Micro Balloons questions.

[Ace-Garageguy]

2 minutes ago, Art Anderson said:

Tom, back in the day, the first microballoons were phenolic resin, but microscopic glass "bubbles" pretty much became the norm by the mid-80's.  Those aren't prone to static electric at all, in my experience, they have just enough weight that they don't even blow around much.

Art

I think you might be confusing micro with fumed silica. which can be almost like very fine beach sand.

Micro always blows around like the devil.

[Ace-Garageguy]

46 minutes ago, Miatatom said:

Just ordered a pound. Any suggestions on handling this stuff? I can use my spray booth for handling and working with it. How do you store it? Looks like it will come in a plastic bag. I'd think something more substantial would be a good idea. Does it pick up a static charge?

It'll come in a double, heavy clear plastic bag, both bags tied at the neck (inside a cardboard box). It's not the best way to package the stuff. Large quantities come in poly buckets or barrels. It will be affected by static, but it's not as bad as it could be. It's best to wear latex gloves (which of course you want to do working with epoxy anyway), a respirator, and an apron.

If you want to avoid disappointing results, you need to be able to make REPEATABLE mixes, which means measuring carefully and recording your results. Experiment, and when you get a mix you like for a certain application, make the same identical mix every time.

Remember to only add the micro AFTER both components of your epoxy are thoroughly mixed.

Read the blurb on the Spruce website. 

Better still,  here it is:

"These bubbles are actually hollow glass spheres. Because this high-quality glass is very crush resistant, the foam is much stronger, stiffer and water-resistant than any foam made by chemical foaming. These foams displace 4-6 times their weight in most resins and improve the handling characteristics of the base resin. They have a low bulk density and are nontoxic. Mix resin and hardener as directed, then fold in the glass bubbles. Upon cure, a strong, low-density product results which is easy to sand and file. May be shaped to form compound angles and curves. 

The term "micro" was applied to the mixture of microspheres and epoxy early in the development of composite structures. Although microspheres have been replaced by glass bubbles the word "micro" is still commonly used to reference the mixture. "Micro is used to fill voids and low areas, to glue foam blocks together and as a bond between foams and glass cloth. Micro is used in three consistencies - (1) a "slurry" which is a one-to-one by volume mix of epoxy and glass bubbles, (2) "wet micro" which is about two to four parts glass bubbles by volume to one part epoxy, and (3) "dry micro" which is a mix of epoxy with enough glass bubbles to obtain a paste which will not sag or run (about five parts to one by volume). In all instances, glass bubbles are added to completely mixed epoxy resin and hardener. Wet micro is used to join foam blocks and is much thicker than slurry (it has the consistency of honey) but can be brushed. Dry micro is used to fill low spots and voids and is mixed so that it is a dry paste and will not sag. Apply with a putty knife. Never use micro between glass layers.

CAUTION - When mixing epoxy and glass bubbles, wear a dust mask and keep your face away from the balloons that may float up into the air. Although glass balloons are inert, they can lodge in your eyes or in your lungs and cause problems. Handle with care."

Edited January 3, 2018 by Ace-Garageguy

[Ace-Garageguy]

You MAY find something useful in this build thread. It is the last time I did major mods using micro, and was swearing by the West System epoxy...though it has to cure 12 hours to sand...but it adheres and featheredges beautifully.

Be advised: using 5-minute epoxy, or even 30 minute, will DRASTICALLY affect the adhesion, which is directly related to how well it feathers and whether or not featheredges come unstuck when you hit the work with primer.

 

 

[Art Anderson]

2 hours ago, Ace-Garageguy said:

I think you might be confusing micro with fumed silica. which can be almost like very fine beach sand.

Micro always blows around like the devil.

No, K&B marketed their's as micro-sized glass balloons.  Of course, back then, my model workshop was a walled off room with one window and no AC, I tended to leave the back breezeway door open, as well as that window---eventually, the microballoons got to be everywhere, on my then 12' long workbench.  However, in the winter, they tended to just "lay there" wherever I was working with the stuff.

[Ace-Garageguy]

On 1/3/2018 at 1:10 AM, Art Anderson said:

No, K&B marketed their's as micro-sized glass balloons.  Of course, back then, my model workshop was a walled off room with one window and no AC, I tended to leave the back breezeway door open, as well as that window---eventually, the microballoons got to be everywhere, on my then 12' long workbench.  However, in the winter, they tended to just "lay there" wherever I was working with the stuff.

In my experience with the stuff, which spans several decades working extensively with both the phenolic version and the glass version (on real aircraft), I can say say that the glass stuff always tends to go into the air and float around whenever it's removed from its packaging or mixed into a binder. A dust mask and face shield is the absolute MINIMUM protection I use, but lungs and eyes are cheap and easily replaceable, so use your own judgement. Even though it's "non toxic", it can still cause problems. The phenolic stuff isn't as bad, and clumps together a little more. The little things are spheres, too, so when they inevitably get on the floor, it's like walking on tiny ball-bearings.

[Ace-Garageguy]

I've been asked several times about which epoxy to use with micro, and this is my standard response for now:

I've tested multiple epoxies, and the only one I can unreservedly recommend for use with micro is the West System 105(resin) / 205(hardener).

MOST of the epoxies I use need to be very carefully weighed on a gram scale for them to work correctly. They also take 24 hours to cure, and need to be post-cured at elevated temperatures to develop full strength.

The West 105/205 is somewhat unusual in that the mix ratio isn't super critical (though care still needs to be exercised in getting it as close to right as possible), but still develops very good strength and hardness. It's so good, in fact, that it's approved in structural applications for use on some full-sized kit planes. Rutan Aircraft specifies it in some applications (Rutan is the guy who built the first small plane to fly around the world nonstop without refueling, and the first privately-built spacecraft to actually go into space    https://en.wikipedia.org/wiki/SpaceShipOne    so that's a pretty solid recommendation).

The down-side for modelers in a hurry is that it takes 12 hours to cure enough to sand, and for cheap modelers, the minimum quantity is around $50.

West 105/205 is available from several sources, including both the aircraft supply sites I posted earlier, Amazon, and others. The smallest quantities available are 1-quart kits.

I have several "hobby shop" epoxies to test, but so far, I just haven't had the time. The West stuff works so well, and I usually stock it anyway, that I haven't really had the need to find anything else.

Maybe the "other guys" referenced in the thread have developed more info on other resins by now.

Bill Engwer

[Miatatom]

On 1/4/2018 at 11:06 AM, Ace-Garageguy said:

I've been asked several times about which epoxy to use with micro, and this is my standard response for now:

What do you think of Bob Smith Industries BSI epoxies? I just bought some 5 minute and wondered if the 30 minute stuff would work well with balloons.

[Ace-Garageguy]

13 hours ago, Miatatom said:

What do you think of Bob Smith Industries BSI epoxies? I just bought some 5 minute and wondered if the 30 minute stuff would work well with balloons.

I bought some to test back in June. Haven't had time yet.

[Miatatom]

On 3/27/2018 at 9:20 AM, Ace-Garageguy said:

I bought some to test back in June. Haven't had time yet.

I bit and bought the 30 minute stuff too. Anxious to try it on an upcoming build. It'll be a recreation of a model I did back in the early 60s.

[STYRENE-SURFER]

5 hours ago, Miatatom said:

I bit and bought the 30 minute stuff too. Anxious to try it on an upcoming build. It'll be a recreation of a model I did back in the early 60s.

If you are going to use that 30 minute epoxy mixed with micro balloons I would say from my experience building giant scale R.C. war birds that

you will end up with a tough to work with gummy situation. I strongly suggest you use a much slower cure epoxy. West Sytem 101-TS is what I

use (its a two packet  they sell, about 16.5 ml of epoxy) or if you have an RC related hobby store near you Zap Z-poxy Finishing resin. 

 

[Ace-Garageguy]

14 hours ago, STYRENE-SURFER said:

If you are going to use that 30 minute epoxy mixed with micro balloons I would say from my experience building giant scale R.C. war birds that

you will end up with a tough to work with gummy situation. I strongly suggest you use a much slower cure epoxy. West Sytem 101-TS is what I

use (its a two packet  they sell, about 16.5 ml of epoxy) or if you have an RC related hobby store near you Zap Z-poxy Finishing resin. 

 

Thanks for the heads-up on that. I believe you 100%, but I'll probably try my own test anyway, just to see if it looks like the mix might work for anything else.

The West 105 / 205 system is the one I swear by for micro as filler. Good to know there's another West product that also works well.

I'll look for the Zap Z locally too.

[STYRENE-SURFER]

Ace, it is the same 105/205 you are familiar with. Just in foil packets 0.56 fl oz. each sold in packages of 6.

Got them at a marine supply store.

 

[Art Anderson]

I still have a one-pint (approximately!) plastic jar of K&B micro-balloons I got from stock in the hobby shop (The Modelmaker) which I ran from 1984-1992 (when I went to full-time resin casting).  The stuff works equally well with 5-minute epoxy, and the much more smelly, but stronger polyester (think fiberglas) resin, which I prefer, but nowadays, since I live in an apartment, upstairs in an older house here,  with an HVAC system shared with two other apartments--odor can be a problem--so epoxy being much less odiferous, that is what I prefer using.  Epoxy with a bit of sticky surface?  Food dehydrator to the rescue--been there, done that, got the Tee Shirt--works for me, every time it's tried.

Art

[Ace-Garageguy]

On 4/6/2018 at 2:29 PM, STYRENE-SURFER said:

Ace, it is the same 105/205 you are familiar with. Just in foil packets 0.56 fl oz. each sold in packages of 6.

Got them at a marine supply store.

Thanks. Good to know. 

6 hours ago, Art Anderson said:

I still have a one-pint (approximately!) plastic jar of K&B micro-balloons I got from stock in the hobby shop (The Modelmaker) which I ran from 1984-1992 (when I went to full-time resin casting).  The stuff works equally well with 5-minute epoxy, and the much more smelly, but stronger polyester (think fiberglas) resin...

The West 105 / 205 is far superior to any random 5-minute goo you may have lying around. Epoxy that has a "sticky" surface is a problem in my world.

Use whatever you want, but if you intend to use the stuff as a high-quality structural filler, and shape the stuff aggressively, and if you need a beautiful feather-edge with no chance of lifting when hot primer hits it (which I do), and have it stay stuck forever (which I also do), use a decent grade of epoxy.

You can't do work like this with 5-minute crapp.

Or this either...

You can SCRIBE very fine lines in West / micro. I was able to scribe the double roof-seam lines, about 1/32" apart, in this roof panel...with NO chipping or edges flaking off. Try THAT with ANY other filler. I have, and NOTHING else will do the job I needed here.

And it's kinda pointless to use polyester resin with micro. All you're making is lightweight bondo...which you can buy already mixed commercially.

A high-quality epoxy resin and micro mix will just flat outperform ANY other filler.

Every time.   

 

Edited April 8, 2018 by Ace-Garageguy

[badcaditude]

I can't believe I still have to ask this question; What's the Mixture and with what? Plastruct Plastic Weld, 5, 10 or more Minute Epoxy, Super Glue, Scotch, Cake Frosting, Gravy, Elmer's White Glue, Gorilla Glue, Clear Fingernail Polish?

[SfanGoch]

Read Bill's replies above. 

[badcaditude]

Are they out of their bloody minds? Have the Fumes turned their Brains into goo? It isn't made of Gold... Is it? There's got to be something a little cheaper. $79.50 on eBay. What's the Mix Ratio? I don't build for a living, I build to live. I'm not entering Contests. The last time I built for a Contest was in my 6th Grade Science Class. Not that it matters, but I did win 1st and 2nd place. I just want to fill Sink Marks and the occasional Fuel Fill Door Lines without the filler Shrinking after Three, Four, or more weeks later. Especially after the Spray Can Automotive Paint or the Hobby Lacquers and Clear Coats have been laid and Cured. There has been only one filler to date that doesn't do that. Wall Spackle. I stopped using it because Squadron Putty was supposed to be better. I stopped using thin Cardboard as a backing to hold the broken pieces of a body together, because Styrene Sheets get soft and hold better. (A very long story involving an ill tempered Family member and an original issue '57 Chevy "Pepper Shaker).

I'm trying a little experiment using Dupli-Color Filler Primmer EFP101 on my 2nd  Body for my ESCI 1/24 Scale Lt1 powered MB 190 E. (My Squadron Putty seems to have gotten too dry in the Tube). The deep Sink marks on the rear area of the Boot, the Rear Quarters, and the Fuel Filler Door Lines. I'll see how it goes 3 weeks from now. I think its a waste of primer.

Do the Micro Balloons have an Expiration  Date?

[1930fordpickup]

Mark, The Micro-balloons are just filler.  You just add it to the glue to thicken it up. For small lines some guys just use super glue gel and sand it down. Stop into the local parts store and pick up 2 part Bondo for the bigger sink marks. 

[Ace-Garageguy]

10 hours ago, badcaditude said:

Are they out of their bloody minds? Have the Fumes turned their Brains into goo? It isn't made of Gold... Is it? There's got to be something a little cheaper. $79.50 on eBay. What's the Mix Ratio?

Do the Micro Balloons have an Expiration  Date?

I can't imagine what you found for $80, but you can get a pound of the stuff for $8.75 from this site:   http://www.aircraftspruce.com/catalog/cmpages/bubbles.php

There is NO expiration date. They are simply little glass bubbles. Glass doesn't expire.

The "mix ratio" works like this: You mix your epoxy, then you add micro until you get the consistency you want. WEAR A RESPIRATOR.

(The mixing time is one of the reasons you want an epoxy that doesn't go off in 5 minutes. It takes a few minutes to get the consistency just right...which is why I mix MINE on a gram scale, after having done a lot of careful experimenting, and record keeping. I can duplicate an exact mix time after time after time.)

For BEST adhesion and sandability, I STRONGLY suggest you use the West System epoxies listed above. Kept in the original, clean, well-sealed containers, they'll last for a long time.

I CAN NOT RECOMMEND ANY OTHER EPOXY FOR THIS APPLICATION.

NOTE: You really don't need to go to all the trouble of acquiring and mixing microballoon/epoxy filler unless you need an exceptionally high-performance product for heavy applications on radical custom work like my examples shown above.

NOTE: If you just want a "non-shrinking" filler to replace the Squadron one-part LACQUER putty for GENERAL use, get this BONDO #801 "PROFESSIONAL" 2-PART polyester from your local auto parts store:

 

 

 

 

 

Edited May 4, 2018 by Ace-Garageguy