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Alcohol in Micro???????


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Hello All,


This is an alcohol question, but not the kine in fuel.


I got a hint from a builder awhile back who mentioned that we could add denatured alcohol to a thick/dry micro that would thin it out. I tried it and it works great!!! It makes the micro very nice to spread and can make it lighter by allowing us to put more micro into the slurry and when the alcohol evaporates it will return to its previous thick/dry state before curing.


Now I went one step further and took some thick/dry micro, you know the one that is hard to spread, and added ALOT of denatured alcohol to the point that the mix is of the consistency of latex paint. This allowed me to paint on the micro slurry that then settled out to a nice smooth level. The goal as to get about a 1/8" to 1/4" thick coating.


It works great and cures just like normal thick/dry micro.


However, with all of the fuel/alcohol discussion I am wondering if applying micro that is really thinned with denatured alcohol might, and I stress might, cause problems? It is in contact with the layup for maybe an hour or two before it evaporates.


I just am looking for some comments/suggestions. I wouldn't want to coat the whole airplane with this only to learn later that I have weakened the entire structure or something like that?


What to youze guys/gals think?



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I ruminated quite a bit over this subject when I was in the finishing stage.

Although many people have used this technique, I just didn't like the idea of possibly messing up the chemical/mechanical properties of the micro.


My technique came down to this:

1) Mix micro to the consistency of thick peanut butter.

2) Smear a big glob/bead on with the heel of my gloved hand.

3) Heat an appropriately sized drywall taping knife with a MAP gas torch and spread micro with firm pressure to eliminate bubbles.

4) Only do 2 strokes over the micro . A third stroke will tend to make the micro lift up behind the blade. You can't put on too much.... Only too little. Then, you'll have to re-apply and get caught in the vicious fill/sand, fill/sand cycle, because as the micro cures, it develops a "hardshell" on itself, making it a pain to re-do. Do your best to fill once, and sand once.


You'll be amazed at how easy the micro spreads and resists peeling off with a hot blade!

"I run with scissors."


Phase One Testing


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The alcohol sounds like a great idea I would like to hear some more feed back on this subject. But I must agree with the last post about putting more on and sanding once. I used a small trowel heated with a heat gun it made life much easier. It seemed to work well when the trowel was too hot to touch and it needed to be heated often. I was going to try one of the small Irons that you use to shrink fabric but I never got around to getting one



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I wonder if one could build a smoothing tool that incorporated a butane powered soldering iron (catalytic?) to heat the base? Might make the smoothing job easier if one could adjust the temperature and keep it there without reheating it or having wires or whathaveyou? As to alcohol, I'm not really inclined to potentially mess with the curing chemistry of my fairing and paint interface layer, even if it is non-structural.

Craig K.

Cozy IV #1457

building chapter seven!


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a smoothing tool that incorporated a butane powered soldering iron (catalytic?) to heat the base?

I have had pretty good results with a 8" drywall spreader and a propane torch. After spreading the micro or West filler with a squeegee, wave the torch over the drywall spreader a few times to heat it up and it will flatten-out the micro fairly well.

Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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