Photoetched Brass   

 

 By Art Braunschweiger

 

 

 

Part I:    Photoetched brass parts in general

Part II:   How to work with photoetched brass

 

 

 

 

 

Part 1: About photoetched brass
 

  

In recent years, ship modeling has been revolutionized by the advent of photoetched brass parts. These are small and highly detailed, intended to replace many of the smaller plastic parts from a kit. Because there is a limitation to how finely parts can be cast in styrene plastic, very fine parts such as found on grills, ladders, railings, chairs, and benches can't be reproduced with any detail or scale accuracy. Compare the difference between the compass tower legs below:

 

 




 

Photoetched brass parts are normally produced in a sheet with many other parts, as with the sheet of general Titanic fittings above. The reason photoetched brass parts can be produced with such fine detail is how they're made: the parts are drawn much larger than the size at which they will be produced, which allows very exacting detail to be reproduced. This high-resolution drawing of all the parts and small lines connecting them, is reduced to production size and then transferred to a high-resolution photographic negative of the same size. A sheet of fine brass is coated with a light-reactive chemical, affixed to the negative, and exposed to ultraviolet light. This transfers the parts drawing to the brass, although it's not visible at this point. Immersion in a second chemical protects those areas of brass that will not be removed:  the parts themselves, and small lines of sprue connecting them together in a sheet.  A final immersion in acid dissolves away, or etches, all surrounding material.

Using photoetched brass parts on your model can add about $50.00 to your model - typically three or four sheets of parts are involved, at $10-20.00 per sheet - but can add immeasurably to the appearance.

 

Cost aside, there are two things to consider before purchasing photoetched brass enhancements.

First is your skill level. While small photoetched parts aren't too difficult to handle, the larger more elaborate pieces such as railings are very delicate and easily bent or ruined. Some, like benches and deck chairs, require bending and assembly. You'll need to learn and develop some new skills to work with these type of parts, and you need to assess your own abilities before investing a lot of money. One suggestion if you're unsure is to start with a sheet of simpler parts (benches, deck chairs and railings are definitely out.) Get a feel for handling them and then work up to more delicate, involved parts.

Second point to consider is how you'll paint them. Parts with a lot of fine, closely-spaced detail - like mesh grills and benches - can't effectively be painted with a brush, no matter how skilled you are, without ruining their finely-detailed appearance. Some parts can be carefully painted, but most demand an airbrush. Airbrushing skills are easily learned, and you don't need expensive, artist's grade setup, but you will need to invest in about $150 at a minimum for one of decent quality plus a protective respirator. On the other hand, you can also use an airbrush to paint nearly everything else on your model, with the superior appearance that will result by doing so.

A brief note as to what's available in photoetched brass. You should be aware that there are several manufacturers, not all parts are available from each one, and two different sets from two different manufacturers may have a few parts in common. Also, the Deluxe Minicraft Titanic kit comes with a sheet of photoetched brass railings (it's the only difference between that kit and the basic, or "Classic" kit.)

The following link on the TRMA site lists all the photoetched brass available, with photos. All are equally high quality. In some situations the parts from one manufacturer may be finer (more delicate) in a slight degree from those of another manufacturer, but this difference will be negligible for most modelers. All are very reliable suppliers with experience in Titanic modeling, so a product from any of them is assured to be a good choice.

http://titanic-model.com/brass.htm


A number of photoetched parts and suppliers are reviewed here by TRMA members. Note that these are the views of individual members and not TRMA.

http://titanic-model.com/reviews/pe.shtml
 

 



Part 2: Working with photoetched brass

Here we'll take a look at the tools and techniques needed for each step, from removing them off the sheet to applying them to your model.
 


Cement for photoetched parts:

CA (CyanoAcrylate) glue is recommended. However, there are different types, and modelers frequently use the wrong one and then become frustrated over their inability to apply their parts with ease. In the United States, ZAP is the predominant brand, but the guidelines here can apply to CA glue of any manufacture.

ZAP CA glue is available in three types:

 Pink label - low-viscosity, instant bonding
 Green label - medium viscosity, 20-second positioning time
 Yellow label (also called Slo-ZAP) - high viscosity, 30-40 second positioning time

The pink label CA glue is the most commonly purchased, yet its use can be a mistake for affixing photoetched brass parts to your model. Because it bonds instantly, it allows no positioning time. Even the most skillful modeler can't be assured of placing a tiny brass window in the correct position every time. Instant-bonding CA also tends to glue the tweezer to the piece, and the low-viscosity of the instant-bonding CA allows it to bleed into areas where it's not wanted. Better is the yellow label CA (Slo-ZAP) - its viscosity makes it much easier to work with, and after dropping the piece down in place it can be shifted slightly with a tweezer tip before it bonds.

However, the pink label CA is ideal for photoetched parts that need to be assembled from more than one piece (like benches), or for parts that require a bend and a subsequent application of cement at a joint or seam. Its very low viscosity allows it to readily flow into joints with ease.


Removing parts from the sheet:

Use an X-Acto or other hobby knife with a sharp blade to cut through the sprue. (The sprue is the little thread of brass that connects the part to the sheet, or to other parts on the sheet.) Your cutting should be done on a hard surface, otherwise you'll bend the piece ever so slightly with the downward pressure from your knife. Lexan (plexiglas) works well for this. Use a firm downward pressure with your knife to cut the sprue.

 


 


Trimming the sprue from the parts:

Once the part is free of the sheet, you can use a hobby knife to trim the sprue from the part, but the best tool to use is a pair of photoetch shears. These makes the job is much easier, and they do a cleaner job. Consider these if you've bought a lot of photoetched sheets. They are also called Xuron shears, and their cutting action works by a slicing cut, not the pinching cut that most small clippers or shears make. Their cut is so precise that the slightest bit of sprue can be trimmed off a piece without any distortion or bending of the piece whatsoever.

 

A note here about magnifiers: A good optical visor with magnification is highly recommended for use with photoetched parts. Equally useful, if not more versatile, is a jeweler's loupe of 3x or 4x magnification. A jeweler's loupe - also called a watchmaker's loupe - also has the advantage of being able to be used much closer to the model.


Handling parts:

You'll need two different tweezers: one pair with very sharp, fine points, and another pair with flat points. The fine-pointed tweezers are used to pick up the parts and move them or put them in place on your model. The flat-pointed tweezers are better for holding parts when you're trimming them with a pair of shears, because the flat points clamp the brass in between them without risk of the piece twisting between the points, or the points offsetting under pressure and flicking your piece of brass into the air. For handling the extremely fine windows, a second fine-pointed pair in a smaller size is helpful.

Small parts can sometimes be difficult to pick up from a hard surface with a pair of tweezers. Press down gently with your finger and it will stick to your skin. With the part sitting on your finger, you can easily get under it with your tweezer tip to grasp it in whatever position is required.


Flattening distorted parts:

Occasionally it happens that despite careful handling, a part inadvertently gets slightly bent or distorted. When this happens, lie the piece down on a hard surface. Using the flat of a tweezer, press down firmly. Turn the part over and repeat.


Bending parts:

Some parts, like benches, require bending. The simplest and least-expensive option, but one that works quite well, is to use two chisel-point X-Acto (hobby knife) blades. Lay the photoetched brass part down on a hard surface. Position one blade where you want the bend, and hold the part firmly down against your work surface. Holding the other blade almost flat, gently slide it under the piece as far as the first blade. Lever it upwards and you'll have a clean bend.  This photo shows the top half of a deck bench being held down by the blade on the left, while the bottom half of the bench is bent upwards with the blade underneath:





 

There are also several tools and bending jigs available; one is reviewed here:

http://titanic-model.com/reviews/tools_holdnfold.shtml


(Note; some pieces like the lifeboat davits and benches require a more complex bend. For benches, the initial bend between the bottom slats and back slats is done as above, but then other more adaptive techniques, not covered here, must be used to apply the proper curve to both parts.)

Some photoetched parts require an application of cement after assembly or bending, but before painting. This is covered under Cementing photoetched parts, below.


Painting photoetched brass parts:

Paint all parts before you cement them, not after. If you're using oil-based paints, no cleaning or priming is necessary. Simply apply the top coat as is, and remember that airbrushing is strongly recommended.)

(Note - GMM ocean liner figurines should be painted and detailed prior to removal from the sheet. This is covered under a separate article at

http://titanic-model.com/articles/painting_figures/detailing_gmm_figures.htm


To hold the parts while painting, make yourself a painting stick. First, get a few paint mixing sticks to keep on hand (the kind you get at any paint store). You'll also need Scotch blue painter's tape - this is a tape with medium adhesion, meaning it's a lot less sticky than regular tape. (Note that this is a U.S. product; modelers elsewhere should look for the equivalent product.)

When you're ready to paint, pull off a piece of masking tape and lay it on your work surface with the sticky side up. (You might need to hold the ends down with two pairs of tweezers.) Then take two other pieces of masking tape and lay them down above and below the first piece, sticky side down, with each one overlapping the middle by a small margin. Lay this lengthwise on your paint mixing stick, wrap the top and bottom around the edges, and you have a paint stick. The sticky section of tape in the center will hold your pieces while you paint - just place them there with a tweezer, and apply only the barest amount of gentle downward pressure. Even the smallest, most delicate pieces will stay perfectly in place while you airbrush them, as shown here on the top and bottom paint sticks:





 

(Note that the position of each has been marked with a felt-tip pin.  This way, should one inadvertently get knocked off, its absence will be noticed.)

 

When airbrushing, less is better. It is not necessary to apply enough paint to cover the blue color of the tape.  Brass is a fairly neutral color that takes most colors very well, and it shouldn't take more than a few passes with an airbrush to adequately cover them. It is far better to do several light applications, letting the paint set in between each, than to apply one overly-heavy layer. Do a pass or two, wait a minute for it to dry, and do another light application.  

 

After you've airbrushed them, remove them from the tape as soon as the paint becomes dry to touch. This is usually a half hour after you paint them. If you wait longer than that, when you remove them from the sheet the paint won't break cleanly and you'll pull some off the tape, giving a somewhat ragged appearance to your pieces. Handle them carefully, as the paint is easily scratched off at this point and still needs to dry another 12 -24 hours. Flat pieces can be gently loosened from the tape by sliding a knife blade underneath them.


Cementing photoetched parts:

There are two ways to do this: you can either apply the glue to the piece, or apply it to the model. Whenever possible, apply the glue to the model and then place the part down. You can better control the amount of glue being applied, and if you drop the photoetched part or have to reposition it in your tweezers, you won't have a sticky piece that wants to glue itself to everything else.

You'll need to have a supply of disposable glue blocks on hand. Any material will work if it's non-porous and can be easily cut. I purchased a sheet of foam art board at a crafts store - it's about 3/16" thick, with a foam core and outer surfaces designed for painting or drawing. Using a razor, I cut it into inch-and-a-half squares. The same square can be used over and over until you run out of space.

You'll also need an applicator. I use a piece of fine but stiff wire will do, about three or four inches long, with the back end bent in a loop for ease of handling (and so you it can be seen it when it's laying down).

For the next steps, you MUST use a hands-free magnifier, like a jeweler's loupe or binocular magnifiers. The amount of glue you're working with is simply too small to see with the naked eye, and it's easy to apply too much.   You should be able to actually see how much glue you've applied in order not to over-glue it.

First, have your photoetched part ready to go. That means right in front of you, where you can grab it right away. Make sure it's right side up, turned around the right way. You want to be able to grab it and glue it without delay.

To glue a piece, apply one drop of CA cement onto your glue block. Take the very tip of your wire and touch it very lightly to the glue. Apply the glue on the model where you want it. Note that CA cement is immensely strong - you don't need to coat the area - a couple of key points is all that's required. For example, if you're gluing a rectangular grill over a stokehold vent, applying glue to the corners is all that's required.

For parts that require an application of cement after bending, the same glue wire technique applies to the pink CA cement used for this application. For parts that are bent and will hold their position by themselves, make sure they will do just that - your bends should be made so your part requires no pressure from your tweezers to hold it in place. Pick up a barely detectable amount of pink CA on your glue wire, and carefully touch it to the edge of your joint. The CA cement will instantly flow into the joint.

 

Make sure to periodically clean the tip of your wire.  As CA glue builds up on the tip, it will increase the amount you pick up each time.  To remove the built-up glue, use the back edge of a hobby knife blade to scrape the wire clean against a hard surface.

For parts that require assembly, where you're joining two separate pieces, follow the instructions in the next paragraph, but do not use instant-bonding pink label CA - use yellow-label CA instead.

For some parts, especially very small ones, it's more practical to pick up a bit of glue on the part instead. LIGHTLY touch the part to the glue droplet.  Using your magnifier (you should already have it on!) look to see how much glue you've picked up.  You will almost always have to transfer some back - you can't usually control exactly how much glue you pick up, and for small pieces only a miniscule amount is required - any more will bleed out from under the part after you apply it.  You should have only a barely discernable amount - if there's too much there, gently touch the glue on the piece to a corner of your glue block to wick some back. To avoid picking up too much glue, you can also pick up some on your glue wire, and then touch your piece to the tip of the glue wire.

 



Immediately lift your part with into place. Gently touch it where it needs to go. Always steady your hand by resting on something, or if that isn't possible, grasp your wrist with your other hand to steady it. With CA cement, all you need to do is touch it in position for it to hold. Immediately nudge it into place with the tip of your tweezer - don't rush, but remember that you only have about 30 seconds. When it's positioned properly, gently press down with your tweezer tip.  If you don't get it right before it bonds, don't despair - a gentle but firm pressure in a twisting motion will pull it off without damaging it. Use the tip of your knife to gently scrape the glue off the model and off the part and try again.

Lastly, a note about loss prevention. Some photoetched brass parts are extremely tiny. Whether you're working with one or several, if you must set them aside at any point to work on something else, place them in a milk cap or film container cap so you don't lose them. Some are so small that they're easy to sweep off the bench with your sleeve if you don't know they're there. And if you're cutting any off their sheet in advance, or painting any in advance, place them in a secure storage container with a lid - one of those multi-compartment plastic boxes with a snap lid works well.