Home Made Vac Former - Forming RC bodies

[yogi-bear 2321]

I've been playing around trying to improve the vac forming and discovering that its a very fine line between not soft enough to too much heat.

Not quite long enough and I don't get the detail around the base properly. I suspect here I am not getting enough heat into the edges though.

 

But heat it slightly too long, I might get really good detail, but I can easily end up with wrinkles all over the body.

[yogi-bear 2321]

small update, I was having lots of heating control problems, getting either too much or not enough heat. Plus the heat was even, heating too much on the left hand side. After looking into how I made the heater box, I realised it wasn't wide enough and there wasn't enough heat getting to either the front or back of the frame.

So I rebuilt the heating box, making the outside of the box greater than the frame. I was initially going to buy longer elements, but ended up using the existing ones and just flaring out the base of the heater box. I made the gap between the elements and the top smaller too, plus adding in some reflective aluminium to try and bounce down a bit more heat.

 

My first test was using 2 mm thick HIPS, I'd been having lots of issues with HIPS before. Not perfect, but better than what I'd been getting lately. Good to see no webbing.

 

 

So I decided to give my Volvo body a go. Its not ready, and its pretty rough, but with a body I can do a test fit. Too much undercutting of the body meant the plastic blew out before it would completely form. But it shaped the body, contouring over all the bits I need to sand and smooth out  It would probably make a good banger body though.

 

The basics line up ok, and the width is good, just have to make the wheel arches bigger.

 

So I then gave some 1.5 mm Lexan a go. I ended up overheating it and it stretched too much. A bit hard to tell, but it was still heating on the left side much more than the right side. It was very noticeable when the plastic was sagging.  The thermostat in the two sides must be slightly different, so getting both to heat the same would be almost impossible. Here I also let it sag too much, and it wrinkled on the top of car as I pulled the plastic down.

 

 

So my solution to the uneven heating was to re-wire the elements so they alternate and both span the entire width of the heater box. Here you can see it with one set on. This should also give me a lot more heat control.

 

So this time I tried some 1.5 mm ABS, I was having no luck with that on the last version of the vac former. So to my pleasant surprise, the results were quite good. This I heated way too much still, so I'm sure if I play around with heat times I can get rid of the webbing. Best of all I didn't need the high vacuum, only the vacuum cleaner suction and it still got pretty good detail. As the plastic is quite thick, so I'll need to carve out the panel lines so they come through more clearly.

 

 

[Ronnyhotdog 221]

Me reading this thread for the first time:

 

[matman 1499]

Looks like your getting there . Good too see your still at it . Yer there look better . 

[firefoxussr 482]

Keep at it !  The evolution of your knowledge is imperative for others that want to replicate OOP bodies.

I found on RC tech this really clever way to make a thin casting of an original shell:

I tried it and my casting thickness is about 1-2cm.

Here's a comparison shot with the CLK GTR shell I tried to cast as multi-piece and use up some of the volume (which didn't work properly).

The biggest issue I had with the CLK was the weight of the plaster distorting the shape, which is also not helped by the CLK being a previously cut shell.  I would fare even better with an uncut shell.  Every other OOP shell I have I've not cut for this reason, the CLK came that way used.

[yogi-bear 2321]

8 hours ago, matman said:

Looks like your getting there . Good too see your still at it . Yer there look better . 

yep, still at it, I'm like a dog with a bone that won't let go   I've been meaning to email you too. After not using my 3D printer for 8 months or so, it now doesn't complete any prints and stops part way through. I was wondering if you had the same problem? Apparently I'll have to re-wire it and the solder joints are dodgy.

[yogi-bear 2321]

6 hours ago, firefoxussr said:

Keep at it !  The evolution of your knowledge is imperative for others that want to replicate OOP bodies.

I found on RC tech this really clever way to make a thin casting of an original shell:

I tried it and my casting thickness is about 1-2cm.

Here's a comparison shot with the CLK GTR shell I tried to cast as multi-piece and use up some of the volume (which didn't work properly).

The biggest issue I had with the CLK was the weight of the plaster distorting the shape, which is also not helped by the CLK being a previously cut shell.  I would fare even better with an uncut shell.  Every other OOP shell I have I've not cut for this reason, the CLK came that way used.

Thats a good idea, I hadn't thought of trying rotacasting. My thought with cut shells was to tape up and pack in riversand. This supports the body quite well and minimises bulges (especially where there is a lot of tape) and loss of plaster from leaks.

 

Currently I've been packing the insides with wood and then a layer of plasticine. I end up wth moulds about 30 mm thick. Bulging is a problem still too.

 

 

I suspect Rotacasting is bound to give a better finish though, less chance of bubbles etc. I might give that a go when I do some hornet bodies I need. I am finding though the casting is not durable, in that it will can eventually dry out, crack and bits break off. I'm currently molding with hydro stone, but I am wondering if I need to some tests to get the optimal strength.

One other issue I need to work out is the easiest way to do two part molds on bodies with overhang. I was going to try casting on an angle part way, spray a release agent and then cast the rest. But I an wondering with plaster if the interface will come out a bit rough. Will have to try that one soon too.

 

With your bodies, have you vac formed any yet?

 

[matman 1499]

3 hours ago, yogi-bear said:

yep, still at it, I'm like a dog with a bone that won't let go   I've been meaning to email you too. After not using my 3D printer for 8 months or so, it now doesn't complete any prints and stops part way through. I was wondering if you had the same problem? Apparently I'll have to re-wire it and the solder joints are dodgy.

I have not used it for so long , it's not funny . I was not having much luck . Not sure if it was me or the printer . Got *******ssed 

off having to fix or start print again .  So i gave up . Plus i didn't have time ti sit there waiting for it to screw up .

Was thinking , i should have waited and got a more better one ? . But this was a learing curve and didn't want to 

pay big $$$$ for some thing i may not get into .  Some things printed well , But when i went to do reprint it

wouldn't work ?. I was thinking of selling the 3d printer , as it was getting too hard & frustrated with it. .

May have too give it another go ? .

[yogi-bear 2321]

45 minutes ago, matman said:

I have not used it for so long , it's not funny . I was not having much luck . Not sure if it was me or the printer . Got *******ssed 

off having to fix or start print again .  So i gave up . Plus i didn't have time ti sit there waiting for it to screw up .

Was thinking , i should have waited and got a more better one ? . But this was a learing curve and didn't want to 

pay big $$$$ for some thing i may not get into .  Some things printed well , But when i went to do reprint it

wouldn't work ?. I was thinking of selling the 3d printer , as it was getting too hard & frustrated with it. .

May have too give it another go ? .

no, not you, these beasts are hard to tame it seems. But the easy to use ones are still expensive, so its a catch 22, but at least they are slowly getting better. For me I'll have a go at some stage at repairing mine, as most of the time I got a good print, but really its just a learning experience until I can afford a better one.

[firefoxussr 482]

On 2/5/2018 at 3:27 PM, yogi-bear said:

Thats a good idea, I hadn't thought of trying rotacasting. My thought with cut shells was to tape up and pack in riversand. This supports the body quite well and minimises bulges (especially where there is a lot of tape) and loss of plaster from leaks.

 

Currently I've been packing the insides with wood and then a layer of plasticine. I end up wth moulds about 30 mm thick. Bulging is a problem still too.

 

 

With your bodies, have you vac formed any yet?

 

I haven't but certainly plan to.  It's been taking so long I think it's best to use everyone's best ideas.  I think the thin mold may be the key as it's easier to add suction points for details & creases in the bodywork. I'm very interested in how vacuum pressure is distributed on the body as I gather that is a primary problem that loses detail.   I've mocked up how my first vacuum box will look, so I know what supplies to buy.

[yogi-bear 2321]

ok, time to get back into some vac forming 

So I'm going  start with some bodies for @Martell , I need more practice at forming bodies and I thinking they might be a little easier to try than the Ford bodies. The do have lots of holes though, so that's going to be a challenge.

So the bodies, apparently old Proline ones. This one actually feels thicker than a normal vac formed car.

 

The inside will pose some challenges I wasn't expecting. All the bits of glue used to strengthen the post holes will have to be filled in once a cast is taken.

 

The Second body, this one fells kinda soft and more flexible, I'm wondering if its a different plastic to polycarbonate. Again lots of big holes to cover.

 

 

So both bodies where given a good wash. I'm probably going to try casting these a couple of times as well and what to use methods that don't damage the body.

 

[yogi-bear 2321]

ok, so starting with the Futaba shell, attempt one will mainly use cloth binding tape to cover holes, with some plastic or metal cut to extend the base at least another 10 mm. 

This is an easy way to get the basic shape of the body without try to cut in a piece to fit the curves of the windows.

 

For the ends, I'll need to make a stronger edge, so that means cutting plastic card to fit in along the edge of the body. I just used paper and traced the edge, and transferred that to card.

 

 

Completed both ends. For the rear I ended up using roofing aluminium as it's easier to shape.

 

So now I can attempt to cast the body. There are a couple of ways of doing this, @firefoxussr mentioned the rotocasting method and this would use the least amount of plaster and given a reasonably thin shell. Thats good for adding in vent holes afterwards and I will give that method a go at some point.

For this particular case, my concern is that the body or bits I've added on could flex, so I'm going to make a box that is padded with sand to hold it firm.

 

now hot glued together onto a base of MDF. As MDF is not great with moisture, so it's been painted to seal it.

 

the underneath of the shell is then supported with wet sand, it's just a course playground sand with some added water to make it sticky.

[yogi-bear 2321]

Before I can cast, I want to reduce the volume of plaster needed. So time for some wood and plasticine. The plasticine helps seperate out the wood from the cast and to help shape it a little.

 

 

and now ready to pour.

 

For this attempt I am using plaster of paris, its pretty common and fairly cheap.

 

 

about 2 hours later it's set enough that I can start taking it out.

 

 

So not too bad, but where the holes are covered up, that will need to be dealt with. I forgot to mention before, when I made up the ends, I did it so they taper away, this is to make vac forming easier.

 

[yogi-bear 2321]

now to get onto cleaning up the body. While its still setting I used a knife blade to scrape as much of the lumps smooth.

Before

 

After

 

 

This is where I had to stop. So I've still got the top patches to deal with, but I will wait until its set properly and then have a go at sanding smooth. Where there are holes, I'll try either adding more plaster or some clays that I have bought to try.

 

[mjvracing 1]

This is all looking awesome. Are you considering selling versions of some of these? I'd pre order an 850 estate right now! 😊

[yogi-bear 2321]

8 hours ago, mjvracing said:

This is all looking awesome. Are you considering selling versions of some of these? I'd pre order an 850 estate right now! 😊

Thanks! If I ever get them good enough, I'll give you a bell. I am currently way behind though, work has been insane this year, so even @Martell 's  small project hasn't progressed much.

I want to do more upgrades to the vac former too, enough that I briefly considered buying one instead, but the prices are way out of my league 

[Incredible_Serious 107]

12 hours ago, yogi-bear said:

...I am currently way behind though....

You're way behind? I only just cut out the first of the sample shells you sent through to me years ago!!!! Trust me mate, you're doing better than some of us! 

This thread is probably the only one I'm still watching on TC, which is a fair indication of how in awe I am at your efforts so far...... so keep up the good work!

Alex

[yogi-bear 2321]

4 hours ago, Incredible_Serious said:

You're way behind? I only just cut out the first of the sample shells you sent through to me years ago!!!! Trust me mate, you're doing better than some of us! 

This thread is probably the only one I'm still watching on TC, which is a fair indication of how in awe I am at your efforts so far...... so keep up the good work!

Alex

cheers Alex, keen to see how you go with those bodies too, make sure you post pictures 

yeah, still think I am way behind  I've been planning more upgrades to that vac former and bought the parts about 2 years ago. Lots of solenoids and other controllers etc to help automate it. Plus I've got further plans on the heating elements and clamps. I have resigned myself to the fact that it won't happen too soon, but I will get to it. The next year or so will also see me building a new house with a much better workshop, and that will help immensely. Should be much better setup and organised.

[yogi-bear 2321]

so I need to finish off @Martell s bodies, that I started a year ago  I was hoping to get to this over Christmas, but that didn't happen. Anyway, an opportunity arose this week with a mate and what better way to get a task done that to pass it off to someone else 

So with the vac former I'd made, I had a couple of issues. I wasn't getting a good seal when forming and the connection from the frame that holds the plastic to the lever system wasn't the best. It had been made of wood which wasn't ideal, so time to bring some metal fabrication in and redesign. The other issue I had was the ball value levers where a bit clunky, and I'd planned on upgrading to solenoids and toggle switches.

 

So this is the updated joint to the lever system. Much more solid now.

The other big upgrade was installing solenoids to give better control over timing etc. Today we work out the electrics and got most of it in place.

Where I could, I went for the biggest ones I could get. So its a mix of 12V and 24V solenoids. This is the one that connects to the vacuum cleaner.

 

And the power supplies are tucked away underneath.

 

 

and laser cutting a new control panel. Cut in clear, reverse etch the labels and then it will be backed with black vinyl. What didn't help is I accidentally etch some of the holes that will end up being cut out.

Next weeks goal is to finish of the control panel and then remake the base so there are no leaks.

 

[yogi-bear 2321]

So also this week, and while not vac former related, I might as well post it here anyway. Months ago I bought a milling machine but wasn't able to set it up. This week that finally happened  This package came with a DRO, something that I would consider essential, especially for a novice like me. In the next couple of months I'll also add stepper motors so I can program it.

 

The other project I was able to start on was upgrading my CNC machine. I'd initially done a poor job of wiring up the controller box, it worked, it was just messy. I've now almost completely rewired the controller box and can now add in a homing plate and limit switches. I'll also add in a better vacuum dust collection system. I'd tried machining aluminium in a while ago, but there was some flex in the base. I have solved that with a 20 mm steel plate, that baby isn't going anywhere! That will make the base a lot stiffer. I still need to reduce the flex where the spindle is located, but this will do for the time being. While all these machines are for work, it is my aim to be able to vac form car bodies and machine in some way my own rims. My first project for the milling machine will be doing some Audi BTCC rims.

 

[WillyChang 1814]

Dayum, envious... if only you weren't 3000km north...!  

[Badcrumble 4201]

‘Vacforminator?’

Love it 

[Re-Bugged 10117]

Geez @yogi-bear, your workshop would put the Mythbusters set up to shame 😉👍🏻

[Incredible_Serious 107]

On 1/17/2020 at 10:32 PM, yogi-bear said:

So also this week, and while not vac former related...

Glad to see you're still at it, mate... only taken me about a million years, but I'm just about finished my first of your shells....

Just the head and tail lights to do, plus some minor details.... and trim the rear body mounts. Still, progress!

Look forward to your new releases... lol... quick vac-forming joke 

Alex

[yogi-bear 2321]

9 hours ago, Incredible_Serious said:

Glad to see you're still at it, mate... only taken me about a million years, but I'm just about finished my first of your shells....

Just the head and tail lights to do, plus some minor details.... and trim the rear body mounts. Still, progress!

Look forward to your new releases... lol... quick vac-forming joke 

Alex

looking good! when do we see a vid of it in action?