I'm working on an Me 262 right now and there are seams everywhere. I tape off the area and use tamiya putty to fill the seam. My question is how do you all go about finishing the seam off?? I sand it down and use a finer and finer grit, but after priming I see all the flaws. I repeat, but then see all new flaws. I never seem to acheive a perfect smooth finish. Is there something I should be doing? What do you polish with?

You can achieve great results by using a more user-friendly putty. I use Elmer's Wood Filler (comes in a squeeze tube). It's water soluable until dry. This means you can spatula it in the seams, wait a minute or two, then wipe away the excess with a damp cloth. This method puts the putty right down into the seams, with minimum clean-up. After a few hours, knock down any rough areas with some 400 grit wet-or-dry sandpaper, then follow up with 600 grit. Now, grab an old cotton sock or t-shirt and gently polish the sanded area and surrounding plastic until it feels smooth and you get a light shine. Prime it lightly with a neutral color, this will reveal any flaws you may have missed. Sand and buff again if necessary. Once dry, Elmer's Wood Filler can be sanded, drilled and painted, and is quite substantial. It will not attack plastics, as some "green" puttys can. And it has no offensive fumes like most puttys have.

Thanks so much. Very informative! I will pick some of that up this week!

Check out my article about doing perfect seams.
http://www.hawkeyeshobbies.com/feature.htm

Excellent tip! Many thanks.

have a look at "filling gaps made easy" in aeroscale beginners forum 12-23-2005 by Nigel Julian, he is one of the editors at aeroscale, his method involves very little or no sanding and has worked great for me