Have to be "Sharpies"?

[HighSchoolBuilders]

Hi all,

A builder visited my project today, notice I wasn't using "Sharpie" Brand markers. He advice I stop using "non-Sharpie" because other brand might have ingredients that damages metal. He also advice to scrub away any markings I made with the non-Sharpies and spot prime those spots.

He built his 7 years ago and I wonder if anyone heard similar information. I honestly never heard of it before, at one point, I did consider import some Sharpies as they don't sell them here in Hong Kong, but I thought about it at the time and couldn't see what harm can it do by using a different brand.

Any feedback is greatly appreciated!
Hank

[SvingenB]

Sounds like utter nonsens to me. The only thing that can damage metal is some corrosive agent or graphite. Markers are made to be safe to be eaten by babies, surely they are safe to use on aluminium.

[roee]

Originally Posted by HighSchoolBuilders

A builder visited my project today, notice I wasn't using "Sharpie" Brand markers. He advice I stop using "non-Sharpie" because other brand might have ingredients that damages metal. He also advice to scrub away any markings I made with the non-Sharpies and spot prime those spots.

That's probably a bit too paranoid. But... Consider that other similar pens are likely to be ok, but we have many years of experience with Sharpies, so we know them to be ok. If you can, find a type of pen that's available that others have used with no ill effects. Otherwise, you are doing a chemistry experiment.

Originally Posted by SvingenB

Sounds like utter nonsens to me. The only thing that can damage metal is some corrosive agent or graphite. Markers are made to be safe to be eaten by babies, surely they are safe to use on aluminium.

Indeed, graphite, metals, or non-neutral pH would be the main concerns with pen ink on aluminum. Not necessarily the same concerns for a baby's digestive system. Many foods we eat have non-neutral pH, i.e. are acidic or basic, and while they're safe for us to eat, they will easily corrode aluminum. You would be wise to keep the orange juice away from your airplane, and keep your kid from eating the Sharpie! Incidentally, while not advised, junior will also tolerate graphite better than your airplane will.

[10builder]

Originally Posted by HighSchoolBuilders

He also advice to scrub away any markings I made with the non-Sharpies and spot prime those spots.

Hank

Just use a little MEK on a cloth to remove those other marks; don't scrub!

[rv9av8tr]

Ummm.... I didn't realize graphite was an "issue" on Al??? Metallurgically, how so? I know there are issues with ink marker pens relative to chlorides, which are prohibited for high strength applications of stainless steels, due to chloride stress corrosion cracking.

[Danny7]

Originally Posted by rv9av8tr

Ummm.... I didn't realize graphite was an "issue" on Al??? Metallurgically, how so? I know there are issues with ink marker pens relative to chlorides, which are prohibited for high strength applications of stainless steels, due to chloride stress corrosion cracking.

There is a common fear of corrosion due to electrical differences between Al and graphite. It is the same idea that says carbon fiber composites against Al is bad, why you should have a layer of fiberglass over the carbon fiber.

there are some people that think it is an "old wives tale" i.e. unproven

[morlino]

Avery Tools sells Pilot brand marking pens rather than sharpies and also ships them with their RV tool kits.

http://www.averytools.com/p-67-pilot-marking-pen.aspx

Originally Posted by Avery Tools Website

PILOT BRAND.Perfect for marking on aluminum and steel for drilling and cutting.Permanent ink will not wipe or rub off easily after drying.Extra fine point.Packaged 3 pens per pack -one each:Red,Blue,&Black.

[Bob Axsom]

I have used other brands although I prefer blue sharpies - Van's training. I wash the area with rubbing alcohol to remove the marking after it is no longer needed. Personally I would sweat the effects of paranoid cleaning more than the difference in chemical composition of the marker pen inks. The airplane was completed in 2004 but I continue to modify with aluminum and fiberglass for speed. No problems due to the use of other than Sharpie marker pens.

Bob Axsom

[jtop]

Usually if you look closely and read on the packaging it should say "Archive Safe." This is suppose to mean that the ink is Ph balanced and safe for delicate documents and what not. I'm sure its good enough for sheet metal.

[Kmacht]

Sharpie or non sharpie shouldn't matter. This probably comes from the issue of chloride in the ink. The chloride will react with certain metals which can cause cracking over time. Typically you have to watch out for stainless and titanium used in high stress or high heat applications. Aluminum isn't one of those metals. Most sharpies have chloride in them. I haven't actualy found one in any color but black that is certified chloride free. If you wan't one that is chloride free the sharpie will usually state that it is T.E.C. certified right on the pen next to the name.

Keith