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Having solved the warping problem, and (apparently) the odd pattern problem with my first layer on PEI, I now have something new… This is Black ABS and while the surface is lovely and smooth and warp free, there’s very obviously discolouration. The bed was perfectly clean before printing, and this wasn’t the first print with black so I don’t think it’s contamination (although I can’t be 100% certain - the previous filament in that nozzle was white).

Anyone else seen this, either on PEI or any other bed?

discolour.jpg
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Still looks like contamination! I get this look when using glue stick.

What was the solution to the first layer pattern problem? Maybe you posted that elsewhere and I haven’t gotten that far today.

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I’d agree with you - if I were using anything on the bed, but I’m not, and never have. This is the bed as delivered, I’ve never used any adhesive (spray, stick or slurry). It’s probably hard to tell from the photo, but the stain is very “organic”; it looks like a liquid spill and really isn’t related to the lines of filament laid down at all - it does look exactly like there was a spill on the build plate that dried, then the print was on top of it, but there wasn’t…

The pattern problem seems simply to have gone away. The last two prints to come off haven’t shown it - and I’m back to using the same filament I was before. I’m wondering if it was the particular section of filament.

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I don’t think you would get this type of organic stain from the filament. Does this stain wash off of the part with say alcohol? Did you clean the PEI bed before printing. I’ve seen this type stain on a injection molded part when we sprayed something like mold release on the mold before molding a part.

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Hi @jfield I’ve not tried alcohol (mostly because I don’t have any that isn’t for drinking purposes), what would you recommend? Rubbing alcohol or something?

I’ve just completed a second print and compared to the first the pattern of “stain” is completely different. The models were printed with the same settings, in the same location and orientation on the bed which strongly suggests it’s not something “on” the bed (and, of course, I’m adamant that I’ve never used any adhesive on this new PEI surface). It’s very strange.

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Yes I was thinking of Isopropyl alcohol, sometimes called rubbing alcohol. You should test first tho on the material. Have you tried checking with a straight edge to see if it is ‘sink’. If you see a gap, then it could be pulling off the bed during printing.

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It is stress on the print. Take a piece of abs and bend it, you will get white marks from the stress. A heat gun supposedly can heat it a bit and clean it up. Its more noticeable with black since whit shows real easy

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Hi @keebie81 YOU STAR!!! Just ran a hot hairdryer over the print pictured (which I thought was trash because I couldn’t use it) and the marks magically vanished!!

I can’t thank you enough! Shout it from the rooftops!

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As you don’t have any “non drinkable” alcohol at home try instead of cleaning the Bed with window cleaner or any other solvent of that kind… Try it with IPA (isopropanol Alcohol) or even ethilic alcohol (mostly used in medical stuff).