Hi Zakewarg,
I'm sure others will have some input to but here's a few pointers for you...
Q1: How would I go about making spherical objects? Such as a helmet (for show), round lampshade etc?
Is there a way to make positive mould for that without getting creases and folds? (I think positive is laying the outer layer first, right?)
For a helmet you would definitely choose a 'split mould' (a left side and a right side which you clamp together and lay up inside, cure, then unclamp and split the mould open. You would choose a split mould because a helmet has a nice big open part where you can get your hand inside to lay your material down.
A round lampshade strike me as being something that would only need a single mould (it's got a positive release if it's the sort of 'hat shape' I'm thinking of. Your carbon fabric will inevitably have a join line but you should be able to make a neat enough job of this (use a little hairspray for none-structural parts to enable you to get a sharp cut line).
If you want to do something around a positive shape (i.e. not inside a negative mould) then you're really looking at sacrificial cores (foam that you either leave inside or melt away using a solvent). If you do this and you shrink wrap it or vacuum bag it then you *will* end up with creases etc on the surface that you will need to flat away and then probably lacquer the finished part.
Q2: I want to add a graphic in the form of a sticker inside the outer layer of epoxy, both in wet lay and infusion, how would I go about this? For infusion, could i mount the sticker directly to the first layer or would that interfere with the epoxy distribution?
For wet lay, I should be able to put the sticker face down into the first coat of epoxy in the mould right?
For your infusion, directly against the mould surface will be fine, it won't interfere with the infusion and the resin should stick to it from the back . You sometime get a wierd bleed under effect where the resin does not fully flow over the front-side of your 'inclusion' which is not ideal but you'll need to experiment with this. If you use something porous (like rice paper) then this problem will go away, but you get a different looking logo.
For wet lay, it's the same story really. It depends on whether you have a gel-coat. If you do, great, put the gel coat down first, then when it's cured and you're laminating the part you can wet the gel again and then drop the sticker down face first before you do the rest of the laminating.
Q3: In what temperatures can I store the supplies? Cloth, release agents, epoxy and everything else?
Could I have it outside in the garage which can reach -15 C? I will of course heat everything before casting.
Really you've got to keep them in a 'room temperature' (15-25C) environment. I would be very worried about any material that has reached freezing point. I'm not suggesting immediately discarding anything that has but I would be very cautious and not be surprised if resins and hardeners and release agents have been affected. -15C would be a real problem.
Q4: Would it be possible to use serial coupled moulds for infusion? For ex; a mould for a longboard with a hose from the opposite side of the epoxy container leading into the next mould? Would the pump be able to pull the epoxy all the way? Any other reasons it might not work?
You wouldn't link them up in 'series' this would be very bad news but you can link them up in 'parallel' without any negative consequences at all. To do this you branch the resin feed line (or have multiple resin feed pots/lines) and also brand the vacuum. This means they will all infuse at the time rate and the same time but that the resistance of the laminate (the drag on the resin as it is pulled through the reinforcement) will not have a cumulative effect (in the way that it would if you connected them in series (one after the other).
Matt StathamEasy Composites / Carbon Mods - Technical Sales