Sanding question

[Welaara]

Hello everyone!

I have decided to redo my Mandalorian costume and ran into a strange situation. When I first started sanding my 3D print I had no issue. As I have painted it and now re-sanding, I'm having issue getting the paint off. It starts to clump and has a sticky texture. I have attached a picture to show what's going on.

This is my first build ever and have no idea what's I'm doing haha. So I was wondering if anyone knew what is causing this difficulty getting this off. Did the paint not cure all the way when I put it on or is the normal? I would like to avoid this in future builds. Thank you for your time!

Sincerely Welaara

 

[Electraknite]

Might not be totally cured, or it might just be melting. If it’s not cured you should let is be for a day and come back to it or use paint stripper, (maybe acetone but 3D prints don’t usually like it) but make sure the plastic of the helmet won’t react badly first or use a knife and scrape it.
If it’s melting just leave it for like 20 mins and check it again.

You might also try changing your sandpaper to a lower grit. My guess it it’s getting pretty clogged from sanding that.

 

[TurboCharizard]

What kind of paint did you use originally?

 

[PlanetAlexander]

There's another couple of things that could be an issue:
1. Did you make sure to completely clean the surface of any dust or dirt before painting? A good way to do so is with isopropyl.
2. If you were printing in cold temps, it's a good idea to leave the can submerged in a bucket of warm water for about 10 minutes to break up any chunks of paint inside, and of course, make sure to shake it well.

(maybe acetone but 3D prints don’t usually like it)

I think that a number of filaments, or at the very least PLA/PLA+ don't react to acetone - at least that's what I found when looking how to smooth PLA prints more easily. Probably best for someone to fact check that before going with it.

 

[MrBlueDot]

I think that a number of filaments, or at the very least PLA/PLA+ don't react to acetone - at least that's what I found when looking how to smooth PLA prints more easily. Probably best for someone to fact check that before going with it.

PLA should be safe with acetone. PLA+ most likely won't be, alot of those filaments are PLA mixed with ABS. Definitely don't use acetone on ABS, unless you are looking to weld pieces together or are trying to smooth it with acetone vapor. Acetone melts ABS, and can cause micro fractures through out the entire plastic piece.

 

[Welaara]

Thank you all for the advice. I am not sure how it was printed since I didn't print it myself. I first cleaned it with a sticky cloth (used for paint) and then used a primer. I let that sit for one night. Then I used a glossy black spray paint and did two coats and between each coat I let is sit for 2 hours in the sun. Overall it might have been a little bit rushed on drying but it felt dry by touch.

Another thing that might have affected it was the majority of the bucket was in a vinyl car wrap. But that had one week before the vinyl was put on. My other parts of the same material, same technique, and same drying period did not have this issue. However it did have more heat exposure due to issues with the vinyl.

I worked on it a little longer and the print does not seem to have been damaged. The paint would bundle up and (to best describe it) looked like eraser fragments.

The acetone works well with my material and I am mixing it with bondo to make a fine covering to fix the ridges.

Once again thank you all for your words of wisdom and I will see which one will work best.

 

[PlanetAlexander]

Glossy paints usually take a while to dry properly. Do you know if it was enamel?

Definitely don't use acetone on ABS, unless you are looking to weld pieces together or are trying to smooth it with acetone vapor

Whoops, thanks for mentioning that, meant to say it myself

 

[Welaara]

Yes, I think it was enamel.

 

[PlanetAlexander]

Yes, I think it was enamel.

Ah yea, the problem with enamel is that it can take weeks to cure properly, so it's best to avoid it unless you know you have time for it to dry all the way. Don't worry, I made the same mistake multiple times when first starting to use spray paint!