Is this for wood, or plastic?
OK, scratch that. Didn't see where you had written magpul.
I stipple my magpul stuff with either a soldering iron, or wood burner. It's real simple. Just takes a little time.
Plenty of youtube videos if you want fancy patterns.
Myself, I think the soldering iron in the low spots of the forend just poked down slightly into the pattern is the best. Don't have to worry about it being slippery.
No way I want Magpul's polymer contaminating my solder joints.
I'm not sure what you're talking about.
If you are worried that you're going to have a little polymer on your tip, that's easy to remedy with some sandpaper or smooth/fine file.
I really wish I could get some snapshots of my middy AR handguard because it turned out really nice. But I don't have access to it at the moment.