Finishing 3D prints - Filling and sanding print lines for props 

I appreciate how you not just explain key points but also demonstrate (e.g. acetone effect on solo cup). These nuances set your video far above others. Well done!

This channel is criminally underrated. This is easily the most comprehensive video I've seen on finishing printed parts

I had no idea the vid lasted that long, this is how a tutorial vid should be. In depth and to the point, with actual demonstration of it.

Commenting just because this was worth the watch and deserves the engagement, thank you.

Tired of seeing RU-vid shorts. I love long firm videos like this where i can really absorb a lot of information. Thank you so much for this!

That acetone-bondo mix is genius - I don't know how I didn't read up on that anywhere else earlier! Very informative

I really appreciate you showing us the full process and technique. Most RU-vidrs only show the interesting parts and cut out the labor intensive sections. This is how it’s really done.

I just ordered my first bed slinger so, I'm benging vids like this. Thanks for the info and the insperation.

Dude, this may be the smartest video I’ve seen. Thank you for all the details and especially for not sounding like the other RU-vidrs (annoying).

the water in wet sanding basically become like lubricant, it make the sanding more smoothly, and the grid come down a little too, but I agree, it keep dust away, making it more effective and literally smoothing out the sand, making you you less likely getting scratch on your primer, hence smoother finished, also this channel is super underrated

Worth the hour of time. Thank you for being thorough. Excellent tutorial.

The Bondo technique is a great way to get it done. I am a woodworker and use a similar techniques with grainy woods, especially Red Oak. I mix drywall mud with water to a pancake batter consistency, then paint it on the wood. After one sanding, the grain is usually filled and once painted, the appearance is perfectly smooth. Great video!

Thanks again Colin for taking the time to document the processes you employ! I wanted to offer two additional tips in sanding if you or someone else wants to try it out. 1) for wet sanding try adding a drop of dish soap to your water and the sand paper will glide over the surface and keep the paper even cleaner. This especially works well on the higher grit numbers like 600+ And 2) I use a sanding sponge or even a scrap of EVA to wrap the paper around so you don’t accidentally get finger marks in surfaces. The soft eva will contour to the surface well. Happy crafting!

Got me thinking that I need to look through my pieces again. The bondo paint concept is a really solid one, and it looks easy to do. Thank you for this tutorial.

Hope you’re doing well man. Thanks for the knowledge dumps. It really helps out newbies like me. Greatly appreciated

Couple of ideas for you. 1) debuting tool for edges 2) heat gun or little flamer burner will reduce a lot 3) seems on some parts you can force the seem to inside of part. 4) Variable layer near the top Leila save stair casing 5) increase top and bottom layers so you don’t blow through Into infill when sanding 6) use acetone with abs to make a glue or use acetone to glue abs parts directly - abs welding

Just a few suggestions/observations for consideration. My current method is to give the part a quick sand with 120grit to knock down any real high spots. I then do a fairly light spray of filler primer. In my experience filler primer will gum up sandpaper if you don't allow it to cure. If you sand too early, the primer is quite soft, but a day or so later it wet sands without any gummy residue or buildup. I sand my initial primer layer down to where I can see the original print. I do this because as the name suggests it is filler primer. Spraying on primer really thick may fill, but the more product you put on the more you change the dimensionality of the part. In my opinion you want the filler primer to fill the layer lines, but only to where the low and high peaks are equalized. Minimal material. Then, I go in with the Bondo. From what I have read, Bondo is actually quite soft even when cured. The function of the product is actually to fill in "spots" of scratches and such. It isn't really designed to fill in deep lines. I suspect a 2-part bondo is more appropriate for this. Using the Bondo as a spot putty means I don't have to use much of it. Only where things are deep are where I need to concentrate it full strength. After drying for a few hours I wet sand this (to keep dust down). Then, I go over the part again with a few thin layers of filler primer. I wait a day or so then wet sand it down with 400 grit. I usually burn through in a few spots, but it is okay because at this point it is quite smooth. I check once again for any parts that might need Bondo, then hit the part with the final few light layers of primer. After a day or so, I wet sand with 800 grit very lightly just to get it all smooth. I try to avoid burning through edges. I find doing it this way wastes way less product. It also avoids filling detail with Bondo/paint that needs to be sanded out or sculpted out with a tool. As mentioned, I also don't think thick applications of Bondo are the most durable, so I try to keep the product(s) just thick enough to bring the low spots and high spots to the same level. Finally, it seems to cut down on added weight. Lathering on product adds a lot of bulk to parts which adds up over the entire costume/prop. There are of course hundreds of methods and I think the one in the video is great. But, perhaps someone might try the method I outlined above to see if it works.

What an AWESOME video. It seems like people don't like to show us how to do this stuff because it's like a trade secret. You did an awesome job and made it seem simple and like anyone can do it. And they can now that you've generously shared your technique. THANK YOU again.

got my new Stormbringer bucket in the other day.. cant wait to sand.. lol

Really great stuff man. I don't know if I'd ever make props, but if I do, I'm subbed and know right where to go!

Ok, underrated, must subscribe, many thanks...

This has to be one of the best ways I have come across to smooth out lines. Thank you!

I don’t know how you weren’t in my recommendations before now. I watch Van Oaks, Smugglers Room and all those guys 🤷🏽‍♂️. I’m subscribed now though!

Good to know . Going to try it out 😊

I am follow8mg all of your tips and tricks for a Fallout NCR Ranger helmet. You have been a great help. Keep up all the great work you do!

Subbed. I didn't realize it was an hour video lol it went by so quick. Thank you for the awesome tips.

Man, this is the masterclass in finishing! Thank you for the awesome video, wisdom and knowledge. 🙏

As always, the GOAT of props!!!

Hello! Thanks for the great instructions. I'm currently in the process of making my first helmet and am grateful to have found your tutorial. This way I don't have to make some mistakes myself and the result will certainly be better!

I had no idea you could water down Bondo, so thank you for that. Side note, PLEASE wear a mask when you're working with that stuff, especially sanding, you do not want that in your lungs. Thank you for the help.

When I finally used the right sanding paper I was so happy 😂 Good paper makes the difference!

Thank you so much for the details. I am starting down this path to learn and this is one of the best videos I have seen!

Glad youre ok and back in the shop... We love you brother

For your initial trimming you might try a cabinet scraper - i think they work much better than a blade

Great info.

Very cool. This is going to help out my mando build for my son.

This is the way.

Thank you for the tutorial! You explain things that's easy to follow 👍

Very comprehensive and detailed tutorial. This helped a lot. Thank you

This is a great tutorial. It too have tried everything and settled on a process that is basically exactly this. Occasionally I'll apply a layer of XTC-3D before doing a final wet sand/primer/wet sand. Doing this makes the surface a bit more scratch resistant since the bondo and filler primer are both so soft.

Great tutorial, Colin! Happy to see you in the shop and hope you're doing well!

Excellent resource and video, as always!

Thank you so much!

This is such a perfect video, im about to be starting on my first 3d printed prop and this video is gonna be such an amazing help

I love your workshop! Looks awesome!

Always good stuff. Thanks for another helpful video. 👍

Awesome video! I have been doing nearly the same process, but hadn’t thought to thin the Bondo and brush it on. Definitely going to try that!

One of the best start to finish... finishing videos I've found. A good friend is printing me a full size 40k chainsword, and it will be my first attempt at this type of finishing and painting. I will be rewatching this several times in preparation. Any tips or videos you could point me at for painting small details that will require brush work? This is also something I've never done.

Glad I saw your post on Mando Merc Builder FB before they deleted it.

Awesome!! Thanks so much, I’ll be using this on my new 3D printed stuff!

Great video! Thanks for sharing your process. I learned a lot and it gets me excited about my next project.

Prefect timing, my first prop helmet just finished printing yesterday! definitely going to use this method

Haha, finally I see someone who likes sanding as much as I do 🙂 Too bad I saw this video only now, I had to figure it out on my own a long time ago. Great work!

Another awesome video! Cheers :)

Wonderful work! Thank you for the great guide.

Another excellent tutorial, Colin!

Super detailed video thanks! Great tips for a new maker!

Super helpful! thanks for sharing

very useful tutorial！ Great work

This is excellent. Thank you

thanks for a lot of information. some great pointers i did not know!

Love the information in this video. I will be able to cut down on soooo much time. Thank you!!!

Thank you for your videos, these have helped me incredibly as Ive started 3d printing!

hey thanks for this video i am getting into 3D printing and this really helps

Great tips. Thanks

Can’t wait to see the video on my metallic as well! Great video.

Mohawk makes a wood putty stick that I like to use for sharp edges and deeper print lines.

Very good vid. Sanding is always the pain 😄In fact I'm watching this while sanding. Yet, that bondo spot putty is great to use. I've tried resin which is ok, but prefer the bondo,

I need to invest in the bigger tube of Glazing Putty. I always forget that it comes in larger tubes.

Thank you!

I can cut the spot putty?! This is going to save me hours!

Great video! You spent a lot of time talking about the process and really appreciate that! I've been wanting to try the acetone and bondo method for awhile. On another note: Have you tried using Clear UV resin? I'm actually getting better at using two thin layers of UV resin and its been working pretty good as long as you pay attention to overlap or globs etc. Cheers and thanks for the video!

I would love to see a video on how you add a metallic finish to your prints as you mentioned at 0:54. I’ve been trying to do that on my own with spray paint. I got one spray paint was retired so I could only buy it off of eBay called Revell chrome spray. From what I’ve seen it’s the only spray paint that actually works as chrome with its mirror finish. Anyways well done on this fully comprehensive video. I just subscribed. I’m looking forward to seeing more of your content.

Hello Master, your videos have given me the motivation to sand even more... hahahaha I want to ask you a question, how do I remove the paint from PLA without damaging it, what product to use and thus start a whole new filling and sanding process? I thank you, a hug and thank you for your teachings, master.

have you ever tried Tamiya or My Hobby primer - for like model planes or cars. the Mr Hobby - Mr Finishing Surfacer, the 1500 awesome, the 500 and 1000 is good go rough surfaces - but it is AMAZING. very fast dryin, and no sanding. and self leveling. plus they come in White, Gray and black. you should try it.

great tutorial and knowledge as always! Big fan of bondo and Acetone myself! I actually use isopropyl instead of acetone though cause thats what I had on hand and I found it works the same! haha also highly suggest silicone cups for the mix, easy to reuse and clean!

I 3D print a lot of tanks. Luckily a lot of tank parts are rough cast so the glazing putty doesn't have to be completely smooth. In fact, I need it to have a rougher texture on things like turrets and cast transmission covers. I've always just used the 3M red putty right out of the tube, but I like the idea of being able to thin it with acetone. Gonna give it a try. What do you use to fill seams that have some flex to them (like where you are gluing two halves of a part together)? Typically glazing putty is chalky and will not do well on them especially if they flex at all.

Amazing video that provides alot of details. I would only comment on the sound which was not good. I can barely hear at some parts and need to constantly reduce the volume on the sanding parts.

Why acetone? Is it just the fact that it dries quickly and can dilute Bondo? Could isopropyl alcohol be used?

preach!

Have you checked out the 3m Acryl glazing putty? I like it a lot more than the bondo. it also smells way less. Goes on much smoother when doing traditional applications. I have not tried with the acetone method.

Thank you for posting this video! Great content. Quick question though, in certain scenes it sounds like you’re wearing a respirator… are you?

Thank you for this video - I was part of the "sand to 80% then lower your standards" method until now. I'm working on higher detailed props (a Pip Boy from Fallout 4). Do I have to modify anything (aside from brush size) for this?

wow what a great video more inforamation then the other 60 videos i watch, thank you, i just printed a Mando helmet i was going sand out all the print lines out but now im going use filler, how much infill did you use for this helmet?

Can I use the type of bondo together with acetone where I have to add the hardener to make it more liquid?

thanks for video! what filament do you use? pla?

Hey! Great technique.. I just tried it and it worked great. How do you clean your brush afterward? Do you soak it in acetone?

Question about washing the parts after initial sand: Have you had any issues with the paint because of moisture? I know regular bondo will absorb moisture, but dont know about the spot putty. Ive just been wiping my parts down with alcohol on a paper towel to be safe, but washing would be a lot simpler. Edit: are the tape stripes under the thigh plates to keep raw pla for velcro adhesion? (Im 40 min in, maybe you havent mentioned it yet.)

Can I ask what size nozzle you used for this. Print lines seem huge but love the process.

Can you mix bondo with something else than acetone? Maybe IPA or Ethanol? I mean, it will evaporate, but will it help thin the bondo? I've got most my stuff printed in abs and don't really want to coat it in acetone mix 😅

Did you sand the full strength bondo before applying the thinned bondo?

Great video! What filament do you use, pla?

How long did you get the filler primer set before going to wet sanding? Also glad to see you back Collin cant wait for more vids.

Colin, can you use a detail electric sander to sand down the bondo?

What would you recommend for smaller printed items like knobs or buttons? Should I try the same method?

How do you stop helmets and armor from getting ruined by car heat? Transport to cons and stuff? how do you insulate it I guess? Pla has become more of a turn off for me but it's cheap and fast

Such a boring video, I gladly watched every minute of it.

This is a great tutorial! I'm using PLA+ filament, do you know if acetone will affect it?

I just tried this method and it was a disaster.... Mostly because i was using the wrong Bondo 😂 It dried on me almost immediately, turning my helmet into an absolute mess! I now have the correct bondo and ready to give it another shot! 😅

so im trying to follow your method. I wet sanded with 220 and it basically removed almost all the bondo. am I doing something wrong?