mpriestley

My Feedback: (1)

I am hoping to get some advise on thinning Dope.

I am finishing a BUSA 1/3 Pup and I am ready to dope the covering.

I am looking for advise regarding the Sig Nitrate Dope.

How "thin" should the dope be for initial (first) coat?

How many coats should it take before I am ready to switch to Butyrate or Primer/Paint?


Thank you very much for any advise.

oh yeah one other question, how important is the room temperature when applying Dope?


Thank you,
Mike,

vertical grimmace

My Feedback: (1)

I think I generally go 1\2 and 1\2. Check out Aircraft spruce and supply. The dope they sell is the same stuff and cheaper I think.

mpriestley

My Feedback: (1)

Thank you for the help.

So in general it should be more like milk vs. a glue like viscosity?

Chip_Mull

My Feedback: (1)

According to the Ceconite/Randolph manual all Nitrate and Buryrate products are reduced one to one with the appropriate thinner. ie: Nitrate thinner for nitrate and Butyrate thinner for Butyrate.

mpriestley

My Feedback: (1)

Thank you guys,

Looks like I am ready to Dope some wings today.

vertical grimmace

My Feedback: (1)

Be sure that it is warm enough outside or in the shop. Dope seems to work best when it is very warm. I love the way dope performs. I have been able to achieve my best results with those paints.
I used Randolph's dope to shrink the Lozenge fabric on my Fokker. It took a full gallon, but still added little weight at 19 lbs.

mpriestley

My Feedback: (1)

Beautiful Plane!

and Really nice paint job.

I have been wavering on what paint I will use.

Butyrate or some other program.

it sounds like you really had a good time with the traditional Nitrate and butyrate Paint program?

Bad_Daddy

When doping the wings, paint the bottom of the wing first and let it dry facing down. Then paint the top of the wing but turn the wing upside down to let it dry also.
Why?
The dope will flow through the covering and settle out on the lowest surface, so by making that surface face down, most of the dope will fill the outside surface of the wing, and give a nice even coat.
Why to do the bottom of the wing first?
Unless you have a fully symmetrical airfoil, the top surface will have more area than the bottom. Doing the bottom skin first will strengthen it, so when you dope the top of the wing (and the surface will shrink as the dope dries) the dope will be less able to warp your wing. On light-weight models like a Guillows, I have seen the wing get crushed under the tension of the upper surface drying first (when the bottom had not been doped yet.)

vertical grimmace

My Feedback: (1)

Thank you.

Another thing, from what I understand, Randolph's makes the dope for both Brodak and Sig. So wherever you get it from it will be compatible. This is an issue when wanting to use color. There are many colors available from SIG and Brodak but from Aircraft spruce you can get quantity of the clear for less money.
Great points BAD DADDY. When I doped the fabric on my Fokker, I used wax on the spars also to prevent the fabric from sticking to them. Inverting the wing while it dried wouls have helped with this as well.

mpriestley

My Feedback: (1)

I really appreciate the tips guys.

I have obviously never worked with Dope before and I was a bit intimidated.

If there are any other tips out there i am all ears.

I postponed the doping until today so I should be in the shop tonight.