Vacuform Bodies

  by Mike Zimmerman

Part One “Mounting & Cutting”

Tools needed are a small toenail scissors (get the ones with the very thin pointed blades. the bigger ones are useless)., body pins & Dremel ½” to ¾” sanding drum or stone & Sharpie marker. The first thing I do is mount my body with the trimmed interior taped in. The motor will usually be the highest point on your chassis. Put a couple of pieces of masking tape on top of your motor as a shim for the interior to rest on if needed. Put the body over the chassis and get it as low as possible without bottoming out on the tires. I like to leave at least 1/8" space over the rear tires up to the top of the quarter panels. This will prevent your tires from suddenly "eating" your interior when your leading a race in the last 30 seconds of the last heat with a Weasel chomping at you.

Before you punch those holes hold the body in position keeping an eye on the centerline of the guide so as not to create a "cocked" condition. Eye up the center of the guide with the center of the front bumper, adjust your wheel height eyeing it from the rear, side & front and then punch your holes. For Flexi or floppy panned type chassis, pans should be at their lowest point. Apply pressure with an index finger on the center section while holding the pans down with your thumb & middle finger. If this is too difficult you can do one side at a time as long as you keep the other side of the body in the general vicinity of it’s final resting place.

Once the pins are in and the body looks straight, I start cutting along the bottom. Grab your toenail scissors. The sides are easy, just keep the scissor flat & cut along the bottom of the chassis. The rear is usually pretty easy too and opens to how you want it. The front is the most critical on this so I leave more excess on my first cut in that area in front of the wheels and cut a little at a time until it's perfect. If you do a straight cut across the front initially, you can then just cut small even strips off until the correct clearance is achieved. I then do the wheel wells cutting right along the tires edge first to get a round cut. Again, if you have pans you need to hold them in the “down” position while cutting your wheel wells. Make sure your cut is perfectly flush & round with the tire's edge. Then all you need to do is cut about a 1/16 to 3/32" strip around the perimeter of your cut keeping your eye on the material rather than the tire. This should allow enough clearance. You don't want any rubbing. The front wells I usually leave uncut to aid in body strength. Later you can mask them with a lane sticker (about a 3/4" circle) to keep them clear. If you need to cut them out, use the same method as we did on the rears.

Pull the pins out and dress up the rear wheel wells with the Dremel sanding drum or stone to smooth the rough edges (very lightly!!!) The little battery Dremels with the slower speed work best for this operation. Pull off your masking tape shims.

Additional notes for open wheel bodies: Use all of the above steps that apply for open wheel bodies. To cut slots for the axle or axle tubes I’ve found that a paper punch works perfectly. I first set the trimmed body on the chassis at the position I think it will be. I then use a Sharpie marker to mark above each axle on both sides. Being conservative I punch the holes a little below where I think they will be at the top position on all four corners. I then use the scissors to cut slots from the bottom, up to the punched hole. Set the body back on the chassis and lower into position. If more material needs to be removed, use the punch to chip away a little at a time until you achieve the correct height. You should leave about 1/32” to 1/16” gap from the top of the axle to the body to allow movement. Make sure you trim enough off the lower nose area to allow free movement of the guide. A masking tape shim also works well here too before mounting.

The final step is cleaning to remove any mold release agent left behind by the “body man.” Very important. Grab a small bucket or plastic “butter tub.” Run some warm water with a couple of squirts of dish soap. All you need is enough to submerge the body. After soaking for about ten minutes use an old soft toothbrush and a soft acid or paint brush to scrub the inside of the body to help release any contaminants. The toothbrush works well on the sides and the acid or paint brush works good for the corners & top areas. Blot dry with a paper towel and then blow dry with a hair dryer or air pressure. Care should be taken with some hair dryers so as not to warp the body with too much heat. Keep it moving and about 6 inches away.

That about does it for mounting. Next step is "masking". MZ

Part Two “Masking”

The following instructions work best for airbrush application of paint. Paintbrush applications and even some spray cans put on too much material and can cause bleeding, cracking and curling problems depending on the type of paint used and the body material type. Also, I NEVER scuff, sand or steel wool ANY vacuform body for ANY reason. It’s simply not necessary and will only get you in trouble causing any or all of the problems mentioned above plus others.

It is very important to start with good materials. I use the liquid mask on occasion for small areas but, find it takes too long to apply it, let it dry etc. The 3M blue striping tape I use for the 1/1 cars is the best I've found for striping and windows. Purchase various widths from 1/8” up to ½”. Some hobby shops carry something similar but, I’ve never used it. The narrowest is 1/8" but I have laid it on a piece of glass and cut it narrower before with good results. Also get a roll of the regular 3M masking tape ¾” wide and a roll of 2” wide. Cotton swabs & lighter fluid round out the material list. For tools, small bladed screwdriver, single edge razor blades, an exacto knife with #11 blade, small toenail scissor and a pair of tweezers is all the tools you need. The razors are thinner & sharper than the exacto and really come in handy when you need that clean cut. I've found I am more likely to cut through a body with a dull instrument rather than a sharp one because when a tool won't cut you end up pressing harder and cut through. With those sharp razors you apply very light pressure & it's done. You develop a feel for it and get better as you go.

You are now ready to mask. Start with the windows first. This can be tricky if you don’t have pre-cut window mask. . Using the 3M blue striping tape, proceed to mask the window from the inside using the correct width. Rub or burnish down the edges with tweezer tips, small bladed screwdriver or appropriate tool. If you look at the tape from the top side you can tell if it’s fully stuck by the way it looks. This is important to prevent “bleeding” of the paint under the taped surface. When tape is down grab your single edged razor or exacto & cut around the perimeter of the window following the molded lines using light pressure so as not to cut through. Use the reflection of light to guide the razor along the mold line. As mentioned earlier you develop a “feel” for this after a couple of damaged bodies.

Another method for windows that may be easier for beginners is to tape the outside, make your cuts and then transfer the tape to the inside or make templates from a variety of transparent materials and transfer them to the tape, cut out, then to the body. I’ve found this method vital for old coupe bodies with vertical windows. With any of these methods it is important to try not to touch the sticky side of the tape so you can get the maximum adhesion possible. I use the tweezers as much as possible for these operations.

Once your windows are done, don’t forget those ¾” round stickers for your front wheel wells. You can place your body on the chassis and use your Sharpie to place a dot on the body at the center of your front wheels. Remove body and using the tweezers place the sticker in the center alignment of the dot. Burnish down for maximum adhesion.

Now you’re ready for any stripes, numbers or graphics you may need to apply. Decide now whether or not your graphics/stripes will be a light color or a dark color. Figure on painting the dark colors first and lay out your tape accordingly. We will explain this further in the painting segment. For stripes cut a length of desired width from your roll of tape. Stick down one end and pull straight across the panel/s where stripe is to go. The 3M blue tape is great for laying out curves. While stretching slightly lay it down a little at a time to form a nice uniform shape or curve. Use your small blade screwdriver to push the tape into the rear spoiler area and any other crevices in the body. Never stretch the tape across a low spot because it will pull back up before you paint causing bleeding. Hold the end of the tape and follow along with the screwdriver and push the tape into the low areas as you go. If your stripe/graphics are to be done first, you will then need to mask around them with your regular ¾” & 2” masking tape. Always make sure the edges are down tight. Paint can sneak under and if you don’t notice it, will show up in your lighter colors. One trick for any stripes, numbers or graphics is to lay them out on the outside and then it’s easier to follow with tape and/or paint on the inside. Lane stickers can also be used as “roundels” on the inside for the older style sports car numbers. Decals can also be placed on the inside using a dampened paint brush to “steal” some of the adhesive from the back and applying it to the front. This will help adhesion but, this is something I don’t do very often because one good hit usually breaks them loose on the more flexible or thinner bodies. I have also used “body tattoos” on the inside of bodies with good results. Follow the instructions on the package, let dry thoroughly, and then paint. We will cover decals in the final segment.

My final operation in masking is to pull off a 12 to 15” length of 2” masking tape and apply it around the outside perimeter of the body. This will prevent over spray from sticking to the outside. Get it as close to the bottom edge of the body as possible so it doesn’t get in the way of spraying. Push the tape down so it sticks well and trim as necessary at the bottom edge. A final cleanup using a cotton swab dampened with lighter fluid will remove any fingerprints or contaminants from the paint surface. After a quick blow of compressed air to remove any lint or dust, you are ready to paint. MZ

Part Three “Painting”

Tools needed include a good grade airbrush. I use the Iwata Studio Series setup with compressor. This is the ultimate but, is not necessary. The cheaper units can do a great job unless you feel you need to be able to spray fine lines and be more versatile. If not, you can do wonders with just about any name brand gun. The key is keeping it clean and maintained. Materials include disposable rubber gloves, paint, thinner, paint mask & paper towels. Make sure you have a clean, ventilated area preferably with an exhaust fan to spray in. After choosing your colors and the type of paint you will use, you can move forward. I have used the Pactra R/C lacquer Lexan paint for many years with great success. Newer water based paints such as Parma “Faskolor” have surfaced in recent years and provide a great alternative that is a little easier on the lungs and provides good adhesion. For PETG or older Butyrate vac bodies, enamel or Faskolor are fine to use. The Pactra R/C paint or any lacquer product is risky on these types of bodies but, can be used with caution. It’s your choice. I have the most experience with Pactra R/C and to me it’s the best on Lexan. If you can’t find your color, you can always try mixing shades together. A food dye chart is handy for figuring out what makes what color. Some trial & error will achieve better results. Start out experimenting with only drops of paint to keep down waste. When you figure it out, mix what you need to paint the body.

As mentioned in the masking segment, the first color you spray should be the darkest one and then lighter as you go. This will prevent a stained look. A good example is spraying white down first and then doing a red stripe. Red is one of the stronger colors and will show through the white possibly giving off a “pink” hue or a blotched, stained type look. Multiple coats of white could make this less of an issue but, the object is to only put the minimum amount of paint needed on your body to cover and prevent a transparent look. Some colors will cover better than others. You will become familiar with these and other problems as you go. Going back a bit, if your stripes are dark and your body light, you may have to adjust the way their laid out so you can spray them first or vice-versa.

The R/C paint is usually mixed with 25 to 50% thinner, that depends on the color and is something else you have to experiment with. Mix your first color, pour it in your gun cup and your ready to go. Spray the first coat on the light side but not too dry. Just a smooth, even coat. Don’t lay it on too thick especially around your taped areas. Let this first coat dry thoroughly and this will create a “seal” around the edges of your tape, hopefully preventing bleeding. Even if the paint appears dry, it may not be. Test it with a finger on a masked area. If it’s still soft, hold off for awhile. Don’t rush; having some patience here will produce a better result. Finish with a second medium coat and let dry (flash off) to a dull finish. The trick here is not to lay on the paint too thick. This can cause numerous problems including warpage, bleeding or cracking & can actually weaken the Lexan. If a third coat is needed apply it as you did the second coat with adequate drying time. Hold the body up to the light to see how transparent it is. Some transparency is fine and not noticeable. Bring the body down to belt level, wave your hand or an object under it. If you can’t see the object or it’s just barely visible you probably have enough paint applied.

After a good dry down time, from one hour to overnight, you are ready to pull the tape. Never pull tape off when the paint is still wet. You will ruin your hard work. The old saying, “haste makes waste” fits very well here. Pull your tape off from as sharp of an angle as you can to prevent pulling paint from the body. This usually isn’t a problem if all of the above procedures have been followed. Once your striping tape is removed, hold the body up to the light. Did any paint sneak under the masking? If so, a little enamel reducer on a cotton swab using a quick swipe will remove it. Never use lacquer thinner for this operation. If your using Faskolor use a swab dampened with water. Novus polish or an ultra fine rubbing compound will also work but, the residue or dust will have to be cleaned up before your next coat of paint. Follow the above procedures for each subsequent color you will be applying. A good overnight dry leaving the body sit upside down is always best before detailing. While your waiting, this is a good time to paint your driver/interior. Spray the interior the desired color. Detailing of a driver and how far you go with it is up to you. Enamel colors work fine for this. You can do anything from painting a helmet & suit one color to cutting out a face from a magazine & mounting it behind the drivers shield along with seat belts, cigarette, and drivers’ suit sponsors and on & on. Some drivers/interiors especially on the more vintage classes give you more of a pallet to get creative. On large dashboards I especially like to do a nice job on the gauges. There doesn’t seem to be a lot of dash decals out there so, you’re stuck with hand painting. With practice, a dash gauge can be done to look pretty good. Once you’ve finished it, a drop of clear epoxy strategically placed on the gauge creates a great look and gives “depth” to it. This is just one example of what’s possible.
Now on to the next segment, Part Four-“Detailing.”
MZ

Part Four “Detailing”

Detailing is totally optional and what you want it to be. How far do you want to go? You can just stick some numbers on your body & go race it, or you can make it into an authentic looking race car and/or concourse winner. It’s your choice. Even a poorly molded body can be vastly improved with good detailing. Tools & materials needed for this segment include some of the previous plus, a variety of paint markers, paint brushes & enamel colors. Brush cleaner, invisible Scotch tape & reinforced packaging tape round out the list. I use sign painter’s lettering enamel. It is a great product and sticks very well. The best thing is it dries slow allowing your brush to move freely and giving you time to work.

If you have decided you need to try hand lettering, this would be the time. Painting on details with a brush is a learned process for most people. For a minor few it comes very natural and they can make it look easy. I am in envy of many artists I have seen of this caliber. It’s a gift from God. I am one of those who has gotten decent results from many years of practice dating all the way back to childhood, building models. My profession of Auto Body repair & painting has helped tremendously in my understanding of the materials and how to use them. For any detailing using any method, a steady hand is very helpful. Positioning of your work piece is also important. I use a “multiple grip” stand purchased from Micro Mark. It has multiple, flexible arms with alligator clips on each one with a steel base. These are great for any modeling project. I placed clear tubing on the jaws of the clips to prevent any possible damage to the work piece. Once the body is clipped in, you can position it anyway you want. This is especially helpful for brush painting your details.

Once you’ve decided on your lettering and where it’s going to go, clean the area using a cotton swab dampened with lighter fluid. Lay out your lettering on a piece of scotch tape with a fine marker the size you want it. Transfer this to your body just below or above where your letters will go. Use it as a guide as you go. Another trick is to perform this procedure before the body is painted, using a template or picture of your lettering or graphics from a magazine or pamphlet. Place it under the body where you want it to go and “trace paint” it on the outside. This method can also be reversed by first covering the outside area with invisible scotch tape and tracing the letters or graphics out with a Sharpie pen. Then proceed to letter from the inside following the lines. If doing the latter, a compatible paint should be used that will not react to your body paint. Lacquer cannot be sprayed over enamel. Enamel however, can go over lacquer. One trick I learned with lettering is to constantly clean your brush. Even the slow drying lettering enamel tends to thicken up after a few minutes preventing a good flow but, a quick brush cleaning and fresh dip into the paint again works wonders. If you can get a constant flow of the paint for each line without stopping, it will come out much better.

With decals make sure the surface is clean, using a cotton swab dampened with lighter fluid.

Sticker type decals are very popular today and probably the best option for vacuformed bodies. Cut around the sticker as close as possible with your knife or razor. Use a tweezer to place into position. As mentioned earlier, keeping fingers off of the sticky surface will provide better adhesion. Pressing & lightly rubbing is usually adequate for good adhesion. With waterslide decals more care needs to be taken. Cut out as small as possible and place in water for about a minute. Older decals may require more soaking time. Remove and test for “slippage” then apply holding the paper with one hand and sliding the decal into position using a tweezer. Decals like to stick to fingers so try not to touch them. After all decals are applied, wait about 10 minutes and apply a decal setting solution such as “Solvaset.” After a minimum 2 hour dry time, seal them with the shiny Scotch tape and use your razor blade to cut around the decal leaving about 1/32 to 1/16” overlap. Future floor wax is another option I’ve heard of but never tried. An overnight dry is best before applying tape or wax to decals.

The next thing I like to do is the body lines, window lines or moldings, and any other detailing using a paint brush or marker such as hood pins or rivets. Mind you, I don’t do all of these on every project I do. It depends on color, type of body represented etc. Body lines or moldings can be made to look realistic with a little patience. Paint markers are a good tool for the beginner. I would stay away from ink type markers because the ink will bleed & smear. Over time it also rubs off much easier than paint. Painting on details with a fine brush is also an option for anyone. One way is to just do your lines as straight and uniform as possible using any of the above methods. Another is to use your #11 exacto knife and lightly scribe your body lines and then apply your paint or, even ink works OK here. When dry, a swipe of a paper towel or swab lightly dampened with lighter fluid will remove the excess leaving a fine line only in the scribed area. Ink and paint will hold up good here because it’s not on the upper surface but below it. Now is the time to do any hood pins or rivets using a light touch of your marker or brush with the appropriate color.

After a thorough drying time I then mount my interior using reinforced packaging tape. Do a thorough job especially in the rear to prevent your tires from rubbing. Then it’s time to reinforce your body. Using the reinforced packaging tape cut out pieces to fit the inside of the rocker panel area of your body to help strengthen the pin mounting area. One layer will do. Next is the front end, which seems to take most of the beating. Cut and fit pieces for the bumper and fender areas, burnishing them down firmly. Again, adhesion is better by keeping your fingers off. Once that’s done strengthen the corners and over the wheel wells with clear silicone adhesive. Hopefully, all of this along with “defensive driving” will keep damage to a minimum and your body will look good throughout the race series. Poke out your pin holes through the tape and mount it. Time to hit the track and try out this monster! MZ