Eliminating 3d print lines on small parts

[Codi]

I did a test on a 1/25th scale AJPE engine block from Shapeways.  The print lines on the side of the block where the "ribs" are were pretty bad. You can't sand that area of course so I took my media blast kit from TCP Global and the Paasche Eraser Compound (very fine btw) and shot it at 45 PSI.  It did an awesome job of eliminating the lines while not messing with the rest of the material.  You'll see some lines on the oil pan but I only passed over that area twice very quickly.  Shot at a distance of 1/4". I think this is very workable for small parts but for larger items, bodies for instance, not a great idea.  Cheers, Tim

Edited July 9, 2019 by Codi

[MrObsessive]

Codi, that is a GREAT tip! I wonder if that compound can be used for Badger airbrushes though? I have a 3D printed Jag D-Type body which is woefully riddled with those resolution lines. The body shape is perfect, but the incessant sanding to get rid of those lines I don't look forward to.

Thanks for showing this, and it is something I'll definitely be checking out!

[peteski]

Badger sells their own version of the mini sandblasting gun, and the aluminum oxide abrasive blast media.  Probably similar to Paasche. 

https://www.amazon.com/Badger-Air-Brush-Co-260-1-Abrasive/dp/B0038D59UM

https://www.amazon.com/Badger-Aluminum-Oxide-Abrasive-Weight-50-270/dp/B000BRLIOY

 

[Codi]

Thanks for sharing those links Pete.  Bill, the bad news is this is really only good for small parts as a technique in my opinion.  It only comes out in a small stream/area and I know you could use larger media material but to do an entire body this way would take forever and use a lot of the material at the same time. Plus I'm not sure what the larger material might do to the body itself.  I'm afraid that for bodies we're stuck with sanding.  I've got the same issue you have and I wholeheartedly agree that you'd have to be a masochist to enjoy the sanding etc.  If my pro mod mustang body that I started prepping was any indication, I'd say you should be able to get a 1/25th scale body in very good shape for paint in 8 to 10 hours of sanding & priming. I hope! 

For those interested, I bought the media blast air brush kit and material at TCP Global for about $50. 

cheers, tim

Edited July 10, 2019 by Codi

[SCRWDRVR]

Great tip, I never thought of that. I have a Paasche air eraser I use for etching glass and I've never thought of using it for something like that...

[High octane]

Sounds like a lot of extra work, so I believe that I will stay away from 3D printed parts as much as I can.

[my66s55]

2 hours ago, High octane said:

Sounds like a lot of extra work, so I believe that I will stay away from 3D printed parts as much as I can.

Nick, you don't need to stay away from 3d printed parts. Just stay away from sources that don't use the latest technology and print materials. I can print this part and you wouldn't have to touch it other than to paint it. 

[Codi]

Now you've got my interest Doug.  Checked out your facebook page.  Can you print the AJPE engine that I included in this thread?  I don't have the CAD? files to do so.  Someone else designed it and offer their products on Shapeway's.  What material should a newb spec out to get "lineless" prints and is it reasonably priced compared to other materials?     Thanks in advance for any insights you might share.  Tim

[my66s55]

I don't have the CAD? 

Herein lies the problem. No file, no print. This technology is ever evolving. The items on my Facebook page are 2 yrs old. What I can produce currently is even better.

Shapeways does not keep up with the technology as it would be cost prohibitive. People need to understand that when they purchase from Shapeways, they are not getting the latest and greatest technology and product. My idea of the best solution is to offer a service that has the files for purchase, not just printed.  

 

[Codi]

So you can print the ape block for me with no lines but I have to pay you to draw your own files up to make the part I want.  Did I understand that correctly?  If so isn’t that going to be more costly for me?

Edited July 10, 2019 by Codi

[my66s55]

Sorry, you miss understood me. I don't do cad files for others. Anything I do have was created because I needed them for my projects and are available

to anyone who wishes one. Currently there are two A block Plymouth dual quad 318's in other people's hands. The engine in my avatar is the 50's Dodge baby hemi that is correct and scaled to 1/25th. It's for future projects as a correct on does not exist. 

 

[KJ790]

On 7/9/2019 at 11:29 AM, Codi said:

I did a test on a 1/25th scale AJPE engine block from Shapeways.  The print lines on the side of the block where the "ribs" are were pretty bad. You can't sand that area of course so I took my media blast kit from TCP Global and the Paasche Eraser Compound (very fine btw) and shot it at 45 PSI.  It did an awesome job of eliminating the lines while not messing with the rest of the material.  You'll see some lines on the oil pan but I only passed over that area twice very quickly.  Shot at a distance of 1/4". I think this is very workable for small parts but for larger items, bodies for instance, not a great idea.  Cheers, Tim

Interesting. Which material from Shapeways was this printed with?

[Codi]

Thanks for the reply Doug.

KJ, I believe it was their "smooth" finish which is also their best/most expensive option currently available on this part. 

cheers, tim

[djflyer]

Great tip - I will have to try this with the small parts I have waiting for some method of clean-up

One thing I have tried that works for pieces the size of car bodies is to seal it.  I first do a rough sanding the knock down any major flaws then spread on a thin coat of superglue.  I let that dry until no longer tacky but no more than a couple hours.  Then sand with finer grit like a 400 or 600 - then prime and paint as usual.  So far it hasnt mattered which brand I use, only that its the thinnest formula possible.  This works best on pieces printed in what I believe is called SLS as the powdered nylon bodies are somewhat porous.  I know that Smooth-On makes a sealer for this purpose but have never tried it.