11 years ago
cheaply) determine if rivets (1/4" diameter) installed in steel sheet
metal are aluminum or mild steel?
Using a small diameter mag pickup didn't work because of the proximity
of the sheet metal. Any chemicals that will react with either steel or
aluminum but not both and give a pretty distinct reaction? (Alodine or
cold bluing / parkerizing? ) Also, scratching or lightly
sanding/filing the rivets is acceptable.