I'm so glad that somebody is showing filling and sanding paper model. I've been doing it for quite a while, although not the using the same products. Instead of plastic putty, I use sandable wood putty. For one thing it's cheaper, and generally less toxic being more akin to thickened wood glue. Second, I noticed some paper pilling in some sanding. Rather than prime the model, I harden the paper by brushing on some nail polish, letting it soak in and dry. A note on the nail polish, while clear is ideal, since one is painting over anyway anything from a store's clearance shelves will do for the most part. I also do this if I add putty to the general area around the fill so as not to pill edges when sanding. I also put extra cardstock behind the area or allow for larger internal tabs just in case I sand through so as to not end up with a physical hole. This is particularly the case in situations where small rounded shapes are needed. Of course this only works on paper models you are going to paint over anyway and finish much like a standard plastic kit. It does improve rounded shapes and some of the "egg crating" that can occur when ribs show through.

Dan, thanks for the tip it's awesome filling and priming the card model. Can't wait to see end result.

OMG!!!! this is amzing!!! Im working on a 1:32 scale Sr-71 and this channel is INVALUABLE!!!

Audio levels are TOO low.