If you’re reading this, then you’re already aware of the process – or at least the results - of vacuum forming: if your RC car doesn’t have an injection moulded ABS body, chances are that it has a vacuum formed polycarbonate body.
Looking something like a demilitarised baby Dalek, or V.I.N.C.E.N.T. from The Black Hole, the Jinguang JG-206 Vacuum Forming Machine offers all the usual elements - heater, sheet material transport, platen – and a vacuum pump, in an all-in-one small desktop unit.
I paid 129.50 GBP for my unit from Amazon, which appears to around the average UK selling price.
A Note on Size
Nowhere across the multitude of brand names and retailers that this unit is sold under (or from) could I find any proper information on the capacity of this machine, just weight and exterior dimensions. A label on the machine itself gives power requirements (220V @ 50Hz) and wattages: 600W heat, 800w “model” (meaning vacuum).
I’ve seen it referred to a being a “5-inch” unit on YouTube, but that’s as good as it gets.
Armed with a ruler, I determined that the size of sheet material required is 135mm square (5.25”) – which means you can get six parts out of a sheet of A3 (420mm x 297mm) material, but a much less efficient two from an A4 (297mm x 210mm) sheet.
However, several factors such as the width of the clamping surfaces, the size of the optional forming tray, protruding screw heads and limits of the hole pattern on the platen, as well allowing for some clearance all conspire to reduce the size of object you can form.
Height is also open to some interpretation. 80mm is the maximum distance (the centre of the clamps to the top of the built-in platen), but that leaves no space for the essential “droop” when heating your material, and the fact that the uppermost heating position is just too close to the element to use.
I found could repeatably form an 85mm diameter round object, 37mm high. I really don’t think you could go any bigger than that – and only 75mm (3”) for squarer objects. There’s another 3mm (1/8”) headroom, taking the maximum height up to 40mm (1 & 5/16”). Hitting both the maximum width and height at the same time may be too much to ask.
This means most aircraft canopies and engine cowls in 1:32 scale will be possible, but not 1:24, and definitely not the larger RC scales. Any slot car racing bodies – even a classic Mini – would be too big. I believe it could accommodate half a fairing for a 1:12 bike. For 1:10 scale & thereabouts RC road vehicles, a torso type driver figure (not including a head), or a small fake tyre cover would be possible.
Size is clearly a very limiting factor of these units – but it’s an inevitable side effect of the physical size, and the cost. The small scale – and small price tag – make them very accessible. It costs as much as a basic Tamiya RC kit and is small enough to put in the back corner of a desk or up on a shelf.
I’ve been thinking about making/buying a machine capable of handling A3/ A3+ sheets (for 1:12 and 1:10 car bodies) for decades now – and the cost – or even just the space requirements had I gone the DIY route – have always been prohibitive for me*.
* And the “art” side of it if I’m honest – see later.
The “branding” of these unit varies – mine was supposed to be made by “Annhua” (and indeed that’s one of the many bits of text on the box) with a blank label on the front. However, it arrived with a “Jinguang” (“Golden Light”) label on the front. The hopelessly optimistically titled “User Manual” doesn’t give a manufacturer name, just a model number. Whatever the “brand” all of these units appear to be the same, finished in the same light blue, hammered enamel finish.
The box will not appeal on retail shelves, being plain corrugated cardboard. It – and the PU foam inside – had done a got job of protecting the machine in transit.
My first impressions were that it has nice paint, but the switch labels and knob on the heater element cover look cheap. That heater element cover also swings around with little restraint with no way of adjusting stiffness, which makes me fear for the long-term conductive properties – and safety of the wiring.
Some of the fasteners look like wood screws, and the unsuitable countersink forms had been fitted with such force that they’d bent the grid they held in.
Also included was a box of small stainless steel balls – more on them later.
An Aside on the Art of Buck Making
From what I’ve seen, it’s easy to get distracted by the engineering when building your own vacuum forming machine, chasing stronger pull with multiple/better pumps, holding tanks and valves, better airflow through the platen, better sheet material handling, better heat distribution, timers, instrumentation, and so on. This looks to be an attractive form of procrastination, and when coupled with chasing better technique for perfect forms, neatly avoids the bit I know I’d find hard – the “art” side of making the bucks required for forming.
Things that are rectangular, or layered, or have predicable two-dimensional curves are one thing – but the complex, three-dimensional compound curves seen on most production cars – let alone the exotica we’re more likely to be interested in – are something else entirely. I’m not entirely unskilled or untrainable, so it’s perfectly possible I could learn to carve one side of a block of wood into something generically car shaped. Making a passable scale version of half an actual vehicle? Very unlikely. Carve the mirror image on the other side of the block to make the whole car? Impossible, at least for me.
One could make the argument that one could CNC carve a buck to form RC car bodies, but I know I couldn’t, and realistically, I think that’s beyond most home RC enthusiasts too.
Making a copy of something by taking a cast of the original is not always a viable option. Plaster of Paris is no longer cheap, and within a few pulls such a buck will begin suffering with surface spalling, shortly followed by it breaking up completely. Restoring the lost size and making a buck hard
enough to withstand the vacforming process, you’re well into “art” again.
I also don’t think that the quality of home 3D printers is anywhere good enough to consider using them to produce a buck either.
My point here – if you’re a sculptor looking to diversify into RC cars, then making bucks and vacforms from them might well be right for you. If you’re an RC enthusiast looking to move into vacforming, recognise that you have a new art to master.
My first buck - as shown below - was made from Milliput 2-part epoxy putty pressed into the inside of a Tamiya polycarbonate MSC. It was already yellowed, broken, and incomplete, so I didn’t mind that the process destroyed it. If it had been a perfect example of something rare and expensive, I wouldn’t have wanted to do it – especially as vacformed objects made from a casting like that always end up smaller than the original (I know, it doesn’t seem like they should, but they do).
A Closer Look
Looking at the Jinguang JG-206 Mini Vacuum Forming Machine in more detail, the flying power lead that initially looked a bit on the short side was 1.35m long, with a UK 3-pin plug fitted with 13A fuse.
The material handling frame half elevator levers are a quite clever design, with a spring/ball/detent arrangement to hold them in the top two positions. I don’t think the positions are named anywhere, but it’s clear that the manufacturer intended them to be for high heat, standard heat and forming. In practice, the highest position is just too high.
It’s a good thing that this material transport is quite robust, as in the absence of any carrying handles, and the top being too fragile – and far too hot in use – it’s almost inevitable that they’ll be used to move the machine about.
The hinge arrangement on the back of the frames looks like it should automatically adjust to different thicknesses, but doesn’t work well – even after checking the torque of each screw.
The unit was stinky on first use, with some volatiles coming off both the paint and the heating element. On subsequent uses it’s just the smell of warming (or melting or burning) plastic sheet you’ll have to deal with.
The vacuum power struck me as ridiculously loud and powerful suck, with the motor starting torque reaction moving the unit around on the bench.
I do have some concerns about future availability, and especially that of spares. My impression of Chinese design and manufacturing is that a lot of the time, they do come up with a useful or popular item, saturating the market with literal shiploads for a couple of years, then supplies just try up, never to be seen again. Admittedly, the only concrete examples I can produce right now are semi-flat packed “occasional” furniture, garden benches with decorative cast metal ends, and reclining wooden “steamer” chairs.
Trying It Out
This was as much me learning as testing …
My first attempt at forming did not go well – I used 1mm polycarbonate (leaving the outer film on) on the lower heat setting. The considerable number of bubbles is apparently caused by the material absorbing moisture, which then becomes gaseous and expands during heating. Overheating doesn’t help either.
A second attempt removing both film layers and heating for a shorter time was slightly better, but still nowhere near useable.
My third attempt was with 0.75mm ABS with some preheating done with the material frame in the “form” position before lifting it to the lower “heat” position to achieve the required droop.
So far, all my attempts had disproportionately thin sides, so for my fourth attempt, I removed the forming tray and seal, and chocked the frame up to a position a little lower than the “lower” heating position for most of the heating cycle. As there was no need for the plastic to cover the insides of the forming frame, this resulted in thicker sides to the final form. There was some webbing evident on the lower third of the 90-degree corners, but overall, I feel encouraged by the results so far.
This is probably the correct method; the forming tray only being needed to contain the “stochastic” stainless steel balls. That’s an interesting use of the word there, but I see what they mean. Assuming your buck has a raised island beneath it, the balls would tend to fill the holes in the exposed section of the forming grid, provide a randomised path to the air around the edge, and the strongest suck directly under the buck – which could be beneficial in forming certain parts. They exhibit the strongest magnetic attraction that I’ve ever seen in stainless steel.
I don’t think it’s going to be practical for me to store or condition polycarbonate in a low humidity environment. However, using new 0.75mm sheet gave better results, and the small bit of 0.5mm that I’d had sitting in an envelope on a shelf for several years was better still – so thinner appears to be better – up to a point.
I also had some 140 micron (0.14mm) clear PV Acetate (just the thing for Wild Willy helmet visors, BTW). This could potentially have formed well, but the clamping force at the front of the frame was almost non-existent, and the vacuum sucked the sheet right out.
I have also ordered some PETG sheet - which has the advantage of not being hygroscopic but is much more fragile in use – but have yet to try vacforming with it.
I would have liked to try 1mm ABS, and even 1.5mm sheet on the same buck as I suspect that’s going to be the material/thicknesses I’m most likely to want to use in the future, just to provide a clear comparison. However, I suspect my buck will have a limited lifespan and I really don’t want to ruin it just yet.
Instead, and especially as I theorised about the upper limits of what could be formed on this machine, I tried a can of tuna. This was 85mm in diameter and 36mm tall. Having made two forms in 1.5mm and 2mm sheet, shortened them and joined the halves, then filled and sanded them, I have two objects which will almost have no future usefulness, but I think did prove the concept, and confirm my thoughts about potential useable size.
To sum up:
* 1mm polycarbonate: major problem with bubbles.
* 0.75mm polycarbonate: some bubbles.
* 0.5mm polycarbonate: quite good.
* 0.14mm PV Acetate: too thin, complete failure.
* 0.75mm ABS: passable.
* 1mm ABS: better.
* 1.5mm ABS: heat sensitive, any less than lightly fuming inadequate
* 2mm ABS: signs of uneven heating, no benefit over 1.5mm.
+ Cheapest entry into off the shelf vacuum forming machines.
+ Nice paint.
+ Small machine size.
+ Potentially very useful for small scale modelmakers.
= Absence of temperature control.
= Variable results, depending on material – and especially thickness.
= Indifferent build quality.
= Design questionable in places.
= Some cheap looking parts.
= Ropy clamp, especially for the thinnest materials.
- small platen (inevitable given the small physical size and cost) means it’s of limited use for the average RC enthusiast.
Something I haven’t mentioned thus far is just how often the word “dental” appears in the titles and descriptions, and how often half sets of false teeth appear in the graphics an any videos. The designers/manufacturers had a clear target market – and it wasn’t RC, or even model making in general.
“Cheap” and “off the shelf” simply don’t go together in vacuum forming machines, or at least they didn’t before this one. The fact that it’s more powerful than it needs to be, and you can form much larger items that were ever intended, and from much thicker material too – is very much to its credit.
However, the low cost does show in places, it could stand to have a bit more care during assembly, and I do have to think about its usefulness both for me, and the readership of TamiyaBase as a whole.
Overall, I’d rate the Jinguang JG-206 Mini Vacuum Forming Machine at a respectable four out of six.
Written by TB member Jonny Retro