Working on the Monogram 1/48 A-10, which has nice rivet detail on the aircraft. My concern is with this rivet detail. I joined the fuselage halves together, and need to do some sanding/filling to acheive a nice smooth fuselage with no seam line, but leaving the rivet detail intact. Although I've been careful in the sanding, some of the rivet detail is bound to be sanded away.

What to do about rivet detail? Sand 'very carefully' around it? Sand over it and reproduce the rivet detail (how?) ?

Thanks,
Peter

Yes, and yes, and with a magnifying glass
Seriously, yes sand carefully, yes sand away what you need to.
To replace them you can use stretched sprue cut down in small (tiny) little numbs (slices). Or if you have good glue control you can use CA droplets.
There may be aftermarket stuff you can buy too.

Be sure to make a template before sanding use a piece of paper and a pencil and overlay the to be sanded area then do a rubbing to get the relief of the area. Then sand, then tape down the template and push a pin through to mark where the rivet goes.

You could try masking tape. Lay a piece each side along the seam as close as you can leaving just enough of a gap to allow you to get at the seam. The tape will give some protection to the rivet details as you use the filler and do the sanding and will reduce the amount of "repairing" you have to do.

I use putty up and remove the excess with nail polish remover routine, worked great, and no sanding needed.

These guys have pretty much covered it. This is one of the main reasons why aircraft builders tend to stay away from kits with raised panel lines.

Best of luck...

Scott