Sharpies and Sheetmetal

[angzt]

Today someone came complaining to me how a sharpie was used to write installation notes on a painted piece of sheetmetal. It was just simple arrow to help with orientation. Their argument was "It stains the paint and it is corrosive."

The only writing instrument I was taught to use in school for all sheetmetal work was with sharpies, then you just rubbed it all away with isopropyl alcohol.... am I missing something here?

 

[djwyman]

since when is a sharpie corrosive?

 

[metaleltr]

As a bodyman I would rather see a peice of masking tape applied to the part, then write on the tape.

 

[kd3pc]

many times, especially with today's paints....the residual marks will be seen in the paint, in specific light and shading.

It would appear that alcohol is not entirely removing the marks. As an old guy, when we HAD to mark a surface, we used crayon or grease pencils. Again depending on the material we were marking and the finish to be applied, there would be bleed through.

I have seen this two or three times on body panels, as finished "new" from the factory. In two of those cases, the manufacturer replaced the vehicle. The third case went to arbitration and I was not privy to the outcome.

Best bet.....do not mark any surface that is to be finished.

 

[shawnspeed]

Son in law is an aviation mechanic, and makes lots of sheetmetal replacement parts...they CAN NOT use #2 pencils or SHARPIES....I told him that is all I ever used...said all they could use was grease pencil, or pen if the material was covered in protective plastic...But yes, I have noticed bleed thru with sharpies...

 

[NUTTSGT]

I'm guessing the subject of this is auto body sheet metal and not duct work ?


I remember years ago, guys talking about using grease pencils. I think Sharpies became more prevalent when they became more popular, finer tip and seemed to show up better on a variety of surfaces.

I started a thread on them at one time. . . .


Edit: here's the link to the thread I started. I'm not sure if anybody talked about any stains left behind by them.


http://www.garagejournal.com/forum/showthread.php?t=127897

 

[bad_idea]

It takes less effort to stick some tape on the piece and write on that rather than try to clean the sharpie off the part or cover it up. Been there, dealt w/ that.

 

[Tinner]

Sharpies will strike through a lot of paint. Depends on the metal, paint and primer used. At the sheet metal shop where I work they ask us not to use them, or wipe it off with lacquer thinner before sending it to paint. On jobs that ship unpainted, the same. If it's near a weld and baked on, you often have to take a Scotch Brite disc or fine sandpaper to remove it.

 

[MoonRise]

Standard black Sharpie marker?

For me, alcohol doesn't remove all the ink mark. Acetone does though. But you don't necessarily want to be putting acetone all over a primed or painted part.

Don't want to leave a mark or have to deal with trying to remove the mark? Put a piece of 'painter's tape' on the piece and make the mark/note on the tape. A quick wipe with a solvent compatible with whatever finish is on the part will remove the possible adhesive residue.

Except if you are welding or otherwise using some high-temp process (other flame like a brazing/cutting torch or a plasma cutter or the like), in which case you can end up with all sorts of crappy burnt residues from whatever got 'heated'.

Also watch out for idjits writing/marking on top of a painted surface with a pencil or a ballpoint pen. The tip can scratch or make an indent on the paint.

 

[machine_punk]

For those of you who need to use sharpie on metal, try using 99% isopropyl alcohol to remove it, instead of 70% isopropyl alcohol. Both are readily available at the pharmacy and it is very environmentally friendly.

I use the ultra fine sharpie on my aluminum (unfinished) all the time...70% won't take the mark all the way off, but 99% will. (But I've never tried to paint over it before, either).

Kev

 

[rlitman]

Son in law is an aviation mechanic, and makes lots of sheetmetal replacement parts...they CAN NOT use #2 pencils or SHARPIES....

Pencils are a different issue. Galvanic corrosion from the graphite on the aluminum sheeting can lead to stress corrosion cracking.

For those of you who need to use sharpie on metal, try using 99% isopropyl alcohol to remove it, instead of 70% isopropyl alcohol. Both are readily available at the pharmacy and it is very environmentally friendly.

The pharmacies carry 70% and 91% alcohol. 91% is the concentration that it forms an azeotrope with water. Above that it gets expensive and isn't much better.

Anyway, denatured alcohol is a better sharpie solvent, and is far cheaper than isopropyl too.

 

[brucer]

We had an offsite R&D lab for a large tractor trailer rim manufacturer... We were told by their engineers to stop using sharpies on the unfinished rims because it was actually promoting stress cracks in the rims when they were being load tested...

 

[kazlx]

Uh, I wouldn't be writing on a finished painted surface. Is it that hard to use a piece of tape? Raw metal, who cares.

 

[Bouchard93]

I work at a manufacturing company that makes a lot of parts for Nissan I use a sharpie to write on my parts that I check every hour but then again they get thrown in the scrap hooper. there are 2 parts everyday that are good and put in the good parts container that is mark on with a sharpie? .... (among all of the other co workers)

Note that the parts, I am talking about next operation is max coating. these are gas tank straps, radiator supports, battery tray ect. nothing real visible after the car gets assembled.

 

[paul2112]

We have special sheetmetal markers at work for aircraft sheetmetal,,,,look like a sharpie ,but cost about 10bucks each

 

[Nick Danger]

Pencils are a different issue. Galvanic corrosion from the graphite on the aluminum sheeting can lead to stress corrosion cracking.



The pharmacies carry 70% and 91% alcohol. 91% is the concentration that it forms an azeotrope with water. Above that it gets expensive and isn't much better.

Anyway, denatured alcohol is a better sharpie solvent, and is far cheaper than isopropyl too.

Alcohol is usually denatured with acetone. Make sure your surface won't be affected by the acetone.

 

[dieselgarage]

I have had Stainless Steel parts that were wrote on with a Sharpie pen, beadblasted then Electropolished and had the writing show up on the finished part. Part of the Electropolis process is a passivation step, basically an acid wash. We now have rules on Sharpies in the shop.

 

[rlitman]

Alcohol is usually denatured with acetone. Make sure your surface won't be affected by the acetone.

There are dozens of denaturing processes. Methanol, gasoline, isopropyl alcohol, MEK, and ethyl acetate and denatonium are other common denaturing agents that come to mind. Acetone too.

I have had Stainless Steel parts that were wrote on with a Sharpie pen, beadblasted then Electropolished and had the writing show up on the finished part. Part of the Electropolis process is a passivation step, basically an acid wash. We now have rules on Sharpies in the shop.

Sharpie is shellac based. Beadblasting will not necessarily remove all coatings. It should be chemically removed before electropolishing.

 

[USAF.Kyle0617]

I'm a sheet metal mechanic, and we use sharpies on metal painted or bare. Some things to note are that the actual sharpie brand is used, and not some imitation. Also, if there is an issue removing the mark totally, use a dry erase marker over the sharpie and then wipe clean, possibly using alcohol again.

 

[dieselgarage]

There are dozens of denaturing processes. Methanol, gasoline, isopropyl alcohol, MEK, and ethyl acetate and denatonium are other common denaturing agents that come to mind. Acetone too.



Sharpie is shellac based. Beadblasting will not necessarily remove all coatings. It should be chemically removed before electropolishing.

You would think the acid bath would remove it. But guess not.

 

[Heavy Metal Doctor]

In any of my machinery fab / welding jobs, I use Sharpies all the time, but I do go back over and remove it with lacquer thinner on anything that will get a finish painted. I have had it bleed through and learned my lesson.

 

[89GLH]

I'm a sheet metal mechanic, and we use sharpies on metal painted or bare. Some things to note are that the actual sharpie brand is used, and not some imitation. Also, if there is an issue removing the mark totally, use a dry erase marker over the sharpie and then wipe clean, possibly using alcohol again.

This. I had the same thing happen with another jobsite I was at, and dry erase then alcohol took it all off. No clue why, just did. And no I dont care about the science of why.

 

[Jere]

I don't like sharpies much because the marks disappear when I cross them with the oxy/ace torch unless it is the high temp sharpies those are nice but hard to come by.

When I worked retail there would always be some **** that would write something on the bathroom doors when I got stuck cleaning them. I just coated the writing with hand sanitizer (like purell) and let it soak a couple of minutes. Didn't hurt the paint and left no sign of the marker.

 

[ZRX61]

I use sharpies for aviation sheetmetal all the time.... but there's masking tape between the metal & the ink

 

[mrobins297aaa]

in years of installing ductwork we always tried to keep the writing on the inside where ever possible, you get tired of hearing the painters whine about the marks bleeding thru and I don't blame them. I think they use to have to cover the writing with a coat of shellac first...........if not it bleeds right thru big time.