Tuesday, January 26, 2010

DIY Panel Line Scribing Tool

Decided to be productive despite the rains by making my own Scribing tool that I can use to panel line my model kits with. Its been a week of torrential rain in my parts and because of the humidity can't really get anything done painting wise. Initially I was thinking of getting a small screw driver then sharpening it with a sharpening stone. After some thinking I thought that it might be difficult drying to get a suitable diameter for panel lining. So my second option was to use a sewing needle.

DIY Panel Line Scribing Tool

So I went to a local tailoring supplies shop and rummaged through their needles. I found a Japanese made sewing kit with the right size of diameter of sewing needles. It cost me about $0.60. I wanted the needle to be made of steel and to be tough in order to withstand the horizontal forces I would be applying to it when scribing. I used the 89 mm needle with a 1.7 mm shaft diameter. This particular needle type was the one used for making furniture covers. So its tough enough to punch through leather.


I got some left over Sculpey Firm polymer clay that sculptors use that I had laying around the house in order to fashion a handle for the needle. Compared to other types of polymer clay this is much better for sculpting because of its firmness. I am however using this because its the one available in the house. Sculpey Firm clay is expensive, about $13 for a 1 lb block. I think however that you can use cheaper polymer clay types not specific for sculpting. I saw some Chinese made polymer clay that was selling for $1.70 for a 56 gram block. Based from my assumption you would probably need 2 at most. If you really want to save money, you can go to some clay artists and ask for some scrap polymer clay from them.

DIY Panel Line Scribing Tool for model kit, polymer clay

Next I conditioned the clay by mashing it together. When the clay was conditioned, meaning it doesn't break up and is homogeneous in nature. I rolled it up into a ball and then slowly rolled the ball between my two hands till it became elongated.

DIY Panel Line Scribing Tool

For the clay to be symmetrical along its length, I rolled it on a flat surface. Afterwards I stuck the needle in till about 3/4 of the length of it was the only thing left exposed.

DIY Panel Lining Scribing Tool for model kits

I measured the length of the needle with a caliper so that I could tell at what point of the rolled up clay the end of the needle would be in. At this point I pressed on the end so that the clay would enter the hole at the end of the needle where the thread is supposed to go into. This is to ensure that the needle won't easily fall off of the polymer clay handle. Then I also made sure that the clay is firmly around the needle by rolling it on a flat surface which again helps to make the handle more symmetrical in diameter.

In order to harden the clay, it has to be baked, so I stuck it into the oven per the instructions on the box. For Sculpey firm it has to be baked at 130C with the duration of the baking depending on the amount of clay. I set mine for 30 minutes baking.

DIY Panel Line Scribing Tool

After the 30 minutes there was some cracks on the handle due to the air bubbles escaping. Minor fix of this was done by dunking it immediately in cold water with ice. Its a good procedure for removing cracks in the clay but it doesn't always work.

Next phase was to test it out on some spare parts of a model kit. This is of course where the bootleg Gundams come in handy *snicker*

DIY Panel Line Scribing Tool

Using a small metal ruler against the part I proceeded to make some test panel lines. I first made some light scratch marks before following it up with heavier pressure. The light scratch acts as a guide for the scriber to follow.

DIY Panel Line Scribing Tool

I made a slight mistake with the chronology of picture above. The one on the right is with the panel lines freshly scribed. Because the part had male pegs on it I decided to place it on top of a roll of masking tape so as not to break the pegs. The picture on the left is the part having been finished sanded to remove the burrs. Came out quite nice actually.

If you have the cash however, I'd recommend buying professional line engraving and panel lining tools from model kit companies at your local hobby shop in order to make your work easier. Online shops that sell model building tools are Hobby Link Japan and HWJapan. I preferred to make my own because the materials were easily available to me and didn't cost me much compared to ordering from overseas.