Hi mattsz
For the wheel, I'd recommend using a rust converter, but 3 or 4 coats of etching primer will get the job done too. Just as long as you get a good prep (rust removal and cleaning before coating) either of the 2 will sufficiently seal and isolate the rust and prevent it from returning. At least, for quite a while. There is no need to top coat the inside of the wheel as it covered and won't be exposed. The etching primer or rust converter will be good enough by itself.
For the swing arm, you'll need a slightly different approach. First, you will probably want to use a sealer/primer after the etching primer to hide any scratch marks you might leave from sanding. If you're not worried about perfect, the etching primer will suffice. Make sure you remove all the burned paint from the welded area and also make sure you have all the carbon removed from the welds. Use 400 grit sand paper and sand ONLY the area you want to spray. The key to painting this part is going to be hiding your blend line, or where the new paint ends. I'd recommend the whole area of the swing arm leg that was repaired, masking off at the cross bars and ALL the surrounding areas you do not want to paint.
Once you've decided where you want your blend line, clean the prepped area with wax and grease remover, rubbing alcohol, or filtered water with a microfiber. No matter which 1 you use, make sure you have a lint free rag and that it is only damp, not saturated. Now start masking your surrounding areas. Leave your taped edges about 1/4-1/2" away from your blend line. Next, take 3/4" green auto painter tape and now tape all your edges where your blend line is going to be. Leave a "tail" on the end of tape off to the side to make it easy to grab and pull later. Also, mask off your new stud, grease works best to protect it, as paint will cause fitting issues and mess up the threads. Wipe it down with a tack cloth and you're ready to spray!
I also recommend hanging the swing arm to spray it. If you have absolutely no safe place to hang it, prop it up against the wall or something in a fashion that will prevent light spots in the paint. Push comes to shove, hold it by the masked area with 1 hand and paint with the other.
If Using Etching AND Sealer/Primer: Spraying light medium coats - Spray 1-2 coats of etching primer, followed by 2 coats of sealer/primer, followed by 4-5 coats of top coat paint. Allow 8-15 minutes between coats, depending on the temperature ( the hotter the working area temp, the shorter time between coats ).
If Using JUST Etching Primer: Spraying light medium coats - Spray 3-4 coats of etching primer, followed by 4-5 coats of top coat paint.
If you are clear coating over the top, spray 2-3 medium coats of clear over the top coat.
NOTE: YOU ONLY NEED TO PRIME THE AREAS THAT ARE SHOWING BARE METAL. IT IS BEST TO SPRAY THE BARE AREAS WITH PRIMER AND SLIGHTLY EXTEND PAST THE AREA THAT IS BARE BY ABOUT 2-3". THIS WILL HELP REDUCE YOUR BLEND LINE WHEN THE JOB IS FINISHED.[/b]
Once the final coat of paint has been applied, wait 10-20 minutes until the paint looks pretty dry, but not completely. Now go back to all the taped edges you layed out for your blend lines, grab the tails and very carefully pull the tape at a 90 degree angle AWAY from the painted area. You're done! Let it dry for at least 12 hours before handling, 24 hours is best ( you don't want finger prints in your paint
).
DON'T FORGET TO PULL YOUR TAPE LINES!It will make a serious head ache if you don't.
Scottie