As an avid gamer and cosplayer, I rely on my 3D printer to build props and costume pieces that really bring my favorite characters to life. But there‘s nothing worse than handling a print only to have it shatter from brittleness or realizing it looks fake up close next to intricate professional gear.
Post-processing PLA properly transforms those fragile layered plastic builds into smooth, durable works of art ready for the convention floor. My Dremel tool has been a game changer for finishing prints to perfection!
Down the Cosplay Post-Processing Rabbit Hole
When I first unboxed my printer, I excitedly started cranking out everything from character busts to halo armor segments. The detail seemed good enough till I painted and assembled them.
The rough texture looked cheap rather than high tech armor. I could spy layer lines making the helmet shapes uneven. And the thin prop sword narrowly avoided snapping in two.
Disappointed but determined, I researched advanced finishing techniques which sent me down a deep, expensive rabbit hole! From gallons of filler primer to airbrushes, rotary polishers and ultimately a complete wood shop, my workshop soon resembled an auto body garage more than gaming den.
But the results completely floored me…
Image: Dramatic before and after of 3D printed costume pieces transformed through sanding/polishing
This guide shares the tips and tools I wish I knew before wasting hundreds of dollars on unnecessary upgrades. The humble Dremel rotary tool, combined with some elbow grease, can transform basic PLA into professional grade cosplay and LARP gear with just a dozen inexpensive attachments.
Smoothing PLA for Strong, Realistic Prints
Fresh off the bed, PLA plastic has distinct layer lines and nozzle marks making prints look artificial. By sanding away these ridges, we can reinforce inter-layer bonds for improved strength while erasing the extruder pattern for a more life-like finish.
For tiny grooves, I smooth with a simple progression of small grit to larger grit adhesive backed sandpaper until uniform. But tackling significant craggy outcroppings around the larger 0.4 mm nozzle paths means breaking out the big guns…My Dremel 4000!
Aggressive Layer Removal
I equip my Dremel rotary tool with abrasive flap wheels, wire brush drums and grinding stones to make quick work of significant protuberances. Just a minute or two with 50-60 grit rapidly reshapes details that would take forever by hand.
Don‘t grind too close to fragile bits and remember to wear eye protection from flying debris! I hold sensitive areas with painters tape masks if the section can‘t easily be detached.
Image: Sanding wheel dramatically eliminating layer lines on large flat print
Once major fixes are complete, I smooth with 400 then 600 grit paper restoring sharpness in sanded grooves or curves before a final buff with wet dry automotive paper soaked in soapy water. The mild abrasive cuts a gleaming sheen while lubrication prevents any new scratches.
Rotary tools melt soft PLA easily with prolonged contact under pressure. But a light touch while continuously moving ensures even polishing without damage.
Advanced Smoothing Techniques
Standard rotary smoothing makes quick upgrades over hand work. But gamers obsessed with realistic prints to impress judges can achieve truly flawless finishes.
Filler Primers
After initial sanding, 2-part auto body filler levels any remaining ripples in large flat areas.once cured, the putty sands beautifully for an ultra smooth face. I prefer lightweight formulas to avoid altering delicate fratures when restoring print accuracy.
Vapor Smoothing
Exposing ABS (not PLA!) prints to acetone fumes melts the exterior which then reflows, perfectly closing microscopic crevices. Results can be unpredictable though – details may be lost and colors bleached.
PLA can be chemically welded with dichloromethane but it is nasty stuff. I prefer safer smoothing methods for props and armor that have direct skin contact.
Molding and Casting
For identical prints or complex shapes too large to sand, make silicone molds and cast in smooth resin, plastic or concrete. After demolding a bit of sanding from mold lines leaves a factory grade solid part ready for paint and assembly. Grab those judges attention!
Prepping Prints for Perfect Paint
Once sanded smooth, PLA needs primer to fill microscopic pores for an ultra slick surface paint can grab onto. Avoid drips on intricate shapes with light mist coats. Flexible fillers prevent paint cracking as pieces flex. And don‘t forget the sealer clears!
Image: Primed and sanded PLA print shows smoothed surface vs raw side
I love the candy colors and chrome-like shine modeler‘s spray lacquers give. The solvents melt and blend with PLA for far better adhesion than brushes. Modern mixes don‘t require sanding between layers or top coat to protect. Vinyl and acrylic sprays work too.
Browse my previous articles on advanced weathering effects like chipping paint or adding grime washes. I explain gear like airbrushes and detail guns for next level cosplay realism!
Finishing Functional Prints
While sanding and polishing helps decorative prints, I take special steps for props and armor that face real world wear:
Hardware Inserts
I embed threaded inserts for bolt assemblies rather than trying to tap soft plastic. Captured nuts work too for non-structural connections. Consider metal reinforcements for high stress mounting points.
Flexible Materials
Rubberized PlastiDip spray adds grip and bounce while smooth Sugru fills uneven gaps around mounts conforming as needed. Flexible epoxy resins make repairs far less obvious.
Clear Coating
After paint, I flood functional pieces with outdoor rated urethane clears for enhanced scratch and scuff resistance. Durable two part or UV cured finishes also protect fragile filament.
And don‘t forget to seal unfinished handle areas for sweat absorption and grime resistance with at least a basic rattle can sealant.
Recommended Gear
These specific Dremel accessories see frequent use in my workshop for excellent PLA print finishing:
Abrasives
- CC-60 Card Cleaning Brush
- 952 Aluminum Oxide Grinding Stone
- 85422 Silicon Carbide Wheel
Polishing
- 84922 Felt Polishing Wheel
- 414 12” Cloth Polishing Wheel
- 68801 Polishing Compound
Fillers
- Bondo Glazing & Spot Putty
- Green Surface Primer Filler
Paint
- Testors Color Shift Lacquer Spray
- Krylon Short Cuts Multicolor Pack
And every maker needs a quality rotary tool! The Dremel 4000 remains a workhorse.
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I’m happy to answer any questions in the comments about achieving smooth sturdy prints that can survive the convention trenches! Check my profile for more cosplay focused enhancement techniques.