I’m very new to composites and mould making, and have a few questions regarding plugs.
To achieve a smooth mold surface how should I prep the plug?! Is the procedure/items needed the same for wooden plugs as they are for plastic and metal plugs??
The plug surface should be as smooth as you’d like the final part to be. For a mirror finish a lot of work has to be done smoothing out the plug as much as possible.
The procedure at it’s basic level is the same, make a plug which matches the shape of your final object, finish the plug as much as you’d like, then make a mold and then the part.
The materials required are different though. Wood requires a sealer of some sort, usually bondo. Shaping a wood plug requires wood working tools.
Plastic and metal plugs generally don’t require a sealer but are much more expensive.
For small project applications wood or foam is your best bet.
I dont do mirror finishing on moulds pointless if clear coating i finish on p6oo and mold realease ready for clear how ever if i was making a part using gelcoat i would polish the mould
Okay, so if I know for a fact, that the parts to be produced in my molds are either glas fiber parts for testing and learning purposes ( which do not require a class A surface), or carbon fiber parts that will be clear coated, I do not need to spend hours on end waxing and polishing the plug/mold surface??
Clear coating in the end sounds a lot easier than waxing and polishing!
Do not forget that a mirror polished mould is much less likely to get problems with demoulding.
Depending on the size and shape of the product, it can be easier or less easy to polish the plug or mould. You could get away with 2K PU paint, which already leaves a nice finish, perhaps polish that to get rid of the last defects.
The plug I am using is made of plastic. It is a spark plug cover exactly like the one in this thread: http://www.compositescentral.com/showthread.php?t=2925
Do I need to give it a primer, or can i just wax and then give it some PVA?
Avoid PVA if you can, it tends to degrade the surface finish. You should be able to just wax it given that it’s plastic. What’s the surface texture like on your plug?
The surface has been airbrushed by the previous owner. It looks and feels dull and a little rugged. I’m pretty sure it hasen’t been clear coated.
Spraying pva is not an option, so I have to apply it by brush. If the mold end up with a bad texture from the pva, can it be polished out or anything??
yes, but it is a pig to do. Can you add a clearcoat? 2K from Zero Paints seems to be a good one.