Keyword

TOPIC:

Home Vac Former For making RC car bodies 4 years 6 months ago #36242

Hi All,
its been quite a while since I've posted anything, the last project I was working on was a resto of a Countach and that was over 2 years ago! (I'm hoping to get back to that soon :blink: ) badword wok kept on getting in the way! Anyway, the last few months I've been trying to work more on some projects and one is a scratch build Volvo 850 Estate BTCC version. I'm part way through that and once moulded I will need a vac former to finish it. So this build thread will be for the making and testing of the vac former.

When building this, I wanted to make it simple so I took to function over form. I also didn't want to spend a lot of money, and I intended to scavenge as many parts as possible. In the end the build cost around $100AUD. The majority of that was for a small portable oven ( nearly $70). The other thing was that I will vac form the Volvo in two parts, with a join around the base of the front windscreen. I'm doing it this way so I can get as much detail at the front and back of the Volvo, while still being able to get it off the mould.

This is the oven I went for:


It could handle the temperature range I needed, around 150C to 250C, and it was just big enough. By the time I make the frame for holding the plastic sheet, I can vac form an area around 350 mm x 270 mm. So while not big enough to do a single car body, big enough for a two-piece version. There are large ovens available, but they were around twice the price, but would suffice. Now you might be thinking why not use the kitchen oven. I strongly recommend you don't do that. Plastics have coatings, contaminates and other chemicals on them that are likely to burn off when in the oven, potentially contaminating any food place in there.

My next post will be on the frame to hold the plastic sheet for vac forming.
The following user(s) Liked this: Jonny Retro, stingray-63, AndyAus, blairis

Please Log in to join the conversation.

Home Vac Former For making RC car bodies 4 years 6 months ago #36243

I've looked into vacforming several times as my "next step" in RC/model making & have always come to a similar conclusion:

1) Making vacforming table/box (or more likely a number sized for A3+, A4+ and A5+ sheet holding frames - box(es) with MDF top & bottom, 2x1" pine sides, connector for hoover, top drilled probalby every 20mm in grid pattern? Hoover gets emptied each time & a new filter to ensure maximum suck, other than that the "problems" are a few £££ on materials, a fair bit of time spent drilling, space to store & setup for use.

2) Making A3+, A4 + A5+ sheet holding frames - more ££ on materials + machine screws & wing nuts, storage again...

3) Developing a heating solution that works reliably & avoids domestic friction - again "easy" if you've got the space, rest is just trial & error (reputedly, once the sheet sags, then goes taught again, it's ready - if the heat & material thickness are a constant, I'de expect to be able to do it with a stopwatch);

4) Making the "buck" to form around.

#4 is the bit that's putting me off - having to learn a whole new skill set and art to produce the part to make decent forms around, repeatedly - and I suspect I just don't have the artfulness in me. Vacforming seems to be really intolerant of flaws in the buck, even dust on it. Nos 1,2 & 3 might be consuming of time, money & space but I think they involve only elementary woodwork & talent, probabably adding up to 0.5% of the whole - the other 99.5% is making a decent buck. There seems to be any number of fools posting vids of their vacforming setup tests over some junk (and often failing) - but none entitled "becoming an expert in buck carving woodwork" or "reliably producing a small batch of shells from the buck what I carved".


Don't get me wrong - I'd love to see you suceed at this, I'd also be very happy to purchase a Volvo 850 Estate to sit next to my FF01 touring cars (currently a Tamiya Volvo 850 saloon, Tamiya Mondeo saloon & Hpi Mondeo hatch) :y: :) so good luck with it :)

Please Log in to join the conversation.

Home Vac Former For making RC car bodies 4 years 6 months ago #36250

Hi Jonny,
agreed, the time is in making the buck. When I first started looking into this about 5 years ago, my only option was to hand carve a buck. And I decided that wasn't for me either. It was when I bought a small cnc machine that I began to think about making my own car bodies again. I'll still have to learn a new skill set, but at least is computer based and extends some of my existing skill sets. With 3D and 2.5D machining I now have a way to make pretty accurate bucks providing I have a 3D model.

I'd started with the Volvo because I found a Volvo 960 3D model version, knowing I would have to modify it a little. In hindsight I maybe should have started with the Delorean (my next intended project) as I managed to find a good 3D model of that. So I am still limited in a way to 3D models I can download until I can learn more about 3D modelling. I'll still continue with the Volvo though, and once I get my bigger cnc up and runner I am hoping it won't take too long to finish.

Still there is a 3rd option for making bucks, and that is 3D scanning. However I am awhile away for doing that successfully. I've been trying with a kinect and the results aren't that great yet. There is also a program called 123D catch from Autodesk. It looks promising, but still not straight forward to use. Maybe in 5 or so years time it will be a lot easier to scan and replicate small items without spending a lot of money on the process.

So back to the build. The next step is the frame. I ended using 12 x 12 mm aluminium angle I bought from a aluminium supplier. 6.4 metres cost me about $14 (I had them cut it up into 4 pieces to fit into my car :) ). Combine this with some right angle brackets (another $5) and some metal clips (I found these) and thats the frame. I also bought a box of screws and nuts (noticed the chamfer on the screws, very important!) from a nut and bolt supplier, which for about 60 units cost another $12 total. And that was all I bought apart from the material to vac form for this project, the rest I had laying around the workshop.


I measured the oven and mitred the corners, using the right angle brackets to hold it together.


Make sure to chamfer in the holes so the screws sit flush, as this is the surface the plastic sheet goes onto. I used a mitre box to get the 45 degree angle cuts. Still they weren't very accurate. I also used a file to clean up the edges and help make the corners fit.


The final frame. You will need two of these, for a top and bottom. I did have to cut down the screws on the shorter sides to allow it to fit properly into the oven.


Here is the frame with some polycarb mounted inside the oven.


So the next step to make the vac former itself.

Please Log in to join the conversation.

Home Vac Former For making RC car bodies 4 years 6 months ago #36251

now, so I don't run a foul of any copyright rules I'll ask first. I was originally going to show making a copy of a Retro Racing Mk 1 Escort body. They were made as a PETG body, which isn't the best option for basher cars. So I am going to re-make it in polycarb. I do not intend on offering any for sale though. It seems on Tamiya Club that will be too much (and I understand they may get pressure from outside parties). Will that also be the case on TamiyaBase? Otherwise I'll do a short build where I make battery protectors.

Please Log in to join the conversation.

Home Vac Former For making RC car bodies 4 years 6 months ago #36254

yogi-bear wrote: now, so I don't run a foul of any copyright rules I'll ask first. I was originally going to show making a copy of a Retro Racing Mk 1 Escort body. They were made as a PETG body, which isn't the best option for basher cars. So I am going to re-make it in polycarb. I do not intend on offering any for sale though. It seems on Tamiya Club that will be too much (and I understand they may get pressure from outside parties). Will that also be the case on TamiyaBase? Otherwise I'll do a short build where I make battery protectors.


Short answer - it's not prohibited by Tamiyabase rules ( tamiyabase.com/...rules.html )...

...but then I'm suprised it's viewed as not allowed under TC rules. As I understand it, the pertinent one (rule 18 under www.tamiyaclub....opic=10738 ) is to stop the trade in and promotion of trade in repro goods - but that the trade in and/or promotion of trade in upgraded parts was fine - witness the a forum section dedicated to the promotion of TC members Shapeways (etc) parts.

Your proposal would seem to fall outside rule 18 as being not for trade, and even if it was, the "upgrade" practice would apply (tougher material). If you've already been told "no" then it's not worth arguing the toss - that decision trumps other rules - even on TC (point 9 under "some good advice") ;)


With my "moderator" hat on I wouldn't see that there would be any justification for interfering with anything posted here under your outline (with the footnote that I'm not the final arbiter, and rules can change and/or be backwardly applicable).

On a personal level, I'd see it as a sensible upgrade - the original using a material that breaks if you fart in it's general direction seems daft to me.

However, I've had my IP ripped off to varying extents on several occasions and it's not pleasant. Assuming you're sucessful in your copying, you then have two bodies, hypothetically what do you do?
Keep the original? In that case you have two bodies but have only paid for the IP in one.
Give the original away? In that case someone else has profited by misappropriation of IP.
Sell it? In that case _you've_ profited by it.
Destroy the original? That doesn't seem like the right thing to do either.

Still on a personal level, for me it boils down to how much of a copy is it going to be, and/or how much reworking of it are you going to do? The key feature of the Retro Racing bodies to me seems to be their 2-part nature - it you're going to copy both parts as is, then that would stick in my craw a bit (though not be against the Tamiyabase rules as they stand).

If on the other hand you're going to take a one piece casting for your buck, then modify it to properly vacform in one go at the right size, then from my perspective that rework would override any claim Retro Racing could have IPwise (unless they do have permission from Ford and are paying a licensing fee?).


... You know what, I can see why TC said "no", it's so much easier :whistle:
The following user(s) Liked this: larbut

Please Log in to join the conversation.

Home Vac Former For making RC car bodies 4 years 6 months ago #36255

Thanks for that Jonny. I did ask TC for clarification as they quoted the same rules you did and I just got a reply. It was really just to warn me not to offer anything I copy for sale. Otherwise its go nuts, which is what I will try and do :laugh:

I agree is a fine line in copying some else's work and ripping off ip, but I think if its purely for personal use its not too bad, even more so considering that the bodies that I am interested in are no longer made. Copying for profit, definitely a no go area.

As for the Escort, my first attempt will be a straight copy. Apart from making a version that I will not be afraid to drive, this is really to learn vac forming techniques as well as plaster forming techniques. So when I come to copying an old body I need, I have some experience and familiarity before I tackle something that is less than perfect. I do however want to modify it a little though and include an opening bonnet and engine bay, but that is more of a wish list though.

Please Log in to join the conversation.

Home Vac Former For making RC car bodies 4 years 6 months ago #36256

ok, the next part for this vac former is to make the base. While this is easy, its also the most tedious. Basically the base is just a box with holes. I opted to go for 1 mm holes, 10 mm apart, which meant drilling 775 holes :blink:

For the base I used a piece of laminated chipboard I had, something reasonably thick and heavy. The sides were just pieces of pine, I had 10 mm wide pieces which where just high enough. Vacuum came from an old Dyson DC05, and I opted to use the thin nozzle that it come with, as this reduced the height of the bed. I worked on the theory that if there is less space, vacuum should be better.

Size wise I made it just a few mm smaller than the frames I had made, that way I can pull it over the base. Pieces where glued with wood glue and nailed together, so nothing special there. The hole for the nozzle I drilled along the edge with a 2 mm drill bit and knocked out the piece with a chisel, and then filed the edges smooth until the vacuum cleaner nozzle would fit. I did not get a perfect fit, but it was close enough.



For the lid you can use anything firm. Years ago a friend use to use plywood, MDF will also work. I ended up using aluminium composite panel as its lightweight and very stiff. I used that as I had some lying around and its very easy to cut. As you can see it was just stapled to the frame.

I drew up a grid and hand drilled them all!


Some time later! Holes drilled and I used double sided tape all around the base to mount the frame to a base board.


A test fit with the frame over the top.


In the next post I will not only show how this pretty rough and simple vac former performs, but also talk about vac forming different materials, including PETG, Polycarbonate, acrylic and polystyrene as well as talking about the various properties of each. Of particular interest is the PETG bodies that Retro Racing made, as I want a poly carb version to bash around it, and it will be one of the items I demonstrate vac forming with.

Please Log in to join the conversation.

Home Vac Former For making RC car bodies 4 years 6 months ago #36258

So now I am ready to vac form something. I had originally bought some 1 mm polycarbonate as that was the easiest to get at the time. However that turned out to be too thick and I can't form it properly at the moment. Either I am not heating it enough, or I don't have enough sucking power. I'll be able get some 0.25 mm or 0.5 mm polycarb in the next week or two.

So in the mean time I will practice with 0.5 mm polystyrene. My first test was molding covers for NiCad batteries. I use to have a tamiya branded polycarbonate one in the 80s and it protected the battery quite well when exposed in my Fox.

So I heat the plastic in the oven at around 150C for 4 mins or so (until the plastic starts to sag). Turn on the vacuum cleaner and place the hot plastic over the buck. The suction part takes a matter of seconds (I'll do a video hopefully this weekend).



Ok, so that test worked, lets try something a bit better. Trini2DBone had sent me a Retro Racing Mk 1 Escort body set. When I started reading up on these, it turned out they were made from PETG. PETG is actually quite strong and is used in a lot of packaging because its cheap and it can form details very well. However, unlike polycarbonate, its not as elastic and so can shatter, and hence its not good for cars that get a lot of action. So time to re-make one in polycarbonate.

The first step is to make a plaster of paris copy. I rushed the pour on this and make the mistake of pouring it in layers. This means there are air bubbles and some of the plaster was a little weak. However I can still test it.


and now to vac form.





you can see some of the detail has been lost in the front area. Here I will drill some holes to the base to help with suction.

Also there are folds at the front base, which I will have to work out how to avoid.

Please Log in to join the conversation.

Re:Home Vac Former For making RC car bodies 4 years 6 months ago #36259

Ah wrinkles ;-)
Nice job looking good

Please Log in to join the conversation.

Re:Home Vac Former For making RC car bodies 4 years 6 months ago #36260

waterbok wrote: Ah wrinkles ;-)
Nice job looking good

Cheers Waterbok, that link you sent me before will come in handy for trying to remove the wrinkles!

Please Log in to join the conversation.

Moderators: Jonny RetroAndyAus
Time to create page: 0.111 seconds
Cookies are required to make this site work. If you continue to use this site you permit us to use cookies.