This is why you coat the thing in PVA first it seals the paper or cardstock , then you resin and fibreglass until you have the desired thickness, too thin and it'll be like an eggshell and crack like humpty-dumpty , you must build up two or three layers ( or more) to build even thickness until you have a thickness suitable for use eg adding hinges for faceplates etc A coat on the inside is always recommended as the finish inside may be rough and sharp especially fiberglass, it's really there so when you line it, it's easier to do - it's that simple also it adds to the overall thickness and ultimate hardness of your helmet .I haven't used PVA on the outside of my peps, but only one or two coats of resin.
But I learned the hard way that the first coat needs to be a very light one. If you flow it on it will soak in and can cause the larger panels to warp. A light first coat stiffens the card enough for a second coat to give it a bit more strength. I have found that using a 50/50 mix of resin and bondo on the inside acts as a good base for the fibreglass cloth or mat.
Anyway - main thing for me is that pepping is a fun activity on its own right - or it should be - so if I mess up one or two pieces on the way I just chalk it up to experience and give to to the kids to play with.
Cheers, and have fun. Phil
welcome to the RPF.
I have a question about the fibreglass stage on the inside. I've watched STEALTH's tutorials and he said to put the fibreglass so it comes over the edges a bit as that makes it stronger, so my question is, after cutting the excess fibreglass that overhangs, do I need to sand down the inside of the helmet? Will there be sharp glass parts inside? I don't want a fibreglass strand in the eye if I plan to wear it!
And finally, at what stage do you cut the faceplate off? After resin and fibreglassing, or after the body filler/bond stage?
Another tip - use a really good respirator, one that has a charcoal filter(s), and use it when you start handling and cutting out the fibreglass mat or cloth as well as when you are mixing and laying the resin. A ray of late afternoon sun came in through the shed window the other afternoon and revealed about five thousand tiny bits of glass fibres suspended in the air that I was breathing. Been vigilant about using the mask more since then.
Don't mean to alarm you or make you think fibreglassing is inherently hazardous, but it pays to be aware of some of the risks.
Cheers, and as before - have fun! :thumbsup
I'm about to begin a project too, also an Iron Man helmet, and I'm also from the UK, so it's great to be seeing all these posts which helps me begin preparation too!