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Building Tips and technical articles. => Paint and finishing => Topic started by: Duke.Johnson on May 08, 2013, 10:08:09 PM

Title: Polyspan then superfil vs. superfil then polyspan
Post by: Duke.Johnson on May 08, 2013, 10:08:09 PM
I know it might be somewhere in the history of the forum threads. But, hopefully this is a simple one.  I bought my first tubs of superfil and didn't know if I put on all the polyspan then laid the fillets with superfil or vise versa?  Can you dope superfil or do you cover it first?  Sorry if this is stupid, but there's a first time for most everything. Thanks for the help.
Title: Re: Polyspan then superfil vs. superfil then polyspan
Post by: Mark Scarborough on May 08, 2013, 10:27:05 PM
Duke,
for what its worth,,
what I typically have done is cover the wing before it goes in the fuse. Most of the work is  done on the fuse as well, covered and doped
Then put the wing in the fuse align and secure.
then Is when I do my fillets, it gives me more strength on the wing being covered first, It also gives you a more stable substrate to create your fillets on.
I then never cover the superfill. Ideally when you are done with it, it wont need anything except a coat of primer...

there are several threads which covered different application ideas, mostly they are subtle differences,, Probably worth spending some time with the search, I think you would find good info as well as any other answers here
Title: Re: Polyspan then superfil vs. superfil then polyspan
Post by: Balsa Butcher on May 08, 2013, 10:59:59 PM
Agree with above. The only thing I would add is I use rubbing alcohol to moisten shaping tools or a finger when applying and shaping uncured superfil. It seems to work better than water. The handle end of an small xacto knife is a good tool to form a radius. I think everyone who uses the stuff has their own preferred tool. Another tip is make sure the hardener (white stuff) is stirred. The liquid hardener can separate from the medium which can cause curing problems. Ask me how I learned that.  HB~> 8)
Title: Re: Polyspan then superfil vs. superfil then polyspan
Post by: Duke.Johnson on May 09, 2013, 12:04:20 PM
Thanks guys.  Do you leave the covering on the wing/fuse joint also? Or raw balsa?
Title: Re: Polyspan then superfil vs. superfil then polyspan
Post by: Balsa Butcher on May 09, 2013, 12:33:55 PM
I apply a few coats of dope to the covering to get it tightly bonded to the balsa then apply the Superfil over it. Before it cures shape it to a radius, sand as necessary after it hardens, then prime/paint etc. 8)
Title: Re: Polyspan then superfil vs. superfil then polyspan
Post by: RC Storick on May 09, 2013, 01:14:59 PM
I apply a few coats of dope to the covering to get it tightly bonded to the balsa then apply the Superfil over it. Before it cures shape it to a radius, sand as necessary after it hardens, then prime/paint etc. 8)

James this is the correct method.
Title: Re: Polyspan then superfil vs. superfil then polyspan
Post by: Randy Powell on May 09, 2013, 01:55:56 PM
Yep, covering, a few coats of clear THEN fillets. Makes it easier to sand them, too since it's harder to go through the clear and paper.
Title: Re: Polyspan then superfil vs. superfil then polyspan
Post by: Duke.Johnson on May 10, 2013, 08:32:50 AM
Thanks again!