"Help!" for: Fiberglassing, Resin, & Bondo

[BuildsByBaz]

Hi 405th! I recently finished pepping my Mk VI helmet by ROBOGENESIS after my fourth try, and it looks great! I'm ready to move onto resining, but I don't have a respirator. My parents are very nervous about me using resin, and wont let me continue if I find out if using cotton face masks (like the ones a surgeon would wear) would be safe enough. Also, is there ANYTHING, and I mean ANYTHING, I need to do to my helmet before putting the resin on? I don't want to mess this up. Thanks!

Mate, good to hear of your perseverance. Never settle for seconds.

Resin gives off a vapour, which a dust mask won't filter. A dust mask is what's called a, "particulate filter." In other words, it filters out particles, not vapour. I would suggest doing this outdoors. I have been sanding both my fibreglass and Bondo components and the fine dust gets in EVERYTHING, EVERYWHERE! It's very hard to get rid of, once it is in every corner of the room and on every object in the room, including yourself and your clothes, in your eyes, ears, up your nose, in your lungs and parhaps in those nether-regions we don't like to talk about.

My point is, don't skimp on the protection. If you can get to your local hardware store, see if they have those paper disposable overalls. They are worth their weight in gold. A respirator might be a little more expensive than paper masks, but you can't put a price on breathing. Get one.

 

[TheRabbit]

Hi 405th! I recently finished pepping my Mk VI helmet by ROBOGENESIS after my fourth try, and it looks great! I'm ready to move onto resining, but I don't have a respirator. My parents are very nervous about me using resin, and wont let me continue if I find out if using cotton face masks (like the ones a surgeon would wear) would be safe enough. Also, is there ANYTHING, and I mean ANYTHING, I need to do to my helmet before putting the resin on? I don't want to mess this up. Thanks!

As mentioned you need a respirator that handles organic vapors, a dust mask won't cut it. You can get one that will work perfectly for you with brand new cartridges for $30 from nearly any home improvement store.

Before resining make sure your model is well supported, I don't think Robogenesis' models have internal support struts like some of the other models do, so you might want to tape some bamboo skewers or popsicle sticks to the inside to give it some more rigidity while the resin dries. Once you've done the layers of resin on the outside you can remove the supports so that you can begin hardening the inside.

 

[Devohter]

Can anyone give me tips on how to pull this back into alignment?

 

[Katsu]

Pull what back into alignment?

 

[SergantTinkers]

I think he is referring to the front of the helmet, which separates. If so, I would add a hinge device of some kind where the faceplate connects to the actual helmet. Unless he is referring to that bit of resin work on the right side, in which case I have absolutely no idea what that is. Could you add some more pictures, good sir?

On to my question: Many of us know that it is a good idea to add primer to a hardened piece, in order to spot imperfections. However, do you add primer before or after you start applying bondo at all to the suit piece?

 

[Katsu]

I personally see two ways to do it.

Eyeballing: You spray primer after sander smoothing down a coat of bondo. This is to eyeball imperfections in the piece.
Sander: You spray primer right before sanding the piece, if you are using a sanding mouse, any spots still the color of the primer after sanding are too low and need to be filled.

 

[misfitjh]

Tinkers...you can go with out the primer as a spot coat right off the bat if you sand your resin coat. I usually do 2 to 3 coats of resin on the outside before hardening the inside. I then run my mouse sander over the outside, the sanded areas which are the high spots will be dull from sanding. The low spots will still be shinny from the resin.

devohter....I think guys he is talking about the area with the tape where the helm seems to have sunk in. Well if it is that then your going to have to build up your bond and sand to match, that or do a complete rebuild. Your first coat of resin might have been to thick and got the paper to wet causing it to sink.

 

[Devohter]

I am referring to hownthe right side of my
Helmet does not lay under the faceplate. How you see it is a good ways out under the faceplate. I wantto brin that back into line. If that makes sense

 

[TMC]

Hi 405th! I am about ready to pep my MK VI ROBOGENESIS helmet, but have a look at the inside...

Yeah, I obviously have no idea on how to support this properly while I resin it. I've read "put popsicle or bamboo skewers in the inside" so many times, but just put it inside doesn't make any sense. Do you put them across the inside of the structure like I have here, or do you glue them parallel to the paper? Any help would be great. Thanks!

 

[Carpathia]

Yeah, I obviously have no idea on how to support this properly while I resin it. I've read "put popsicle or bamboo skewers in the inside" so many times, but just put it inside doesn't make any sense. Do you put them across the inside of the structure like I have here, or do you glue them parallel to the paper? Any help would be great. Thanks!

Basically, there is no wrong or right answer here. Set your helmet on a table and lightly push down on different areas (the crown, the brim, etc.) and find out where there will be the most flexure, then reinforce those areas.
Likely the area that will need the most reinforcement is around the brim/visor area and the opening (where your head goes in). Since you've pepped the visor in place, you're probably fine there. The opening can be reinforced by simple gluing a few skewers or dowel rods across diagonally (form an "X").

I know it sounds a little vague, but first hand experience is the best teacher, so give it a shot and see what happens. If nothing else, take a look at the supports in Flying_Squirl's helmet and try to mimic those. That may be a good start. Good luck!

 

[Azmyth]

Is there any reason to use fiberglass mat over fiberglass cloth? Does it matter? Is one easier to work with?

 

[Dh748]

Is there any reason to use fiberglass mat over fiberglass cloth? Does it matter? Is one easier to work with?

Fiberglass cloth is much easier to work with, I don't even use gloves with it. Mat on the other hand is very messy, and leaves fibers everywhere. NOT GOOD. Fibers that you can breath in and potentially harm you. I've heard Mat is stronger but in my working with the two I think cloth is better overall. Not like we're going to battle with the stuff right?

 

[Katsu]

Mat bends corners easier is another I've heard. But strength wise my impression is that 2 layers of mat = 2.1 layers of cloth. The strength difference is negligible (in our application, maybe it matters for boat making, or battle as mentioned!)

 

[misfitjh]

A good idea is to use both, like Katsu said mat bends easier. So you can use the mat for bends and corners and details and cover the large areas with the cloth. Thus getting the best of both worlds.

 

[Yayu]

Coating the the N7 helm with resin at the moment. Having about say 98% of it covered - would it be wise to slush some resin inside (as evenly as I can) to get those hard to brush places places? Figure it would be a route to go being that I'm gonna be hitting the inside with rondo anyway.

 

[misfitjh]

Yayu...if your going to rondo the inside then doing a resin coat inside is a waste of product. 2 coats on the outside and rondo on the inside are more than enough to get the job done.

 

[Yayu]

Ah, right on. Guess I'll just pour some resin into those tight corners and poke out the excess. Thanks man, you saved me a couple bucks.

 

[VeeEight]

What are some opinions on aqua resin?

 

[Carpathia]

What are some opinions on aqua resin?

I've never used it. It's too expensive for me. I know that it's non-toxic, so that's a positive if you're restricted to indoors, but IMO it's not a good enough of a trade off for the ease and low price of fiberglass resin.

 

[virusq]

Hi guys! I'm cosplaying EDI from Mass Effect 3 for PAX, (jumping on the plane next week!), and I'm trying to build her "hair" helmet out of pepakura.

I have everything printed and scaled and working. I've coated the inside and outside of the form with resin. I'm getting ready to lay fiberglass and ...

I have no idea how to get fiberglass into her hair tips. They're conical, closed, and wrapped around a blind corner.

I was thinking that I could possibly stick some fiberglass on a ruler and stuff it down into both sides of the hair, but that will be so sloppy that it defeats the purpose.

I'm leaning toward using expanding foam to fill the cones, but I'm seeing mixed reviews on how well that works with pepakura.

I purchased two bottles of Great Stuff Red (the crack-filling 1"-expansion kind) and ... I'm wondering if there are any tips? Should I create vent holes in the piece for the foam? Stuff the piece with fiberglass and then spray foam fill it?

Should I lay fiberglass around the rest of the accessible places before I use the spray foam?

Thanks!