Blue Alodine?

zsadecki · #1 02-14-2005, 06:58 AM

I'm trying to use the 'brush it on' method of applying alodine. Several of my parts treated this way have a blue tint, or blueish-green streaks. I'm speculating that this the part of the chemical conversion and just didn't get dyed by the alodine colorant. Is this OK, or do I have to do these parts over again (in a bath)?

zsadecki · #2 02-14-2005, 08:27 PM

After a little web searching I ran across two other references to blue alodine. The first had something to do with a plastic bucket, the second was from the 'brush on' method I was using. I have a suspicion that this is from the brush material reacting with the acid. I guess I have to re-etch and re-alodine all those parts. Super! 2 or 3 hours of work wasted!

planenutz · #3 02-15-2005, 12:56 AM

Hi there,

I wouldn't be too worried about this change in colour.... I've seen it several times while repairing production aircraft and we had no trouble with painting afterwards. One noteable incident was when rebuilding a fairly old Mooney that had ended up going for a swim off the end of a strip that turned out to be a bit short... the blue was quite noticeable and the experts put it down to a slightly higher copper content in the aluminium alloy.

Have fun!

Mike