Thursday, January 21, 2021

SIN: Freehand Scribing

I’ve been using dymo tapes, as well as making my own scribing templates using PS sheets, but they’ve become a tad too tedious to use, especially with a lot of parts involved. I’ve also used my old college metal drafting template, but that too was a bit limited.

So I started practicing scribing freehand, which significantly simplified my workflow, opting to use straight-edges as a last resort for long line and complex curved surfaces. I also sketch panel lines on paper first and practice on thick board, and later on, scrap parts.

The Basic Tools

For those who are just getting their feet wet, you can always make your own tools. You can achieve good results even with just these tools with enough practice, especially if you are using guides.

  • Pencils - for sketching and planning the scribe lines. When I make a mistake or am not satisfied with the result, I can simply erase and start over. Penciling over initial scribe lines also makes the panel lines more visible on white and yellow parts.
  • Blunted/Chipped X-Acto Blades - I never or rarely throw away used blades since I can still use most of them for scoring and cutting most PS sheets. But I can also use these blades as scribing chisels. I convert chipped blades into 0.1~0.5mm scribers, while unchipped ones can be converted into 0.05~0.1mm scribers.
  • Needle points - Certain Hobby knife sets, like DAFA, also include needle points, but you can basically use any sturdy needle point, like compass needles, or anything long enough for you to hold, or at least, mount on a knife shaft or pin vise. Needle points can be used to scribe initial lines, as well as put corner points where angled lines meet.
  • Precision Screw Driver (not shown) - Those micro screw drivers used in eyeglass and cellphone repair can be sharpened and converted into 1.0mm (or wider) chisels. I’ve even converted one of my old Tamiya flat screw drivers into 2.0mm chisel, and it worked well enough for scribing basic panel lines.

Tools of the Trade

The Simplified Workflow

After sanding most of the surfaces that needed it to make it ready for pencils, I penciled in the panel pattern, then, I lightly scored the plastic using a blunt X-Acto blade with a broken tip, gliding over the pencil marks very carefully to make sure the resulting scribe line is straight as needed. I try to achieve close symmetry, but a little bit of asymmetry does make things look a little bit more interesting.

After the initial scoring, I re-scored the line, still with the same blunt blade for a deeper line, then after, flipped the blade and used the broad side of the broken tip to create the |_| panel line. For wider lines, I used the same blunt blade as a chisel to carve out a wider area. In some cases, I also use scribing saws for cleaner lines (0.2mm).

Side calf armor section of the Stein

Any excesses or burrs that creep out of the resulting line can be quickly sanded off and refined further by running the chisel a few more times in the line again. A folded high-grit sandpaper should smooth off any ragged edges, and a used, soft-bristle toothbrush should remove the accumulated dust.

The Sinanju's Side Booster:,Intitial scribing and painted

The Corner Conundrum

Most who do panel-line scribing for the first time would often be hesitant to do these lines, and it’s understandable, because they don’t want to screw it up, in turn damaging the part. Gunpla is expensive, and although scratches and scribe line mistakes (crooked lines) are easily fixable, most people would rather not go through the dilemma. So, there is such a thing as being too careful, as hesitation can lead to small mistakes especially when dealing with corners (gaps, overshoots and small curves)


Hesitation Corners
 
You can avoid these hesitation corners by marking the planned corners with a needle point, much like how way points are plotted on a map.
  • Pencil the panel line on
  • Mark the corners very lightly with the needle point
  • Scribe the initial lines
  • Finalize and sand

You can deepen and vary the widths as needed later on.

Alin, alin, alin ang naiba? Isipin kung alin ang naiba...
 
Duplicating Details

I usually just eyeball mirror details, but, I also do cheat from time to time. Masking tape is always a good implement to have, and is rather simple and straightforward to use. When mirroring a panel line detail from one section to another, I tape over the scribed lines, pencil out the detail on tape, attach the tape to a piece of PS sheet (there’s a tongue-twisting pun there somewhere) then cut the sheet, which becomes a template for the mirror side. This is the same technique I use with PS plating, using precut sheets as templates.

Masking Tape Magic
 
Tool Upgrades

After a while, I realized that even if I could get good results with my makeshift tools, they are still a bit limited when it comes to the variety of widths I can achieve. Blunt and chipped blades also become a bit uneven over time, so I needed a tool upgrade. 

There are several chisel options available, from the practically affordable (Wave HG Chisels) to the uber expensive (BMC), but they work the same way and will give you similar if not the same results. Ultimately, results will depend on you and how you use these tools.

I got a Wave HG set which includes four chisel bits (0.1, 0.2, 0.3 and 0.5mm) and a handle. Seeing that I’ll be using the 0.3 and 0.5mm bits, I opted to get additional 0.3 and 0.5mm bits, including 0.8 and 1.0mm, as well as extra handles to minimize having to replace bits while I work, which can also help avoid damaging the chisel bit.

The Wave HG Chisel set is a good starter set for scribing

With these tools, I can gradually widen the panel line width, which prevents the surrounding plastic from getting micro-cracks, which later leads to crooked-looking lines, much like how one gradually drills into certain materials, like ceramic tiles, with smaller to larger drill bits to avoid damaging the tile.

Wave HG Chisels are the most affordable high-end chisels
The Final Result

With some trial and error, I was able to refine the technique. Strangely enough, gliding the blunt blade to score the initial scribe line is more challenging on a flat surface than it is on a curved one. In some cases, especially with long lines on flat surfaces, I still use a straight edge to scribe the initial line.

Prefinal Scribe Lines

After proper sanding, priming and painting, these added details should look as if its part of the original kit.

Mirror, Mirror on the wall...

Here's a nifty step-by-step video of the process:


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