When do you guys use Rondo?

[Djstorm100]

I've been searching to to see when you guys use Rondo. When to use it/how to use it etc. From what I gather it is to make the inside surface smooth and not run the risk of having sharp points like you get with fiberglass sometimes. But do you use the Rondo as the agent to hold the fibgerglass down? I normally spray adhesvie and try to use large section of fiberglass cloth to get a uniform look and feel. I would basically "glue" the fiberglass down and then pour the rondo in there and spread it around with my hand? I image you can only do small sections at a time when working with objects like COD since it is full of curves. Was thinking about trying it on a peice for giggles and experiment.

 

[laellee]

Rondo isn't going to soak into your fiberglass like straight resin, and also you really want to brush the resin into your fiberglass for uniform strength. Smooth-laid fiberglass pretty much eliminates all those edges, except of course for overhangs that get trimmed anyways. Also, my rondo comes out heavy, but I just slush it around with really no tool-work. I would (personally) not trust applying rondo over fiberglass resin and cloth unless the resin is still curing, otherwise your rondo layer would be more likely to release from the fiberglass layer. It's either that, or scuff the heck out of the fiberglass layer before rondoing, IMHO. Good luck!

 

[Djstorm100]

So why use Rondo? What is it def. purpose?

 

[laellee]

Depends on who you ask.Some people put in Rondo as a strengthening reinforcing layer with fiberglass mat and resin (or even rondo again) over it. Like I said, I don't like using rondo straight on fiberglass, because I want the fiberglass cloth to be DRENCHED for strength. I have also heard of rondo being used alone with no mat for armor. Problem for me with that is the Rondo mixture is not getting ANY of the strength that the fiberglass matting imparts to your pieces, and Rondo by it's nature is not going to be stronger than resin it's made of. (bondo is essentially just resin with added binders).
I guess what I'm trying to say is, I would rather lay an extra layer of fiberglass or two in than usin rondo for strength, and if the fiberglassing is done cleanly the inner surfaces will be fairly smooth (no sharp edges). The only time I use Rondo now is on very small peps that I can't get inside to glass, like a lot of weapons. I just leave an access hole and essentially roto-cast the pep by hand (after resining the outside). Anyways, that's just what I've learned works best for me.

 

[Crank729]

I used to use rondo as a replacement of Fibreglass cloth....after a few coats of Fibreglass resin, I would slush a few layers of Rondo inside the piece for strength.

I can't exactly recommend it though. It's ridiculously heavy, very brittle, and I had a few coats that cured quite finicky.

 

[Darth Lars]

Never. I have completely migrated from polyester-based products to epoxy-based resin and fillers. I mix my own filler from epoxy and powders. I won't need industrial-strength approved ventilation and breathing masks when mixing and laying it on, it has better adhesive properties and it is less prone to cracking when the armour flexes. I use a different blend depending on the application: microballoons for filling, microfibres for strength and colloidal silica (Cabosil) to prevent it from running.

 

[Balmung]

I only use it when I make some papercraft, like a helmet, which I will take a silicon mold

 

[The Ronin]

Rondo can be used in place of fiberglass IF you are making a piece that you don't plan on needing any strength. A lot of the guys that plan on casting their peps use Rondo instead of glassing the inside because they don't need the pep to last any longer than the casting process.

Rondo really isn't strong enough to last on a worn piece, and it's too heavy to be practical.

 

[mdb]

Mat and resin is much stronger and lighter and far less brittle. Lets put it like this. You have a boat or a surfboard. You do not build either from bondo/rondo you build it with layers of matt/cloth and resin- usually epoxy.

Rondo and the ilk is better for surface treatments, to smooth a surface and be easier to sand back. Not for building- unless as per above it is a master.

I use only epoxy resin with a range of glass cloths and fillers (Usually West Sytems fillers as they are niiiice). I will also mix chopped mat into my mixed resin and mix a little filler to thicken slightly. The matting will gel and make for a really super strong and smooth backing material but only if the mat has a chance to really soak and absorb the resin. The filler mainly helps make the layer opaque and to help it stick a little more with vertical layups (though it still slumps until I add more filler and then lose a fair bit of the gel effect.)

Also you are supposed to laminate the layers while the first layer is not fully cured. Why? So that bonds form between the first and second layers and not cause shearing. I have not yet managed this, or rather appear to have been really lucky with slow curing epoxy being just cured enough to handle but still able to form shallow bonds.

 

[Murdoch]

I am not understanding the comment of rondo being brittle. My helmet fell from the top of my locker and bounced. No cracks or anything. I was shocked yet pleased...GM

 

[Djstorm100]

If I understand lay first layer down. Wait a little bit and lay the 2nd layer down with more resin?

 

[laellee]

Haha, you have to clarify with what you are trying to do at this point when you respond. I'm assuming you are responding to what mdb was saying perhaps. ON that, Mdb is completely correct. Lay your first fiberglass and resin layer, and as soon as it will not run on you, start again. Bonus, the first coat will hold down a second layer of fiberglass mat (or cut) pretty nicely.
Applying mat in layers that are still reactive allows cohesion between those layers, essentially bonding them chemically better. Without the opportunity to bond, two layers can release from each other easily, quite cleanly. This is what mdb was speaking about shearing; two unbonded layers will release from each other when poorly joined, scrape and fail.

And Murdoch, Rondo is the result of what you make it from. Work with me on this, I don't doubt your support.
Rondo (depending on it's mix) is not brittle perhaps, but it will certainly break and shatter. If you had a rondo helmet drop from five and a half feet, and no cracks or separation happened, awesome.

 

[Djstorm100]

Thanks for the info. Sorry I was about to walk in to movie to see war z. Lol