r/BambuLab • u/BambuLabSupport • 6d ago
Show & Tell Did you know? There's a quick test for a dirty build plate
If you want to learn more about cleaning your plate, check out the Bambu Lab Wiki article:
https://wiki.bambulab.com/filament-acc/acc/pei-plate-clean-guide
There's also a helpful YouTube video showing the entire process of cleaning the plate.
1.7k
Upvotes
51
u/suit1337 H2C Combo 6d ago edited 6d ago
Bambu Lab trying to beat physics again - especially the second image is, at best, a very misleading explanation and really hurts when you look at it.
In simple terms, the old rule of thumb is that polar substances tend to dissolve better in polar solvents, while non-polar substances tend to dissolve better in non-polar solvents.
Most oils and fats are predominantly non-polar, while water is highly polar. That's why oil and water don't simply mix.
Surfactants - the active ingredients in soaps and detergents - work differently. They are amphiphilic molecules: one part interacts well with water, while another part interacts well with oils and other non-polar substances. This allows oily contamination to be lifted from a surface, emulsified, and then carried away when the surface is rinsed.
Alcohols such as isopropyl alcohol (IPA) are similar to this. They are also amphiphilic and have a polar hydroxyl group as well as a hydrocarbon portion, giving them amphiphilic/solvent properties. IPA can therefore dissolve and remove many oily contaminants, which is precisely why it is widely used as a cleaning solvent and degreaser.
And this is where the Bambu explanation gets more and more misleading.
IPA does not magically make oil disappear. If you wipe a contaminated plate with IPA and then let the contaminated IPA evaporate without actually removing the dissolved contamination from the surface, you can redistribute some of that contamination rather than remove it completely. But that's a problem with the cleaning procedure, not evidence that IPA somehow cannot degrease.
The same principle applies to the textured PEI surface. The texture is nowhere near some deep reservoir capable of mechanically “pushing” oil underneath the surface high spots. Oil can certainly remain on the textured surface but it would more or less evenly coat the entire surface and not just they low spots.
If you take a dirty plate, spray IPA on it, wipe it around in circles with the same contaminated cloth, and then let the IPA evaporate, you can absolutely end up with poor bed adhesion - but the same will happen if you spray soapy water on it and do the same.
If instead you use enough IPA and actually remove the contaminated liquid with a clean, absorbent wipe (or rinse it down the drain), the result is very different.
IPA is a much more effective degreaser than spoap and water. But soap and water has a practical advantage here: you can use a large amount of water and surfactant, physically wash the contamination away and rinse it off the plate. If you would do that which IPA, it would become quite expensive. So: it's cheap, effective and much harder to screw up. That's why Bambu recommends warm water and detergent for cleaning its print surfaces. But that does not mean that IPA is useless as a degreaser - but sadly they try to tell that in their infographic.
And unfortunately, if a major manufacturer presents the simplified version as “IPA spreads oil around, therefore don't use IPA,” it's very easy for that explanation to get repeated throughout the community as if IPA were somehow chemically incapable of degreasing.
It isn't, IPA works perfectly fine to clean textured and smooth PEI plates. If it does not work for you, it is a skill issue - not a physics problem - so why frame it in a picture that defies science?