Blue Powder Coating Not Coming Off

[Cody Greene]

I am having tons of trouble trying to engrave blue powder coated cups. I have a customer that has brought 2 different cups in for me to engrave and I keep getting the same outcome which makes me wonder if it's my settings. I have a Gravograph LS100 35w laser. The attached picture is 100 power, 35 speed and 300 dpi, 3 passes, wiped down with DA and a magic eraser. I have tried higher DPI with the same power and speed on a different cup but still got a haze and end up "scorching" the metal. Anybody got any suggestions?

Thanks in advance

[Kev Williams]

Acetone will work much better than DNA, BUT, I suggest hitting your local grocery store to get some 'watered down' acetone, aka "nourishing" fingernail polish remover. Every store around here has a generic version of it. Pure acetone only has a working life of about 2 seconds before it starts attacking the surrounding coating, the FPR is much more forgiving, and still gets the goo off...

That all said, I've ran into several colors, that blue, white, some oranges, that just plain refuse to be vaporized. In those cases, I shoot for a consistent look and call it a day. The one in your pic is VERY consistent, if you can do that all day call it a win. Before you do a bunch, have your customer examine, and explain that 'this is as good as it gets'. I have several customers who bring me Hydroflasks and SIC cups regularly, and they're perfectly happy with how they look. :)

--and for what it's worth, I don't think you scorched the metal, what you likely did was scorch the residue...

[vic casware]

I have a similar issue with Blue or Red Stainless drink bottles
I found running the or dipping in hot water then immediately
cleaning with one of those spray kitchen cleaner products
and rubbing while it's still hot works most of the time,
i find it worse on some batches but not all.

[Cody Greene]

Didn't think about trying finger nail polish remover, I'll have to grab some and see if it helps any. The customer said they don't mind so guess I am good to go. Thanks for your reply

[Cody Greene]

I will have to give that a try and see if it helps, thanks alot

[Scott Shepherd]

We have engraved a lot of powder coating over the years. We were doing a product for a customer that is repeat business and we had it all dialed in for each color (each color engraves different). Then they changed powder coating suppliers. It now takes almost double the passes and once it's done, it's never what appears to be right down to the metal. For an experiment, I ran one piece for an hour once. At the end of it, it still had a terrible haze on it. I've never seen anything like it. I don't know what the physical difference is, but there is certainly a substantial difference in the 2 products. I suspect one vendor is using lower end powder and one vendor is using a higher end powder with different bonding agents.

Powder coating is an odd thing to engrave. It varies so much by color, thickness, apparent manufacturer of powder that it can end up taking long enough to get it down that it's not worth the time. Kind of hard to charge enough to run 5 passes on a stainless tumbler.

[Kev Williams]

The last SIC cups I got (1ea of 5 different colors) the white cup actually left a powdery gray ash, not unlike the aluminum leftovers when fiber etching black anodized, and no clean base metal when done. So yeah, I have to agree there's something going on with certain powder coatings...

[Harvey Lentchner]

With some plastics, notably the red and blue, residues seem to be left. It is not really a residue, it is a redeposit of the color that does not burn in the laser.

Try in an inconspicuous place first to be sure it does not affect the coating. (It should not, but safety first.)

Get some DOT 3, NOT DOT 5, brake fluid. Put a minimal coating of it on the mug. The thinnest amount you can. It will prevent the color and ash from sticking back on when lasered.

I use this for plastics, it should do the same job here.

Harvey

[Mike Null]

Harv

Good to see you post here. Our friend, Joe Hayes, recommends Zep 505 from Home Depot in combination with a Magic Eraser.

I'll be doing an order of black Yetis this weekend so I'll let you know my results.

[Doug Fisher]

Definitely give Kev's suggestion a try (thanks, Kev!). It really cleaned up a blue tumbler for me last night and got it true silver instead of the partially blue similar to what you have. I did a first pass with a paper towel + nourishing nail polish to get the major gummy off and then had to come back with a generic magic eraser pad wetted (sp?) with the nourishing nail polish. This latter step took a bit of rubbing but then it revealed the nice silver base of the stainless steel. I didn't notice but a little bit of very, very slight cloudiness on the power coating in a few areas. This was easily corrected with a full cleaning of the tumbler with Fantastik, letting it fully dry and then doing a quick light buffing with a virgin uncontaminated magic eraser pad.

I better be clear that the testing I reference above was done on Ozark Trail/Walmart powder coated tumblers that have a matte/pebble finish. I haven't tried it on high gloss coatings.