I sure like fiberglass and finishing Epoxy.....

I thought I was doing well; 3 coats of SIG Nitrate dope, 1st coat thinned 50/50 subsequent 25/75 and my open bays felt good. 1 week later I am applying Butyrate Dope and I notice my open areas are sagging. Perhaps too heavy of a brush. I continue on but 3 hours later, sitting in the hot sun, my now finished stab is still loose!

Do I have any options?

If the open bays are sealed with dope, then setting it out in the sun to dry will heat up the air inside the wing and stretch the covering, thus leaving it loose when cooled down.

That has happened to me before. Wait a day or so and things will be drum tight again. It takes time. Butyrate dope never stops shrinking, just be patient. Best of luck!

I learned a long time ago to make sure that any structure can breath; i.e. no closed compartments that does not allow air pressure to neutralize on it's own. A hole between every rib and at least one hole to the outside atmosphere, not just a pin hole but one large enough to let air flow under very mild pressure differentials.

OK, rather than start a new thread I thought I would ask thgis ame question in several threads in hope of getting an answer fast.  I just started covering my PT60 with Sig Coverall.  (first time coverall user)  In all the threads I have read here everyone says to overlap by about .25 in.  I used Stix-it on the balso everywhewre I thought I wanted the coverall to stick to balsa.  The problem I am having is the top layer where I am overlapping is not sticking to anything.  Should I be applying Stix-it to my overlap area? 

In a word Yep! Coverall has no adhesive. Anywhere you want it to stick to has to have some kind of adhesive applied to what you want it to stick to be it balsa or another layer of coverall.

Thanks....I guess I was thinking the first layer would wick through.  Its obiously not doing that.

What fabric did you use Hughes500? Also dont force dry dry it. Butrate comes in either shrinking or non; if you use a natural fiber you need some shrinking type but it is best not to use it all the way through for our size planes, because it does keep shrinking forever.

I used Glenn Torence's Lozenge Fabric. My choice of Butyrate Dope for the WW1 Fokker D8 was the flat coat and it does say low shrink!

It has tightened up some since posting this but I would like to see it tighten up more!

I'm a first time user of Koverall too. Is it possible to shrink it after it has been doped? My wings aren't really tightly shrunk, and I'd like to get it as tight as possible.



Thanks!

Hey Airwarrior,  the Koverall shrank very well on my model.  Just a little iron heat did it.  Today I applied 3 coats of Minwax polycrylic.  I will sand tomorrow and then add another coat.  The poly seems to be very lghtweight so far.  Dont know if it will still shrink but I seriously doubt it.    Of course, dope is another story.  Never tried it.

I should add that I've only doped on the tapes so far, and that the rib bays are still undoped.