Glen Cauley has a great method, and he has worked with Archer Transfers to create a BEAUTIFUL set of resin welds and rivets on decal film! Beautiful! Great stuff!
But if you only need to replace welds, the tape ans green puty REALLY is simple and works well.
Now, if you have lost some rivets, or wonder about the weld pattern, the Archer Tranfser set is superb. I have seena set and am very impressed, working on some pix. A bit expensive, but it will push your model over the edge.