Donald 4 & basic building ?'s
 

Hi,
I wasn't sure where to post this but since I'm building a seaplane I'll post it here. First a couple of basic questions.
Building materials:
What is/are microballoons?
What does the PFM stand for in PFM Glue?

Donald 4 question
In step 4 it says:
Sand and cover the rudder with iron on covering. Make sure all the edges are sealed well. Or paint with 3 coats of polyurethane varnish or dope. Drill a 1/16" hole for the water rudder.
What's the reason for the covering? Whats best to use? The iron on covering, varnish, or the dope?
As you can probably tell I'm new at kit building so please bear with me. I want to build a couple of kits then scratch build. My first scratch built project will be an Ugly Stick. Anyway, the rest of the directions look understandible. But I'll probably have a couple more questions. I have already built 1 heli, and the mechanics for another (for a Bell 222, which I need to paint & finish), and 2 micro planes.
Thanks in advance for the help!
Joe

RE: Donald 4 & basic building ?'s
 

Never mind. I got help at my LHS this afternoon.