Mjolnir Mk VI Pep build, and some questions

[Burns31]

Hello Spartans,

Hope everyone is having a great first day of Autumn. This is my first time posting, but I've been an on-and-off reader for a few years now and have a pep build to show and wanted to ask some questions I hope to find answers to. First off, here is my best pepakura work so far: a Mk. VI helmet build that I am hoping to complete in time for Halloween this year.

I think it came out pretty well! Before I move on to the next steps I have a few questions...

I've read all the sticky posts and tutorials I could find, but I'm still quite confused and unsure about what the exact order of steps are once I am done with the pep work. It seems like every tutorial I find is either incomplete or has it's own method of doing things. From what I can gather, the process seems to be as follows:

1) Pep work (done)
2) Gather materials (resin, body filler, brushes, respirator, gloves, goggles, and mixing containers)
3) Resin the outside (?)
4) Resin the inside (?)
...and then everything gets sort of confusing, with body filler on the outside (??) and fiberglassing the inside (??), and spot putty, etc...

It's all very confusing, and it seems like a lot of the links in the stickys are outdated, dead links, or only explain one step in the overall process without much indication about what the order of the steps are. If someone could lay out the process, step by step, in order from start to finish (meaning a complete helmet that looks finished), I would greatly appreciate it. I would like to finish this helmet so that I can wear it for Halloween and any help I can get is greatly appreciated. Hope you all like the helmet so far! I look forward to your feedback and advice!

 

[Bullseye]

So your pep work looks clean I had kinda the same problems my first time around.

For the resin stage since you have the supports in I would resin the outside first and let that cure for 24 hours. Try and apply it as smooth as possible or you will get running like paint but it can be sanded down so no bit deal. Once that's cured you should be good to cut out the supports and warping shouldn't occur.

I personally used 3M spray adhesive and glued in my fiberglass inside my piece and once the whole inside had fiberglass glued in I then applied my resin. Try and keep the fiberglass patches as big as you can not the 1 inch strips. I also used some plastidip on the inside to seal any sharp edges or missed fiberglass.

As for bondo you want to use it in places that have polygons so around the top,back and cheeks that are multiple pieces trying to be round. I sprayed everything first with a coat of primer to high light any imperfections then I mixed about a golf ballish size of putty to a 1 inch strip of harrdener and it gives you about 5-8 minutes of work time. I just used a gloved hand and my finger to apply it some people have used cut up milk jugs as well to apply. I knocked down the roughness with a 60 grit then went to 120, 180, then 320. Hit with another coat if primer to look for any more imperfections. You coats of bondo shouldn't be super think so it might take a layer or 2 to get a smooth surface.

As for spot putty around seams were you glued pieces together might show under primer I add spot putty to most of the seams to round them out. It sands easier then bondo and is easier to apply as there is no mixing. Also spot putty Is good for little pin holes you couldnt sand out if the bondo.

And that's about it if you have any more questions ask away also I have an active post kinda documenting my process if you want to check it out for pictures. And good luck.

 

[FlyinPhil]

Here's a reply that i made on another thread. It should answer some of your questions.

If you are concerned about messing up, practice on a few scrap pieces first! We all start somewhere.

Personally, I wouldn't spend the money on spray adhesive. Just put a very light coat of resin on the part you want to glass, place a piece of fiberglass onto the resin (it will stick) then gently brush more resin on top of it. I usually 'poke' the piece of fiberglass with the bristles of my brush in order to help the resin penetrate it and work out any bubbles. You don't need a lot of resin to saturate the pieces, any excess resin will be added weight with minimal strength benefit.

Another tip, work in small, symmetrical areas. Fiberglass impregnated with resin will change shape ever so slightly as it cures, and it would be a lot of work to try to do a helmet in one go. So plan ahead before you start mixing your resin. Cut out pieces of fiberglass, as the gentlemen above recommended. Bigger pieces are better, but fiberglass also doesn't like sharp corners, so take that into account when you are getting ready.

So once you have your fiberglass pieces cut (I would just cut out enough to do one section of a piece at a time. Say enough to do the visor portion of a helmet. dry fiberglass is very light, and pieces can get blown around, especially if you are working outside) mix up your resin. I would work with an ounce or so of resin at a time, so you won't be rushing to use it all up before it starts to gel and cure. Some sections may require a little bit more, but that's up to you to figure out!

Also, to answer another question you posted, I always try to coat the inside of a part with a layer of resin as well to saturate the cardboard model. Once that is cured, I begin to fiberglass. The reason for this: on my first pep model, there was some warping. So naturally, I tried to sand down some of the higher areas to even things out. Unfortunately, I didn't coat the inside of the model before using the rondo method, so I ended up sanding into parts of the cardstock, which required me to scrape out the cardstock in some areas and spend time filling those holes with bondo.

So my personal favourite order of operations:
-make pep model from cardstock
-reinforce inside of model with Popsicle sticks, cardboard, etc. (Gives rigidity and prevents warping)
-coat outside of model with resin, doing it in small sections, not all at once, will help minimize warping.
-remove supports and coat inside of model with resin
-add a few layers of fiberglass to inside of model
-sand and bondo outside of model as needed. I say as needed, because not all areas of a model necessarily need to be hit with bondo. A lot of the sharp edges just need a light sanding and maybe some spot putty along the corners drying the final stages of finishing.