Scribing panel lines

by Saso Knez

THE BASICS

For all of you that are not close to airplanes, and don't know very much about engineering here are a few explanations about the panel lines.

What are panel lines?

If we put it very simple, the fuselage and wings of a metal aircraft are nothing but a bunch of sheets of DurAluminum banged over the structure of the aircraft (ribs, bulkheads etc.). Now because of the aerodynamic laws, the aircraft is a very complex and streamlined shape. If you would try to make an airplane from a single sheet of metal it would be impossibile. If you don't belive me try taking a banana and cut a piece of paper in such a shape that it will cover the surface of the banana exactly. So the aircraft designers design the sheets, so they cover an certain area of the plane. These sheets have to meet somewhere. Usally the overlap each other or meet with their edges. And these lines where one panel ends and the other begins is what we call panel lines. So this must be cut into the surface

On most models in our scale, you will find raised panel lines. You know now that this is not correct. You see for the companies, when they are making a mould for a model, it so easier to scribe a line in the mould (this line is latter injected with hot plastic, and will appear as a raised line on the plastic surface), then to scribe a whole panel area in the mould. Nowdays with the tehnologic wonders of CAD programs and the combination of CNC and electro-erosion tools, it doesn't really matter anymore, so the companies try to represent the airplanes as accuratley as they can, and so we (will) have recessed panel lines on the models.

THE PREPARATIONS

OK, in the above photo is the Me 110G4 kit by Revell. It has the raised panel lines.

The first thing that you have to do is to check if the panel lines are accuratly positioned. If they are, move to the scribing part.

If they are not, then sand off the panel lines and draw new ones with a pencil. (Use scale drawings of the plane and a various tehnical measurement equipment like vernier callipers, or vernier sliding mesures etc. of course if they are at hand-tehnical families only...). Fortunatly very few models have the paneling totally misplaced. But if you are careful, you will always find a missing or a surplus panel line on the kit.

One last thing during the research; be careful, when modeling Mosquito or La 5, or Yak 3, or the Great war subjects. The thing is that these all have wooden parts. The Mosquito from Revell has a big mistake-raised panel lines of the wing, when on the real thing the wing was wooden...again do your research.

THE TOOLS

Sawing or scribing?

I ussaly saw in my panel lines. You can see above to tools that I use. Both are home made. The first is The Saw. This is nothing more than a cutter from a Selotape container. A few modelers that I know use a razor blade, which they formed into a saw like razor edge. This tool is used to cut every panel line that is straight (it can be on a curved surface, but the panel must be straight).

The second tool is a tip of a syringe mounted into an discarded paint brush. This is used for the paneling which is curved.

It is very important to decide about the time, you will scribe the model. Many modelers scribe the model before putting it together. I am not confident enough about my abiltiy, and also I am not sure that the panel lines meet. Let's say that a panel line goes from one fuselage half onto another. If I want to scribe the kit before putting the fuselage halfs together, the original panel lines MUST meet perfectly on both sides, and secondly you MUST scribe the panel line exactly! I much rather glue the wing or fuselage halfs together and and then scribe in the panel lines, so they match up exactly, with not much truble...

If you have removed the panel lines beforehand, you must now make a leading grove with a hobby knife. Just cut into the panel lines. Score very lightley! Then insert the tooth of the saw into this cut-in leading grove. It is advisable to use this tehnique,if you are not to certain about your scribing skills.

I start with the straight lines. When you get the hang of it, you can score directly on the surface the first time, and use the existing raised panel line to guide the tooth of the saw. The first score must be very gentle. The idea is to make a leading grove, for the next stroke. Repeat untill the panel line is deep or wide enough.

When the striaght panel are sawed in tackle the small access hatches. Personally I made templates for these, and you can also get PE templetes. Use the syringe brush for this (or a comercial scriber).

This process can be done on a medium size model in about two modeling sessions (admittedly sribing a B-36 would probably take three!).

When you are finished sand the whole model with the finest sanding paper you can find. The excess plastic dust will fill out the panel lines, and thuse revaling any mistakes. When you discover these mistakes, place a drop of super glue on a piece of metal (now you can work with this drop for about 10 min!), then pick up some super glue from the drop with the other end of the syringe brush (the blunt one) and fill out any mistakes you made. When the super glue has set just sand it level with the surface and rescribe if necessary. This process of correcting mistakes can be done alongside other work done on the model, and does not take much time.


And this is how a nicely scribed area looks like

So there you have it-scribing is easy. All you need are the right tools and some practice, and the best thing about it, is that if you have made a mistake, you can always correct it!

© Saso Knez