Microballoons???
 

My daily dumb question is what are micro balloons and do I need them?

On page 23 step 2 of the [link=http://www.greatplanes.com/manuals/gpma0220-manual.pdf]Manual[/link]
It says to mix a small batch of 30 minute epoxy and microballoons.
Use the mixture to glue the guide tubes in the exit slots...

Can I glue the tubes in without micro balloons?

RE: Microballoons???
 

Microballoons are like very small foam balloons (sort of like styrofoam dust) that get mixed with epoxy and act as a filler. On one model I have, they were used to fill in the gap that was left when joining the wing halves together.. where there was not an exact fit between the two surfaces. This filled the space in and added strength. I'm sure you will get more and probably better explanations from others on here.

RE: Microballoons???
 

Microballoons (MB) are used as a filler when mixed with epoxy. You mix in the MB after mixing the epoxy and you add enough MB to make the epoxy the consistency of whipped cream or peanut butter.

A blob of MB mixture is lighter than a same size blob of epoxy and the consistency helps the epoxy stay where you put it. It also makes it easier to sand after the epoxy sets up.

You could build the part without MB but make sure as the epoxy cures that it stays where it's supposed to be. As it heats up (part of the curing process) it will get thinner and will tend to run away from where you stick it.

Don

RE: Microballoons???
 

OK, since it is a filler I just mixed some balsa dust with the epoxy. Looks like it should work.

RE: Microballoons???
 

Micro balloons are actualy tiny glass bubbles. Do not breath them. The small amounts you guys are going to use problably won't hurt you, but why chance it. I buy them by the 5 and 10 pound bag and use a ton of them building full scale. Over the past few years I have gotten very good about wearing a resperator when using them. Didn't for the first few years. A friend just died and we really question how much of this stuff he ingested in his life building full scale planes and how it shortened his life.

As stated, you mix them with glue to make it thick, like peanut butter was a good one. That thick, there is very little weight and it is strong. You could also hold the control rods in with silicon, but I don't like that as much. Micro balloons don't add strength so don't use it thinking you are making a piece stronger. If you want to strengthen something like a firewall or landing gear, there is a product called cotton flox that we add to epoxy and it makes it harder than anything. I have used it on firewalls and landing gear and it makes it stronger than heck.

Don't use these products with 5 minute. The quick glues go off long before you get the stuff mixed in and it makes a mess.

RE: Microballoons???
 

Yes, you can do it without the balloons. If you can get to the area from behind, you can put a piece of tape (any kind- masking or cellophane) over the seam to help prevent the epoxy from falling through. Mix just a very small amount of epoxy and just tack the tube into place. This will build up the area and when you go back later for a second epoxy application it should keep any excess from falling through. Build up the area carefully and you won't need to do ANY sanding. Just take a little time, we already established this isn't a race didn't we? 5 Min epoxy should be fine for this type of thing also. Longer would be OK, but 5 min fine. The 30 min is to give you mixing/working time for the balloons.

Sounds like the fun is continuing. Where is our photo update???? :D

RE: Microballoons???
 

Microballoons are actually small hollow glass spheres. When you sand them the glass in the surface balloons shatters, so be carefull about breathing the dust. Do your sanding outside if possible &/or wear a paint mask & eye goggles.

The microballons do not soak up resin like the balsa dust, & hence, will be much lighter.

RE: Microballoons???
 

There are two different microballoons, glass and phenolic. The glass mix up as a white paste, the phenolic as a brown base. Both work about equally well and really help if you are trying to form fillets etc.

RE: Microballoons???
 

This is everything you wanted to know about microballoons but were afraid to ask. Great information, folks. I was not aware that they are glass or phenolic. Was not sure what they were made of, thought it was simply ground up styrofoam! Thanks for the information. You not only helped Skynyrd but probably lots of others that 'were afraid to ask'. Thanks! Breathing protection time!

RE: Microballoons???
 

Trust me on this, don't screw with the lungs.
I believe I got my cancer from years of roll grinding. I ground a lot of chrome on these rolls. The chrome builds up on the ends and we would use a hand grinder to knock the build up down. No mask, just chromium flying in your face.
I worked at 3 different places roll grinding and all did it the same way.

RE: Microballoons???
 

Yup, I am sure that the cancer that killed Sam was from the glues and other stuff he was breathing building kit planes and even the big stuff he was breathing at work. Not a good thing. It sure screws a person up and when we are young and dumb, we think we are impervious to the stuff. I know I didn't like the resperator so I never wore it. Now I wear it even to sand balsa and have a suction fan box that takes the stuff away from me when I am working. It makes breathing later so much easier.

RE: Microballoons???
 

Yep, that same over-spray (fumes or dust) that gets all over your clothes and glasses and face etc is also coating your lungs and eyes. With the quality of fuel proof paints and other chemicals we use, it is there for LIFE, no matter how short we are making it. Even a cheap filter mask helps some or even a rag over your face if you are too cheap to do the right thing. THINK of your families!!! I'm sure you can get a cheap respirator at Harbor Freight.com and some safety glasses/goggles too.

Try one of these:
http://order.harborfreight.com/ search keyword "respirator"

[:'(][:@][:@][:'(][:@][:'(][:o]

RE: Microballoons???
 

I use a double charcoal mask for most now. I don't think those cheap white paint masks do much. They don't fit right, too many gaps and I don't think they are worth much. Doesn't matter what a good one cost. It is worth it.

When it comes time to sand my full scale, I may just get a full suit that has a hose to a fresh air source. Seems extreme, but when I sand on that thing, I can put an eighth inch of glass and micro dust on the floor of the entire shop in short order. Its a big plane and I am taking off a lot of material.

RE: Microballoons???
 

What about Bolly's Q-cells they work like microballoons making epoxy thicker but also makes it stronger. It's a white:) "dust" I have used it buit don't know what the actual ingredient is

RE: Microballoons???
 

Woodcraft has the phenolic microballons. 5 quarts for $29.99.
Item number 124530. (www.woodcraft.com)
FWIW
DaveP
(Under their Epoxy listing I think.)

RE: Microballoons???
 

You know, nobody mentioned it so I thought I would... I've never used this method myself, so I can't speak for how well it does or doesn't work, but I've been told by several people in the past that you can use baking soda (or maybe it was baking powder?) as a replacement for micro-ballons... Supposedly works real well and most people have it laying around the house... I dunno...

RE: Microballoons???
 

I think baking soda makes epoxy thicker but I don't think it improves the strength of the bond

RE: Microballoons???
 

Microballons don't add strength either, in fact they weaken the epoxy slightly depending on how much you add. See post #5 if you want to add strength or add carbon fiber in the proper manner where applicable.

RE: Microballoons???
 

Baking soda may thicken it, but it does nothing for the weight. Micro balloons are micro glass spheres which make the mixture light because it thickens it, and adds mass and a lot of air. Baking soda would thicken it, but add dead weight, not light mass. Compare the same size box of baking soda and the same size box of micro balloons and you will be surprised.

http://www.aircraftspruce.com/menus/cm/thickening.html

Heres a link for them cheaper. $6.29 for a pound, which is a huge bag, or I buy them by multiple bags of 5 pounds for $28.25. Its a good way to buy them. If you don't use them a lot, which most modelers don't, then just get a small bag at your local hobby shop. It will cost you as much as a pound of them, but you won't have a huge bag laying around.

RE: Microballoons???
 

The ballons do not make the glue stronger, the makes the glue more flexable. I use them in the ski industry to fix blown edges and sidewalls. Allows for filling holes without have a solid piece of glass in the hole.
If a solid piece of epoxy is frozen and hits with a rock it will shatter. The ballons stop this effect by allowing a tiny bit of flexablity.
Heat helps flow the mixture.
I mix alot in until the epoxy almost rejects taking any more in.

RE: Microballoons???
 

I agree that balloons definately DO NOT make the epoxy stronger, just the opposite, somewhat less strong. I also find that the balloons do not make the epoxy more flexible, just the opposite, much more firm although more easily sanded.

RE: Microballoons???
 

I guess you should see a 2 foot ribbon for a ski's top sheet. Or 12" sidewall/edge replacement. It does flex with no shattering or cracking noises.

We are talking about a smooth gradual flex, not a sharp one. We've had ballons at our shop for 10 years or so. Before that it was cutting up 3/4oz glass strips to mix in then reshape.

They handle vibrations very well.

RE: Microballoons???
 

You can get a pretty good respirator at Lowe's for about $25, probably cheaper at the local hardware store.

I'm going to start using one after reading this thread. I smoked two to three packs a day for nearly twenty years. I started smoking at age 12 or 13. I've quit for a year now, and I sure as he** didn't go to all that trouble to get killed by my airplane. I new I could get cancer from cigs. I just didn't realize I could get it from Sigs as well.

Good advice everybody, thanks.


Ray out.

RE: Microballoons???
 

Do a little research and find out what kind of filters work best for the chemical you will be using. Different products require different filters but I think charcoal filters are good for almost everything and will need to be changed periodically.

Flyboy- Sounds like you use these things professionally the most. Got some advice here??

RE: Microballoons???
 

I do use a charcoal mask with 2 filters. Don't know what is the best, but that keeps everything out. I don't use the little white dust masks. Those things are pretty much worthless. Used them painting when I built my house and I had as much paint in my nose when I was done as I would have without it. Blew white for a week. hahahaha . The good masks are not real comfortable as opposed to none, but I know a guy who has to wear one full time now because he breathed the chemicals so much he can't breath the air now without one because of all the particals in our normal air. Breathing unfiltered air really screws him up. That would suck using one no matter where you are. People make fun of him pretty much everywhere he goes because he has to wear it. That would suck.




Rodney, there is a huge difference between flexible and sandable. Micro in epoxy makes it very sandable. Thats the purpose of them in most of the stuff we do with them in full scale building.