More on poly-tissue "fuzzies"

After messing up many airframe parts with “fuzzies,” I finally figured out how to use poly-tissue. I have been using a slightly thicker material called Dacmat. It weighs 35 grams/sq. metre, as opposed to Polyspan, that weighs 25 grams/sq. metre. Everyone told me to use it with the shiny side up. Sometimes it works, and sometimes it comes up with bad fuzzies. Maybe I’m just getting old, but I always battle to see which side is the right side. I took an old bust wing, and covered two sections. One with the shiny side up, and one with the dull side up. I used the same technique on each section of carefully putting it on with clear dope around the edges, and then shrinking it carefully with a heat gun. Using an iron directly on the surface, seemed to make things worse. Both surfaces received one careful coat of clear dope with a very soft brush.

I could not see much of a difference after the clear dried, so I took a section of each piece, and rubbed it hard with a paper towel and some clear dope. The piece with the shiny side came up immediately with fuzzies, and the other piece stayed fine. I then covered the stab of my new stunt ship once again, with the dull side up. I even used the iron to shrink it, without being very careful, and then I “sloshed” some clear dope on, brushing it out in all directions. No problems at all!

A quick way to check if you have the right side, is to take a corner of the tissue and rub it with a paper towel, and some clear dope on it. If it stays fine, then you have the right side. I then tried actual Polyspan, and found that the shiny side is the right side, but that it’s more sensitive to abuse than the Dacmat. The good thing about all of this stuff is that it comes off quite easily if you need to fix it. You can use a little thinners if it sticks too well. I hope that this helps anyone battling with poly-tissue.

Keith Renecle

I've had good luck using a heat gun to shrink polyspan and then using 50/50 thinned dope, which I slide on with a fully laden brush and let expand out over the surface. Takes several coats before I even consider sanding and even then a light touch is all you need.

I believe you need to do the sanding on the airframe before you apply the polyspan and very little after until you have build up a gloss coat of clear on the materal.

Even then, a fine grit and a light touch is preferred.

My two sense.

Cy