Newbie "Rondo" Question

[Enigma516]

First I want to say thank you for all the amazing information on the site. I am looking forward to start working on a project shortly.

I am a newbie to this process. I keep hearing / reading the term Rondo. However I can not seem to figure out exactly what it is.

I believe it is a mix of Bondo and resin... Is that correct? If so what type of bondo? and what is the ratio of bondo to resin?

Thank you all for the help.

 

[Chernobyl]

Welcome to the forum!

Rondo tends to be a 50-50 mix of resin and bondo, or a similar ratio dependant upon how viscous (runny) you want your bondo to be. Since bondo itself is simply a filler powder additive to resin, you're simply re-diluting the bondo back to a more resin-dominant form, so experiment until you find a consistency that's suitable for your purposes. It's generally useful to use the same brand of resin as bondo, to ensure maximum compatibility between your hardeners.

As for the use of rondo: it's best used to 'build up' details on your work that would otherwise be difficult to assemble in Pepakura form (raised areas, etc). It's not recommended that you use it as a primary strengthening method to your props, since it's a very brittle substance and will shatter with reasonable impact.

That's a brief outline of rondo - if you need further information, there should be one or two decent threads around here that explain the benefits in more detail.

Good luck with your builds!

 

[Enigma516]

Thank you very much that is very helpful.

 

[Alkatraz]

Adding to what has already been said, be careful with rondo, it generates very large amounts of heat, painful burning heat. Also if you have decided to use hot glue in a pepakura model it can melt the glue and cause it to bubble or warp. These glue bubbles can be easily wiped off though, so just be careful using rondo, as with any chemical mix we use here.

 

[peterthethinker]

I was at a friends home last week helping with glassing his armor. he did a Rondo pour in a arm.
Oh dear My, If Iam ever suck in a auto store in a power loss , I think that stuff has enough BTUs to warm a room with a gallon!.

Its get Really warm. and know I see why folks preferr super * CA* glue as it does not get loos when it cooked by the rondo.
Granted Ive been doing my glassing on my armor with 2 part Epoxy. Ive not had any heat issues . the resin in normal glassing mode is also rather exothermic .


Peter...

 

[FlyinPhil]

Just chiming in here... I used rondo to harden my helmet (would fiberglass if I had to do it over again), amd I had no issues with the fact that I used a low temp hot glue to assemble the model. Here is why:

Using rondo doesn't allow you to skip the resin process. Your helmet should already be hardened with a coat of resin on both the outside and inside, which will be more than strong enough to withstand a little heat.

It may be easier to just slosh rondo around in a prop, but fiberglass will give you a far stronger and lighter finished product.

 

[Philthy Stache]

Adding on to what Phil said, some will do a rondo slosh after using fiberglass sheets just to have a smoother surface inside their pieces.

My first build was an Iron woMan suit for my daughter and I used the rondo process for each piece and I don't have anything bad to say about it. It's also helpful if you plan on sanding/grinding/cutting away parts on the outside and you feel that you might break through the whole piece as you do. It just adds depth and material so you aren't left with a hole.

Another combination you might also consider is something I picked up from Thorn696. He once talked about using bondo hair instead of fiberglass sheets. I used this method in my above mentioned Iron Man build and I was happy with the result. I haven't had a chance to see the durability of it over the sheets as I'm not finished with it yet, but I'm still happy with it. You can PM me if you want to know more about it and I'll send you the link to my thread to see some pictures.

 

[Enigma516]

Thank you, I think I am going to build a few test peaces to learn how each of these processes "feel".