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17:47 Jan-09-2010
David Bunch
What is the best instrument for writing through couplant?

As the title implies, what is the best writing instrument for marking through couplant when doing ultrasonic testing? I've used mechanical pencils (don't show up well enough), paint markers (smudge), pens (doesn't mark), soap stone (makes marks too wide). The only thing I've had a moderate amount of success with is fine-tipped permanent marker. When it does manage to make a mark I can see, it can easily be cleaned away with rubbing alcohol.

But is there a better marking instrument?

 
19:50 Jan-09-2010
Michel Couture
Re: What is the best instrument for writing through couplant? In Reply to David Bunch at 17:47 Jan-09-2010 (Opening).

David,

One thing you have to consider when you want to write on metals during UT inspection is to see if your markers are compatible with the process. For example, many of my clients are doing work which will is classified as "Nuclear Work". In this case, although not the best because of smugging or width of the marker; you still have to use markers that are "Nuclear Complient".

If you do not this problem to contend with; I would suggest watercolor pencils from Staedtler. They work very well with couplant. On thing though, once you are done with it, wipe the couplant of the lead, otherwise it will go soft on you and smudge. Those are a little expensive especially if you it comes out of your pocket.

I've also used different coloring crayons. They work well too. You jsut have to find the ones that you like. The beauty is that you can have a variety of colors. I normally keep some whites, reds and yellows dependinf of the background.

Try to find a store selling painting supply for artist. Ther you'll be able to buy crayons as a single units.

Cheerio's

 
20:09 Jan-09-2010

anjafo

NDT Inspector
Norway,
Joined Aug 2009
204
Re: What is the best instrument for writing through couplant? In Reply to Michel Couture at 19:50 Jan-09-2010 .

cracking question :)

I used those paint markers that look like a pen, usually white or yellow. I forget the brand name.

They do smudge but if you slow it down a bit and let them dry they usually work ok. Plus slowing down always helps in UT inspection.

 
22:09 Jan-09-2010

CIRO

NDT Inspector,
D.e M.I. srl,
Italy,
Joined Oct 2009
86
Re: What is the best instrument for writing through couplant? In Reply to David Bunch at 17:47 Jan-09-2010 (Opening).

test with wax crayons
ciao

 
04:38 Jan-10-2010
Jawahar B. Goradia
Re: What is the best instrument for writing through couplant? In Reply to CIRO at 22:09 Jan-09-2010 .

Glass-marking pencil (wax crayon - different colours) works particularly well with oil-based couplants.

 
12:40 Jan-10-2010

anjafo

NDT Inspector
Norway,
Joined Aug 2009
204
Re: What is the best instrument for writing through couplant? In Reply to Jawahar B. Goradia at 04:38 Jan-10-2010 .

they do work well through liquid or couplant but they are a real pain to work with.

 
13:29 Jan-10-2010

Joe Buckley

Consultant, ASNT L-III, Honorary Secretary of BINDT
Level X NDT, BINDT,
United Kingdom,
Joined Oct 1999
512
Re: What is the best instrument for writing through couplant? In Reply to anjafo at 20:09 Jan-09-2010 .

Chinagraph pencil.

(Wikipedia says they are called grease pencils elsewhere in the world.)

 
14:57 Jan-10-2010

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1197
Re: What is the best instrument for writing through couplant? In Reply to Joe Buckley at 13:29 Jan-10-2010 .

Joe...I think you used the same "sort" of marker we did (in the old days). We called them China Markers...I liked them because it had a peel off wrapper that was easy to use when your hands were messy with couplant
http://www.sharpie.com/enUS/Product/Sharpie_Peel-Off_China_Marker.html
The wikipedia location is more general but a good illustration of the item
http://en.wikipedia.org/wiki/Grease_pencil

 
22:59 Jan-10-2010
J Mark Davis
Re: What is the best instrument for writing through couplant? In Reply to David Bunch at 17:47 Jan-09-2010 (Opening).

The China Marker is a good tool. One of the items we use in my UT Class is a ereaseable board marker with a fine point. They are water based and will mark through the couplant. And is easly removed after the inspection is complete. But, they will gunk up depending on the couplant used.

Another thing we use is magnets. There are inexpenvise magnets which have plasrtic caps which can be marked upon. There are small ones which can be used to mark the stop and start on an indication. Notes or remarks on the suspect area may be written outside the couplant area.

Of course if it is non magnnetic that blows that idea.

One important thought: Is is the marker of choice approved for writing on the component? What about Chlorides, etc.

I hope this helps.

Mark Davis
University of Ultrasonics

 
22:55 Jan-11-2010
David Bunch
Re: What is the best instrument for writing through couplant? In Reply to David Bunch at 17:47 Jan-09-2010 (Opening).

Thanks for all the advice. I've tested out the china markers (we call them grease pencils) and water color pencils today. The water color pencils work extremely well. I'll have to try the dry erase markers and magnets.

Yeah, the chlorides in permanent markers and paint markers have been well explained.

 


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