Using a vacuum forming table to make NPC armor?

[FrankManic]

So my brother asked me to make him a suit of stormtrooper armor, and after telling him no and directing him to some DIY sites I started wondering if a home made vacuum forming table could be used to make a lot of cheap, reasonably durable armor bits to spruce up monsters, NPCs, and other plot characters. Vacuum forming seems like a pretty simple way to, say, make up some grungy breastplates for that band of orc raiders to wear, or a set of helmets to identify the elite gnolls.

Has anyone worked with vacuum forming before? How cost effective would it be if you already have the space and the tools (heat gun and vacuum)? If I were to, say, make a cast of a breast plate about 20 x 24 inches, what do you suppose it might cost to make each one?

 

[Wraith]

I've done a bit of research into it, but haven't had the room to test it out. Not to mention not wanting to haul a bunch of armor the 300 miles to the nearest chapter to see if they want it.

 

[jpariury]

Cheapest high impact styrene I've found is from US Plastic Corp. A 40"x72" .06 costs just under 20 bucks. (I use it for 40k modelling) Even if you went with the thickest stuff they have (and I don't believe you would necessarily need to), at 24x20, you can get 6 pieces out of a single $100 investment. I've been wanting to build a vacu-form rig, but apartments don't lend themselves to much workbench space.

 

[FrankManic]

Tell me about it. I've got about a third of a functional shop crammed into a closet in the back of my apartment.

Still, ~20 dollars for a piece of armor is a pretty good deal, especially if one were to make it in numbers that would help to bring the price down. Painting and making the forms would add to the price, but not unduly. And the time investment in each piece would be relatively low. I've seen ten minutes quoted as the time to heat and set the plastic, plus another hour or two to give it a basic paint job and strap it. The next cheapest armor solution I can think of is leather scale armor, which involves cutting out hundreds of scales, punching, and lacing them for each suit. Time is definately a factor there.

I've got friends I can draw on to help me with the scuplting of the forms, and the table itself is pleasantly low-tech. The ability to, say, make a standard breastplate form, then modify it by adding additional pieces to the form before pulling the plastic means you could create a lot of variations easily. And if you used the right material it would probably last forever and a day.

Poking around the net I found a possible alternate source for the plastic. HDPE food grade plastic barrels apparently get used for all sorts of processes, and I have a sneaking suspicion that if you spent enough time with the phone book you could find people willing to let you take some off your hands. Give them a good wash, cut them, flatten them in an oven or with a heat gun, and stick them in your vacuum forming table. Apparently large soda distributors like coke and pepsi are a likely place to start looking for freebies.

I think I'm going to give this a shot. It might have to wait until summer, but it looks like a viable process.

 

[markusdark]

Here's a little tidbit of information. My first job out of college was in New York called "Costume Armor" that made plastic armor for Movies, TV and Broadway (http://www.costumearmour.com/). Someone from NERO (when there was only one game as in only the game in MA) came down to have a chest plate custom made for them and gave me the 2nd edition rulebook when he left. My love affair for LARPing then began.

Vacuum forming is a quick way to do multiple sets of things if you have the right machine set up. I even made plans for one that can be stored under a bed (apartment guy here too). However, I wouldn't bother with making one unless I had guaranteed plans of producing at least 100 units of something. The good news is that if you actually built one that you could use easily, you could make the molds for stormtrooper armor and sell kits (currently selling for over 500 per set - and you could sell it uncut if you wanted to).

The part that's not mentioned here is making and storing the molds for said items. I guess since it would be impossible to make an industrial strength machine by most people, you wouldn't need the molds made of plaster and wood - a breast plate mold weighing around 60 pounds. But plaster is the easiest way to sculpt the form. Then there's. And having about 6 molds would mean losing a good amount of square footage to storing them - this coming from the guy who has mask molds tucked into every corner at home.

 

[jpariury]

But plaster is the easiest way to sculpt the form. Then there's. And having about 6 molds...

Then there's what? Curse you, man! Don't leave us hanging!!!

Frank, if you get it up and running, you should post up some pics. I could see you making some decent pizza cash churning 'em out.

 

[Wraith]

I've got the plans around here somewhere for using a vacuum pump and an good sized air tank to get enough pull for the heavier ABS plastics without the investment of an always on vacuum source that's industrial strength. Unfortunately, they're on my other PC, which is in pieces scattered around my closet.

They were based off of these plans however.

 

[FrankManic]

Two questions about the molds, then. Firstly, could you use a metal example of what you wanted to make, like an actual metal breastplate, as a mold? And secondly, could you create a modular mold by making a base, say an unadorned breastplate mold, and temporarily attaching details to the base mold when you're actually pulling the plastic?

 

[jpariury]

I've never seen someone use metal forms. I suspect that metal will conduct and reflect back the heat of the plastic.

 

[markusdark]

But plaster is the easiest way to sculpt the form. Then there's. And having about 6 molds...

Then there's what? Curse you, man! Don't leave us hanging!!!

Frank, if you get it up and running, you should post up some pics. I could see you making some decent pizza cash churning 'em out.

Sorry about the "and then" it was leftover while I was piecemealing my message. Funny thing, a vacuum form machine doesn't make a good pizza oven. Often the heating coils are much hotter than an oven in order to quickly and uniformally melt the plastic. So you get a crispy top and raw bottom. Things you try with a vacuum form machine while you're slow at work. I won't mention the dead horse experiment. oops.

You could use a metal example - the only issue with it is the heat retention of the metal. It could cause the plastic to not hold it's shape by keeping it warm. You want to cool the plastic asap. Also, you will need to put a 'body' under the breastplate. You can't have any undercuts else the plastic will lock with the mold. Not to mention the metal could deform due to the pressue (although with a home setup, that probably won't be an issue) Also, it is always good to dust the mold with baby powder before the pull to stop any sticking issues.

Although you could concievably attach details, the detail from a vacuum pull is very faint at best. What we did was make latex molds of the detail work and then hot glued the latex pieces to the plastic before painting. Of course with LARPing, those things would probably get knocked right off. Also, when you start wanting detail, you have to drill holes through the mold in the places you want the plastic to be pulled down into (the 'valleys' of the mold).

I have WAAAAY too much experience in LARP related subjects.

 

[FrankManic]

Hrm. So I'd be better off making a relatively simple form and adding any details after the vacuum forming was done?

Some days I wish I had access to a couple of hundred dwarves and whatever it is they use to make car body panels. Hmm.

I'm tempted to take a HDPE shield, glue various kinds of adornments too it with different adhesives, and see which ones hold up best to the rigors of combat.

Is there any particular reason that one could not make both a positive and a negative form, then sandwhich the hot plastic between the forms and quickly apply pressure to shape the plastic? To my ignorant mind it seems like you could get a bit more detail on the surface of the plastic this way, though it also seems that making the positive and negative molds out of something sufficiently durable would likely be very, very expensive.

 

[jpariury]

I suspect you'd end up with a sandwich, with the plastic acting as a bond between your two forms.

 

[obcidian_bandit]

When you vacuform you don't need to sandwich, the plastic takes even pretty minor details on the positive.
I've never heard of anyone doing it with a metal form. If you're worried about it heating up, maybe throw a piece of dry ice under it? Metal heats up faster, but it cools down faster, too.

 

[markusdark]

When you vacuform you don't need to sandwich, the plastic takes even pretty minor details on the positive.

Only if the plastic is thin enough or the design simple enough or the vacuum strong enough.

Here are some examples of what an industrial strength machine can do:

I believe you could get this with some slightly thinner material and a home made machine. I should note that the shield above is about two feet in diameter so the tentacles are roughly 2 inches wide. The more fine detail you put on the mold, the less likely it will come out well. Also, the paint job is specifically done to bring out the highlights. So if you went with simple stuff, then yes it would work. You'd want to test the plastic after making a pull as the plastic does thin a little upon processing and could easily break or tear upon combat.

If you have a breast plate you'd want to duplicate, my suggestion to you would be to use duct tape to turn the inside of the breast plate into a 'bowl' that you could fill up with plaster. Then, put the plaster mold onto two sheets of 3/4" plywood that are the same shape as the bottom of the mold. You need the extra height as when you pull the mold, the plastic will bow and web at the bottom of the mold. You'd also have to drill holes through the mold for any detail work. For example, in the first picture, there are 8-10 holes drilled along each flute line.

The sandwich techinque only really works when everything is done when heated to temperature then allowed to cool (including the forms). The moment the plastic hits the form, it begins to cool and won't get into the form as deep as you'd think. In addition, you'd have to line it up perfectly for each hit and hit the entire piece at once. Hard to do without the proper machinery.