When covering open bays with Polyspan or Silkspan, I put several coats of either Nitrate or Butyrate on the material to make sure it is filled properly.  After that, is where the process gets a little unsure for me.  Should you make your final coat before priming, a coat of dope mixed with Zinc Sterate (spelling ?) and sand with fine sandpaper, then spray primer, sand carefully again and then shoot your color? Or, just carefully sand the doped open bay prime over the final dope coat, carefully sand and then shoot the color?

I would appreciate anyone who could share their process steps.

Thank you
Mike

Well, I don't use filler coat .  Follow the Phil Granderson method. I put 3 or 4 unthinned coats of non-taunting clear over the silkspan then sand flat and smooth. I sometimes shoot an additional thinned coat on and examine (usually with a flash light with the overhead lights off) and touch up as needed. Then on to base color.

Thank you Randy
Mike

Mike, Dave,
If you are using dope as the basic finish (not auto paint) then once you get to the point of about 4=5 coats (could be a few more to get it drum tight) of 50/50 clear (I usually do 2-3 coats taunting - Sig super coat clear, 2 coats non - Sig lite coat or Brodak clear) then you can do a coat of butyrate plus zinc stearate (I get mine from Randy Smith) as filler (some add a few drops of black dope to get a grey tint) after which you sand smooth with 600, spray on a coat of 60/40 clear to seal, then go to block coat. I do not use rattle can primer with dope as they are acrylic lacquer based and dope do not stick to it well and acrylic lacquer can be heavy very fast.

Another option is to use Silver as the filler coats. With the silver you use it as the filler and block coats. The trick with silver is to let it dry hard before sanding. There are some videos on YouTube that cover this but the idea is to spray on silver, find dings, and off silver (600 paper) reapply silver - sand off repeat until satisfied with the surface then go to color.

Some use a block coat of Dianna Cream for light colors. Most important part of this method is to let the dope dry completely, especially the silver, before sanding. It seems that using Brodak or Randolph thinner gases off in a day or so, Sig takes a few days. Once done you can top coat with death paint (2K Max) and it is bullet proof.

Best,   DennisT