That is about 130 degrees and it needs to be free from air bubbles. I think that is not an easy task when you need a lot of layers for getting the mold to about 5mm thick.. The guys from the shop that destroyed my mold has a epoxy i can use for making the mold that can handle the heat but they don´t have any gel coats. They suggested biresin s8 or sika s8 but it is hard to get a hold of.. Using that doesn´t need a post cure to handle 130 degree ether if I understand correctly.   I need to learn to do infusions for other parts and projects so I just might start with this roof anyway.

I will get some pictures up so you guys get a better idea of the contours and the shapes of the mold. There are some 90 degree bends where the drip molding or roof moldings are or whatever they are called in English. Also where the roof meets the wind shield and rear hatch there are a 90 degree edge. I am a bit worried how to get all the layers down enough in all the corners without bridging.. When I did the wet layup I had the tack of the first epoxy layer as help. 

I need help thinking this through..

Clear gel coat in the mold or not??.. I want my part to be UV resistant and able to take the sun as any other body part of the car.. Also I want to be able to polish it as the rest of the car using a professional polishing machine. In the beginning I was thinking about to do the infusion without the clear gel coat and then have the finished part clear coated by a professional  car painter. But then i saw a tutorial of the makeing of hood using infusion by easy composites and they used the clear gel coat as a first layer in the mold.

The layup then.. I am thinking of 5 layers of 200g CF or maybe    2 layers off 200g and then a part of 300cm x 600cm of soric where the roof hatch used to be and then another 2 layers of 200g over that. I am afraid of the edges of the soric coming throu to the surfice.. Any thought on that? I am avoiding the heavier CF fabrics because of the difficulties getting those around the sharp corners in the mold otherwise I would use a heavier reinforcement. 

Also I have some thoughts where to place the feed and vacuum attachments to the layup..  My thoughts was to have infusion mesh over the whole mold and have the feed in the middle center of the mold with some spiral (80-100cm) along the mold centerline. Then the vacuum at the edge with spiral all around the mold.


I am also getting a degassing chamber and catch pot for this.. I rely want a perfect part.
 

Reading around this site I found a way to spray tack the first carbon fiber to the mold.. Mixing epoxy with hardener and dissolve it with 10-15% meth spirit.

I was planning to use easy composites infusion resin IN2 slow.. Which had a pot life of 1-2 hours.. Making the tack with that I would guess takes forever to be tacky?..
Could regular laminating epoxy be used? I think I have some.. not from easy composites though..

My advice would be to watch the Easy Composites tutorial several more times, and then practice on smaller parts first. You're going to make mistakes, and you're going to waste time and material, I virtually guarantee it. It's better that you make that waste on a smaller scale, otherwise you are going to find yourself extremely disappointed again.

Secondly, forget about the autoclave. I'm extremely surprised the guys you took your part to were willing to give it a go, because it was never going to work. Unless you used a very special polyester tooling system, it can't handle anywhere near the heat let alone the pressure. A typical polyester system can only handle around 60 degrees C, and won't handle much pressure. Your typical vinyl ester rapid tooling systems may be able to go as high as 120 for a couple of pulls before they start to deteriorate, and you can get epoxy tooling systems that will handle the heat but not the pressure. For autoclave use, you need a suitable mould material - metal, pre-preg, etc. You can get special hand laminating tooling systems for pre-preg use as well, but wet-laying a tool for autoclave use is not an easy task. All of these materials are also ludicrously expensive, and they will all require a post-cure prior to use. I don't know of any resin systems that can go straight off a room temp cure to 130+ degrees without any sort of post-cure, it just doesn't work like that. You don't need an autoclave to get very high quality parts, certainly for cosmetic perfection it isn't necessary at all. You may like to use an out-of-autoclave pre-preg for some of your parts, but it tends to be more suited to smaller more complex components. A roof is not something that needs pre-preg at all, it is much more suited to infusion.

I would suggest ditching the old mould as well. If you really want a perfect part, then your mould needs to be perfect. If you have suspicions that the mould is distorted, in addition to a lot of surface repair work to do... It's a recipe for disaster. You will spend less time and effort in rebuilding the mould, ideally using Easy Composites Unimould system if you can because they will be able to give you the support you need to get a perfect result. If you can't get Unimould, then try for something similar - a vinyl ester tooling gelcoat and coupling coat, with a polyester tooling resin for the bulk of the laminate is ideal. Lots of companies make such systems, so look for Reichold or Ultratec etc. Being based in Sweden, I'm sure you can get something quite easily. I would recommend not cheaping out on the mould; buy the quality materials to get the quality results you want, I really can't stress that enough...

Once you have your mould sorted (and again, I would suggest starting somewhere else with something smaller), the rest is easy enough. I am a big fan of in-mould coatings like the gelcoat that Easy Composites use in their video, provided your mould is perfect and you are using a chemical release agent like Easylease. If you are using PVA release agent or your mould isn't the exact surface finish that you want on your finished part, then I wouldn't use an in-mould coating or gelcoat - the point of using the in-mould coating is to be able to pull the part out of the mould with an absolutely perfect surface. If you need to do any refinishing work to get the finish you want, then you may as well put that work into getting the part clear coated. You also need to have the facilities to spray the coating in-mould, it can't be brushed in. So if you can't spray, you're better off not using a gelcoat and taking it to a professional spray painter to get it clear coated. In all honesty, if you are only making one part, it is going to be easier to get it professionally clear coated.

As for your layup schedule for the actual component... I would worry about getting the mould sorted first. Practice with other parts first, get an idea of what infused carbon fibre feels like. 5 layers of 200g is going to give you a component around 1-1.2mm thick - Not thick enough if the roof needs to have any sort of structure, and you may want to check your local regulations on what you are allowed to have on a street car. I know that here, any composite body panels must be a minimum of 3mm thick. 3mm is a good thickness for most street car body work anyway, so I would recommend aiming for that. The lightest (and cheapest, compared to solid carbon) way to do it will be with a core like Soric or 3D PET core (I prefer the 3D PET core myself, Soric is heavy). Yes, if you use a small section of Soric then it will print through to the surface, especially on the edges. Avoid this by building up the laminate thickness so that it is equal with the thickness of the Soric (so around an additional 8 layers of 200g around the edges of the Soric). The use of heavier fabrics is also something I would recommend - again, if you play around with smaller parts first you will learn how to get it to conform around tight corners.

I have no doubt that Easy Composites will be able to provide you with the support, advice and materials that you need to get a good result, so have a chat to them and listen to what they have to say. The rest is easy!

Hanaldo is right, is isn't a good idea to test a completely new precess with a large and expensive part. I would recommend redoing the mold, too. In the composite world, trying doing it cheap usually means doing it again the right way, or looking motivation and quit the project.
A simple part like a car roof will come out just as fine via infusion, as with prepreg.

Thank you for the reply..

Yes pre-pregs are out the window at this time.. Also the company that "helped me out" the last time..  They have made several bodies for WTCC type of cars using pre-pregs and their epoxy they got and the sika s8/biresin s8 gelcoat.  I am not 100% it was without post cure since I talked to them about 2 years ago but that was my understanding. Also that kind of mold will not last they said. One offs would work though.

Yep.. I have a feeling I will not get the first parts right.. Other parts I need is panels for the body work. The interior is taken out of the car and the panels I need for it are not as hard to make as the roof so despite how I look at it I need to do the roof for the first time some time anyway.. But I agree.. I need to make something to get at least some  experience.. 

The tooling I bought for making my first mold worked alright. 2 coats of tooling gel coat and 1 or 2 layers of  200g fiberglass to support the gel coat in the corners and then several coats of 4-600g fiberglass to make it 5-10mm thick. I hurt the mold when releasing it from the original roof so it needed repair and went to the paint shop to get it painted for a perfect finish. I used PVA on it when I tried to make my first parts and my idea was to have it clear coated afterwords. I have no plans to make several more roofs at this time. I have the facilities to do all the work. I will use easy lease and wax next time.  Due to how the roof moldings/drop moldings are fastened, work has to be done ether to the stock roof or the mold to get finished parts looking right or release from the mold correctly.. 
Any suggesting how to prep the roof so I can use fillers on it and pull a mold of it without having it painted by a paint shop with 2k paint. A mat or satin finish in the finished mold must be possible to wet sand polish glossy. Can you fill the small small pores in the filler with release wax and then use PVA etc or will the filler stick to the mold anyway? Any tips or tricks?

I will examine the old mold more today and try to decide whether to repair it or make a new one.  Maybe both and have to old one to do some training in the corners on..

The stock sheet metal roof is max 0.8mm thick so 5 layers of 200g or even 4 should work.. Especially since I have the the stock "skeleton" that will support the roof when glued in place.
The car itself has a roll cage and is registered here as "altered/rebuilt vehicle". You have to do that if you are building a super7 type of car also.. It involves several inspections during the build etc for safety but body panels is not an issue as long as the chassis is rigid. That way you can build your own design of tubing chassis and get them road legal.

It becomes clear that I need to be able to do my own painting as well.. puh

I inspected the old mold I had and it is full of not just holes but hundreds of small craters.   When sanded the surface with 600 grit it became obvious..   The mold is toast.. It looks like a gut damn salami after a bit of sanding.. I got a new roof to make a mold of but it has some dents in it I need to fix. Also I need to figure out how to get a good flange all alround the roof..  I´ll see if I can get you guys some pictures tomorrow.

A poor surface won't be good for the finish of the parts. So a new mould might be best!

You can use  Fluted Signboard to make the flanges.  Like in our bonnet video, use hot melt glue or similar to bond them on around the edge, then finish the join with some filleting wax for a neat transition.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Finaly got som pictures..



The old mold messed up. The air holes were grinded out so they would fill with body filler but as mentioned before I decided to scrap it and do a new mold.:





The car without roof but with the stock skeleton left to glue the carbon fiber roof to.:


The new roof I got..:


The new roof had a few dimples in it and I need to smooth them out with body filler.. My plan was to use a 2k rattle spray can for the last finish and wet sand the transition and polish it up to a nice glossy finish. Then I read in a post on here that that kind of paint can make the surface of the mold of the roof bad. 
Any suggestions what to use?

Possibly one of the simplest panels you could ever make, theres nothing complex to be scared of there. In response to your original post, I would say don't bother with the spray tack. You will get a much better result without it, and you certainly don't need it for that roof. Rather put your time into watching the EC infusion videos and study how they deal with the bagging so that there is no bridging in the corners.

2k paint is very hit and miss, especially the rattle can stuff as it contains a lot of solvent. If you don't have a compressor and a spray gun though, it may still be your best option. But I would recommend using PVA as your release agent to make the mould. It is much easier to polish a PVA mould surface up to a full gloss than it is to fix alligatoring caused by the gelcoat attacking your paint. 

Thank you.. Good advice.. 

I do have a air compressor but I only have a cheap paint gun and I have very little experiance of using it at all. But it should be fairly easy to dial in the gun to get a deacent result I guess. 

I need to get a better gun but i am almost up to £2000 of stuff as it is right now..


Back to the mold.. The thing I am worried about are the 90degree corners along all the edges combined of 5 layers of 200g carbon fiber.. I am afraid that the layers will "lock" themself to eachother under vacuum to make it very hard to push the layers in to the corners without bridgeing.. 

Also when making the mold for this big flat roof I need it to be very thick to get some kind of stiffness if I am not useing some kind of braceing..  I would think about 10mm.  Any advice on a good way to brace the molds backside?