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

[Katsu]

Sorry ice4dragon, but using a window with a fan is a VERY bad idea. It doesn't work. I even experimented with building a wind tunnel using garbage bags, resin just permeates so strongly that you can't do this unless you have an industrial grade fume hood, and even then it won't get everything, the one I use at TechShop still lets some resin fumes escape.

You have three options:
1) Spend extra money and sacrifice some strength and go with aqua resin. It's a water based, non toxic resin alternative, but it is not as strong or reliable as polyester resin.
2) Get a friend with a backyard. I'd suggest a TechShop membership, but the closest one would be in Detroit across the border.
3) Go foam instead.

 

[ventrue]

Hey guys, i will be living in an apartment next year and i wont really have a ventilated spot to leave my pieces to dry after resining and fiberglassing. Is it safe for me to let it dry in like a bathroom or something? if not, how long should i wait until i bring it inside?

Thanks!

I tried something like that - forget it. If you have to work inside, you need to use a different material. Many people use epoxy inside, which is not exactly safe either, but doesn't smell, and the safest material would be Aqua Resin.

 

[MuffinMICHI]

Hey guys,
I pepped an assault rifle (not many details), but I was just wandering how can I make it hard. Because I can resin it from the outside but I can't put the fiberglass in the inside. So I'm just asking if the resin on itself is hard enough or if there is an other way to make it harder...
Thanks

 

[TheRabbit]

Hey guys,
I pepped an assault rifle (not many details), but I was just wandering how can I make it hard. Because I can resin it from the outside but I can't put the fiberglass in the inside. So I'm just asking if the resin on itself is hard enough or if there is an other way to make it harder...
Thanks

Resin alone on the outside will stiffen it, but not enough to actually make it hard. You can pour Rondo (50/50 mix of resin and bondo) in on the inside and just wiggle it around so it gets into all the corners and crevices, but even that isn't as strong as just a single layer of fiberglass.

 

[Katsu]

If you want it super strong, you resin the outside and rondo the inside as mentioned by the rabbit, that will get you decent strength, but won't survive falls. If you want to beef it up further, once it's rondo'd you need to cut it in half, fiberglass the insides, and then reconnect it. This is a massive pain, though, I'm doing something similar with my needler.

 

[S0327]

thanks guys for the help, i'll have to look into another place to let my pieces dry or into aqua resin. thanks again!!

 

[MjolnirGraphics]

What sorcery is this?!?!

Ok, so I keep seeing people posting WIP images like this:

Which I get, I understand the process to get to hear completely (I think...).

But then their next WIP image looks like this:

(Sorry Katsu, I think I snagged these images from you)
What the heck happened? I feel like there should have been a couple images between these two...

I'm reading through the guides, but I'm still lost on this process between these two stages. Is there a video of this process I can watch that will demonstrate this better?
I'm a bit lost by the guides, seems like they go:
-Apply a layer of resin to the outside
-Let dry
-Apply a layer to the inside along with a layer of fiberglass cloth
-Let dry
(And here's where I get lost)
-Now, apply bondo and sand accordingly

What? Where do I apply the bondo? The inside or the outside? How much? How many layers, argh...

Chances are I just haven't found the right guide, or thread or just not using the right search string...

 

[Katsu]

I understand the confusion, and don't feel bad about using the images, you gave credit and that's what is important! Haha!

If you look at my build log, specifically pages 1, 2, and 4, you can see the process to some extent for the outside work, though the "rough" outside work on page 4 is of the visor, it's still the same principle.
http://www.405th.com/showthread.php/36142-Reach-for-the-Front!

There ARE videos you can consult:
http://www.405th.com/showthread.php...-Chief-**-A-Step-By-Step-Tutorial-(My-Way)-**
Although his don't cover fiberglassing, which is an important step for me, but not a required one.

But to answer your question, you have the steps right for a simple build. The bondo goes on the outside. It's a putty that you smooth over the outside in order to fill in the boxes made by the polygonal look of pepakura. You want to work in very small sections, using not a lot of bondo. If your confusion is on the bondo stage, Cereal's videos are amazing, and definitely worth the time to watch. If you have more questions, do not hesitate to ask, we're all willing and happy to help.

And not to toot my own horn too much, but the odst and blamite threads in my signature also have some good pictoral information. But for sure definitely check out Cereal's videos for a good "live" demonstration.

 

[MjolnirGraphics]

Thanks! Those videos have been a big help so far.

So for like the chest piece you wind up with:

(Outside)
[Paint]
[Primer]
[Glazing Putty] - uh... when did he talk about this part? He kinda skipped it...
[Spotting Putty]
<Sander>
<Rasp>
[Bondo]
<Rasp>
[Resin]
[Paper]
[Resin]
[Rondo]
(Inside)

I'm a little confused about the Fiberglass though... he didn't use any on the chest piece, but everyone says to use it on the helmet?
Is the fiberglass specific to the helmet only? Does it go on after the paper is resin-ed but before putting rondo inside?

 

[TheRabbit]

Glazing Putty and Spotting Putty are the same thing. You probably want to do a layer or two of clear coat to protect the paint on top. You want to fiberglass anything that needs to be structurally stable. I assume Cereal hasn't fiberglassed the chest because he's going to make a mold of that too. Whereas he fiberglassed the helmet because at the time he was planning on actually wearing the helmet and not using it to make casts.

What I've done on the inside is:
[...]
[Paper]
[Rondo]
[Fiberglass]
[Fiberglass]
[Padding]

You don't need to resin the inside if you're going to be putting a layer of rondo on. You resin the outside to keep the model structurally stable enough to remove the struts so that you can rondo the inside.

 

[Katsu]

The thing about fiberglass is this...
Rondo is super fast and hyper easy to use. Just mix it and pour it and it will give you smooth easy hardening on the inside. Its main drawback though, is that it is brittle. Despite what some people say, it will not survive good drops or hard wangs against tables. The reason Cereal doesn't use it, he actually briefly mentions, is because he is mold casting his set, and so durability is not an issue, thus trading strength for a faster build time.
Fiberglass is VERY strong and VERY light compared to bondo. If you lay it right, you can stand on your helmet, since fiberglass is meant for boat hulls. The drawback is that it is slower and harder to work with than rondo, and if you don't lay it correctly, you can get airbubbles which will ruin your piece when you are rasping the first resin layer on the outside (imagine a pocket of air between the pepakura and the fiberglass, and you dig into it with the rasp, it is not pretty).

A popular workaround for the shortfalls of these systems is to marry them together. I picked up this method from the Sean Bradley, is to first pour rondo on the inside of the helmet. This fills in the little details and corners where fiberglass tends to form air pockets, giving the inside a smoother, more uniform surface. Then lay your fiberglass over that rondo layer, and it will go on very smoothly, and even if it gets air pockets, you won't be hitting them because you'll hit the rondo layer instead. This is also very nice for modding, so when you go to carve detail lines or mods, you are carving into the rondo layer, and not into the fiberglass layer that is needed for strength.

 

[MjolnirGraphics]

Ok, so for the helmet at least, you're going to sand through all the paper down to the Rondo? Then shape the rondo? So the helmet exterior will wind up slightly smaller than the paper one?

 

[Aster Tea]

Ok, so for the helmet at least, you're going to sand through all the paper down to the Rondo? Then shape the rondo? So the helmet exterior will wind up slightly smaller than the paper one?

Not necessarily. You just want all the polygonal edges gone where it needs to be. Sanding through ALL the paper is extremely excessive. You can use bondo to smooth it out on the exterior so you don't have to worry about how big it looks on the outside.

 

[CoolC]

Ok, so for the helmet at least, you're going to sand through all the paper down to the Rondo? Then shape the rondo? So the helmet exterior will wind up slightly smaller than the paper one?

Rondo is used to replace fiberglass resin. It is meant to hardened the helmet. Bondo is used to smooth out the helmet. Think about the auto industry. Bondo is used to fix any dents to the bodywork. Nobody would sand all the way down to the frame and then apply bondo.

 

[Spinazania]

Hey 405th, I haven't started to resin and reinforce yet. I just wanted to know if a Gas Mask (S10 NBC Respirator) would be OK for use with resin I have sealed filters and just wanted to know if this would be okay.

 

[TheRabbit]

Hey 405th, I haven't started to resin and reinforce yet. I just wanted to know if a Gas Mask (S10 NBC Respirator) would be OK for use with resin I have sealed filters and just wanted to know if this would be okay.

I'm not familiar with that model, check if it says it handles "organic vapors". If it does, then you're alright.

 

[Redshirt]

Hey 405th, I haven't started to resin and reinforce yet. I just wanted to know if a Gas Mask (S10 NBC Respirator) would be OK for use with resin I have sealed filters and just wanted to know if this would be okay.

No, that filter is for other chemical agents (not necessarily organic) as well as fallout and microorganisms. The filters for a commercial mask are designed to work against the type of organic chemicals found in paints and resins. The commercial filters also breathe easier because they are not also filtering for fallout and germs. Unless your resin came from Chernobyl, this isn't really a good match. Besides, nothing but misery awaits you if you try to do your project with a full face mask rather than just a nose and mouth piece.

Redshirt

 

[TheRabbit]

Unless your resin came from Chernobyl, this isn't really a good match.

The resin is supposed to glow in the dark though, right?

 

[ViperB77]

Haha! It has been a late night, and I needed to brush up on my fiberglass information, but I must say, Rabbit, that is comedy.

 

[BuildsByBaz]

This Pepakura thing is the answer to my boredom prayers, to keep me sane and creative. Awesome.

What I like is that the cutting, folding and shaping is very fiddly, technical and requires a lot of concentration, patience and planing. Awesome.

Here's where I am at so far. Just applied the first coat of resin to the outside. It looks a bit rough now but it will be awesome.

P.S. the old paper shuttle is one I made a couple of years ago. Need to dust it off and repair it to hang in the observatory, along with my paper Cassini and Galileo models.

Baz.

1. Humble beginnings

2. Assembled and painted with first coat of resin