stunthanger.com

Building Tips and technical articles. => Paint and finishing => Topic started by: the original Steve Smith on October 12, 2013, 10:18:27 AM

Title: Dope won't dry
Post by: the original Steve Smith on October 12, 2013, 10:18:27 AM
Using Brodak clear to prep wood prior to covering wing with polyspan.  Used Brodak thinner as well.  Both butyrate. Brushed on a 60/40 mix. 

Still tacky and even wet in spots after leaving overnight.  Here in St. Louis at this time of year not extremely humid.  One clue, left the cans in the garage over the winter (does dope freeze?).

Will I need to buy new and strip this mess off or is there some way to fix?

Thanks!

Steve
Title: Re: Dope won't dry
Post by: Jim Kraft on October 12, 2013, 11:07:52 AM
I don't think dope will freeze. I have never heard of this happening before so I really cannot give you the answer. Dope usually dries to the touch in minutes. I would guess that what you have is by some mistake not dope. Sounds more like polyurethane but could be anything. Maybe someone else has had this problem.
Title: Re: Dope won't dry
Post by: 55chevr on October 12, 2013, 11:40:06 AM
Lacquers don't freeze ... I have stored lacquers and butyrate dope in the garage for years and it sets up the same as new.   It appears you mixed something not compatible as the thinner.

Joe
Title: Re: Dope won't dry
Post by: Randy Powell on October 12, 2013, 12:56:57 PM
Generally, when something won't dry (dopes) it's usually either a contaminant or the temp. I've had dope take days to dry when it's either humid or very, very cold. I left a plane I shot in the winter when I lived in Idaho in the garage overnight. I had shot the plane in sub-zero weather (outside) then put the plane into the garage to dry. Next day, it was still tacky. I took the plane in the house and it still took 3 hours to dry (probably because the airframe had to warm up).
Title: Re: Dope won't dry
Post by: Derek Barry on October 14, 2013, 06:33:47 AM
I would try and warm it up like Randy said. Maybe fire up a heater where you have the plane and let it bake for a few hours...

Derek
Title: Re: Dope won't dry
Post by: Tim Wescott on October 14, 2013, 10:08:11 AM
Steve:

Let us know how this comes out.  I have never, ever had dope not dry in the cold -- but January "cold" in Oregon's Willamette Valley is usually a pretty wimpy, ice barely frozen in the puddles sort of "cold".
Title: Re: Dope won't dry
Post by: Mike Griffin on November 05, 2013, 09:20:11 PM
Ty Bob Dixon who was in my club when I lived in Georgia, does that.  He will put a model in the back of his SUV in 100 degree heat and leave it in there for weeks sometimes.   He has been doing this for years.

Mike
Title: Re: Dope won't dry
Post by: John Leidle on November 13, 2013, 01:49:41 AM
   Steve , I had this problem 10 years ago with some dope. After 2days I put it close to the heat register & it finally cured.  It's10 years old & looks nice today.
   John
Title: Re: Dope won't dry
Post by: Balsa Butcher on November 14, 2013, 05:26:56 PM
A very accomplished builder in a "breezy" part of the country used to preach that dope will take 30 plus days to dry/cure and to wait at least that long before sanding/rubbing it out. Patience is the key here. 8)