Vac Forming

[Ironwing]

I know Klaus is building a vac forming machine and as such he has enjoyed success. They are handy little gizmos to have on hand. Along time ago (in my previous modelling life) I converted the Hasegawa F-16A to a "B" model. The conversion wasnt mechanically difficult. The canopy however posed a problem which required a vac form machine bigger than the Mattel I had.

 

 

The following is a brief pictorial on the machine I built. It was modeled after the Mattel unit which was available many years ago in most toy stores. I dont know if they are still around. Just the same, it isnt difficult to make and adds a great deal of capability to the shop.

 

This is the original Mattel. On the left of the box is the vacuum platten. On the right is the heating element. The two parts sticking up in the air hold a 3.0 by 3.5 inch piece of styrene up to a thickness max of about .030". Ive never gone any thicker.

 

Geoff

[Ironwing]

Another view of the Mattel unit with a piece of 3x3.5 in. plastic trapped between the two sections of the holding unit. That unit lays flat above the heating element during the heating operation. When the plastic has become sufficiently warm (it sags) the entire assembly is flipped to the other side and a vacuum is drawn by rapidly pumping on the handle which is visible on the right side of the box. You need to be quick so the plastic doesnt cool before it covers the master. The nice thing is, you dont have to directly handle the heated plastic.

 

Note: When vac forming, keep the parts to be formed slightly elevated so the vacuum can pull the plastic down and slightly under under the master. This assures good sharp edges and a tighter pull.

The Bull Dog Clip holds the two parts together so you dont have to.

 

Geoff

[Ironwing]

This is the unit built so I could vac form the F-16 canopy. The canopy, one of the few things left of the model is on the vacuum platen for size comparison. Its constructed of bits and pieces of wood I had in the shop left over from other projects. The PVC elbow I picked up at the local Home Depot. Most any Plumbing supply should carry the same. The shop vac hooks directly to the PVC elbow and serves as my vacuum source. The Mattle unit was for the most part duplicated. The parts sticking up in the air capture a sheet of plastic just as the Mattel unit does.

 

Geoff

[Ironwing]

Another view of the unit from the end. At the bottom there is a carpenters ruler in the pic for reference

[Ironwing]

As with the Mattel machine, once the plastic is heated to the proper softness the entire holding assembly is flipped over and down onto the vacuum platen. The vac should be on in advance, that way, it immediately draws the plastic down over the master with minimal cooling.

 

Geoff

[Ironwing]

The heat source is a ceramic furnace. The next photo will show how it works with the vac machine

[Ironwing]

The furnace lays on its back under the plastic holding part of the assembly.

[Hacker]

and here l thought you where just sucking on an end of a vaccum hose But seriously l build two one small one large. l was lucky enough to get a couple of peice of perfrated metal plates wiht 1/16th (or they are less then that even) l made the box and frames out of wood and sealed them and l glued a shop vac attachment end that l hacked off in the hole and sealed it as well. l have used it a couple of times but l have not had the chance to really get down and dirty with it amd make parts.

 

hacker

[Ironwing]

...another view. During the heating operation, a piece of aluminum foil is placed on the exposed side of plastic to help retain heat from the furnace. Dont let the word furnace fool you. It puts out hot air but it takes a few minutes to warm a sheet of styrene to the point where in can be vac formed. Another thing to be careful of is vacuum leaks. Make sure all edges are sealed and fit tightly. This one is seal with GE, RTV 3145 Silicone.

I should also note that the vaccuum does not draw directly on the platten. Rather, the vacuum pumps on a plenum under the platten. The Mattel machine draws directly on the platten with a piston in a cylinder.

[Ironwing]

I should have put this one earlier in the sequence. Ths shows the card stock holder closed. FRom this point it can be flipped to the right to go throught the heating cycle and then over to the left (180 degrees) to undergo vacuum.

[Ironwing]

Im hoping this will be of some help to anyone interested in building there own machine. Please feel free to ask any questions you might have. Ild be happy to share any info I have on building one of these things.

 

Hope everyone is well,,

 

 

Geoff

[Ironwing]

hack,

 

You haven't lived until you've pulled your own with vacuum.

[Hacker]

hack,

 

You haven't lived until you've pulled your own with vacuum.

 

Man that could be misconstude so many ways

 

 

hacker

[maverick728470]

Geoff,

Got to ask this of u.How much for making that canopy for a two seat version i'm planning on doing.Larry

[Ironwing]

Hi Larry,

 

Ill look for the master I used for the canopy. God only knows where it got off to. If I can find it, Ill gladly shoot a canopy for you. To be honest, I would like to do another B or maybe a D. If I can't find the original master, I think I can pour a new plug using the canopy I have here. Then, I can shoot that. Let me know when you plan on doing your B/D and I'll work up a new one for you. No charge.

 

Geoff