Hey oh! Bit of a long time lurker but this is my first post.
I've been working with pepakura, resin and body filler for the first time, with a Rocketeer helmet as my first project. So far it is looking devent in my opinion for a first timer, but as I get close to the final stages of adding the rivets, painting, and such.
I was curious that is there any recommended method of adding a coat of something to further protect the work I've done either before or after painting? I've been going in with spot putty and found it can be a bit delicate when dried. Such as how easy it sands away when go in to I clean it up from applying it. (perhaps I haven't let it harden enough?)
I was talking to someone I work with who suggested autobody primer with enamel. Any suggestions would be great. My apologies if such a question has already been asked, I've tried searching all over the place and haven't found any luck.
Thanks!!
Spot putty is typically just that, a light repair medium used for small imperfections such as knicks and pin holes created through the curing of materials. It should not be used as a strengthen-based filler, it simply doesn't have the binding agents to have any durability supporting itself.
Using a primer-sealer that is sandable can help quite a bit. Not to be confused with a simple primer, the primer-sealer works to both eliminate chemical reactions between your base and paint layers, while also giving the surface a 'tooth' to help the next layers of paint adhere to. Sandable primer-sealers also allow you to build up a layer (even heavy sprayed) to repair light (very light) imperfections that you can sand out, repeating with coats as much as necessary. Spot putty fills deep knicks, primer-sealer can be applied and then sanded out to remove scratches, light ripples (with enough layers), etc...
Long story short, there is no quick way to work through your project. I would recommend spraying with a good primer-sealer, letting it dry, and then hold it under a light source (preferably with the helmet lightly wetted with a rag) to see how it looks. Circle your areas of work with a pencil or chalk, and then concentrate on smoothing them to the degree you want. Knick: spot putty. Rough-looking surface: primer-sealer. Anything more: Body filler, preferably a feather-light bondo-type body filler, applied VERY LIGHTLY. Apply, sand, prime-seal, wet, look, repeat until it is the quality you want. It is a lot of work to do right, but if you can see ugly areas when you are just looking at a wetted primer coat, they will look ten times worse on your finishing paint coats.
I'm probably forgetting stuff, just got off work, but hopefully this helps you. Good luck.