Working with PE - Basic Tools and Operations

Etched metals are essentially pre-cut materials ready to be fabricated into parts, with some small details already incorporated. We bend them into 3 dimensional shapes, then attach them to construct the component we need.

In other words, we need to execute 2 categories of tasks: Shaping and Attaching. The aim of this article is to provide you with a set of solutions to perform these tasks.

Before anything else, we need to cut our PE pieces off from frets. The best knife for this is a 9mm art knife such as the NT Cutter  pictured (Fig.1 Part. 11). The handle will accept 9mm snap-off blades (such as the one in Part.12, a Tajima brand).
These utility knife blades are made of hi-carbon, rating close to 60 on the Rockwell Hardness Scale.  They are much harder than the stainless steel blades of X-acto knives, and will cut through PE connections like melting butter.  The petit 9mm form will also allow you to reach the PE connections easier, give you room for a clean cut. Try to get the 30° replacement blades. 45° blades will also work, 60° blades are sometime too blunt in the front.
A knife will lose its edge sooner or later, especially if you're cutting metal with it. Using snap-off blades is also an economical solution. A pack of snap off blades cost only couple bucks, that's 50 -100 segments, they can last you  a while.

Remember to bend the snap-off blade segments away from the face with etched lines when you separate them. This is opposite to what we do with PE, where we almost always bend towards the lines.
Some might argue that surgical knives are better, and some of them have profiles just as petit. But at what costs? Couple trustworthy brands for 9mm utility/snap-off blades are NT Cutters, Tajima, KDS and Olfa. Each brand has its own styles of handles, the 9mm blade design is universal.

Shaping

1. Curling

We often have to curl a PE piece into an arc, sometimes even a cylinder. This is straight forward if we have a correctly shaped object to press against . Tricky part is to fix the arc in place, we will deal with this later in the article.

An arc always has a diameter. If you have a cylindrical object of the diameter you want, then curling PE over that object will allow you to obtain the desired arc. We would need to have a collection of cylindrical objects of different diameters so we can always find one suited.  If possible, solid metal cylinders are the best , so we can anneal the PE while it's wrapped around the cylinder, soften it, and force it to stay in shape. Fig.2 is a panther cleaning rod tube shaped out of 0.2mm brass. Picture taken before the ends were soldered together. This was done with a 5mm brass rod.

There are some products  that provide modelers with cylinders of assorted diameters. The Small Shop has a rolling set, and Mission Models produces 2 sizes of "multi-tool" that provide you not only cylindrical shapes, but also cones. These are good starter kits to have, but they are not going give us all the diameters we need, so it's important to keep an eye out for similar objects along the way.

When you curl something tiny, like top of the German tool clamps, it's best to just use a needle nose tweezers and do it manually.  Curl it a section at a time to obtain a smoother arc.

To construct movable hinges, we need to roll a section over 360°. This is a special type of operation and will be dealt with in our next segment - "Making German Tool Clamps and Movable Hinges".

2. Bending

If the bend line is longer than 2 millimeters, you want to use a bending brake, and not to monkey fuck it with tweezers.

If you watch American Chopper, you probably have noticed their Baileigh bending brake, which evidently also has fingers, like an etch bending tool on steroid.
There are quite a few modeling bending brakes out on the market,  some good, some shitty. The2 best designs are Mission Model's Etchmate 3C and Small Shop's Hold and Fold. From our experience, the Hold and Fold design is superior. The best and most versatile model being the 5.5 inch (Fig.3). This model features many "thin" fingers that allow you to bend narrow C cross sections (Fig.4). And for long bends, the 5.5 inch straight edge in the back should meet 99% of the needs in 1:35, 1:700 and 1:350 scales.
Etchmate 3C has a groove in front of its fingers, we find this feature counter-productive as it sometimes trap very small PE piece in and prevent it from sliding under the fingers smoothly. It also lacks the "heavy" fingers for bending thicker materials. The "thin" fingers don't bite down on 0.5mm brass all that well.

On our etch, the bend lines are always relieve etched to  half the thickness of the material. Edge of the finger should line up with far side of the bend line so the entire groove is visible.  To align finger accurately, you will need to put on an eye loupe. Preferably a single eye-piece as it's easier to focus with just one eye (depth perception isn't critical when you're that close to the object). We recommend a 10X or 15X loupe (Fig.1 Part. 10). You want to see things very clearly so your alignments can be precise.

Use a razor to bend the PE (Fig.1 Part.9 Razor blade is 1-sided, the safety handle is just for storing the blade). Hold and Fold also come with a long razor for bending longer pieces. The Mission Models long razors are plastic and a little too thick to get under a tightly clamped piece of PE.

Bending with a razor will scratch surface of the bending tool, this is inevitable. Take it apart and sand the surface down with 800+ grits sand paper. Like a tooling table, you want it clean and smooth.

3. Complex shapes

Sometimes we have to perform multiple bends on a single piece. Storage bins for 1:35 Panther tanks in example, requires more than 10 bends on a single flat sheet of PE. There is no trick for this.  Figure out the order so you can perform all the bends on a bending brake, plan your steps, and be careful.

Joining

Once we have bent and rolled the PE pieces, we need to fix that shape in place, and sometimes join multiple pieces to construct a component. We can do these with either glue or solder.

1. Gluing

Cyanoacrylate or CA (superglue) is one way of joining metal pieces together.  Not the best, but easiest, and sufficient in a lot of cases because PE structures on scale models bear very little weight, and don't need to be very strong structurally.

Superglue come in different viscosities, and the thicker it is, the slower it cures. The moisture in the mixture is what keeps the glue from drying out, but too much moisture then the glue becomes too thin and will not dry out to the correct density to form the right amount of surface tension. Once a superglue bottle is opened, it should be kept in a place with low humidity so it can stay good for a longer period of time. In a frig for example.

For larger joints we can use the slow drying type, and the easiest way of applying that is with a crafting knife or needle. Smear glue over the joints and press the pieces together. You only need very little superglue so watch out the volume you apply.   You don't want the glue to squeeze out from underneath when the pieces are pressed together, or you'll need to clean up that ugly residue.

To join pieces cleanly, especially those smaller pieces, we recommend using thin superglue, so it's easier to control the volume. These thin superglue also dry quickly, and the smearing way of application takes too long, so we want to apply the glue more directly.
Part 5,6 and 7 on Fig.1 are what you'll need. Part 5 is an all plastic package from Krazyglue, can be purchased in any walmart or hardware store. The glue comes in a small plastic vial inside the packaging tube. It's better than the toothpaste type of packaging  as you don't need to worry about squeezing it too tight and blowing out the bottom. Having glue gushing out from the wrong end can ruin your day. The packaging tubes of these Krazyglue are also resealable so you can maintain the glue longer.
Part 7 is your everyday q-tip. You need the ones with thick plastic handles so you can heat it over a candle and stretch it into a thin plastic tubing. Cut the cotton heads off and you now have 2 sections of mini funnels. Fit a funnel over the Krazyglue vial and you can now apply your glue in tiny drops.
Sometimes your q-tip handle will not fit the glue vial. Get some Testors glue tips (Fig.1 Part.6), they can act like a sort of universal adapter for your mini funnels.
So how small a drop is enough?  Well, small enough so it won't be visible. If you want to glue a 0.5mm bolt head, then the drop has to be a lot less than 0.5mm diameter right?

Another advantage of thin glue is that you can soak up the excess with a small chunk of TP or paper towel.  Try not to apply too much glue at the first place. If you accidently squeezed out more than you need, you can suck it up with that funnel.
If the excess glue had dried out and you really don't want to clean and reattach the parts, then try to use a small knife to scratch that dried glue "film" away.  Or if you want to clean that part up and redo the gluing, then use superglue removal solution (it's marketed as "Un-cure") and clean the piece thoroughly.

Tip: Glue back of the part, or where it won't be visible.

2. Soldering

Soldering is the proper way of joining metal pieces, but not all soldering techniques are suitable for scale modeling. We will introduce the butane torch method here.

Why butane torch? Why not an electric soldering iron?
Because an electric solder conducts heat through the metal (PE).
Solder melts at little below 400°F (This is normal 40-60 lead solder), but to conduct enough heat through brass  so the solder reaches this temperature, the heat source needs to be much hotter, and this means heating the metal to a higher temperature. Which degrades the metal.
With a torch, you're heating the solder directly. Move the torch away once the solder had melted, so the metal beneath the solder is only heated to ~400°F and much less than the temperature at which it will sustain serious damage.   Air is a poor conductor of heat, and butane flame burns at very high temperatures. By adjusting the distance of your flame and the solder, you can reach an optimal distance where you're heating the solder to exactly its melting point.
An electric soldering station, with adjustable temperature and a micro chisel tip can be very useful in cleaning. However, if executed correctly, butane torch soldering will leave nothing to clean.

First you'll need a butane torch. I have a Power Probe PPMT (Fig.1 Part.1), it costs $26. Please use better butane refill than Ronson. A good butane torch can focus its flame to very small, very short. My PPMT can't, it cuts off if visible flame is less than 1.5cm long, which is barely enough. I used to have a Bernzomatic that can adjust the flame down to 0.8cm, but it broke, oh well.
You want the smallest soldering wire you can find. Mine are 0.3mm (Fig.1 Part.2), and if you look closely at Figure.5, you can see they are hollow in the middle. Most solder wires are like this, with a rosin flux core to help it melt and distribute. Compare to a dime, you can see the size of the chopped up solder chunks are tiny. Smaller chunks are easier to melt, and you don't need a lot of solder, so you don't need to clean.

We want the pieces (or faces) need to be soldered together pressed against each other. You can use tape (Fig.6 This is Tamiya's modeling tape, Kapton high temperature tapes are ok, I just don't bother with expansive stuff), or you can use reversed tweezers (Fig.7). In Figure.8 I used 3 pairs of reversed tweezers to press 4 sides of a 20mm flak magazine all against each other.  When faces (or pieces) are pressed or taped tightly against each other, the gaps between them will create a suction, or capillary action, which we utilize to distribute melted solder.

Once the pieces/faces are fixed against each other, smear tiny bit of soldering paste (Fig.1 Part.3) onto the joints, then place the little chopped up chunks of solder (definitely need the 10X loupe here). It's better to heat and melt the soldering paste before placing solder chunks, or it may bubble when you're soldering and push the solder chunk away from the joint. The solder needs to touch the joint in order to benefit from capillary actions.

Then we heat it and melt the solder. Like in Figure.9, I start with my flame an inch above the solder, and gradually lower it till the solder melts. Solder melts at its melting point, this is not a range. It'll melt completely once you have reached the melting point. You should now see melted solder getting sucked into the gaps almost instantaneously. Move the flame away and leave the piece to cool.

We left a question earlier, about fixing curled pieces in place so it would retain its arched form. The answer is already presented. Tape it up with another piece and solder them together. If you're worried about the tape burning through, wrap more layers.

Couple things to remember.
1. soldering paste must be cleaned thoroughly before using super glue over the same area. Or superglue won't work.
2. thicker and chunkier metal pieces will take longer to cool. Don't let go of pressure before it's cooled.
3. If you messed up, don't panic. Reheat and separate, then clean up with a hot knife or chisel (electric or butane types are all fine). You can always redo as long as the brass isn't subjected to intense heat and damaged.

We always try to solder when making samples of our products. Check out our product pages, you will see many examples of soldering, all were performed with this method.

Is there easier way to solder? Yes. Resistance soldering for example. Because the heating elements also behave like tweezers, you can grab and solder in 1 motion, and skip some of the pre-positioning work. American Beauty's superchief 500 is an excellent tool, but at $400+, definitely on the expansive side as far as tools go, and it doesn't eliminate the need of butane torch soldering.

Again, if you don't already have one, get yourself a 10X or 15X jeweler's loupe.

Next time we'll deal with German Tool Clamps and Movable Hinges.