Marking parts

[tshort]

I'm about to disassemble everything for deburring, dimpling, priming, etc and was wondering what is the best way to mark parts for orientation, etc. The plans say it is OK to scribe - any specific tool? How much is too much? Anyone have any pictures or anything?

Thomas

[captain_john]

A Sharpie marker.

I have yet to scribe anything. The paint doesn't cover the Sharpie.

See? Look:



See inside the lightening hole on the lower left spacer?

CJ

[Spike]

The idea of Scribing sends shivers through me spine. Go with the Sharpie. Paint doesnt seem to cover it up and unlike scribing it can easily be removed if you so desire.

[rick6a]

I'm about to disassemble everything for deburring, dimpling, priming, etc and was wondering what is the best way to mark parts for orientation, etc. The plans say it is OK to scribe - any specific tool? How much is too much? Anyone have any pictures or anything?

Thomas

Intuitively, you would think scribing is extreme. Not really. Way back when, when I built the spars up, the factory scribed many of the spar components and all of the many identical looking (oil wrapped) spacers. Such identification was essential in locating the parts to the proper stations correctly. When using an electric pencil to scribe, use light pressure, don't etch any deeper than necessary to be legible. Alternatively, prior to priming you can use etched metal i.d tags temporarily safety wired to the component. In almost all cases though, a sharpie pen or similiar is perfectly fine. Do note that the ink *can* leach through some primer treatments if that is a concern.
Most people know this, but the information bears repeating. Never, never, never use a common #2 lead pencil to write on bare aluminum. The interaction has been demonstrated in military tests to promote corrosion.

[tshort]

Lest I start any primer wars ... it was my understanding that the alumiprep / alodine process would remove the sharpie I've used and AKZO would cover it up...

[Wicked Stick]

I don't think it's a good idea to scribe thin parts. I suppose it might be ok on thick Alum Angle or such, but why bother when you can use a sharpie marker.

Even when you have washed and alodined the parts, you can usually still see the faint outline of where your writing was. Simply re-trace/re-write over it again with the sharpie before priming and you should be able to see it fine through the primer. If you have covered it with primer, I'd dare say you may be spraying too much primer on it.

Sometimes I will make set of lines with a sharpie, or a dot or dot's near parts that must line back up when put back together for riveting with my spring punch, but that's only on thick parts, and I don't go very deep with it.

Just my opinions/comments, you mileage may vary.

Dave "WS" Rogers
RV-8 Fuselage

[mustang]

I use one of those little theft prevention marking pencils for most parts. I have used this scribing tool on all my tools about 25 years ago. Not one of those tools has ever failed or cracked or....... so I do not worry about it too much. Also, I make sure to mark the part in a place that would be a candidate for a lightening hole. In other words, in a broad shear web area. Consider that most cracks propagate from a hole or an edge. Therefore, I mark in the center of a part, and usually just an "R" or an "L"

Cheers, Pete