Hawkeye’s Squawkbox

I’ve received a lot of requests for this as well as a link to my thread about “Reading the Seams” that I did on the Aeroscale forum. I will be reworking the thread to make it into an article which will appear here soon.

Perfect Seams - Part 1, by Gerald Voigt

As I evolved as a modeler one of the first areas I wanted to improve on was seams. Aircraft fuselage seams can be the most unsightly flaw in an otherwise great build.

A seam should be as smooth as the surfaces surrounding it, and be as realistic as its 1:1 master. I’ve found the best way to mate two components together is to weld them. Using a solvent applied through an applicator works best for me. It is only one method to apply solvents. You could also brush them on, but you take the chance of leaving brush strokes in the surface.

A smooth seam, like the one pictured here, allows for easy scribing of missing or removed panel features. A properly mated seam, like this one, has no pockets or holes along the seam. It’s as solid as the rest of the piece. Like a good weld in steel, it penetrates all the way through. Ever try to lay a decal over a dip or ridge on the surface? With this method, flaws can be repaired more easily with less damage to surrounding details and features.

We need to have some basic tools to use. Here is a picture of what I used to do this article.

Step one:
Removal of a part from the sprue itself

NEVER EVER break a part off the tree. Use a sprue cutter, cut with a knife while pressing against a safe surface (self healing pad), or saw it off. Super fine razor saws are becoming the rage. They provide a flush clean cut, needing only a tad of touch up, which can be done with a polishing stick.

Test fitting

This is something you’ll do a dozen times before even considering mating the two surfaces together. The two surfaces, especially on fuselage halves, must be square.this] [ not this > < or this } { or even this } [. You get the idea. If you are a modeler who wants exact scale, for example . the width of the fuselage and you test fit and tape together to check dimensions and find it too narrow, you can add a strip of styrene between the halves. To widen, you’ll need to sand it down, but I personally don’t go that far unless it is grotesquely obvious. From a couple feet away, who’s going to notice a 1/48 scale model missing four or less scale inches or about the width of two of your fingerprint ridges?

Alignment

True up the halves as best you can. Sanding on a full sheet of paper secured to a thick piece of plate glass or a metal surface is my method. I have an extension to an industrial table saw that is made of cast iron and machined. It is perfect for laying out sandpaper. I use magnets to hold the paper down while I sand.

Locator pins not locating? Lop them off with your X-Acto knife. They are not needed. Unless the model is one of those shake-the-box kits, the pins usually don’t accurately line up anyway. I use pieces of masking tape and my thumbnail to align the pieces. Once everything is lined up to my satisfaction, I start the welding process.

Welding

Welding plastic with solvents dissolves the plastic just enough to melt the two pieces in contact together, just as a welding rod does with metal. This forms a stronger, gap-free bond. My particular solvent of choice is Weld-on 3. When I need a cooler or slower solvent I use Tenax. I use a Touch-n-Flow applicator to apply the solvents. A brush can be used and at times its use is appropriate to attach small parts where you don’t want any solvent residue marks around the part.

More to come!

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I know many of you have seen this done before but I think there are as many who haven’t seen this technique. How to cut a curved line. Simple all you need is some string or heavy thread. Essentially the thread takes the place of a coping saw blade. I start by drawing the line I need to follow on the model. Then a tape the mode to the bench so it overhangs the edge to allow you to hold the length of thread above and below the object being cut.

By running the thread up and down you cut the plastic. Be careful not to use too much pressure or too much speed, this creates heat and will cause the plastic to melt and thread to snap. I cut through both halves of this helicopter in just a couple of minutes. It’s easy and it is fun. I was able to keep the tail boom and engines intact so it can be reused. Give it a try yourself.

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We originally published this as a “Featured Article” back in September 2006 on the Hawkeye’s Hobbies website. With the website makeover in full swing, I’m going to republish some of those articles to keep them accessible as well as a way to answer questions from the many new subscribers. This particular subject has been a topic of recent discussion on one of the modeling forums. Hope you enjoy reading this and the other encore articles that will be appearing soon. Gerald

Painting On the Tree - by Al Jones, Milwaukee, WI

There’s nothing unusual in the practice of painting first. There are some advantages which I will list. But, the hardest part for most people who try the system is choosing a proper kit.

Since you will not be removing most of the pieces from the trees before beginning to paint, you must have some reassurance in your mind that the thing is going to fit well, or you will end up removing all the paint in sanding, and fitting once you start assembly. So, pick a kit that has a good reputation for excellent fit as your first move.

Then, there are some parts that have sprue attachments on the exterior surfaces of the model. The new Razor Saw from Unique Master Models, which will be available soon here, at Hawkeye’s Hobbies, will remove 95% of sprue attachment plastic. But, some sanding will always be necessary on these places.

So, what I do is to cut the sprues into 2 inch sections which can then be glued somewhere onto the inside of the part where it won’t be seen on the finished model.

I use alligator clips to hold the sprue sections while I’m painting the parts which can then be stuck on a toothpick set upright in a piece of foam board (Styrofoam) while the part dries. The rest of the parts stay on the trees protected from handling fingerprints and other flotsam and jetsam until the paint is dry.

I should probably say something about sanding any plastic surface that will later be painted. If you want the paint on the sanded surface to look like the paint on unsanded surfaces, you need to make the sanded area look like unsanded plastic. I have pieces of wet or dry sand paper in my collection with grits from 400 down to 2000 which is available at auto paint stores.

But, even paper that fine is not enough. I use finger nail polishing sticks to bring the plastic surface up to the same gloss as it had coming out of the mold. You know the ones: they are multi-colored with the final buffing surface always a smooth gray color.

Start buffing with the rough surface; that’ll take out most of the sandpaper scratches. Then buff with the intermediate surface . . . many times this is the white surface. Finally, buff with the smooth gray surface and your sanded plastic will be ready for paint. One warning on the polishing sticks: watch out for rubbing in too much heat where the polisher will begin to break down.

The rest of the parts on the trees can then be painted immediately. The razor saw will take the parts off the trees after the paint dries with minimal touchup required.

Sometimes I touch up with the airbrush and other times with a hand held paint brush. Just a little dab’ll do ya’! I no longer use nippers or shears for removing parts from trees.

These tools crush/damage the plastic in your model if you cut close enough and sometimes those spots need to be fixed later. I don’t like to have to fix later.

OK! Everybody’s model building nightmare is fuselage seams and the leading and trailing edge seams. You need to have some philosophy here. My philosophy here is the KISS principle. You know, keep it simple s______!

I hate fillers of all kinds and avoid using them with a passion. If fillers are necessary (remember that when you choose a kit you are choosing one that fits well; so, you shouldn’t need fillers), use whatever you’ve become accustomed to: melted plastic, body filler, epoxy, super glue. Smooth the filled area with sanding or whatever your normal procedure is. Finish off with a polishing stick. If your filler is softer than the surrounding plastic, you may want to spray a coat of primer which you can then sand down and polish after the primer dries thoroughly.

Warning: NEVER use the intermediate and final polishing surfaces of a polishing stick on PAINT.

So, with regard to seams, in order to avoid using fillers, you need good parts fit, you need to get into the habit of carefully dry fitting parts to see if any tweaking is necessary before assembly, and you need to learn how to glue parts together in a way that produces plastic “bubble-up” along the seams. I use a “Touch-n-Flow” applicator with Weld On #3 liquid solvent for my glue. Good solvents will melt the surfaces to be attached sufficiently so that some of the plastic in the seam will “bubble up” from the seam when the parts are pressed together. It’s a good idea to use some kind of clamping system here so that the bubbled-up plastic does not sink back into the seam. Let the bubbled-up plastic dry thoroughly, a couple of days, and then slice off the bubbled-up plastic with a new #11 X-acto blade. Wallah! No seam to fill.

Protect the paint along the seam with tape. Currently, I’m using Tamiya’s masking tape because it comes off clean–it does not leave any adhesive residue on your paint. Another good tape is from 3M; it is the stretchable plastic masking tape used by house painters. Sand the seam lightly between the tape edges. Polish the seam and after removing the tape, touchup the area with your airbrush.

Why use this method? You never handle painted parts until they are thoroughly dry.

Fingerprints do not show up on these painted parts. During the assembly process, you are not stopping, starting, forgetting what you were doing because you have to paint and then wait for the paint to dry. You just proceed through the assembly process one step after the other. It is like you used to do when you were 9 or 10 years old and you put a kit together in one afternoon. It is much easier to remove paint from surfaces to be glued after the paint is dry then it is to try to remove the paint from those surfaces while the part is sticking to your other hand. Some guys struggle with touch up after the parts have been removed from the trees. For me, I figure I’m going to have to do some touch up anyway. Why not do it in an organized, logical way.

That’s it. No secrets. No special skills. Just straight forward model building. Ah! I can smell plastic. I’m gone!

Al emailed me an addendum:

Now, what do you do when the kit is less than a Tamiya? I still pre-paint parts on the trees? The worst moldings that have the large sprue attachments and 3-dimentional mold seam lines which are a big job to clean up . . . I just take those parts off the trees first, clean them up, attach short sprue segments to an inside surface, hook up an aligator clip, and go ahead and paint before any assembly. It is important to remember that glue does not hold well to painted surfaces; so, I still have some prep to do before assembly. My goal is to assemble these kits with little or no filler that requires sanding. Once painted, parts can be dry fitted, mating surfaces can be matched by sanding on a piece of 400 grit wet or dry paper that has been contact cemented to a piece of plate glass. My favorite filler is window glazing compound which can be applied to both painted and unpainted surfaces. A smooth steel tool–spatula, awl, exacto chisel blade, etc.–can be used to put a glossy finish on the filler which can then be painted immediately. No sanding, no waiting for the filler to dry. The one flaw in the filler process is that the glue joint where the filler is applied must be firm. Any flex in the joint will crack the filler. Remind me that later I should talk a little about gluing upper and lower wing halves. There is a philosophy that I use which is helpful and some techniques and tricks, too. aj

I will, and I am looking forward to including it here! Thanks Al!

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