Space Otter
New Member
Im new to this I'm almost done putting resin on my halo 3 scout helmet (need about one more coat) so I was wondering what to reinforce the inside with rondo or fiber glass cloth?
HELP rondo vs. fiberglass cloth
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GenericCola
Jr Member
Rondo will fill in your details better, but fiberglass is sturdier and lighter. The best results will come from using rondo to get all the details, then going over the whole thing with fiberglass to strengthen it.
NoMaybeYes
Member
I havent tried this and its just theory but you could also do a light rondo coat to fill in details then cover that with fiberglass mat.
SpartanC185
Member
When it comes to rondo vs. fiberglass, rondo is a whole lot less messy, and fills in all the details better. I find it easier to work with. However fiber glassing is stronger. If you're looking to save money I would go with rondo. If money isn't an issue (and you don't mind fiberglass slivers) I would suggest using both, Like Zaff said and using the rondo to smooth it all out.
Spartan 420
Member
All I'm gonna say is getting sheets of fibreglass lined up INSIDE of a helmet while trying to coat them in resin is not only INCREDIBLY messy, but in general a huge pain in the backside. I've only ever used Rondo for detailing, but next time I do a pep helmet I'll be reinforcing with it. I never want to relive the nightmare of fibreglassing.
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- S613
i do both i usually fiberglass on the resin then rondo over to cover the rough hardened fiberglass
I first heard about that method from Sean Bradley.
I think it is good for display pieces, but that is a lot of coats of rondo and a lot of extra weight (and bulk inside). It's a bit easier on the neck to do rondo -> fiberglass x2/3 -> rondo. This method overall (rondo layer + fiberglass layer) is a pretty commonly used method, not really theoretical. It does a great job of smoothing the inside of the helmet with rondo to allow the fiberglass to lay more easily to get a strong, bubble-free cover, and the first rondo layer also lets you grind/sand into the helmet from the outside without cutting up the fiberglass you put inside.. since you're grinding into that rondo layer.
In reference to rondo with fiberglass, there is bondo with fiberglass mixed in and we tend to call it "hairy bondo", but you can also mix in your own. This will not be as effective as resin + fiberglass for three big reasons: 1) you still have bondo (which is brittle) as a bonding element in hairy rondo so it won't create a flexible crack resistant matrix like resin+fiberglass, 2) mixing the fiberglass in can mean it's not getting a uniform distribution, where laying down two or three layers of fiberglass cloth/mat will, and that matrix is fairly important to the functionality 3) The weight to strength ratio is a lot lower on hairy rondo.
It's not to say it's a bad idea, it definitely works for a lot of people and can make for a quick way to do a medium strength build, but like any method it has its drawbacks to take into consideration too.
Basically it boils down to how durable and light you want the end product to be. One way or the other you're still going to use both resin and bondo, it's just a matter of whether you mix the two together and swish it around or if you add fiberglass to make it lighter and more durable. I know in a way it doesn't make sense that adding another material to the mix would make it lighter, but it does.
If, strictly as an example, your end result will be a piece that is 1/4 thick. Cardstock obviously isn't going to be making up a great deal of that thickness, even the 110lb stuff. If you do a 1/4" coating consisting of layer after layer of rondo, basically you're just going to end up with a thick chunk of dried body filler held together solely by the hardened cardstock, which will quite likely have been sanded, etched, drilled, and in any number of other ways structurally compromised. The resin itself really only serves to make the bondo more fluid without affecting the overall weight all that much per volume, nor does it make the compound more solid or durable. And because it's essentially a solid piece of body filler, it will be very rigid, very prone to cracking or snapping with little to no flexibility at all, and quite honestly when it comes to repairing such a break, you're almost better off just scrapping it and starting over, because it is going to be a huge hassle.
On the other hand, first you harden the cardstock with resin or a thin coat of rondo to help level off some of the smaller details from the inside, the details which I'm sure Spartans 420 and C185 are referring to. Then, once it's dry, work in small areas at a time (don't try to do an entire helmet or even a full side in one go). Brush a bit of resin onto the inside and press the fiberglass onto it, and continue out and around from that spot, letting whatever you lay down get tacky (meaning it's already begun to cure and harden) before turning the piece to work on a new area (thus avoiding the chance of the fiberglass slipping or bunching). Once you've got the whole thing covered evenly (to prevent warping due to too much weight in one area and not enough to support it in others) you can add a second layer following the same method of spreading some resin, then adding fiberglass. You can achieve that same 1/4" thickness with 2 layers of fiberglass, then essentially a rondo layer (whether mixed together or resin to harden the fiberglass and bondo to cover it) to smooth the inner layer (the part that's going to be closest to your body). It's important when working with fiberglass to remember to have resin between each layer, as well as to lay down a coat before the first piece of fiberglass, and over the final layer of fiberglass so that it can be hardened all the way through.
The fiberglass adds to the thickness and is hardened by the resin while not having nearly as much weight as a straight rondo mix, and the fibers of the fiberglass will bond together along the entire piece to make it much more durable, as well as making it semi-flexible. It may still crack from too hard a hit or fall, but it's not so likely to shatter. Think of the difference between dropping a ceramic mug (the rondo-only piece) and a hard plastic cup (the fiberglass piece). Yea, there's a chance for either one to get chipped or cracked, but the mug is pretty much guaranteed to shatter into several pieces, because it has no flex in it to absorb the impact, while the plastic cup may very well bounce and not get more than a scuff on it.
If you're just doing a display piece that will get put on a stand, mounted on a wall, or set on a shelf and not see much use or movement, a pure-rondo approach might work. If you want to wear it, carry it, move around in it, or do anything beyond just looking at it, adding fiberglass for structural integrity is definitely a much better option in my opinion.
If, strictly as an example, your end result will be a piece that is 1/4 thick. Cardstock obviously isn't going to be making up a great deal of that thickness, even the 110lb stuff. If you do a 1/4" coating consisting of layer after layer of rondo, basically you're just going to end up with a thick chunk of dried body filler held together solely by the hardened cardstock, which will quite likely have been sanded, etched, drilled, and in any number of other ways structurally compromised. The resin itself really only serves to make the bondo more fluid without affecting the overall weight all that much per volume, nor does it make the compound more solid or durable. And because it's essentially a solid piece of body filler, it will be very rigid, very prone to cracking or snapping with little to no flexibility at all, and quite honestly when it comes to repairing such a break, you're almost better off just scrapping it and starting over, because it is going to be a huge hassle.
On the other hand, first you harden the cardstock with resin or a thin coat of rondo to help level off some of the smaller details from the inside, the details which I'm sure Spartans 420 and C185 are referring to. Then, once it's dry, work in small areas at a time (don't try to do an entire helmet or even a full side in one go). Brush a bit of resin onto the inside and press the fiberglass onto it, and continue out and around from that spot, letting whatever you lay down get tacky (meaning it's already begun to cure and harden) before turning the piece to work on a new area (thus avoiding the chance of the fiberglass slipping or bunching). Once you've got the whole thing covered evenly (to prevent warping due to too much weight in one area and not enough to support it in others) you can add a second layer following the same method of spreading some resin, then adding fiberglass. You can achieve that same 1/4" thickness with 2 layers of fiberglass, then essentially a rondo layer (whether mixed together or resin to harden the fiberglass and bondo to cover it) to smooth the inner layer (the part that's going to be closest to your body). It's important when working with fiberglass to remember to have resin between each layer, as well as to lay down a coat before the first piece of fiberglass, and over the final layer of fiberglass so that it can be hardened all the way through.
The fiberglass adds to the thickness and is hardened by the resin while not having nearly as much weight as a straight rondo mix, and the fibers of the fiberglass will bond together along the entire piece to make it much more durable, as well as making it semi-flexible. It may still crack from too hard a hit or fall, but it's not so likely to shatter. Think of the difference between dropping a ceramic mug (the rondo-only piece) and a hard plastic cup (the fiberglass piece). Yea, there's a chance for either one to get chipped or cracked, but the mug is pretty much guaranteed to shatter into several pieces, because it has no flex in it to absorb the impact, while the plastic cup may very well bounce and not get more than a scuff on it.
If you're just doing a display piece that will get put on a stand, mounted on a wall, or set on a shelf and not see much use or movement, a pure-rondo approach might work. If you want to wear it, carry it, move around in it, or do anything beyond just looking at it, adding fiberglass for structural integrity is definitely a much better option in my opinion.
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