Techniques and tricks: MODELING

In this section show the materials and the techniques I use to make my models. Most materials are easily found in model shops (e.g. plastics) or even in hardware stores (adhesives, sealants ..) and the techniques very simple but, as always, in some cases you need to practice until the results are as required.

The points to discuss in this section are:

• Adhesives
• Puttys
• Plastics
• Various tools
• Models finish

ADHESIVES

What kind of adhesives we can use for our models? There goes the list:

• BICOMPONENT ADHESIVES: Within the broad range of adhesives of this kind on the market, I can speak knowingly about the following:
  • Nural 92 . Bicomponent glue special for plastics. To paste parts that need strong joints (tails, wings, lugs to attach the body to the chassis, axle supports...). It is very dense and hardens very rapidly, much more even if heat is applied with a hair dryer. If the mixture is well done in an hour can be sanded smooth but preferably allowed to dry at least 24 hours.
    
  • Nural 3. High transparency bicomponent adhesive. I use to stick pieces which unions have to be transparent, e.g. glass or details of the body, such as headlights and similars. Is similar to above but unions are not so strong. Glue is very sensitive to variations in the amount of the two components, so that often the mixture don´t gets the right consistency. Anyway for what I use it well worth. Further, is a glass has glue stained on it as it hits, can be easily removed with a cotton swab soaked in alcohol, if the glue isn´t dry. As dfault, noted that yellow slightly over time.
  • Araldit Bicomponent adhesive for general-purpose. There are several models (transparent, fast, standard ..), all of them, the one I like is the standard (blue and white tube) followed by fast (red and white tube). Becomes very hard and has the peculiarity that if once the mixture is made by heating with a dryer it is very liquid and can penetrate well in potholes. At the time it cools and hardens very quickly.
  
• Instant Glue (cyanoacrylate). I use it in the initial steps of gluing of parts or to paste details that are not been going touched, especially in the interior. Also used in combination with bicarbonate (sprinkling once applied adhesive) unions gain a huge strength. In this last way, I usually use as a step towards strengthening the joints with bicomponent glue.
  
• White glue for wood. Applied as-is, or diluted with water, is ideal for pasting the details of the bodywork, headlights, grilles, photoengravings..., or the drivers tray to the body. Ultimately, any joint we want to undo at any given time. When dry it is almost transparent but unions aren´t very strong.
  
• Special glue for plastics. It is the glue that is often used for scale models, which are made of polystyrene. This glue melts the parts of the pieces where it is applied to generate a very strong unions, but can only be used for bonding polystyrene, for other pastics best to use any of the above adhesives.

Here I show are products that I use but on the market there are others that will give the same results like these. The photos are indicative of the product.

PUTTYS

The putty is very a useful product for our transformations, to widen a wheel arch, bonnet bulge, plug holes...
I´m going to speak only of that I use or have good references but have not ever used. There are other similar fillers that can be found in stores, not named because I haven´t experience with them and don´t know the result they can give, which doesn´t mean that there would be perfectly valid for these jobs, even better than the ones I talk about below.

• Bicomponent putty - Pattex Repair Express. I use it for model large parts such as wheel arches, bumpers ... It can be treated easily and adheres well to any surfaces. Once hardened has a certain flexibility that makes the piece doesn´t broke in case of shock (ideal for shaping bumpers and not splitting if you put the car on the track...). As disadvantages I can say that hardens very quickly, very heavy (because it is very dense) and have that certain elasticity that could mean more work to mold the piece. The mode of application is simple, a bit is kneaded until both parties are well mixed and stick where we want molding a little bit until the mix longer permitt because it harden very quickly (3 to 5 minutes). Once attached it is advisable to let it dry for 24 hours before sanding or polishing the piece. Sometimes when you mix is not quite right and you will see a few pieces of very hard putty of a different color. In that case it is best to remove these pieces carefully because as time goes by they tend to come off the model surface.
• Repairing wood putty - Nural 41. Putty-like Pattex Repair Express but less dense and more rigid. Ideal for modeling parts of the body that will not suffer strokes or are in the top of the body (to not raise the center of gravity of the models) and internal modeling. To be very rigid once dry works very well with the sandpaper or file but can split if the parts are subjected to strain. It applies as above but allows more working time (approximately 10 minutes). Again, ideally, allow to dry 24 hours before working the piece.
• Two-component filler - Nural 34. To date I haven´t used but I have good references about it. It appears as though the Pattex Repair Express. but the two components are in separated bars, the mixture tends to be more homogeneous, adheres better to the body and is more dense and weigh more. Those who use it moisten their fingers with water before handling for a easy modeling.

Although puttyes are a good material for our transformations, we shouldn´t abuse them for large pieces, then would be very complicated to work. The ideal is to use them in combination with plastic pieces such as those presented in the following section.

PLASTICS

The puttyes are useful for making certain amendments in the body, bulging wheel arches, change the drop of a bonnet or a bumper ... but in others it is necessary to use plastic parts to make more complex shapes, such as a wing with multiple levels, windows frames, engine mounts .. In short, along with the putty and glue is the most important material to make our transformations.
Inside the plastic world there are many varieties (ABS, PVC, styrene, lexan ..), some are easier to work and others not, some are better suited for some jobs (the lexan blisters for windows, ABS from other toys for body parts ...), the ideal way is try to get the desired result.

• Commercial plastics: Are sell in model stores and similar in brands such as evergreen, plasticard and others. As advantage there are a variety of sheets of different thicknesses with different patterns (smooth, grated squared ..) and different profiles (tubes, measuring rod, double "T", triangular ..) that we can use in our models. The disadvantage is that they are relatively expensive, although their usefulness worthwhile. In this sense, the ideal is to make the most, keeping the cuts that are often very useful.
• Everyday plastics: With this denomination I refer to plastics that every day pass through our hands and often go away (always to the yellow container, of course). Here is the imagination of each one allowing the use of them. For example credit cards can be parts for wings, the cap of a bottle of soda of a radiator, some acetate from blisters for glasses, headlight lenses for our model lights... The possibilities are endless, you just have to let your imagination run wild.

As we going to use commercial plastics, building scale models, cutting bodies... we will be keeping a amount of smaller or larger cuts of different plastics. We can trow away the smalest ones and keeping the large pieces then we can come in handy. Especially interesting is going by keeping the pieces of commercial plastics (evergreen, plasticard ..), the more it is used less times we will have to buy (and spend our money).

VARIOUS TOOLS

The tools I normally use to make the models are:

1. BLADES, CUTTER AND SCISSORS

They are tools must not be absent in our case. The scissors should be better than craft ones because the materials to cut are more varied and tougher than the cardboard or paper, for example. The modeling cutter with suitable blades also will be of great help. On the latter, the straight are the most used, although there´s no harm in to have a set of modeling knives with curved blades and in different shapes, is not expensive and take out performance.

2. FILES

They are one of the most useful tools to make scale models. You do not need anything sophisticated, with a set of needle files of 5 or 6 pieces we covered practically all the needs. The one I use is formed by a cylindrical, triangular, square, half round, flat top and flat parallel. As almost always we are going to work on soft materials is advisable that are of type "second" that crawl the material well, not easily muffled and leave a acceptable finish.
Although less useful than needle files, a small file of 4 inches will allow us forward more quickly in rough tasks over large areas (narrow wheel arches, first steps of molding a bumper, etc ...). In this sense, a parallel flat or rather a half-round file is more than enough.
I do not advise the fine-tooth files unless you like to be cleaning all the time because they leave to file. For these purposes a small steel brush type "clean sparks" is highly recommended.
Regarding the quality of the files, for the work we do not need anything professional, which sold in model shops are more than acceptable. If you want something better or something concrete, in hardware stores you can find more variety

3. SANDPAPER

I know an avid scratch fan from Los Petiflauticos forum who´s signaure is: "sandpaler, is never enough". This phrase describes very well how we have to use sandpaper to make our models. And is that if we want the best possible finish for our models we must be patient and to work energetically with the sandpaper. And is that a good job of molding putty and can go away for not having care when sanding all the imperfections that have been left. Likewise, the sandpaper is essential if the paint finish has not been the expected and we want to left the body ready for another coat of paint.
Within the existing broad range of sandpaper, the ones I use are:

• Sheets of sandpaper for wood, grain 60, 100 and 220. The first two for low blobs of putty or sand the plastic body if you want to delete or modify some detail somewhere, for example. The last one to finish one-piece molding as a prior step to the finer sandpaper. Whenever it sand putty it must be completely dry, otherwise it will form lumps in the sandpaper that leave it unusable.
• Sheets of waterproof sandpaper grains 220, 500 and 1200. The first two are very good for the car model finishes, especially the 500 a little worn. These abrasives can work small details and leave a fine finish but it is not advisable to use them to remove large amounts of material because the task can be eternal. The 1200 grit is so thin I just use it to polish the paint or primer if it hadn´t been well implemented (cracked or orange peel). Being waterproof sandpaper, can be used both dry and moistened with water, task very appropriate if we are giving the last sanding to the primer before painting the body.
• Sheets of sandpaper for metal grit 60 and 100. I only use them when I have to reduce the tires profile narrow them a little. They drag a lot of material.

The sand sheets are cheap and will greatly help us with our models, whether they are new and if they are a bit worn. There will be times we want to use a piece of sandpaper used better than new one, because it left a thinner surface, because it adapts better to the shape of the body, for better polish paint .. It will be seeing as we make our models. The same applies to using the waterproof sandpaper dry or wet, the result is different, thinner in the second case, but also requires more work.

4. MINIDRILL

One normal, doesn´t need a much sophisticated for these works, so that with a simple (and small) may be sufficient, even if it has speed control even better. Logically the mini drill is useless without their accessories, grinding wheels for grinding, cutting wheels of iron, drills of 1 mm. 3.5 mm, and sanding discs. In theory, no more are needed

• The grinding wheels I used are the coarse-grained soil. As well as I use them to "hard" work doesn´t matter how left the piece because I always finished it by hand.
• The cutting discs I use are for metal cutting, being abrasive wheels aren´t the best suited for cutting thin plastic but as also use them to cut the steel axis of cars and other materials give me a good result. Ideally used for plastic toothed discs that cut well and do not melt the material.
• Drills, I have them from 1 mm to 3.5 mm in steps of 0.5 mm and in some cases of 0.25, in principle, well used, they last much, even the thinest, because the materials to be drilled are very soft. So far I´ve only broken one of 1 mm due to a carelessly treat, so that the investment is fastly amortized. I also use larger drills, but manually, as the chuck of mini drill doen´t admint drills beyond 3.2 mm. diameter approx. It is not hard and as being soft materials there´s problem to drill.
• Engraving accessory. It is useful to remove material in areas where the teeth do not fall or must be more careful at work and that this accessory is thin and allows for more precise work.
• Sandpaper discs. Useful when we have to sand delicate areas and if we do with sandpaper takes too much time and labor, for example in the early stages of modeling the wheel arches.

Therefore, the mini drill is very useful in all sorts of jobs that do not require a fine finish, cutting material, trimming of putty, etc ... and logically to make holes, which does not mean that it is essential, because practically all we can do with a mini drill we can do it by hand.

4. BRUSHES AND AIRBRUSH.

Although we paint our car modes with spray, we always have to detaill some things (lights, the slots in the body, the window frames ...) with a brush. It don´t takes a broad variety, if they can be sable hair better, and with due care last long. If we can afford the ideal is to have a brush for light colors (white and yellow) and anothers for the dark. This is because although we want to clean the brushes always remain traces of paint, so that we avouid spots of another color, especially with the white.

The airbrush is a very useful tool. Maybe at first we feel a bit of hesitation to use for the "complication" that means but it is not. The airbrush allows us to use different types of paint, to paint from large surfaces to fine lines, to paint degraded ... We can paint large areas or small details without wasting paint as an eyedropper can dispense the exact paint your deposit. In short, the advantages over aerosols are many but it also has disadvantages which are mainly, they require a compressor or compressed air canister to provide air and must be cleaned after working with them.
On their use, do not intend nor do I have enough knowledge to speak in depth about airbrush painting. To do this already exist many books and online documentation that address the topic in depth and with much more authority than I can have. That said, what I indicated is a basic management points about airbrush handling and from there everyone can delve into the topic all you want. Therefore, to initiate us into the airbrush must be considered:

• Air Supply. The airbrush needs a supply of pressurized air to launch the paint which may be a can of compressed air or a compressor.
  The compressed air cans are a good solution for specific cases, when we use the compressor a few times, or for an emergency. If we use often are expensive and they has the disadvantage of losing pressure as they are depleted so that the paint will not spray out well and can even botching the job.
  The compressor is the ideal complement to supply air to the airbrush. The most common models are the diaphragm and piston.
  • Diaphragm ones are simpler and cheaper than piston ones, but provide less air pressure and the haven´t boiler to store compressed air as the latter. If we don´t need much air flow with a diaphragm compressor will be enought.
  • Piston ones offer many more possibilities than the diaphragm compressors. They have a boiler to store compressed air allowing a more continuous supply of air, with more flow and more pressure, which will help us if we have to paint large areas. The disadvantages are a part of their larger size and the other the higher cost tnat the diaphragm.
• Cleaning. It is the most tiresome of the airbrush, especially when using enamel paint. If we want that the succesive times we use it will work correctly we mus make it a good cleaning. To avoid spent all the time cleaning it the ideal is to paint better many more things with the same color. So better take advantage of that painting because when cleaning it lost some paint. Another interesting idea is to paint light colors first and then dark colors. Between colors, rather than a thorough cleaning can wash the cup with some water, alcohol or solvent based on paint in question and then put the darker color paint. By doing this, for example, we could paint with white, red, blue and black in this order without having to thoroughly clean every time we change color. In contrast, if first paint red and then paint white wash would be better if we do not want the white one is white and pinkish.
  To clean the airbrush will have to dismantle completely and clean all parts, through which the paint to remove all traces. You must first wash off the airbrush. We fill the cup with the appropriate cleaning fluid as I mentioned earlier and spray on any surface. At this point, cleaning boats are very useful as they allow us to spray measured without fear of leaving home with paint chips. Here is a picture of one of them:
  
  The airbrush is inserted through the side and emptied its contents into the boat where we have previously pour a bit of water. Thus, we can spray to clean without staining anything. You do not need a boat to clean, we can always spray on an old rag, or within a paint cabin (if you have one) but it is undoubtedly helpful.
  For thorough cleaning inevitably have to disassemble the airbrush, being careful not to damage the needle or the shutter. With a brush, an old toothbrush or a cotton swab can be cleaning up the remains of paint and then drying with some kitchen paper. In case the airbrush is very it must be dismantled completely and immerse in liquid for cleaning. May be water, alcohol or solvent. I´ve tried it with one AB300 and can be completely immersed in solvent without fear, do not attack the o-rings or anything, but be careful if left too long under water, because some of its pieces do not have anti-corrosion treatment (e.g. the spring) and can oxidize, like has happened to mine.
• Where can paint? In most cases we will paint our models at home unless we are fortunate to have a little (or big) local or shop where calmly enjoy our hobby. As most of the time this won´t be our case we miust to make it at home. If don´t want the paint to spread throughout the house when paint with the airbrush we must to do it in an open terrace (not always possible or weather permitts) or get a small paint booth, which may be of selling ready-made or build it ourselves. I have a commercial booth, I won too expensive and does its job. It isn´t a wonder, has a small extractor and a filter used as the kitchen extractor hoods and absorb enough paint that is left floating in the air but not all. The main fault I see is that the fan is underpowered and breathe in the same room so we must always have clean filters if you do not want the painting that come in for the front come out from behind. But it is far better than nothing. For some message forums and web pages about our hobby I have seen that have been made homemade cabins have very good looking, probably work better than mine, so if you are crafty and have time I encourage you to build one. Otherwise, a comercial one is an valid option.
• Drying cabinets The scale model painted process is delicate and many factors can ruin the job if we are not careful. A finger placed where shouldn´t where be or a blast of air or dust can leave a neat finish painting become a disaster. Maybe we can recover the mess by placing the decals, or with a soft coat of fine waterproof sandpaper, but better safe than sorry. To do this, nothing better to isolate our car model from outside when the paint is drying. I use a homemade boxes made with plastic containers such as olives or candy to those who have screwed a weld robot at the top. The cover itself serves as a base and then when I just end to paint put the pot over paint. Furthermore, it is a very tight closure that will prevent dust and spoil the job. For the paint to dry before, small holes in the bottom allow the air to enter.
  

To be honest, the disadvantages of the use of the airbrush aren´t nothing compared to the advantages so if any of you are in doubt about buying an airbrush or use it for "fear" I encourage you to try it, you will soon handle much good and take advantage.

MODELS FINISH

To give shape to putty or plastics sticked to the body, nothing better than to use:

• FILES: In case to file body parts I use a set of 6 pieces needle files 6 (rounded, triangular, square, half round, flat top and flat parallel) medium grain. Once used it is advisable to clean with a wire brush to prevent residues and stop file.
• SANDPAPER:
  • Hard smooth. Sheets of wood sandpaper grain 100 or 220 depending on whether to drag a lot of stuff or give a definite shape.
  • Fine smooth. Sheets of waterproof sandpaper, grain 220, 400 or 500. I use them moistened in water to refine the parts earlier sanded. As prevuious step befor paint, I use 500 grain worn sheet to polish the primer a little bit.
  • Paint polish. If the paint has not been well applied (e.g. "orange peel" effect) and not to strip paint from the car, I passed a fine waterproof sandpaper grain 1200 to match the surface before repainting again. In cases where the failure isn´t severe, you can try to polish the body with a cloth and toothpaste in soft circular movements.
  • Tire turning. To lower the profile of the tires when needed to I use sandpaper for iron grain 60 or 100.