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Building Tips and technical articles. => Paint and finishing => Topic started by: frank mccune on July 28, 2013, 09:46:51 AM

Title: Old dope that has turned very thick. What to do?
Post by: frank mccune on July 28, 2013, 09:46:51 AM

     Hi All:

      I have about 2.5 gallons of clear dope in a 5 gallon can that has the viscosity of honey. Can I save this dope by adding thinner?  Should I put the dope in smaller containers to retard the tendency to thicken? I have about 3 gallons of thinner for this brand of dope also in a 5 gallon can.  Same questions.

       Does anybody still use dope in finishing model airplanes? Lol


                                                                                                             Tia,

                                                                                                              Frank

Title: Re: Old dope that has turned very thick. What to do?
Post by: Gerald Arana on July 28, 2013, 10:29:53 AM

Mix it up! It should be just fine. My friend that builds full scale gave me some left over dope that he used and it was very thick. Worked well when thinned.

Cheers, Jerry

Title: Re: Old dope that has turned very thick. What to do?
Post by: frank mccune on July 28, 2013, 11:53:25 AM

   Hi Jerry:

    Thanks for the reply!

     Yes, I do remember purchasing some Randolph dope and thinner from an airport about 35 years ago.  It too was very thick and had to be thinned before use.  Perhaps this dope is not getting too old!

      I mixed a sample of it 50/50 and put in a jar which was placed in a vibratory tumbling machine for about 3 minutes.  It came out very well with no bubbles!

                                                                                                 Stay well,

                                                                                                 Frank

Title: Re: Old dope that has turned very thick. What to do?
Post by: Tim Wescott on July 28, 2013, 03:47:25 PM

I've mostly used dope for stick & tissue planes.  In that case thinning it works fine as long as it hasn't completely set in the can.

I'd be kinda interested to see one of the real paint heavyweights give their opinions, though.

Title: Re: Old dope that has turned very thick. What to do?
Post by: Will Hinton on July 28, 2013, 05:16:31 PM

An FBO I was working for discovered a twenty or so year old 55 gallon barrel of Randolph butyrate that was thiiiiicckkk.
We were recovering a couple of Piper Colts at the time and used the stuff with no bad results.  I've done the same with nitrate from a local airport and as long as you use the right thinner you'll be fine.

Title: Re: Old dope that has turned very thick. What to do?
Post by: Noel Corney on July 31, 2013, 12:44:12 AM

Make sure any left over dope is put in smaller cans, as full as you can get them, even put some extra thinner to top up, then making sure the lids are on securely store them upside down( inverted) Stops the air getting in.