Bacteria's project - making a vacuum forming table

bacteria · Post by **bacteria** » Tue Oct 14, 2008 4:40 am

Ok, as reported in the Playstation forum here, time to try my hand at making a vacuum forming table so I can hopefully make some quality cases!

I saw one available from the US which was about right, but would cost about Â£90 or so shipped; nah, I was going to make my own anyway! If I can build cabinets and desks for my home (as I have done) I have the skills to make this too - if it works well enough is a different question entirely. If I can make one, then anyone can make their own if they follow my guide!

This could end up being rather successful or a flop; either way, as is usual for my projects, I will provide a step-by-step guide on this thread, to making a table and the vacuum forming itself.

Just bought some materials:

* Sheet of fibreboard (like you use for picture framing), 3mm thick, 606mm x 1220mm. This should be all I need, if not, I just found a second sheet in the garage I could use. It should be strong enough as the table will not be very big.

* 2 x strips of pine strapwood, each are 2400mm long, 18mm x 10.5mm. These will make the frame for the styrene, the surround, joints and basic frame for the owen unit.

* two pieces of plumbing - one 90 degree piece and one short straight piece. This will ensure the vacuum suction is directed to the centre of the board for evenness.

Total cost of the above: just under Â£10 (about $19). Nice and affordable!

I have an old Dyson vacuum cleaner which doesn't work for the carpet anymore (so I replaced it a while back) but the tube extension works great, lots of suction. Using the Dyson is ideal as it is powerful and also, if it dies, doesn't matter - was only using it for jobs like vacuuming the car anyway!

I have enough tools and drills for the job, and a good quality staple gun too with 12mm stapes, power drill, saws, screws, glue gun, etc. To keep everything airtight, I have some silicone you use for the bathrooms and also "no more nails" to help too.

Out of time today, intend to work out all the measurements for everything tomorrow, so can make a start.

HBN · Post by **HBN** » Tue Oct 14, 2008 8:13 am

Good luck. I might use your guide if it works out. We use a Dyson around the house (One of the newer Dyson Ball's. The purple/Pet version.).

Dysons are awesome (Anybody who doesn't own one, should buy one), and I actually wondered before if they'd do VacForming. I'm keeping an eye on this one, bacteria... Like a hawk.

One thing you should know: The Dyson we have has an internal safety valve that will "Pop" if there is a major clog and cut suction from the container (Cuz it can, and sometimes will cause that dirtcatcher to implode). Yours may have one too. You might have to remove it, if it does.

To find out if it has one of these valves, turn the vac on (Without the beaterbar being on, if possible) and cover the "Wand" with your hand. If you hear a slight "Pop", and the vacuum gets louder, it's got one. If not, then it was before they added that feature.

As I said, good luck, and I hope I've been some help.

bacteria · Post by **bacteria** » Tue Oct 14, 2008 1:08 pm

Thanks for the comments. My old Dyson is a few years old now, about 8-9 years, so probably doesn't have the valve!

HBN · Post by **HBN** » Tue Oct 14, 2008 1:10 pm

If it does, I don't foresee it being to difficult to remove it.

bacteria · Post by **bacteria** » Tue Oct 14, 2008 3:38 pm

I will test the vacuum cleaner by keeping my hand over it to block the airway for several seconds and see what happens. The system is bound to sound "a bit stressed", but as long as it keeps chugging along and continues to try and suck as soon as I release my hand, I will assume it works fine - after all, that is a pretty fair scenario of what will happen on a vacuum table.

bacteria · Post by **bacteria** » Wed Oct 15, 2008 2:45 am

Test vacuum cleaner, put hand over the tube whilst machine was on, kept suction going, no increased noises, etc, no cut-off; removed hand, suction still as good.

Ok, here is my WIP diagram below.

The brown strips are the 3mm fibreboard, the sandy yellow blocks are the 10.5mm x 18mm pine stripboard pieces, light blue is the polystyrene sheet, orange is the plate to hold the mold with holes for the air to suck under, dark blue is the PVC plumbing attachments for the vacuum cleaning nozzle.

The design means that when the polystyrene sheet (screwed in place sandwiched between two frames) is placed over the mold, the sides of the frame will drop into the table and maintain an air tight seal (just need to put in some foam or whatever needed). You don't want to hang about after all, once the plastic comes out of the oven it needs to be placed over the mold and into position on the table quickly.

The centre of the table top only needs one hole, to suck air from the centre of the plastic sheet (where the screen goes, hole will be cut out there anyway), the main airflow will be more on the mid and outer section. It would be counter productive to have too many holes in the case as each hole will reduce the suction of the others. More on that later.

Here is the design so far, just working out the sizes I need to make everything:

(updated pic)

I will also have to make a container for the frame, when in oven. Only needs to be simple, and allow for a drop of about 9" max for when the plastic heats in the oven.

If it results that there isn't enough suction in the system, I can change the plumbing pieces and have two vacuum cleaners sucking at the same time to double the power. Hopefully I won't need to do this.

Oh yes, forgot to add: the plastic is 325 x 220mm as mentioned before. Each side of the frame takes away 18mm for the usable area. This means that the largest surface area for the process will be 289 x 188mm. This will give about 20-30mm gap on each side of my mold for the console (case designed to be c. 222 x 140mm, although I might make it just a few millimeters more so everything isn't quite so crammed together!.

Should be enough. Buying larger plastic sheets costs a lot more money and the larger the vacuum table you make the weaker the suction, so hopefully (?) my system will work efficiently; at least, that's the theory!

bacteria · Post by **bacteria** » Wed Oct 15, 2008 4:46 am

Run out of project time today, back tomorrow with more installments!

I have so far cut out the wood for the two frames for the plastic sheet and screwed them together. I took a pic of one of them (both are identical) and for the purpose of illustration, put the outline of my proposed case inside the frame. On the left, is the plumbing attachment (two pieces connected, a connector and right angled joint).

(This is my V2 version, the first one I made too big)

I will have most of Monday and Tuesday for project work next week, so hope to have the build done by Tuesday sometime. I don't have to make the table look pretty, far from it, so that saves time. It does need to be quite airtight though.

For most of the rest of the build I will continue using screws, so quick assembly.

I am hoping there is enough clear space for the mold to work. It will be made in two halves, so the total height of the mold will be about 24mm or so (so about 30mm to allow for extra on the sides to trim).

As there isn't as much clearance as would normally be ideal, I know, so I will probably only drill holes in the table around the perimeter of the mold itself, to ensure best suck in the right places.

Have enough materials to make the table, however I don't have a mold yet, forgot to get something from the hardware store so will need to go back again soon.

I have a 2000W hot air gun; looks like a large hair-drier. Bought it at a car boot sale a few months ago for Â£2; just tried it, wow, it gets really hot really fast! I plan on using it if the plastic doesn't form around the mold completely to "re-encourage it"; this baby will be good! I will need to be careful though not to overheat the plastic with it.

I have put quite a lot of thought into this system and think I have a good crack at making it work; although time will tell.

collinE · Post by **collinE** » Wed Oct 15, 2008 12:34 pm

That's going to be a nice setup there.

Mine is a 12x12x4in box with a hole for the vacuum hose. Cost of $10 total and looks like it.

Can't wait to see more and maybe a video of it in action.

bacteria · Post by **bacteria** » Wed Oct 15, 2008 1:21 pm

collinE - Thanks! Yours is about the same surface area as mine then. I basically looked on e-bay for the sheets that were a decent size but not too big and therefore expensive. I paid about Â£20 for 8 sheets of the stuff delivered (you can pay much more!). They should arrive in the next couple of days or so.

Mine will cost about twice yours; I could have made it for free from off-cuts, however as these off-cuts are 18mm MDF it would have been heavy and hard to tool; so paid a small amount to do it properly.

Mine will look semi-crap, that doesn't matter; what matters is that it works properly!

I will try and make a video, however my camera only works for a couple of minutes before running out of video space, and the process from oven to system might take longer; anyway, will do what I can in due course.

Question - I don't have heavy duty tools for shaping hard woods; would Balsa wood be strong enough to survive the vacuum forming process as a mold? I am trying to think of a material that is strong enough to survive the process and also be easy to shape, sand and file to size. Ideas?

HBN · Post by **HBN** » Wed Oct 15, 2008 1:28 pm

bacteria wrote:Question - I don't have heavy duty tools for shaping hard woods; would Balsa wood be strong enough to survive the vacuum forming process as a mold? I am trying to think of a material that is strong enough to survive the process and also be easy to shape, sand and file to size. Ideas?

Answer - It MIGHT. I'm not sure, though. It could give you rounded corners (As the corners are the weakest part of a balsa brick). I suggest using plaster as a mold, actually. Its far easier to work than balsa.

If not plaster, maybe Poplar wood? Its harder than balsa, but works a lot like balsa.

bacteria · Post by **bacteria** » Wed Oct 15, 2008 1:45 pm

Poplar wood? What's that (and where do I get it)? If not, might try plaster.

HBN · Post by **HBN** » Wed Oct 15, 2008 2:15 pm

Poplar: http://en.wikipedia.org/wiki/Poplar

Its a hardwood. Very fast growing. Some hybrids of poplar can snap in high winds.

Seems durable enough for vacforming.

Not sure where you can get it. But that wiki might give you some ideas.

Tibia · Post by **Tibia** » Wed Oct 15, 2008 6:58 pm

Personally, I don't understand why balsa wouldn't work. Yes, it is a soft wood, but as long as you're using a solid form of it, it isn't going to collapse. I admit, I don't do vaccuum forming, but if I get into it, I'd probably use balsa forms. It's very cheap and very easy to work.

bacteria · Post by **bacteria** » Thu Oct 16, 2008 1:25 am

Yes, been giving this thought. I used to use Balsa wood when I was a kid, making aircraft models from designs I made. It is quite weak as wood goes, and may not be suitable for vacuum forming if laid along the grain (ie wood flat) but if the wood is carved with vertical pieces, it would be far tougher as using the grain of the wood more. This is consistent with what I am looking to do; as the hard part of the vacuum forming will probably removing the mold from the plastic afterwards (as collinE discovered with his plaster mold). If the mold is made up of 4x3 blocks, or whatever, you just remove a block at a time until the rest drop out, leaving the plastic covering; that is my idea anyway. If the wood needs reinforcing, varnishing it before using as a mold will seal and make it stronger.

bacteria · Post by **bacteria** » Thu Oct 16, 2008 6:44 am

Some updates:

After making both frames the right size, stapled some mounting board onto the sides (as one piece). This will help keep a strong grip on the board and also make it airtight. Obviously, can't paint it as the paint will fire when in the oven (hence staples).

Then the acid test - preheated my oven to 230 degrees celcius (about 445 farenheit) and put both frame sections in for 10 minutes. Came out fine, no smoking, hot to touch but not extremely hot. Next acid test was to put the wood frame onto foam and press in place for a while to see if the foam gets marked or burnt - nope, absolutely fine. This means I can take the frame straight out of the oven, press it against a foam base (to be airtight) and no issues - great!

The browning on the foam is not from the heat, it is old foam I had lying about, looked like that before.

The polystyrene will be sandwiched between the two frames (and the mounting board) and all held in place by screws to keep it secure.

My 8 sheets of polystyrene arrived and the glue (it is described as plastic welding not bonding, so really tough).

Ah, the 2mm polystyrene is very attractive, however it is flexible a bit, not rigid and solid as I like. I don't like my casing to give at all when being held; so I will have to allow a little extra space in the case to allow for reinforcement possibly. I know the material has to be a little flexible, after all the plastic for vacuum forming has to buckle under heat, so I will work around that one.

Last update on project today:

Yes, I know full well this vacuum forming table will be "fugly" when done, I don't care, it is what it will produce, if it works ok, which is important; it is purely functional. There is no point rounding off the corners nicely and making things fit "just right", and you can't fill and paint it (as it has to withstand oven heat); spending time to make this look pretty is just a waste of time, so it will be "fugly"!

Cut out a piece of 3mm fibreboard to fit loosely inside the frame, so there is enough space for the surrounding foam to sit into. I thought, there is no point making lots of equidistant holes in the top, as is normal practice. This table is being made for one purpose - so why not simply just put holes in the wood where they are needed, thus getting best suction in the right places? Seems logical. If I need to make a different shape, I just make a new top piece and screw it in place to replace the old one - simple! The hole in the middle is because I intend to have a hole in the middle of the mold, where the screen will go (so will be cut out anyway), so air can be sucked here too.

Comments so far??