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August 30, 2005
Cleaning-up a lo-res 3D printer part
1. The Back story
The Dimension BST is a great machine. It’s in the small-company price range and capable of producing functional prototypes with just a little post-build finishing and assembly. For exhibition or theatrical prop quality pieces, the surface finish is pretty crude. Curved surfaces are ribbed. Flat surfaces have thin patches where you can see the honeycomb subsurface. The limited build area often requires parts to be divided into multiple prints. The following is some step-by-step instruction in how Michelle and I clean-up the poor surface finish of simple FDM parts and seam two parts together.
This process is courtesy of FX artist and sculptor Brett Klisch.
The object we are demonstrating this process on is a replica 1/3 scale model of our living room table that Michelle is making for the
set of our current project.
2. The tools we use:
a. Rigid Putty Knife
b. Glazing Putty by Bondo
c. Sand paper (250 – 400 Grit, Wet-sanding pad)
d. Locking pliers
e. 5-Minute Epoxy
f. Dust Mask
g. Latex Gloves
h. White, Black or Grey Primer
i. Paint color of you choice
3. Putty
Apply the glazing putty directly to the surface of the piece. Squeeze out a small smear of putty on the part from the tube. Use the putty knife to spread it around. Try to spread a little bit of putty across as large a surface area as possible. You should be able to see the plastic surface through the translucent layer of putty. Remember to always close the tube between smear applications. The air will thicken the putty and it won’t spread around as well. Let the putty dry for 5 to 10 minutes.
4. Sand
Use 250 grit sand paper to sand the putty layer smooth. Sand in small circles until the surface is very smooth to the touch.
5. Repeat Steps 3 and 4 two or three more times depending on the roughness of the original surface.
6. Prime and sand
Once you have gotten a few layers of putty on the piece to fill in the crack, apply 3 or 4 coats of primer in whatever color you'd like. Between each coat sand the painted surface with 300 - 400 grit sandpaper. Let the paint dry for 15-20 minutes before you handle or sand the part.
7. Join
To join the two parts: mix up a batch of 5 minute epoxy. Apply a thin layer to both of the surfaces you want to join. We used the locking pliers to hold the parts in place. This is key when joining two parts. You have to find some way to preload the two surfaces together for 30-60 minutes. It is best to let it sit for a few hours to make sure the bond is strong.
7. Repeat Steps 3 - 6 three or four times until the seem between the two parts in nearly invisible.
8. Once the primer surface is dry, you can apply your top coat of paint. In our case we used glossy white since our table is metal with a white powder coat. We applied three layers of white gloss, sanding the surface with a 400 grit sandpaper between every layer but the last. Finish off with your final layer of top coat.
Be prepared for the inevitable scratch or chip. That is just life.
And don't be surprised if someone kicks you to the curb because of the fumes.
When we finish the table, I will upload some images of the completed project and you can see Michelle’s gilded table legs.
Posted by powderly at August 30, 2005 01:52 AM
Comments
Neato.
Just curious with all the time, wouldn't it be cheaper to get it done in wax instead for this scale of work?
also "seem" together -> "seam"
Posted by: Troy at November 11, 2005 04:49 PM
