Body Mods How To by GTmike400

Here's the tutorial that you guys have been asking for. This is a tutorial comprised of many elements of body modifications, fabrication, and other tips to help you with your projects. It will cover stuff from the basics, to the advanced fabrication.

Table of Contents

  Types of Putties
    --General Putty Information
    --Body Fillers
    --Epoxy Putties
    --Polyester Putties
    --Glazing Putties
    --Super Putty
    --Putty Warnings
 How to Use Putties
    --Choosing the Correct Type of Putty
    --General Application Information and Preperation
    --Application
    --Shaping/Sanding
    --Paint Prep
  Styrene
    --Introduction
    --Uses
  How to Use Styrene
    --Choosing the Correct Piece of Styrene
    --Cutting
    --Attaching
    --Sanding
    --Bending
    --Quick Widebody Buildup
    --Paint Prep
  Tools
    --Hobby Knife/Razorblades
    --Hobby Saw and Miter Box
    --Sandpaper and Needle Files
    --CA
    --Liquid Cement
    --Compass and Dividers
    --Dental Scribes
    --Zinser BIN

Types of Putties

General Putty Information
Putties can be very useful, but they can also turn on you when after you paint. There are several varieties of putties, each have their pros and cons and each have their special uses. One part putties while they are the easiest to use for a lot of people, they can really make you cry after you paint. One part putties dry by evaporation of moisture. This will cause shrinking, and the shrinking continues on over a long period of time. After painting the putty continues to shrink, and can ruin a perfect paint job. One part putties should be used for fixing very small pinholes and scratches. Bondo's Spot/Glazing Putty is intended for just that, fixing little tiny spots, and glazing scratches. Many people have thought that the Spot/Glazing Putty can be used for modifications, and filling. Unforuntately people are blinded by how easy it is to use and cant see the aftermath. Don't try using one part putties where a two part putty should be used just because you don't want to mix. If you do, you will end up spending more time in the long run trying to remove the putty and fix your mistake. Caution: Stay far away from one part oil base putties. When they are wetsanded they fall apart, plus they are incompatible with many types of paints.

Two part putties should be used for filling, major body mods, and other stuff. There are several types of two part putties; Bondo Body Filler, Evercoat Everglaze, epoxy putties, and polyester putties to name a few. Two part putties are much better than one part putties. Two part putties require the base, and the catalyst. By having two parts the putty cures chemically instead of physically. Since it cures chemically it cures much faster, creates a much stronger bond, doesn't shrink, and doesn't absorb paint. Since two part putties are much stronger they can be used for filling without any problems. Two part putties are reccomended as much as possible. If you have a couple scratches and pin holes, wait until you mix another batch of two part putty and fill the holes and scratches that way. You will have a much better result with two part putties. Another benefit is they don't absorb moisture when wetsanding (some one-part putties do).
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Body Fillers
Body fillers are excellent two part putties. They cure quickly, dry hard, cure chemically, and best of all they sand easily. Body filler's main benefit is that they sand very well. When they cure they are hard enough to withstand working conditions, yet soft enough to cut with a razor blade or hobby knife. Sanding is extremely easy with body fillers. When cured it can be molded into the desired shape with some 100grit sandpaper, and then smoothed out with some 400-800grit sandpaper. Side Notes: Bondo Body Filler does not stick to plastics. Evercoat Euroglaze is an excellent two part glazing putty that does stick to plastic. Evercoat products are higher end putties but they are much finer and sand smoother than Bondo products.
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Epoxy Putties
Epoxy putties are superb for attaching pieces where asthetics are valued. Epoxy putties are super adhesive and super strong for attaching pieces back together. They can also be sanded into a desired shape. So if you need to put something back together, but the joint needs to look good, use epoxy putty instead of epoxy. There are several grades of epoxy putties. Marine and automotive epoxy putties, and model epoxy putties. There are several flavors of model epoxy putties that come in a variety of grit. The grit is determined by how smooth, and how fine the particles are. Marine and automotive putties are almost as good as model putties and comparitively are more efficient because of the cost. Model brand epoxy putties are normally more expensive and harder to find. Marine and automotive putties are less expensive and easy to find and do the job just as adequately. The downside to epoxy putties strength is the ability to be sanded. Epoxy putties are extremely hard to sand since they are very tough, and they also produce a very fine dust and easily clog up sand paper. Also once its on there and cured, its not coming off easily. However, even though they are harder to sand, they can be formed into the desired shape before they cure. The reccomended use is for creating asthetically pleasing joints, not filling and shaping. Epoxy putties also stand up to many varieties of solvents.
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Polyester Putties
Polyester putties are two part putties that are a similar cross between a body filler and a glazing putty. Polyester putties can be sanded very smooth and are very good for filling, and shaping. They sand very easily, but are very durable. Just like body fillers, they can withstand many varieties of paints, but not solvents. The glazing factor is they polyester putties can be spread very thin and then sanded smooth for a nice glaze coat. If you need to fill tiny pin holes or scratches polyester putty is reccomended because it will not shrink like a one part glazing putty.
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Glazing Putties
Despite the easy use, these putties can come back to haunt you. Many people think they these putties can be used for filling, shaping, and "building". That is a very misleading interpretation. Glazing putties use is all in the name, glazing. Don't try to use it to fabricate. One part putties shrink; the more you use, the more it shrinks. Glazing putties are decent for smoothing plastic joints, or mould lines. Once again, do not use one-part glazing putties for building; the results will be disastrous after painting. When painting a really good sealer should be used because one part putties absorb the moisture and reducers out of paints. To be safe, and to save time, don't use one part putties. One part putties lead to disaster 75-80% of the time.
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Super Putty
There isnt a real name for it, so we will call it super putty. Super putty is a good way to make super strong CA joints. All that sanding dust that you make from plastics and putties isnt a waste. When you use CA for a joint sprinkle some of the sanding dust on the CA while its wet and it will create a super strong joint that is shapable. Its best use is for attaching styrene together. Its almost like a superglue filler. Its very handy, but not an alternative to a filler or epoxy putty.
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Putty Warnings
This is the most important part to using putties, its about your health. ALWAYS wear a respirator, even when sanding. The vapors (when mixing) and particles (when sanding) can get in your lungs and affect your brain cells. A dual cartridge resperator is reccomended, if you do not own one you should invest in one. They only cost about $30 and can be purchased at many home improvement stores. The paper particle masks are only efficient when sanding. Be sure to mix the putties in a very ventilated area. Now don't let these warnings scare you from doing body mods, or using putties, just play it safe. The warnings on the putty labels warrant death, and other illnesses. Those warnings are a little drastic, but always keep your health and safety in mind.
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How to Use Putties

Choosing the Correct Type of Putty
Think about the benefits and drawbacks of each type of putty, and then compare it your application. If you want to fill some holes, or build a body kit use a body filler or polyester putty. If you need to put to car halves together, use an epoxy putty because it creates a strong joint and can be aesthetically pleasing. If you fixing seams, use a polyester or two part glazing putty. Yet again, stay away from one part putties. Many people swear by Bondo's Spot/Glazing Putty but the long lasting results are displeasing and will cause a lot of agony.
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General Application Information and Preperation
Remove the paint, dust, grit, and grease. Putties adhere better to a rough surface instead of smooth surface. Rough up a metal surface using some 100-150grit sandpaper, rough up plastic surfaces with a 220 grit wet/dry sandpaper. If you are applying a putty over aluminum, steel, stainless steel, or other type of non-white metal you must spray a sealer or epoxy sealer/primer over the metal first. The resin in the putties can react with the metal and corrode the metal and make for a bad putty job. Primers are not sealers (putties can eat through primers too), be sure to use a good sealer or epoxy sealer/primer.
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Application
Read the label for instructions on how to use the putty. Each putty has a certain mixing ratio. Bondo Body Filler is usually mixed to a nice pinkish khaki color. Evercoat Euroglaze is usually mixed to a nice light blue color. Epoxy putties usually are a one to one mix ratio of base to catalyst. Read the instructions on how to mix. After awhile you will become accustomed to the mixing ration and will be able to mix by eye. Go to the dollar store and pick up a large pack of popsicle sticks to mix polyester, glazing, and body fillers. Don't forget to wear your respirator.
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Shaping/sanding
Use a variety of automotive wet dry sand papers. Automotive sandpapers are the most accurate grade of sand paper. 3M automotive wet/dry sandpaper is excellent quality and can be picked up at most home improvement and automotive stores. Most automotive wet/dry sandpapers start at 220 grit, for that reason it is ok to use standard 100 grit sandpaper for the initial shaping of putty. Use a variety of sandpaper from 100 grit all the way up to 1500-2000grit.

Needle files are also superb tools to shape putties. Make sure you have a rag near by and consistently wipe the file on the rag every few minutes to keep it from clogging. Files load up very easily but are still excellent tools. To unload them either use a file card or soak them in lacquer thinner or another solvent.

Dremels can be used for the rough sanding. When you the roughed out shape with a dremel use sandpapers and needle files to do the intermediate and final sanding and shaping. Only use the dremel if you feel comfortable in using it.

Don't forget to wear your respirator.
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Paint Prep
Standard procedures apply usually. The only difference is that a good sealer should be used before spraying the primer. Some putties will aborb the primer and reducers and be cause for a variety of problems. If you don't want to spend the money on an epoxy sealer, there is a home improvement sealer called Zinser BIN. Zinser BIN seems to be a pretty good sealer so far, and is compatible with most primers. Zinser BIN can be found at Lowes and Home Depot for about $5 for a spray can.
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Styrene

Introduction
Now what is styrene? Styrene is a type of plastic also known as polystyrene. Styrene is available in many shapes and sizes and is available at many hobby shops. The cost of styrene varies from quanitity, size, and shape. There are many benefits to using styrene; it is lightweight, it doesn't shrink, it can save a lot of time, there are many many different uses, and the shapes are endless. Styrene comes in a variety of sheets in a variety of thicknesses, tubes in a variety of sizes, rods in a variety of sizes, hex rod, triangular rod, semi circles, quarter rounds, I-beams, variety of strips, and many more shapes. Most people start out with a pack of styrene sheets, and very quickly their surplus of styrene grows from a few sheets to a ton of different sheets and shapes. The top of the line leading manufacturers are Evergreen and Plastruct.
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Courtesy of Evergreen Scale Models

Uses
The main use of styrene is fabrication. Since styrene comes in so many flavors it is easy to fabricate pieces quickly and efficiently. Styrene takes the place where putty would take inefficient or would be impossible to use. With styrene you can fabricate interiors, widebodies, fenders, hoods, spoilers, body kits…the possibilities are endless. The only limit with styrene is your mind.
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How to Use Styrene

Choosing the Correct Piece of Styrene
Only you can decide on what piece to use for each application. This tutorial can only point you in the right direction while ultimately you choose where to go. All it takes is just some ingenuity, and creativity to be a fantastic modeler with styrene. For starting, a good base is to use some .020 Plain Sheet and .030" Plain Sheet. Those are the most commonly used sizes for constructing. However, different applications will require different thicknesses. Another benefit to styrene are the styrene strips. They are very easy to use, and are not very expensive. They have a variety of uses too. If you cut a piece to short, you can use a piece of strip styrene. The uses are infinite.
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Cutting
Most styrene can be cut with a razor blade, a hobby knife or even a pair of scissors. Hobby knives and razor blades make the cleanest cuts. Scissors are best used for styrene sheets up to .030". When using scissors to cut .020"-.030" styrene sheet the cut is not perfectly smooth and needs to be sanded with some 220 grit wet/dry sandpaper. Scissors shear the styrene unlike cutting it. Each cutting tool has its benefit and only you can decide which tool is correct for the application. Do not use a dremel. Dremels will melt the plastic and create an extremely messy cut.

Perfect circles can be cut using a compass or set of dividers. Put points in both ends of the dividers are compass. Calculate the radius of the circle to be cut and set the compass or dividers to that measurement. Place the compass or dividers on the styrene sheet and start spinning the compass/dividers around just like the way you would draw a circle on a piece of paper with a compass. This will cut through the styrene and create a perfect circle. The cut isnt perfectly clean so sand it with some 320 grit wet/dry sandpaper.
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Attaching
Styrene can be attached a variety of ways. For attaching the styrene to a material other than plastic you should use CA (superglue). For attaching styrene to plastic use a liquid cement (i.e. Testors Plastic Liquid Cement, Ambroid Pro Weld, Tenax Liquid Cement , etc.).
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Sanding
Same thing as putties. Use a variety of automotive wet dry sand papers. Automotive sandpapers are the most accurate grade of sand paper. 3M automotive wet/dry sandpaper is excellent quality and can be picked up at most home improvement and automotive stores. Most automotive wet/dry sandpapers start at 220 grit, for that reason it is ok to use standard 100 grit sandpaper for the initial shaping of putty. Use a variety of sandpaper from 100 grit all the way up to 1500-2000grit.

Needle files are also superb tools to shape styrene. Make sure you have a rag near by and consistently wipe the file on the rag every few minutes to keep it from clogging. Files load up very easily but are still excellent tools. To unload them either use a file card or soak them in lacquer thinner or another solvent. Another benefit to needle files is that if you have a piece cut out of styrene but it is a little off, you can use files to shape it correctly.
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Bending
Styrene can be bent over a flame, soaked in near boiling water and then bent, or rubbed with plastic liquid cement while bending. Bending styrene takes some finess, and some practice. Its pretty easy once you get the hang of it though. The main way to bend styrene sheet and rod is with a flame. The cement is used for bending strips.
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Quick Widebody Buildup
Here is a quick build up sequence of how a widebody on a 1/43 Civic Hatchback was built. This should give you a quick idea of how to build it up and how styrenecan be used. Step 1: Building the skeleton. A variety of strip styrene is being used to layout the frame work for the widebody. The styrene is glued to the diecast using CA (Superglue)



Step 2: Layering the skeleton, a little further progress since Step 1. Now liquid cement is being used to attach the strip styrene to the lower layers of strip styrene. The joints are also glazes with a little bit of CA (superglue) to help speed up the process and create a reinforcement while the cement dries.



Step 3: Skinning the skeleton. During this step .030" styrene sheet was used to cover the skeleton and give it some definition. Liquid cement is used to attach the sheet to the strip styrene skeleton. The joints are also glazes with a little bit of CA (superglue) to help speed up the process and create a reinforcement while the cement dries.



Step 4 (Not Pictured): A little bit of Evercoat Euroglaze was used to smooth out the joints, as well as fill some sink marks. Before applying the putty the styrene was roughed up using some 220 grit automotive wet/dry sandpaper so that the putty would adhere. After applying the putty it was sanded using 220 grit automotive wet/dry sandpaper, 400 grit automotive wet/dry sandpaper, and then 600 grit automotive wet/dry sandpaper. It doesn't need to be smooth as glass because often times the sealer will smooth over the rough areas.
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Paint Prep
Standard procedures apply usually. The only difference is that a good sealer should be used before spraying the primer. Sometimes styrene will aborb the primer and reducers causing the styrene to expand and leave ghost lines and also cause for a variety of problems. If you don't want to spend the money on an epoxy sealer, there is a home improvement sealer called Zinser BIN.
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Tools

Hobby Knife/Razor Blades
Hobby knives (also known as X-Acto knives) and razor blades are used for a variety of things relating to body work. They can be used for cutting styrene, trimming styrene, trimming putties, so on and so forth. It is always handy to buy a bulk pack of razor blades and just break a piece off and put them in your hobby knife. Razor blades are often cheaper than buying X-Acto blades.
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Hobby Saw and Miter Box
A hobby saw is very important for cutting delicate pieces of diecast, such as a chop top. Hobby saws are also excellent for cutting some pieces of styrene. Miter boxes are almost a must have for cutting styrene tubing, rod, or strips. It makes perfect cuts quick and painless. Its good to have a couple different saw blades that have different size teeth for different jobs.
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Courtesey of Widget Supply

Sandpaper and Needle files
3M Automotive wet/dry sandpaper is perfect for a variety of sanding jobs, from sanding putty, to color sanding paint. Automotive wet/dry sandpaper is a refined grit and also holds up to wet sanding. Needle files are great for removing mould lines, shaping styrene, shaping putty, and many more things. Its good to have a set of these around.
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CA
One of the most important tools for gluing stuff to diecasts. Know as CA (Cyanoaceletate) and Superglue it is a quick adhesive that creates a good bond when the joints are flush. If you use some accelerator joints dry even faster.
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Liquid Cement
Liquid cement is used for gluing plastics together. Liquid cement contains MEK (Methyl Ethyl Ketone) which melts the plastic slightly, when the two plastics are put together they "weld" to each other. The joint is very strong, and nearly unbreakable.
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Compass and Divider
Used for cutting out perfect circles out of styrene. Take the lead out of one end and put points in both ends to cut circles out of styrene.
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Dental Scribes
Dental scribes are really good for creating panel lines in putties and plastics. They can be purchased from Harbor Freight for a few dollars.
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Zinser BIN
A good sealer compatible with most primers. A good sealer is a must for body work. $5 for a can of Zinser BIN can save you a ton of trouble when painting. The sealer will keep the putties and plastics from absorbing the primer and paint and prevent ghost lines. Zinser BIN can be purchased at Lowes with the home paints (usually not with the other spray paints)
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Courtesy of Decorating Direct