Vacuform kits.... any advice?

[Jet Beetle]

I have a couple of Vac kits just sitting in my closet doing nothing - I really really want to build these but I've had so many people tell me these kits are a real pain to do correctly. This keeps me from even trying because the kits are old and somewhat rare - if I screw them up it will be a long time before I'll get my hands on one again. Anyone have any advice or perhaps a tutorial out there of how to tackle these things?

Thanks

 

[micdavis]

What kind of kits?

Spaceships? Props?

VF kits ARE a pain. Trimming and fitting should be done in small increments.

Mating halves is tough unless they are REALLY well done.

If you're holding Lunar Models kits, just burn'em.

 

[tk1608]

I've only done a couple, and they can be more difficult than injection moulded stuff, but it's possible to get good results. If you draw round each part with a pencil, before cutting out, this usually gives a good indication of where to sand each part down to, after being cut out. Keep checking the fit frequently as you sand to make sure you don't sand too much off.
You'll probably need to glue tabs to the inside of each part to add strength and give more area to glue the parts together, and a bit of scratch building might be needed too.

Here's a couple of brief tutorials

http://www.clubhyper.com/reference/vacformbg_1.htm

http://www.scale-models.co.uk/quick-tips/1754-how-build-vac-form-kit-part-1-a.html

Hope this helps a bit.

Any chance of seeing some pics, what you have sounds interesting

Cheers

Phil

 

[SSRN Seaview]

I would also suggest use of expanding foam to give some substance to the assembled kit. Nothing worse than holding too tightly and popping a seam.

 

[Jet Beetle]

Here are some pics of the kits I have

As you can see they are from Japan and came out around 82 from a company called General Products. The advice so far is good but it makey me vary scaredy.

 

[Invicta]

It's been years since I built a Vac Form kit. If I had those kits I don't think I'd start with them. My suggestion is to get a cheap VF model similar in size and, if possible, shape and use that one as a "try out" model.

The last VF I built was a 1:1 Pulse Rifle... and OH BOY was that one a pain!!

TK1608 has provided a couple of nice tutorials ( thanks by the way). But with any new technique----take your time. My Pulse Rifle took me about three months.

 

[micdavis]

If you are VERY concerned about wrecking them, you might think about pouring an RTV mold on the OUTSIDE, then make resin parts for a solid model.

 

[tk1608]

They look cool, I've never seen those before. I reckon that you'll be able to build 'em no problem. It is a bit daunting starting them off, but once you have the parts cut out, you can treat them more or less like a normal aircraft kit.

I can't see if they have a cockpit interior with the kits or not, but you can get after market resin seats for 1/72nd scale jets, and etched brass interior details that could be modified to fit. Also some scratch building with thin styrene sheet is worth a try too.

I like the idea of a resin copy though...never thought of that..

Seems a shame to have them bagged when you could be admiring them on a nice stand..

Cheers

Phil

 

[Jet Beetle]

Man guys thanks for all the helpful words. It's nice to know I'm not fearing these kits for no reason. I like the idea of pouring a a resin version of the kits but I think it's far beyond my skills as a kit builder. I may need to proceed with caution, but I hope you won't mind me keeping this thread going with questions as I take my first steps.

1 question I do have now -- does the expanding foam provide weight and strength to the kit?

thank you all

 

[GKvfx]

Expanding foam provides a lot of strength and only nominal weight to the model. Basically, the model goes from being hollow to being solid.

Quick primer on AB foam -

I don't use the stuff from home depot that comes pressurized in a can. I don't like the material or the delivery system. I use the stuff you get at a plastics shop. You mix up equal parts of the A & B and pour it into your item (vacform shell, mold, cavity, etc). As the mixture kicks off, it will expand. The more you mix, the bigger area it will fill. If you pour it into a confined area, and you use too much, there is a danger it will pop a seam. Therefore, I recommend that you fill the separate halves, trim them, and then glue them together as if you had two solid halves. You can use 5 minute epoxy or even Bondo to glue the halves together.

So experimenting is the name of the game.

AB foam is available in different densities - 2lb, 4lb, 6lb - etc. This is the weight of a cubic foot of the material. The higher the density, the greater the weight and the more dense it is. For filling a model, I generally use 2lb or 4lb. If I have to do carving and need to fill up the cel structure with Bondo and filler, or try to get a smooth shape, I use the denser stuff.

The stuff is messy to work with - wear old clothes and make sure you have plenty of paper covering the table and floor. The stuff is sticky once it starts foaming. But when you watch the stuff, you'll be fascinated and you'll realize the possibilities.

Gene

 

[vaderman1701]

I agree with everyone here.

1. If you are not lighting, use expanding foam to provide some internal support. If lighting, you should build some type of armature to support the plastic and run wiring.

2. I would also recommend taking a thin strip of styrene along the edge of 1/2 of the parts in order to create a lip. This lip will allow you to mate two parts together at the seams and also help give it stability.

Vacuform kits can be difficult, but if it was made from a good master and the plastic is of decent thickness (anything lower than .040 is too thin in my opinion).

It also depends on if the mold used in vacuforming were negative/female molds or male molds. Female molds, the plastic is sucked into the mold and typically produces sharper detail models. Male molds the plastic is stretched over the top of a master leading to lesser surface detail quality and potentially thin spots where the plastic stretched too far.

Just looking at the pictures, I believe yours were made from female/negative molds, so count yourself lucky.

Just take your time. Invest in some Apoxie Scuplt (you can get some at www.starshipmodeler.com). It is a modelers best friend. I would also get some Bondo Glazing Spot Putty (single tube, not 2 part). This is great for filling in seams. Just be careful not to put too much on at a time, because it could weken the plastic. Just use a little at a time, sand, and then reapply if needed.

Good luck and be sure to post progress. PM me if you have any questions.

Scott