I've been trying to research edge finishing for aluminum sheet parts like bulkheads and ribs, but the more I read, the more I get conflicting opinions. The two extremes seem to be:
Cut, debur, rough sand, run your finger over the edge and file/sand anything that catches your fingernail.
Sand with 60, 120, 200, 400, 600, 1200, and 2000 grit sandpaper, rub with 200, 400, 800, and 1200 thread count Egyptian cotton, polish with fine silk, have an unicorn sneeze fairy dust over the edge, then use your atomic force microscope to remove any individual out of line atoms.
I'm guessing the first attitude is not enough for everything, and the second is great if you plan on a 20 year build. I suspect that the minimum edge finish for the spar web and leading edge skins may require a bit more care than a bulkhead flange.
I'm not building a show plane, and, while I can be a perfectionist, I know that "you can't be too careful" can easily turn into "you won't ever finish this". The bulkheads that I've made so far I cut near the edge with snips, belt sanded to the line, hand sanded with 60 then 120 grit until I could not feel any roughness with a fingernail or see any areas that were not smooth. I stopped there because I was unsure how much more (if any) was needed on these parts.
I know there's a lot of opinion on these questions, so I expect some disagreement, but I'd like to know experienced people's thoughts on these questions:
What is a safe minimum edge finishing standard?
Does this vary by part?
Does it vary by the method of cutting?
Where do you think it crosses the admittedly fuzzy line from "good enough" to overkill?
Cut, debur, rough sand, run your finger over the edge and file/sand anything that catches your fingernail.
Sand with 60, 120, 200, 400, 600, 1200, and 2000 grit sandpaper, rub with 200, 400, 800, and 1200 thread count Egyptian cotton, polish with fine silk, have an unicorn sneeze fairy dust over the edge, then use your atomic force microscope to remove any individual out of line atoms.
I'm guessing the first attitude is not enough for everything, and the second is great if you plan on a 20 year build. I suspect that the minimum edge finish for the spar web and leading edge skins may require a bit more care than a bulkhead flange.
I'm not building a show plane, and, while I can be a perfectionist, I know that "you can't be too careful" can easily turn into "you won't ever finish this". The bulkheads that I've made so far I cut near the edge with snips, belt sanded to the line, hand sanded with 60 then 120 grit until I could not feel any roughness with a fingernail or see any areas that were not smooth. I stopped there because I was unsure how much more (if any) was needed on these parts.
I know there's a lot of opinion on these questions, so I expect some disagreement, but I'd like to know experienced people's thoughts on these questions:
What is a safe minimum edge finishing standard?
Does this vary by part?
Does it vary by the method of cutting?
Where do you think it crosses the admittedly fuzzy line from "good enough" to overkill?
