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

Sandbagger

Sr Member
Hey guys! So I have a pretty broad question, but it should fall into this thread. The thing is... I'm just lost. I've bondoed the top of my MK VI helmet, and now I just find myself going to the garage, sanding a bit, and then just wondering it's actually necessary to bondo EVERY PART of this helmet... It seems like bondoing everything is impractical, as you'd lose all the edges and such... Any help would be appreciated.

See the iron man helmet above. Bondo all over. It's worth it for the final finish.
 

Katsu

Well-Known Member
You should only bondo what needs smoothing out, usually to hide the polygons pepakura makes. If you are losing edges and details, you are probably laying it too thickly though.

I strongly suggest getting a set of rubber spreaders (like 2$ at a hardware store, sold next to the bondo, made by bondo too!). Mix the bondo, glop a bit on the helmet, and then press the spreader on the helmet and pull it across the helmet to smear the bondo.

Watch this video:

Specifically, he starts applying bondo at the 10 minute mark. From there you can see how he uses a spreader to smooth the bondo over the piece, which makes sure you don't lose detail.
 
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Carolina1093

New Member
Hi everyone! I'm new to everything and I just started to resin a test piece yesterday using Bondo fiberglass resin. For some reason it is not hardening the paper. I know I added enough hardener because I checked on everything about thirty minutes after I finished adding resin to the piece and the leftover resin was rock solid but the resined card stock was still flexible. Is it supposed to be this way until I add fiberglass? Or are my coats of resin just too light?
 
If the resin itself on the cardstock model is notably hard, then you should be fine. What you should remember is that the only reason you put resin on the outside of the model is because it makes it strong enough to withstand the weight of fiberglass. However, it should still be quite flexible, and pretty brittle as well. Only when you apply fiberglass to the inside will it become rigid.

Also, I prefer to add two coats of resin to the outside of the smaller pieces, and three to the larger ones. But, remember that you don't want to apply your coats too thick. Doing so will just mean your resin will harden in ugly drips that can only be solved by a dremel tool.

In my suit build (the link in my description), I tried my best to explain the fiberglassing process for anyone that may need help or tips. Maybe it can shed some more light on the situation, so feel free to check it out. :)
 

Carpathia

Sr Member
Who high should the temperatur be in a heatbox?

Since the minimum temperature for most polyester resins is 40 degrees F (5 degrees C, make sure by checking the resin's specifications on the packaging) heat boxes only have to be warmer than the outside cold. When I build my heat box, I will be aiming for an internal temperature of 80 degrees F (27 degrees C). Anything hotter, and you might start running the risk of damaging the box or the pep, and (depending on your heat source) of starting a fire. If you line the inside of the box with aluminium foil or some kind of insulating material, that will make a more efficient box, losing less heat allowing for a less powerful heat source.

Of course, since I have yet to build a heatbox, this is purely conjecture on my part.
 

lordhood32

Active Member
I have a noob question i have seen fiberglass Glass aka the ones with the strands and it says it can get rid of the need for fiberglass mat should i use that
 

icedragoon31

New Member
Fiberglass glass or body filler glass? im intrigued. I've got a noob question as well: Would doing a "rondo" mixture with bondo hair and bondo glass be significantly stronger than just a basic filler resin mixture?
 
Icedragoon brings up a good point. When I glassed my fallout helmet, I put several strands over the pep joins where the glue was holding the paper tabs together. When I put the fiberglass inside, not one join separated. Golden!
 

Carpathia

Sr Member
Icedragoon brings up a good point. When I glassed my fallout helmet, I put several strands over the pep joins where the glue was holding the paper tabs together. When I put the fiberglass inside, not one join separated. Golden!

Well, that's the whole idea behind fiberglass, to strengthen the piece.

Fiberglass glass or body filler glass? im intrigued. I've got a noob question as well: Would doing a "rondo" mixture with bondo hair and bondo glass be significantly stronger than just a basic filler resin mixture?

It's possible, but having not worked with the stuff before I couldn't say for sure. I imagine that the fiber strands would be beneficial. Planning on trying it? Let us know how it goes. I'm curious.
 
Um carpathia, I know that's what the fiberglass is for lol. I put a few single strands on the outside when I resined it. It prevents the item from falling apart if the glue comes unstuck. Not particularly necessary but it helps to prevent the need to start all over again.
 

Carpathia

Sr Member
Um carpathia, I know that's what the fiberglass is for lol. I put a few single strands on the outside when I resined it. It prevents the item from falling apart if the glue comes unstuck. Not particularly necessary but it helps to prevent the need to start all over again.

I know you know what fiberglass is for. Why would you be worried about the glue coming apart? Has that happened for you?
 

Katsu

Well-Known Member
Fiberglass glass or body filler glass? im intrigued. I've got a noob question as well: Would doing a "rondo" mixture with bondo hair and bondo glass be significantly stronger than just a basic filler resin mixture?

Hairy bondo is stronger than bondo, but weaker than fiberglass. It is not worth the huge amount of weight it adds to the structure of the piece, and doesn't sand as nicely as straight bondo/rondo. To me it does the jobs of two different things but very mediocre-ly. If you want strength and pourability, pour some rondo inside the helmet evenly. When it's dry lay fiberglass over it. The smooth rondo surface will make laying fiberglass very very easy compared to trying to fit it into the corners and nooks of a normal pep. You will get the fiberglass to strengthen the helmet, and the rondo will be a good buffer layer to cut and sand the outside of the helmet.

Fiberglass gets its strength from being woven with resin soaking into the matrix it creates. Hairy bondo has a much low fiberglass-strand to area ratio than fiberglass mat, and the bondo doesn't give as much strength-weight as resin does and impedes the ability for a good matrix bonding you get versus two layers of fiberglass mat.
 

Katsu

Well-Known Member
Where can I buy Resin, Fiberglass and Bondo in Australia?

It can be hard to find the answer, is here what I said a couple days ago:

This is a common problem. We get used to using the brand names for these products, but there are lots of variants that are easily available.

Go to a local Auto store and look for "laminating fiberglass resin", "fiberglass mat/cloth", and "auto body filler", the body filler is supposedly also known as "bog" in australia.

I am under the impression that stores you should check are "super cheap", or "repco", or "auto-one"

The bondo/bodyfiller is the only weird one. Fiberglass is a very universal and easily accessible material. Go to the autoparts store of your choice and ask them about it, and they will surely be able to point you in the right direction.
 
Hey guys, got a question for ya.

Im trying to get a carbon fiber look on my n7 build but obviously I'm not shelling out for actual carbon fiber. Someone suggested using di-noc to do it but that isn't terribly cheap either. So I'm wondering, has anyone spray painted regular fiberglass and resined it? How did it turn out if you did? I just did a few test swatches and preliminary results
Look promising but I really don't want to screw up my build trying this.

Any input would be appreciated.
 

relaxis

New Member
You can use a method that cold casters use to mix polyester resin with graphite powder and paint it on, the resin dries transparent and the graphite stays on top. Sand and relayer. Casting resin is best.

Question, i think I messed up on the amount of hardener I put in the resin, there is hardener in it, jut wondering if it will cure eventually or just never? Was 3 hours in my boiler room and was still tacky... However my test helmet which had the same thing seems to have hardened ok but took a week...

Also, when resining the fibreglass, I noticed that it comes apart really easily and messily, any way to prevent this?
 
Why would you be worried about the glue coming apart? Has that happened for you?

Yeah it did once with a test piece of chest armour i was experimenting with. A low def halo Mark 6. It hasn't happened again. Even without the single strands of fibreglass matt. But putting the little strands of fibreglass matt on the outside over the edges seems to help the items stay in shape I've recently discovered. I need to further experiment with this as it has the potential to prevent warping without having to put in supports that have to be taken out later. Ill let you know how it goes.
 

relaxis

New Member
OK, I did a test by nearing a halogen lamp near the helmet and the resin just melted and ran into a gooey mess, the hot glue came apart too. Back to basics. This time I will use more hardener!

I use Motip polyester resin, it comes with a tube of pink hardener paste, can anyone recommend how much to use per ml?
 
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