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

kdbar said:

Hello!

I would like to ask for input on my plan for hardening my pieces.

1. One layer of resin outside with supports inside to maintain shape.
2. After that cures, a second layer of resin outside with the supports still inside. After curing is done, then I can remove the supports and work on the inside.

This is where I'm not sure where to go:
3. I was originally planning to put a layer of resin on the inside, but it seems like the better option would be to put a layer of rondo on the inside?

4. After the inner layer of either resin or rondo is done, use adhesive spray to attach fiberglass cloth for the flat areas and fiberglass mat for the sharp corners.
5. Once the fiberglass mat and cloth is settled in, do I cover with another layer of resin or another layer of rondo?

Thank you!

Also, if I go the rondo route, I heard using something a bit thinner would be good, so something like 3 parts bondo to 1 part resin? How do I measure that to make sure it's accurate? I heard people say to use golf-ball size amount for bondo, but how much many ounces of resin for each golf ball sized bondo?

Thanks again for helping me out!

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1 and 2 are spot on. After you remove the supports, you can add a layer of resin on the inside, but it's not necessary. Rather than trying to stick the fiberglass down with spray adhesive, I brush down a small patch of resin, then lay a small rectangle (2" x 4") down into the wet resin, then dab it down into the resin with a brush, adding a little more resin if needed. You definitely want to add resin with fiberglass. Fiberglass is useless without it; it's the combination of fiberglass and resin that give the piece strength.

There is no real guide for measuring rondo. You simply add resin to the body filler until you have the right consistency. Body filler is just resin with a thickening agent added in; which is why the two are compatible.

Is there any tips for working with the fiberglass cloth with small/tight/sharp spaces? I heard it's difficult to apply the cloth for those areas. Also, what's the best way to apply the cloth along with the resin? I notice that whenever I get resin on my gloves, they get all sticky. I imagine it would be hard to apply the cloth with sticky gloves?

Thanks!

When working with tight spaces, i usually dont use fiberglass but rondo instead. But it also depends on how tight the piece is. If its super tight/sharp, i would use rondo. But in most cases, do what carpathia said. Puy a layer of resin inside and put the cloth on the end of the brush and push it in with a little resin to make it stick on to your surface.

Yeah, its hard for me to not get resin on my gloves too. Just do what carpathia said in his earlier post and you should be good. The trick is to not use your gloves but your brush as most of the support. I think either way they will get sticky with resin. Hope they are disposable .

I finely got the program I need to view pepakura files.

I hand traced the recon helmet blueprints do you think it could work?

carpathiavh99 said:

1 and 2 are spot on. After you remove the supports, you can add a layer of resin on the inside, but it's not necessary. Rather than trying to stick the fiberglass down with spray adhesive, I brush down a small patch of resin, then lay a small rectangle (2" x 4") down into the wet resin, then dab it down into the resin with a brush, adding a little more resin if needed. You definitely want to add resin with fiberglass. Fiberglass is useless without it; it's the combination of fiberglass and resin that give the piece strength.

There is no real guide for measuring rondo. You simply add resin to the body filler until you have the right consistency. Body filler is just resin with a thickening agent added in; which is why the two are compatible.

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Thanks for the tip! So I don't really need to use rondo then? Just 2 layers resin outside and then apply fiberglass cloth and resin on the inside at the same time. For the small cavities, do I just use a smaller piece of cloth and apply with resin? How much resin do i coat the cloth with? Also, I don't have a dremel or any power tools, is it possible to sand down the fiberglass cloth with just a sanding block and sand paper after it cures?

Thanks again

You don't HAVE to do rondo, you also don't HAVE to do fiberglass! There are different methods for different needs.

Here are three common methods:

1) Just rondo is very quick and easy to harden a piece, but it is extremely fragile. One drop of more than a foot will probably crack the piece. Also this is heavy

2) Just fiberglass is relatively easy and VERY light by comparison (bondo is heavy, rondo has bondo!), but fiberglass is prone to creating bubbles that you can punch through from the other side, usually around fine detail areas, or sharp edges and corners. 2-3 layers of fiberglass will get you through most normal wear. I don't think it's useful to go over 4-5.

3) A thin layer of rondo poured first, and then laying fiberglass over that, is my personal favorite, the rondo fills and smooths out small indents and sharp edges, making the fiberglass lay a lot more easily. But this method takes a bit longer than the other methods, and can be pretty heavy.

Katsu said:

You don't HAVE to do rondo, you also don't HAVE to do fiberglass! There are different methods for different needs.

Here are three common methods:

1) Just rondo is very quick and easy to harden a piece, but it is extremely fragile. One drop of more than a foot will probably crack the piece. Also this is heavy

2) Just fiberglass is relatively easy and VERY light by comparison (bondo is heavy, rondo has bondo!), but fiberglass is prone to creating bubbles that you can punch through from the other side, usually around fine detail areas, or sharp edges and corners. 2-3 layers of fiberglass will get you through most normal wear. I don't think it's useful to go over 4-5.

3) A thin layer of rondo poured first, and then laying fiberglass over that, is my personal favorite, the rondo fills and smooths out small indents and sharp edges, making the fiberglass lay a lot more easily. But this method takes a bit longer than the other methods, and can be pretty heavy.

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Thank you so much for the breakdown of the methods. I always see variances with every build that I get confused and don't know which way to go. I think I'll go with #3! What kind of mixture of resin and bondo do you use? And when you say to layer the fiberglass, do you mean to have a coat of rondo in between each layer of fiberglass?

For something like the lip of the helmet, it's hard to put cloth in there neatly since it's such a small opening from the inside. What would be the best way to go about hardening that area and other similar areas?
Thank you again, all this help is inspiring me to power on!

So.. if you are interested in that method (and really, 2 and 3 are great methods, so neither is worse really)

There are two ways to do number 3 I've seen.
3.1) A thick layer of rondo first, this gives a buffer zone so when you carve into the outside of the helmet, you are carving into the rondo which will give nicer details and not ruin the structural strength, where if the fiberglass is closer and you cut into it, you can get strands fraying and reduce the strength if you cut them too much. This method is best for filling pieces that have a lot of deep indents and sharp edges that fiberglass could have trouble filling without bubbles. You pour a thick layer of rondo in the helmet, and then lay two or three layers of fiberglass + resin over that one layer of rondo.

3.2) Thin layers of rondo and fiberglass alternated. This I first read from Sean Bradley, it's a good way to get a nice spreading out of the strength. This might give the best strength, and you'll still have a bit of a buffer layer (though it will be thinner). It's a bit harder to do though, as you have to keep mixing new batches of rondo which can be a bit of a pain. The reason this is stronger is... Rondo/Bondo will always be your primary cracking point, Bondo based layers are always going to be fairly brittle and heavy, and by thinning it and spreading it between layers of fiberglass (which is VERY strong), you reduce the chance of cracks. method 3.1 above has a small risk of cracking if you bend it too hard, but really the crack resistance on a scale of 1-10 would be 9 for 3.2, and 7.5-8 for 3.1, and like 3 for method 1.

How you mix the rondo is a bit of an art, especially in that there's no single way to do it, but a general rule of thumb:
1:1 ratio, equal parts resin and bondo will be VERY runny. This means it will be hard to prevent it from pooling in one spot if you pour too much (aka mix too much since you pretty much have to pour all that you mix into the piece), but it will give a great spread to cover a wide area in a thin layer.

3:1 ratio, 75% bondo, 25% resin will be a lot thicker and as such, won't run as well. If it's a hot day, you won't see it slush very far beyond where you pour it in, so be careful. Mixtures like these are for when you want to thicken out the rondo layer. If I were filling a visor bill (that lip that extends over the visor), I'd probably use a thicker mix like this and make sure it stays that way. This one also probably sands/cuts a bit better because of the higher concentration of workable bondo.

I'd experiment with various mixtures in small batches at first, to see which one fits your needs best. Also if you haven't yet, check out Cereal Killer's video tutorials. He talks at length about the rondo/bondo process, and gives some fantastic tips that are best shown in practical demonstrations (videos)
http://www.405th.com/showthread.php...-Chief-**-A-Step-By-Step-Tutorial-(My-Way)-**

Has anyone used epoxy for really small spaces like the flash light pockets on the sides of a helmet? It is two parts that is applied with plunger syringe with a 5min to 20min cure depending on what you buy?

Thank you! I will attempt to follow 3.1. After putting in the rondo, do I just lay the 2 or 3 layers of fiberglass cloth on top together and then wait for the rondo to cure? Then after it's cured, go over the fiberglass with a layer of resin right?

Also, I think for some parts like the visor bill, you said to fill it out? Does that mean to fill the entire space with rondo, or did you mean to just have a thick layer of rondo in there and slosh it around?

I also found a product called Bondo Glass? It's supposedly something like bondo with fiberglass strands inside of it. I was thinking of making a rondo mixture with resin/bondo glass and use that to harden the inside. Has this been done before and is it viable?

Thank you!

Hey guys,

I have some pepakura pieces put together and I was looking to maybe do some resin coating this weekend, but I had a few questions that I was hoping I could get answered. Any help would be appreciated.

1. I'm using Aqua Resin and I remember reading that the fumes were not as caustic. If I'm in an open area, like outside, would a full respirator be necessary?

2. On a scale of 1 - 10, how necessary is it to Fiberglass the inside? I'm having trouble finding a local supplier ( Any good online ones? ). I'm not really planning on having many of these pieces be my "final" parts, I'm just trying to put a "quick" and dirty set together for Halloween, and planning on upgrading the parts later.

3. My dad has worked with Resin before, but not the stuff I'm using. He cautioned against getting a dremel for sanding, and recommended I just use Sand Paper for the finishing. He was concerned the RPMs from the dremel might heat the resin and turn it sticky/pliable. Has anyone encountered something like this?

4. Kinda off topic, but can anyone ballpark how much a finished suit might weigh? As I mentioned, this will be a quick and dirty build, so probably won't do any electronics, just really the fiberglass pieces and under armor.

Again, thanks for any help you can provide.

kingerthethird said:

Hey guys,

I have some pepakura pieces put together and I was looking to maybe do some resin coating this weekend, but I had a few questions that I was hoping I could get answered. Any help would be appreciated.

1. I'm using Aqua Resin and I remember reading that the fumes were not as caustic. If I'm in an open area, like outside, would a full respirator be necessary?

2. On a scale of 1 - 10, how necessary is it to Fiberglass the inside? I'm having trouble finding a local supplier ( Any good online ones? ). I'm not really planning on having many of these pieces be my "final" parts, I'm just trying to put a "quick" and dirty set together for Halloween, and planning on upgrading the parts later.

3. My dad has worked with Resin before, but not the stuff I'm using. He cautioned against getting a dremel for sanding, and recommended I just use Sand Paper for the finishing. He was concerned the RPMs from the dremel might heat the resin and turn it sticky/pliable. Has anyone encountered something like this?

4. Kinda off topic, but can anyone ballpark how much a finished suit might weigh? As I mentioned, this will be a quick and dirty build, so probably won't do any electronics, just really the fiberglass pieces and under armor.

Again, thanks for any help you can provide.

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1. I've never dealt with the stuff, but according to everything I've read, Aqua Resin is non-toxic, so a respirator should not be necessary

2. If you want the piece to last longer than wearing it once, 10

3. I've never had this problem, but you'll have better control with sand paper. Also, you could consider what Cereal Killl3r does to shape his pieces. He uses files rather than power tools. I did this with my torso, and it turned out better than I could have done with a power sander. This is all assuming that you plan to put body filler on the exterior.

4. If you're using fiberglass, it will be very light. Even with all the body filler in my suit, I did not get fatigued, even while wearing it for the 5 hours at the launch of Halo 4.

carpathiavh99 said:

1. I've never dealt with the stuff, but according to everything I've read, Aqua Resin is non-toxic, so a respirator should not be necessary

2. If you want the piece to last longer than wearing it once, 10

3. I've never had this problem, but you'll have better control with sand paper. Also, you could consider what Cereal Killl3r does to shape his pieces. He uses files rather than power tools. I did this with my torso, and it turned out better than I could have done with a power sander. This is all assuming that you plan to put body filler on the exterior.

4. If you're using fiberglass, it will be very light. Even with all the body filler in my suit, I did not get fatigued, even while wearing it for the 5 hours at the launch of Halo 4.

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Thanks for the quick reply. I guess I'm going to have to glass the inside then. Is there anything special I need to consider since I'm using Aqua Resin, or is it just business as usual? Looking at this stuff: http://www.thayercraft.com/1080.htm

I'm a little unclear on the Body Filler part, is it just another layer that goes on over the resin? I assume it's so that when sanding the pieces come out smoother? I don't suppose there is a tutorial/video/crash course somewhere, is there?

Thanks for the help.

kingerthethird said:

Thanks for the quick reply. I guess I'm going to have to glass the inside then. Is there anything special I need to consider since I'm using Aqua Resin, or is it just business as usual? Looking at this stuff: http://www.thayercraft.com/1080.htm

I'm a little unclear on the Body Filler part, is it just another layer that goes on over the resin? I assume it's so that when sanding the pieces come out smoother? I don't suppose there is a tutorial/video/crash course somewhere, is there?

Thanks for the help.

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As far as I can tell, you use Aqua Resin the same way you'd use fiberglass resin.

That fiberglass looks like a pretty tight weave, but it might be ok. Do you have an automotive supply store near you? You can typically find the type of fiberglass used for this hobby in automotive repair sections.

Body filler is what everyone here refers to as "Bondo." It is used on the exterior of your work to smooth everything out. Take a look at this thread by Cereal Killl3r. He covers a few things (including the use of "rondo," an alternative to fiberglassing using thinned body filler, another technique used by quite a few people around here)...

http://www.405th.com/showthread.php...-Chief-**-A-Step-By-Step-Tutorial-(My-Way)-**

As I mentioned before, his method for applying and shaping body filler is one of the best techniques I've seen.

This might be covered within the 254 pages, but I couldn't get past fifty before my eyeballs decided to rebel and take hostages.

I am planning on using the Cereal Kill3r method for the shaping and detailing of the armor, but want to include fiberglass to strengthen it. Would I lay the fiberglass before the rondo on the inside or after the rondo on the inside?

I would lay it down after; I did this with my Mk VI helmet. The rondo will fill in all the tiny crevices, smoothing the inside of the piece out and leaving a better surface to lay down fiberglass.

Yo guys just reading this ^^^^ Super useful.
Though I was wondering if there is an alternative to using fiberglass cloth and resin to line the inside of my armor.
I don't want to use hot glue, i've tried rondo but it's too brittle. I've seen people slush-casting their armor with some sort of casting resin but because I am in the UK I have no idea what the equivalent is.
Any suggestions? Thanks

Hey Jason-078 you can buy bondo with fiberglass in it, I believe it's called " cat hair" bondo. But like carpathiavh99 said, do the regular rondo first before doing a second coat. That way if you sand through you will have rondo under it and not fiberglass which is a pain to get smooth.

phixix, there are 3 methods if you pep your part. 1) Rondo which it sounds like you've tried and found the downfall is brittle. 2) is fiberglass which is a lot more work but stronger than rondo. 3) is smoothcast which is a plastic type product, and you slush cast it. It's lighter than both the others but more expensive. I'm sure there might be another mothod but I can't think of it.

Resin the outside (light coat, don't cake it on) and make sure the shape stays about where you want it to after it dries.

Then hit the inside with a coat of resin or resin with the glass pads. If you're really pressed for cash, you can cut up old shirts or whatever, soak them in resin, and use them to line the inside of the helmet too. Wash those undies first, it's going on your head It's also going to be a bit heavier.

And wear a respirator in an area with good ventilation and a nice breeze ideally.

There's a really good series of videos on youtube by C3real Kill3r (or something like that), where he does a great job breaking the steps out and makes some fine recommendations.

Best of luck and keep us posted.