I agree with widescreen. Why reinvent the wheel? The time and cost you put into pep armor would be a heck of a lot more than if you start from scratch, plus you'll have something that you can wear or display in weeks, rather than months...or years...or never (due to frustration). Of course there is a certain satisfaction you get from building it yourself...Hello,
Blimey, are you sure you want to go down that route. The kits are not expensive to buy & a lot less hassle.
There are plenty of threads with the information. You'll have to do a search for the right post.