Thursday, 25 May 2017

A Step-by-step guide to post-processing a thingiverse Darth Vader without any sanding or acetone Part 1

EQUIPMENT USED:

  • Plastic plate
  • Soft Paint brush
  • Clean water
  • Methylated spirits
  • Soft, clean cloth
  • Hair dryer or fan.

PRODUCTS USED:

  • Poly-clean Plastic Cleaner
  • Proto-fill Liquid Plastic (Jet black Ultra-matte finish)



3D Printed Part - Before Post-Processing


METHOD:
First clean your object’s surface with Poly-clean Plastic Cleaner.

Before using Proto-fill, be sure to stir the contents thoroughly before you start, as the ingredients tend to settle on the bottom. The product may be sprayed if you have the equipment. Use a disposable plastic plate to place your model on, which are made from a type of plastic, that Proto-fill won’t stick to. Some take-away containers and lids are also suitable.

Brush the first coat of Proto-fill, in a horizontal direction, or in the direction of the grooves. The product goes on like a liquid plastic and is shiny when it’s wet and dries to a matte finish. Because of the rich nature of the resin-system, allow the product time to self-level and even out before applying low heat from a hairdryer or air movement from a fan.


After First Coat - Drying Process
DRYING:
Depending on your environment and how thickly you apply the coating, it takes around 20-30 minutes to air dry. A hair dryer (only ever on a low setting) or a fan can be used to speed up the drying process. Movement of air over your model is more important than applying heat. Too much heat will dry the top layer, but because there is still liquid underneath, it can cause the coating to craze slightly. This is easily rectified, however.

Once the coating is touch-dry, use a brush or soft smooth cloth, dipped in methylated spirits to re-soften and smooth the coating. Never sand the coating at this early stage, as you may tear the coating film. This “smoothing” technique will also fix any dried runs or drips. Being water-based, there is virtually no smell when applying or after drying; great for students or people who don’t have dedicated post-processing areas. Spills can be cleaned up with water or methylated spirits.

As the Proto-fill dries, it reduces by around 25%. Two coats seem to be sufficient to fill most fine print lines. Some deeper print lines may require additional coats. Although the product is viscous, it is still a very thin coating and intricate details are retained, just one coat of the matte finish makes most printed objects appear less “plasticky” and more like a moulded object. It is a good practice to address any runs or bubbles, in between coats.

Applying the second coat


Final result after drying

"ADJUSTING” THE COATING:
Once the products is touch-dry, use methylated spirits on a cloth or your paint brush to soften and “re-distribute” the product and even out areas which may have been over-filled. After a few coats, there is no need to apply more product, instead re-distribute the product from where there is too much, to areas which need more coverage. This technique is almost like, being able to pause time and resume when you’re ready. Making fine adjustment is like photo editing, you can add detail in, or take detail out. When you start sanding or vapour smoothing an object, there’s no going back.

Up next: We will be applying a colour coat to the same part. Stay tuned for PART 2.

For more information or to buy Poly-Clean and Proto-Fill, visit https://www.objective3d.com.au/coating-systems/