ABS Plastic

About the ABS material:

All models are printed from ABS plastic and partially assembled for surfacing and posing purposes and they are all almost fully articulated (the Bunyip has one joint that has to be glued). You can assemble the model, pose it, move it around, make it dance, etc. without gluing it.

 

The ABS material that is used to construct the models is the same kind of common plastic that milk jugs, model kits, plastic forks, etc. are made from. It is very light and quite durable. The printing process is a lot like decorating a cake. The printer heats up the plastic in an extruder and squirts it down in very small layers (about 0.2 mm). The final product has a grain a lot like wood. With the grain is very strong and flexible but when stressed against the grain the layers can separate. Luckily, fractured pieces glue back together very easily with a little super glue, usually without any noticeable breaks at all. The separations don’t tend to happen all at once so they are easy to catch, glue and clamp together for drying before significant damage occurs. Also, if absolute disaster strikes I can print off individual pieces and send them out, generally free of charge.

You have to be careful when using a hobby knife and cutting with the grain of the material. I have slipped and sliced my fingers a couple of times this way as it take far less pressure to cut with the layers than against them.

The pieces are printed in a way that they have exterior layers and a hexagonal infill of about %15 so the pieces are not solid all the way through. This cuts down the weight and material usage. A problem with this method happens when big drill bits are used on the surface layer. When using a large bit (1/4″ plus) in a low RPM power tool such as a cordless drill, the bit tends to grab and tear at the outer walls. A dremmel works much better as the higher RPMs and smaller bits alleviate the problems of the bit grabbing and tearing at the plastic. It is still possible to drill the pieces with a larger bit and slower tool, but you will want to start with a small diameter drill bit and work your way up in sizes to the desired diameter.

 

The ABS plastic has a slight lined texture from the printing process but this can be remedied with some primer and a little sanding. It is much lighter than cast resin and is more durable in almost all respects. When it does fracture it tends to be along the grain, but this is easily fixed with a dab of superglue.

 

You can smooth out the texture in two ways.

 

  1. Acetone – Acetone on a paper towel will smooth the surface out. Just remember that acetone melts the ABS so don’t dump it in a vat of it or it will turn into goo.

 

  1. Sanding – This is your fairly straightforward method of working down from a large to small grit sandpaper. It also helps if you sand, prime, then sand again as the primer, then prime again. This helps fill in the gaps with primer.

If you have any questions please do not hesitate to ask.

Thor.

 

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