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Vacuforming

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What You'll Need

There are 6 essentials items in starting out vacuforming models from scratch.

• A heat source
• A vacuum cleaner
• Vacuform machines and boxes
• Molds or blanks
• Sheet plastic
• Glue

And, of course, finally building the model.

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Heat source

The heat source can be (and usually is) your kitchen stove. There are variations on what part of the stove to use. Some use the elements on the cook top, but I prefer to use the broiler on an electric range. If you use the cook stove top, you have to ensure that the plastic never comes in contact with the heating element. This is something hard to control, whereas if you have a electric range then the broiler elements are on the top, and if one is careful, you are less likely that you will burn your plastic.

If your home's cook stove is a gas oven, than I would suggest that you use the oven element for general cooking. Be sure that you place the plastic well above the cooking/heating elements, and watch it closely. In other words, never close the oven door while you are heating your plastic. If you do not get your plastic hot enough, it will not suck down around your molds, and you will have to do it again.

How do you know when the plastic is heated enough? By experimentation and practice you will soon know when the plastic is ready. Essentially the plastic is ready when it sags enough that it is touching the oven rack. Besides waiting until the plastic is resting on the cooking rack, the erasure end of a pencil is helpful in checking the condition of your plastic. Edit

Vacuum Cleaner

The vacuum cleaner can be an upright, canister, or shop vac. I use a shop vac that I've had for many years. Any vacuum cleaner that comes with hose attachments will work, with the exception of those small vacuums used for cleaning out your car. They generally do not have enough power to suck the plastic over your molds. You will need to measure the hose attachment to decide the size of the hole to drill in your vacuform machine/boxes. If at some point you change vacuum cleaners, than you should be able to find PVC tubing, as in for building water pipes/plumbing, about the same size. You will benefit by having someone throw the switch of your vacuum cleaner, as your attention will strictly be limited to the proper placement of the heated plastic over the mold. You need three hands if you do not have a friendly volunteer.

You will pull the heated plastic over the mold until the outer rim of the plastic is in contact with the grate of your machine. Then the shop vac is turned on. This ensures that the air will be limited to the area that is supposed to be sucked down. Don't try to have the vac on while you are moving from the stove to you mold. You are only wasting time and plastic. Edit

Vacuform Machines or Boxes

The third crucial part of your vacuforming is the actual machine/box that the molds/blanks rest on. I have made 3 machines that I use to make my models. Yes, I have the Mattel, from when I was a wee one, but IMHO it is useless.

The first box is the smallest one and my newest. I made it from part of a cigar box. The top is 3.75" x 4.5." The grate on top is made from a food grater (also in the picture up top). As with all 3 machines, a 1.25" flat (sometimes called a spade) drill bit was used to drill the holes in each machine. The size is the same diameter of the hose attachment for my shop vac. The frame that holds the plastic consists of 2, 3/8" pieces of plywood that I cut out about 1" wider and longer than the box itself. The inside of this frame was cut out with a bandsaw, but a schroll saw will work just fine. Binder clips hold the sheet of plastic between the plywood frames. If you don't know what binder clips are you will see them later as we build the Whitestar.

The second box is the one if I first made many years ago. It was my first built machine. It is made of plywood with an aluminum plate that I drilled holes into. The frame that holds the plastic has hinges on one side and a C-clamp is used to lock or hold the plastic in place. The size of this machine is 5.5" x 4.75".

The third, my largest is made of 3/4" pine with a cardboard bottom. The grate is made from peg board, the type that is used in shops to place hooks for holding tools. This machine is 7.25" x 10.25," and to date is my largest. Now, when using peg board on such a large machine, you will need a center support or the suction will suck the plastic, mold, and the peg board down. This support can be a wood dowel cut to length, and glued, or nailed, or screwed in place. In mine, I had a piece of a light diffuser, the kind used over florescent light fixtures that have numerous .5" square holes. Strips of 1/8" strips of pine and binder clips secure the plastic in a frame while it is being heated.

Each machine is sealed with either caulk, glue, or duct tape - "the handyman's secret weapon," or a combination of all of the above.

Remember, you don't want any air escaping from holes other than the grate where your mold rests. If air does escape, then it might not vacuform properly around you mold. Seal your top plate/grate in place, as well as the sides and bottom. Edit

Molds or Blanks

Molds or blanks as discussed in this article will be of the male persuasion. Female molds have the plastic sucked or blown into a concave mold. This is harder to do than making male molds, or blanks in which the plastic is drawn or sucked down around the outside of the mold. The molds can be made of practically anything that can stand the heat of about 150° for about 40 seconds.

Let's say you are down to your last Leggs pantyhose egg, and you want to make a copy. If you try and vacuform over this, it will possibly distort you egg mold due to the heat. You can however invert the Leggs egg, fill most of the way to the top with water, and place in you freezer until solid. Then you can make a copy of the egg without it distorting.

What else can be used to make molds? You can use all of the following and probably things I could not even think of:

• Plaster of Paris
• resin (as in the 2 part resin used to make resin model kits)
• Sculpey
• wood
• metal
• potters clay
• cement

Say for instance you find this really cool blister pack that some item came in. A blister pack is packaging that an item is purchased in and is usually suspended from a hook in a department store. A blister pack in itself is a vacuformed item. You can fill this blister packaging with plaster of Paris, resin, or Sculpey let it cure and vacuform over it, as many times as needed/wanted. Just for this article I took finished part # 2 and pressed Sculpey into it to show how a part can be reproduced quickly with a baking clay and then vacuforming. Though this picture does not show the detail very well, you can almost make out the scribe line.

For the purposes of illustration we will look at wood as this is what I used for making the Whitestar.

Any type of wood will work for making the molds. If you have access to a belt sander, finishing sander, scroll/bandsaw, I would recommend using pine. You can still get pine rather economically in a width or length of your choice. I usually use .75" or three-quarter inch thick pieces. It is sturdier, and can be reused several times making new vacuformed pieces. If you don't have such items as a belt sander and finishing sander about your house, you will want to stick with the more costlier bass and balsa woods. Bass and balsa are easy to sand with simply hand held files. I use a combination of pine and balsa or bass wood. I make most of the pieces out of pine, and some of the smaller pieces out of the more costlier woods.

Another reason to use pine as much as possible is that the wood is hard enough to allow you to use the mold as a cutting background or cutting block to cut your vacuformed piece to size. Also, using pine will allow you to drill a hole in the back or bottom of the mold, insert a wood screw, thus allowing you to more easily remove the mold from the finished a vacuformed piece. Patching either wood is simple with something like Squadron putty. Have to use balsa or bass? Soak the finished item in several generous drops of superglue. This in effect makes the wood more durable. Edit

Sheet Plastic

Sheet (polystyrene) plastic can be purchased at any hobby store, but at a very high price. If you live in a metropolitan area, look in the yellow pages for plastic dealers. I buy my main plastic in 4' by 8' sheets. A .040 thick piece of plastic in a 4x8 foot size cost about $14 a year ago. I've made several models form this one sheet of plastic, and I still have about 2' by 4' left.

For objects that do not have a lot of exterior detail such as the Whitestar, .040 is perfect. It gives the model strength and is self supporting without a lot of additional support. What do you mean by self supporting? Well if you have a part of the ship that is fairly long and a small diameter, and you are using thinner sheets of plastic, then you are going to have to laminate pieces inside your finished product to give the extra support so as the model will not start drooping or sagging over time. For models that have a lot of surface detail such as raised panels, I would suggest going with something around the .015 to .020 thickness. This can also be found in 4' by 8' sheets.

As clear sheets are fewer and farther between, than just go with the sizes available at your local hobby store.

For clear parts it would be nice to be able to use soda pop bottles, but forget it. It just don't work. You can save the clear plastic from all those blister packs for vacuforming, because most blister packs are of the right type of plastic, and about the right thickness works extremely well. It was the recycling blister packs that made me build my smallest vac box. It made the clear plastic go further.

As an aside, there is a method for recycling those empty Coke bottles. The process is called "theraforming" by some. Essentially you have a small, and I do mean small part that you want to make in clear plastic. Mount the small mold in a vise. Use hemostats or pliers to hold a piece of the coke bottle over a candle flame. Make sure you don't hold it too close. Once the plastic starts to give, then quickly force the pop bottle over the part. This will work only so so, and the mold will have to be very sturdy. Another example of theraforming is with my NCC-911 U.S.S. Lister. The entire secondary hull is one piece of pine. I then laid a piece of plastic along part of the hull and baked it until it fit around the one side. Rotated the blank did this again. Then the 2 strips are glued, and a sheet of plastic is vacuformed over the entire wood blank for the secondary hull.

Vinyl is also useable as a source of plastic. The vertical stabilizers (or whatever you would call them) on my Whitestar are made from some "For Sale" signs that I got cheaply from a hardware store that was going out of business. The only problem with vinyl is that superglue or model glue does not react with it, thus an epoxy glue must be used. There may be some special glue out there that works, but I do not know of it. Vinyl does vacuform just as easily as polystyrene plastic. For an interesting effect such as organic skin on a ship, use vinyl signs that have been heavily painted. It gives a texture such as what is seen on Whitestar 90, (I believe that is the correct call sign.) Edit

Glue

You will probably want to have an assortment of glues on hand. Superglue is the usual choice, but there are times that plain old model glue will work. Sometimes you will need an epoxy glue. I also recommend 2 part epoxy glue for filling areas that need support or will be drilled out to add something else to it.

With injection plastic models you usually have alignment pins that mark where your parts go together. Well with vacuform models you have to make your own alignment pins, but in this case it is more like alignment strips. Either using strips of plastic already cut and packaged "expensive," or simply using left over scraps, you would start gluing the strip to the inside of one side of the part leaving a lip or rim for the adjacent piece to attach to.