Micro balloons versus zinc sterate as a filler in dope

[Mike Quinn]

Hi

Any experience or opinions on how/if  micro balloons  compare against zinc sterate as a filler when used with dope?

Thinking about initial coats to fill the grain.

Cheers

Mike

[Dan McEntee]

  That's a good question. I don't think I have ever heard of or read where anyone has done that. I would think micro balloons have more "volume" for lack of a better word. But is zinc sterate heavier? I wonder how it compares to talcum powder, which is what sterate replaces??Is zinc sterate cheaper and easier to purchase?  I'll be following this.
  Type at you later,
   Dan McEntee

[Dave_Trible]

Hi

Any experience or opinions on how/if  micro balloons  compare against zinc sterate as a filler when used with dope?

Thinking about initial coats to fill the grain.

Cheers

Mike

Mike I and a few others use neither for wood grain.   We are using the ultra light spackling paste you get from your home improvement store.  The stuff that feels like the container is empty when you buy it.   Scrape it on all the wood on the outside surface using an old gift or credit card.  When dry sand most all of it away save for what is actually in the grain and other pin holes and cracks.   Use a swiffer or tack cloth to remove the dust and you are ready to proceed with dope and covering.   The grain is completely filled,  the stuff is vinyl so doesn't shrink or soak further into the wood and adds nothing to the weight of the airplane.  Also is a bunch cheaper than the dope and filler needed to do the same job.  There are also no chemical issues with dope or whatever you are going to finish the airplane with.   It is water based.  I do sometimes brush on a thinned dope first and sand off the fuzz before I apply the spackling.   This stiffens the soft wood a little to aid in sanding.

Dave

[Dan McEntee]

Mike I and a few others use neither for wood grain.   We are using the ultra light spackling paste you get from your home improvement store.  The stuff that feels like the container is empty when you buy it.   Scrape it on all the wood on the outside surface using an old gift or credit card.  When dry sand most all of it away save for what is actually in the grain and other pin holes and cracks.   Use a swiffer or tack cloth to remove the dust and you are ready to proceed with dope and covering.   The grain is completely filled,  the stuff is vinyl so doesn't shrink or soak further into the wood and adds nothing to the weight of the airplane.  Also is a bunch cheaper than the dope and filler needed to do the same job.  There are also no chemical issues with dope or whatever you are going to finish the airplane with.   It is water based.  I do sometimes brush on a thinned dope first and sand off the fuzz before I apply the spackling.   This stiffens the soft wood a little to aid in sanding.

Dave

      If you review one of Allen Brickhaus' articles where he details his method of finishing a model for a rattle can paint job, he used spackling compound but thinned it with water to a brushing consistency and then sand it off. I think he made a couple of applications like this before going to the next step. I know at least the Beguine article went into detail on the finish.

  Type at you later,
  Dan McEntee

[Frank Imbriaco]

I'll just add to the lightweight spackle filler.  Works great. Word of caution. Some name brands now mix in a primer with the spackle. Wasn't keen on that. While browsing at a Dollar Store / Dollar General noticed they carry it without primer.

[944_Jim]

Just curious...somewhere along the way I seem to remember reading MicroBalloons (trademarked) is nothing more than glass bead. That is, the same stuff I glass bead aluminum and steel with.

Please DO correct me if I'm wrong. This one has been banging around in my head for close to ten years...especially each time I fire up the bead blaster.

[Brett Buck]

Just curious...somewhere along the way I seem to remember reading MicroBalloons (trademarked) is nothing more than glass bead. That is, the same stuff I glass bead aluminum and steel with.

Please DO correct me if I'm wrong. This one has been banging around in my head for close to ten years...especially each time I fire up the bead blaster.

   A phenolic balloon, as far as I know, not glass. Phenolic is the base material of bakelite, etc.

     Brett

[Paul Smith]

I can easily buy a quart of microballoons at the local boat store.  They don't weigh anything.  I'm only a third of the way through a quart after fifteen years.

They definately accelerate the cure time of 30-minute epoxy, maybe to only 10 minutes.

[Paul Smith]

I have no incentive to look for an alternate to Micro balloons.

[M Spencer]

I get ' TALC ' from an art store . He saqys its TALC , Not talcum Powder . Poms & talcum Powder - fill of oil and scent , for babies undersides & other parts  .

the art store TALC seems heavy . But I havnt weighd it ., finish wise . Its chalky like stuff . micro Ballons seem a lot lighter , In the Bag .

[Motorman]

Don't they have glass and phenolic balloons? One is white the other brown or, am I remembering something different?

MM

[Ken Culbertson]

for babies undersides & other parts  .
the art store TALC seems heavy ..

Maybe it is used?

Ken

[Lauri Malila]

   A phenolic balloon, as far as I know, not glass. Phenolic is the base material of bakelite, etc.

     Brett

There is many kind of microballoons, it can be glass- nylon- phenolic- or metal spheres, for example.
The most common white ones is glass. Phenolic is red/brown and in my opinion the best for our general use.
The problem when mixing with dope is that they all float, and you must keep mixing the dope during use. L

[Dave_Trible]

There is many kind of microballoons, it can be glass- nylon- phenolic- or metal spheres, for example.
The most common white ones is glass. Phenolic is red/brown and in my opinion the best for our general use.
The problem when mixing with dope is that they all float, and you must keep mixing the dope during use. L

My one try with micro balloons many moons ago left me with that impression.   balloons floated to the top,   all got sanded off,  so that just dope was left to fill the grain.   Thats when I decided to use JUST dope anyway to fill the grain - until I found the spackling.  I have used the talc some but it was always a source of extra weight I wanted to avoid.

Dave

[Ty Marcucci]

I have used zinc stearate since 1999.. It weighs nothing, Talc (soap stone) is a from a rock and is heavy.  About 99% gets sanded off, leaving some in the grooves/holes in the wood. I use the micro balloons for big gouges or fillets. Mixed with epoxy.

[doug coursey]

I watched one of windys videos and he said it didnt work out for him with the spackel but i dont remember why...i think it was in a paint video...IT WAS IN HIS ADVANCE DOPE FINISHING

[EricV]

I've used Zinc Stearate for dope filler for years as recommended by Randy Smith to me way back. The Zinc Stearate is way lighter than just about anything else and mixes in nicely and stays in suspension quite a while.

As far as sanding and breathing goes, zinc stearate is generally considered to be less toxic than talc powder. While talc can be a source of asbestos, or carcinogenic and maybe even mildly radioactive (I know I know Brett), zinc stearate is considered a non-toxic substance with low overall toxicity. Micro balloons of any type are something I would want to avoid breathing while sanding as well.

Bottom line, occasional use probably won't ever affect the typical 1 plane per year builder, but I'd wear a particle mask just the same when sanding anything, period, because even something as seemingly harmless as balsa wood has a cumulative allergic effect on a lot of people over the years. YMMV.

EricV

[Steve Helmick]

Researched zinc sterate online some years ago and found sources for a good price if I wanted to buy large amounts, like 1,000 lbs or something nuts. I got some from Randy Smith. He may still sell it, but IDK for sure. I'm not at all sure about what Randy is up to these days. 

Seems to me that I've read about using microballoons in clear dope before and it wasn't a good thing. I do know that you can put a lot of clear dope on something without much weight penalty. The first coat is the one that adds most weight. PIGments are vile things, and aptly named.

I would bet that the lightweight spackle is microballoons of some type. Perhaps the fine print on the label would give clues about what the binder is? And, I seem to recall that dope & vinyl might be incompatible....latex for sure. Caution is a good idea when you have so much time, work and $ invested in a project. Test samples would be good!  Steve