This tutorial will explain all aspects of using photo etched (PE) metal parts on scale models including a step-by step guide for creating a complex three dimensional object.
A description of how PE parts are made and their characteristics is given in the article ‘Model Kit Materials’ so it will not be repeated here. This article will concentrate on how to actually use PE parts.
Sometimes model kits are provided with PE parts in the box in which case their use will be shown in the instructions. However, if the PE parts are purchased as an aftermarket set, then you will probably have two sets of instructions – one set that came with the model kit and a second set that came with the PE set.
Building a model kit can seem complex enough without the additional problems of replacing some kit parts with PE parts. As with many things in life, it is always wise to plan ahead – if you were going to travel to Mexico, you would not go without first looking at a Spanish dictionary . So, take a good look at the kit instructions and the instructions with your PE set. Find out where PE parts replace kit parts and where they supplement kit parts.
Compare the kit parts with their PE equivalent and decide whether or not to replace the kit parts. Sometimes the kit part may be every bit as good as the proposed PE replacement, or there may be so much work making the PE parts for such a little improvement, that you may decide stick with the kit parts.
Where you do decide to replace, or supplement kit parts, update the instruction sheet for your kit, so that you do not forget to use the PE parts as you construct the model.
Preparation And Tools
As with many aspects of scale modelling, a good starting point is to clear your workspace of other models and tools and set out the tools you will need for the particular task ahead.
|Photo etched parts are small and sharp. Wear eye protection and beware of stepping on PE parts|
The tools you may require are:
- Cutting surface
- Sharp knife or PE scissors
- Fine files, or ‘wet and dry’ sandpaper
- PE folding tool
- Fine pointed pliers
- Masking Tape
The cutting surface should be fairly hard and an old CD or DVD is ideal since it is firm but will not unduly blunt your blade. Parts can be removed from the PE fret with either specialist scissors, or a sharp hobby knife. I find the hobby knife works best for most parts as it is sometimes difficult to position even small scissors and they can easily distort small parts when cutting. This will blunt the blade of the hobby knife fairly quickly so be prepared to change it as necessary.
No matter how careful you are cutting PE parts from their sprue, you will often be left with small stub of sprue that will need to be filed away with either a very fine needle file or ‘wet and dry’ paper.
A PE folding tool is not absolutely essential as parts can be folded with pliers, but a folding tool makes working with PE much much easier and I would heartily recommend getting one if you intend to use PE parts on a regular basis.
The most popular models are the ‘Etch Mate’ from Mission Models and the ‘Hold And Fold’ from The Small Shop. PE folding tools come in various sizes. If you are planning to fold large parts such as fenders that run the full length of a tank, then it will be necessary to get one of the large models. However, the vast majority of PE parts are small and one of the smaller (and cheaper) folding tools will be fine for these.
PE parts can not be glued with polystyrene cement. The most popular alternative used is cyano adhesives – also known as superglue. These come in various thicknesses from ‘super thin’ to ‘gap filling’ and each thickness is useful in different situations. For very tiny parts it is possible to use glues such as Clear Fix, paper glues or even gloss varnish providing there is sufficient surface area. The bond will not be strong, but often it does not need to be. An alternative to glue in some cases is to solder metal parts together and this is covered in a the article ‘Soldering Metal Parts.’
In order to hold the very tiny PE parts a good pair of tweezers is indispensible. In fact several pairs of different types will come in handy – especially the spring loaded self-closing types. Small needle nosed pliers are useful for holding parts and bending them. Look out for the type that have a smooth rather than a serrated holding surface. It is possible to buy sets of small pliers at a low cost and this is a good investment.
Small strips of masking tape will come in useful for holding parts together, or to the model while glue is applied and while it dries.
The above may seem a long list of equipment, but the vast majority of it is also used for other modelling purposes, so most experienced modellers will already have most of these items. The only exception is the folding tool that does require something of an outlay, but regrettably there is little alternative if you are serious about bending PE parts on a regular basis.
Attaching Very Small Parts
One of the biggest challenges with working with PE is that of holding and gluing very tiny parts such as buckles. These can be almost too small to hold with tweezers and if you can manage to grip them how do you apply the glue?
The method I use normally is to employ a small paint brush and gloss varnish. Paint a thin layer of gloss varnish on the small area where you want the part to be placed. Then while the varnish on the model is still wet, use a small paint brush soaked with a little gloss varnish to touch the PE part and pick it up. The natural stickiness of the varnish will be enough to pick up the PE part where it can be placed on the model on the area that you have varnished. Coax the part off the paintbrush and on to the model, maybe using a cocktail stick.
You can then move the part into the correct position with the end of the paint brush and/or the cocktail stick. When the varnish has dried you may wish to paint another thin layer of varnish over the part to make sure that it is secure.
Now we will work through the process of creating a mudguard to replace those on Tamiya’s 1/35th scale Panther tank.
The PE set used is Aber’s update set number 35A24 which is often sold with set 34024 to make a complete update package for the tank. The first stage is to identify all the parts needed to build the mudguard by referring to Aber’s instruction sheet.
The parts are then separated from the fret with a sharp hobby knife using an old DVD as a cutting mat. Care is taken not to lose any of the tiny parts. Consider putting masking tape over the fret and cutting through it and the fret together to prevent small parts flying away.
It is a good idea to place all the pieces in a small container such as a jam jar lid so that they are easy to find and do not get lost.
The next step is to examine every part and either cut, or trim, any stubs remaining from where the parts were attached to the fret.
The main part of the mudguard needs some bending and shaping. The sides need to be bent 90 degrees and the front needs to be gently bent to form a curve. When it is necessary to perform multiple bends on a single part, it is very important to plan the order of the bends. Sometimes, making a bend on a PE part will prevent another type of bend. If in doubt make a copy of the part by cutting it out of paper, or thin card and try making the bends on this. Once a PE part has been bent, it is very difficult to unbend it without causing damage, so this is something that needs to be done right first time.
In this case, I decided to make the gentle curving bend first. This was done by using the round metal handle of a hobby knife as an anvil and pressing the part down on it gently bending around the handle. It was done in several stages to obtain a gradual smooth bend. The part was bent a little, moved a couple of millimetres, bent a little more and so on.
Next, the two side pieces of the main mudguard were bent 90 degrees inwards using the ‘Hold and Fold Bug’ tool. Bends on some of the other smaller parts were also made.
Once all the parts have been prepared, they need to be fixed together and once again, it is worth spending a couple of minutes planning the order of assembly and trying a dry run. This advice applies to any model building.
It is important to make sure that the surface of the parts is clean and greasefree. At the very least, firmly rub the surface with a cloth soaked in white spirits or some other substance that will remove oil and grease. If possible rub the surface to be fixed with either fine ‘wet and dry’ paper, or fine wire wool (1000 grit).
When joining metal to metal, I prefer to use solder and this process is covered in a separate article ‘Soldering Metal Parts.’ Most modellers will use superglue/cyano adhesive. Where there is a large surface area to be joined a good method is to hold the parts together and then place a drop of thin superglue on the edge which will be drawn in between the two parts by capillary action and will set almost immediately.
For parts where there is little surface to join, or where there are gaps, then the thicker gap-filling superglue will need to be used. Once again, position the parts and hold them in place with clamps or masking tape, then carefully run superglue along the joint. The gap-filling superglue may take some time to set, so you may wish to apply accelorator to speed up the process.
Once the parts have been fixed together, inspect them and clean up as with any other modelling sub-assembly. Clean away any excess adhesive with a knife or sanding sticks/paper and fill any gaps. Remember that fillers designed to work by bonding with plastic will not work well, so you will need to use something like epoxy putty to fill gaps e.g. Milliput, or Apoxysculpt).
Finally, on this mudguard it is necessary to make some paralell raised lines on the mudguard. Aber have made the mudguards thinner where the lines need to be impressed which not only marks the position well, but also guides the tool used to make the impression.
I used a common ball point pen, which was pressed on the mudguard while it was placed on a self-healing cutting mat. The cutting mat has a rubbery surface and this is important because it would not work on a hard surface. The impression is made by gently moving the tool (pen) back and forth several times gently. Avoid trying to do it all in a single pass. There are also some bolt heads to be created and these are simply done by pressing the undersided of the mudguard with the ball point pen.
Once this has all been done the mudguard is completed. Unfortunately that is only half the job. In this case it is necessary to cut the original plastic mudguard off the model because it is moulded as an integral part of the upper hull. A modeller’s work is never completed!
Working with PE parts is a challenge and requires learning new skills and using different products to those used for modelling with plastic. Remember that good quality models can be made without ever resorting to PE, so do not feel compelled to use it, particularly if it is likely to detract from your enjoyment. However, if you are up to a challenge and want to take your models to an even higher level of excellence, then follow the guidelines in this article and you will probably find success.