Are there plans out there for a large Vac Form machine?

[patsmear]

I have been doing some set dressing, and I got to talking about building a vac form machine for us to use. They love the idea, because lugging around, phone boxes, radiators, and fire hydrants, is a big pain!

Well, I thought hey, we could build a vac form machine, but all of the plans I see are for small guys.

I really don't want to spend $18,000 for a machine.

I thought about just upping the measurements, but then not sure how to figure out what size vacuum I would need.

Any other ideas?

Pat

 

[exoray]

Your biggest concern when upping the size is the heating requirements not the vacuum itself... When you double the size of the heated area you in theory double the power requirements to run that heater and that can get out of hand real quick...

I'm going to say anything much larger than say a 2x4 feet is unpractical for residential wiring, my 2x4 table requires a 50 Amp 220 supply... That is why most of the plans are for smaller units, anything large will require commercial grade electrical or at minimum reworking the residential wiring to handle the capacity...

 

[patsmear]

That won't be a problem. We have a warehouse, and they are willing to run whats needed.

I figure, we have carpenters, welders, and electricians in house, so we should be able to get it done.

 

[SomethingPCom]

check out makemagazine on youtube you will find it

 

[exoray]

That won't be a problem. We have a warehouse, and they are willing to run whats needed.

As long as you can supply the juice than no issues with that, my warning was more about residential wiring... In my area many of the older (pre 1980s) houses only have 60 Amp service panels for the entire house, so without a major upgrade you won't get far... For commercial and new buildings they have higher service specs so then you are just limited to the expense of running the wires...

How big do you want to go? A full 4x8 foot machine is grand but overkill for many things unless you build special adapter plates to reduce the bed size... I did that with my 2x4 I made sheet metal reducer templates so that I can do smaller sheets but I still end up heating the entire area because of the original table design...

I gave a lot of advice to TK560 when he was building his initial model and a lot of it applies to even bigger designs... What you want is a quick high volume snap of vacuum, followed but a tight pull of vacuum... Commercial machines will generally have a high volume vacuum pump to do the snap and then kick in a secondary pump to finalize the pull... But for the DIY'er I highly suggest (to save money) is to create a large network of vacuum tanks to produce the snap, and even ultimately the tight pull... This will allow you to save a ton on the vacuum pump! You can use the most basic AC service vacuum pump to bring down the tanks and get a huge snap of air vs a high volume pump that will cost a small fortune...

This is the setup I suggest, with some experimentation you will find the 'optimal' vacuum to apply to the tanks so that you don't rip the plastic... After the initial snap you can fire up the pump to great that final tight pull if needed... But once you experiment and keep notes of heat time, plastic thickness and type as well as how far you pulled down the tanks you will likely find a sweet spot that you can pull the tanks to and get near perfect pulls without the secondary vacuum stage to pull tight... But it's always nice to have the pump on just to make sure you get a tight pull on the secondary...

For the tanks I suggest the cheap slave tanks from Harbor Freight they have 5 gallon ones and 11 gallon ones. The number of tanks needed will depend on the size of the machine you want to build....

Here is a link to TK560 site where he compiled much of the information from his thread here on the RPF...

www.TK560.com: Vacuform Table IV

He also has a good forum with lots of ideas here

www.TK560.com :: View Forum - Vacuum Forming & General Stuff

FIY I advice against the shop vac approach for any thing beyond the most basic small machine, it only provides the quick snap not the tight pull...

 

[Gorgot3000]

yes it's just like mine , i made a 2'x2' , supplied by 120v, one size only , heat source was made of electrical bbq and dishwasher element , and i use my 5 hp vacuum

 

[patsmear]

Thanks for all of the info! I think a full 4' x 8' is over kill too, but He is thinking big, for old roof panels, signs etc.

I am going to show him all of this the next time I get a call in.

Thanks so much!

Pat

 

[patsmear]

OK, Do you think home wiring, would run a 4ft x 4ft machine?

Also does the thicker the plastic mean the higher depth to the pulls? Like if we cut a fire hydrant in half and hit it with the plastic, is it the thickness that matters, or is it more, the distance from edge that matters?(i hope I am clear enough).

Another thing, say we do something like a hydrant, would it be best to pour a plaster copy into the first pull and use that to make subsequent copies?

I figure lifting things like a hydrant would suck each time we had to use it.

Pat

 

[propsculptor]

There is a set of plans in the Propbuilders Handbook.

IF I had the Money and the space... I'd build one of the Larger machines from the plans they offer, and it does discuss using a Vacuum Pump rather than a Shop Vac so you will get the Maximum Pull from each casting.

 

[exoray]

OK, Do you think home wiring, would run a 4ft x 4ft machine?

Kind of a crap shot answer, but I'm going to say 'maybe' but I wouldn't recommend it in most instances...

Every house is going to differ depending on what kind of service is supplied to the house... That will vary by building codes, build date and what not...

As I said previous my 2x4 table requires 50 Amps @ 220 volts, so to simplify things you are likely looking at 100 Amps @ 220 volts to run a 4x4 table heater... As I said in my area older houses only have 60 Amp service panels, so you can't pull 100 Amps from them without doing dangerous things like bypassing the service panel... Most new construction in my area has 100-200 Amp service depending on the size of the house...

With that said if you have 150-200 Amp service yeah you could wire in two 50A circuits to run the heater... Although with say 100 Amps service or less it 'could' work but IMO it's dangerous as you are taxing the entire system to it's limits... Even turning on a single light bulb in the house would in theory push you over the limit...

100 Amps @ 220 is A LOT of juice for residential hookups, there is certainly enough juice on the poll outside and likely the wires from the poll to the house, but from the service panel into the house is where you encounter issues...

My honest advice is to consult a local electrician that can evaluate the house and either upgrade the service or tell you that you have enough already...

Commercial, especially in industrial parks or what not should not have any issues beyond wiring up two 50 Amp plugs to run the thing...

As for thickness and depth of pulls that is one factor but as you implied so it distance to the edge or next part... Also the thicker you go the less detail you have and the harder it is to pull and heat... A fire hydrant shouldn't be an issue doing two sides...

As for plaster bucks they will wear out, a real hydrant would certainly outlast plaster... Pros and cons of both choices, as well as creating metal filed resin shelled bucks backed by a lighter weight material like a fluffed plaster, or even embedded wood... Plaster is certainly cheap, and will work but it has a shorter life than other methods...

 

[cgjeff]

if you're looking to just buy one not build one, and not spent huge amounts of money Stelter makes a 4x4 version, never used one myself, but from what i can tell in their videos they're pretty nice quality.
Vacuum Forming

or you could just base your own design around theirs, it's not really all that complicated of a design, and follows the pump and tank method described earlier in this thread.

 

[exoray]

Stelter makes a 4x4 version...

IMO a little costly for what they are but they look to be made pretty nice, and I would certainly inquire about the amount of juice that size machine requires... From their page is states "The heat is provided by (12) 750w ceramic heating elements." for the 2x2 table if they are running 220 that is 40+ amps right there for the 2x2 size... If they scale that same heating unit up to a 4x4 size it would require 164 Amps that is a boat load of power!!!

*** Edit I just looks the video of their 4x4 it uses 21 more spaced out heating elements so it requires about 72 Amps, still a sizable amount of juice...

 

[Eric0101]

This are just too engineering for me, I've bought a heat vac form machine that's like 40cm x 30cm with heating and vacuum pumped installed for around 1500 USD, pretty expensive.

 

[patsmear]

Looks like this project is a go! His buddy is coming over to wire up the warehouse for 220v. I think that a vertical machine would be better but we'll see. I think the welder will be getting the scrap metal for the frame. Will let you all know how it goes!

Pat