Screen Printers Open - A Forum for Screen Printing and Embroidery

Im a newbie but have good skills in other areas. My project is to screen print labels on a circuit panel for a homebuilt airplane.  The metal has been powder coated in a matte black finish and the lettering will be white. 

I purchased an EZprint Hi-Res screen printing kit w/ Jacquard Professional Quality #118 White ink.  It took awhile but after a few attempts I am getting great screens and the printing looks good.  All of the print areas are small and the 4x5 hi-res screens are adequate.  So I'm feeling pretty good.

Today, about a week after printing, I took one of my practice plates and attempted to scratch the ink off with my fingernail to test durability.  I was surprised how easy it came off.  From instructional videos I did heat set the ink with a hair dryer but did not know how long or how hot to get the ink for heat setting.

My questions:

Did I use the wrong ink?

Is there a spray 'fix' that will protect the printing?

What is the correct heat set process?


Please keep in mind this is a one-off personal project with a tight budget.

Thanks and thanks for being here!

Im a newbie but have good skills in other areas. My project is to screen print labels on a circuit panel for a homebuilt airplane.  The metal has been powder coated in a matte black finish and the lettering will be white. 

I purchased an EZprint Hi-Res screen printing kit w/ Jacquard Professional Quality #118 White ink.  It took awhile but after a few attempts I am getting great screens and the printing looks good.  All of the print areas are small and the 4x5 hi-res screens are adequate.  So I'm feeling pretty good.

Today, about a week after printing, I took one of my practice plates and attempted to scratch the ink off with my fingernail to test durability.  I was surprised how easy it came off.  From instructional videos I did heat set the ink with a hair dryer but did not know how long or how hot to get the ink for heat setting.

My questions:

Did I use the wrong ink?

Is there a spray 'fix' that will protect the printing?

What is the correct heat set process?

I would say if the ink required heat to cure it then it was the wrong ink for printing metal. Also curing with a hair dryer will not cut it. You would be better off sticking it in you kitchen oven set at 350. Just get ready for the stink.

The only thing I can suggest is spraying a clear coat epoxy over it but like Johnny said, your ink may not be compatible with a clear coat.

In the future I would suggest using an ink from Nazdar that is made for what you are printing. A call to Nazdar and they can tell you which ink to use. Here is there substrate chart.
<a href="http://www.nazdar.com/Nazdar_Ink_Chart.pdf" target="_blank">http://www.nazdar.com/Nazdar_Ink_Chart.pdf</a>

We print on a lot of weird stuff like that but never powder coated. Most of these items we use the Nazdar solvent based, air dry inks, best to contact them to see what they recommend. But for a one shot or low qty job regular oil based paint should work fine like Johnny said. You could also use a good sign painters ink. The item must be clean and oil free. You also need to work quickly so the ink doesn't dry in the screen and clean up has to happen right away or you will loose the screen. Paints and solvent inks will adhere better to metals that are warm, above 70 degrees.

Another option would be to have plastic or stainless plates engraved. You can apply a double sided tape to the back (it needs to be thick in order to stick to the textured surface of the powder coat), then secure it with a couple of small screws. Local engraving shops will be able to make them up or you can visit  http://www.bereng.com/custom.htm

I am printing on all kinds of metal substrate on daily basis and I can tell you that it is easy if you choose right ink.
Best ink in my opinion, for that kind of printing is Maraby. German ink, beautiful formulated, you just can not go wrong with it.

http://www.marabu-northamerica.com/

For powder coated metal you have to use two component ink (ink + catalyst)
There are two kinds from Marabu range

Glass ink

http://www.marabu-northamerica.com/products/product-overview/screen-printing-inks/detail-view/products/Glass%20Ink-126.html

and ink for metal

http://www.marabu-northamerica.com/products/product-overview/screen-printing-inks/detail-view/products/Marapur-143.html

My advice is to use ink for glass (GL) as it is drying harder and has better scratch resistance.

After printing you have to put in oven for 1/2 hour and set recommended manufacturer temperature.
When you pull out leave it to cool down and it is ready for delivery.

Two component inks you can leave printed for about week to sit and it will harden up. I would not recommend you to do it as it will never be as hard as when you put in to oven.
Reason is humidity that is degrading catalyst mixed in ink over the period of time you live to air dry. Catalyst does not like humidity.

Also, if temperature dropped under 15 degrees C it will kill catalyst and whole process of bonding to the metal.

If you are lazy, and can not be bothered to take them to the owen you can use heat gun to cure them. You will have to go over them few times and make sure that each time they get so hot that you can not touch them.

Also, if you are overprinting two component ink, make sure that first layer is not completely cured before you overprint it.  Otherwise, second layer won't stick.

Just try it and you will be amazed how easy it is