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Slot-A-Holic
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*Part of this has been posted in another vacuum forming machine thread but i thought it would be nice to have my own thread with my "progress"

Well here is stage 1 of my vacformer


All made out of stuff i had laying around...total cost until now is 0 CHF.

First up to mouse hole i sawed at the same diameter as the vacuum tube.



Stainless steel mesh i had laying around..very dirty use to be high luster.
Not just handy for car intakes in the grill i noticed.



A simple box construction where the seems have been closed with kit.



And the bottom part is now as good as finished...



All i need to do now is to make two 'window' frames to hold the 25x25 and 25x50 cm PET-G sheets.
Will make them oven size and preheat the stainless steel mesh with my heat gun and maybe the window frame with PET-G to but it leaves the option to heat it in the oven if needed.
And will use isolation tape on the edges of the box so that when i push the window frame over the mold it seals airtight.
and a 25x25cm piece of flat board with a insulation edge to be able to cover half of the vac-forming mesh if necessary.

Thanks Howmet and others for the inspiration




It is made to fit two sizes of PET-G so i can do larger and smaller objects without to much trouble,
the cover will be screwed on and the the isolation tape can be pushed down to make a airtight seal.



All in all it cost me nothing to make,
the wood was sourced for free.
the paint was a left over of my previous track.
the isolation tape was a left over from a job i did.
the stainless steel mesh i saved from the bin at my previous job
the kit was left over from a job i did from a costumer and so where the screws.

It seems will popping here in Pampigny
 

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Slot-A-Holic
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For all you Swiss out there...the source:
PET-G

I am using the 0,5 Thick 50x25 cm sheets which i cut in half.



A rubber adapter from my little proxon bench circle saw will help seal the connection from vacuum machine and the box.



The complete ensemble.



First attempt,
heating up the mold and the PET-G





Well who would have thought...No1 total fail.




And number 2 also failed:





Number 3...guess once..:





 

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R.E.F.
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Bravo Jaak


I see your using the old box method, if you want ? I can suggest a few things you might want to try. Is your mold made of plaster? I never heat my molds, also done in plaster too. I did a lot of experimenting with different systems when I started out. Just a buddy tring to help


i-ray
 

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Slot-A-Holic
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Discussion Starter · #4 ·
U-ray i be very great-full for any tips hints and tricks,

I am a mere rookie with only 4 pops on my score sheet and all are fails,
need all the help in the world and you being a Master popper....need i go on


Hope to stand in your shadow one day.
 

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Hi Jaak

I'm sure you just let your plastic get too hot and sag too much. Just use less heat and wait patiently- first the plastic will crinkle, then it will go smooth. As soon as it does, dump it on the mould!
I do heat up my moulds by the way. But different strokes suit different folks, eh, brother Ray?
 

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Slot-A-Holic
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Heya howmet,
(Another one of The great Vacformers i hope to come close to one day)

My problem is when i use less heat the PET-G wont follow the contours of the mold on the underside.

Another one of my problems is that at some parts it folds.(webbing?)
Especially at the front and the two sides where the point ends and becomes straight,
also at the then end of the straight side on the back corners it does that.

My first attempt was using the oven alone to heat up the mold and sheet,
but the sheet was not properly mounted on the frame so when i put it on the vacformer it created an opening letting "false air" in.

My second attempt was using the oven to preheat the mold and sheet until it just started sagging and placing the mold warmed up on the vacformer followed by the sheet,
after that i used a heat gun (Bosch paint stripped) on lowest setting to heat the sheet and make it follow the contours of my mold, causing the holes in the sheet you see in the pictures.
Still not solving my "fold" (webbing?) issues.

Third and Fourth where done in similar ways with slightly differences and no better results.

Contemplating if the thickness of 0.5mm may have something to do with it,
i seen other posts suggesting to make a raised base to eliminate the webbing issues.
So when i made my mold i already took that in account.
(may still have made a wrong shape mold if that's possible)

Yes the mold is made of plaster and plaster filling*

*Filling to give contours and shapes and correct sanding errors.
 

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re: My problem is when i use less heat the PET-G wont follow the contours of the mold on the underside."

hi, Jaak
How do you feel about taking advice from someone who's never done it? LOL I'm wondering if you'd be better off with a small extra piece at the bottom of your master with perforations
at the bottom and the sides, to suck the pet-g towards the mold at your underside edges.

Meanwhile...excellent progress so far! Great thread...

best of luck,
John
 

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R.E.F.
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Hi Jaak,

Timing is everything- on my system- it only take 5 to 10 seconds to rap the mold and additional time, 15 sec., is to get the detail. The reason I ask what matterial you use to make your mold is, it makes a difference if you pre-heat or not. I found that pre-heating plaster makes it more brittel in the long run and reduces it's life span. I have molds 10 years old that are still in great shape and mold great bodies. I learned from John that a heat gun can be your best friend lol. be careful not to over heat areas though. as you proably figured out ? I did try the oven method to heat the plastic first too, only manage to burn my arms though lol. ouch!! I use an old electric fry pan to heat my plastic and Snappy the vac is and old timer too!!! 1-1/2 hp. My system is what I call a: " flip-o-matic "
sits right on my work bench.
As john mentioned already, the plastic will crink, then smooth out, then droop, the length of the droop is important ! not enough and you get webbing, to much droop and it will web/thin out plastic. again timing is everything ! thickness of the plastic and kind of plastic,( PET-g vs lexan) does make a difference in the allowable droop distance.
More thoughts later!
i-ray
 

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Jaak- pay heed to the master i-Ray! I agree, timing is all. But pointing that big old Bosch paintstripper at the part-moulded shell will only cause local hot spots that will pull through- make holes. The whole sheet has to be an even temperature, or it will only stretch locally, deform and puncture where you point the air gun. From the ripples on your mould, I'm sure that the plastic sheet was initially too hot and sagging, but by the time you'd got it out of the oven and onto the mould, it was starting to chill- that's why you got loose folds all over the upper surfaces, but it wouldn't pull all the way down the sides. Raising the mould on a base will only make this problem worse in this particular case, I think.
The folds came because the plastic was sagging too low, and got stuck to itself before it had a chance to spread itself evenly over the mould. Like Bro' Ray says, length of droop is important! (you can probably get arrested for saying that in a lot of paces). It will come with trial and error, Jaak. Don't worry.
I use the old flip top box and a free-standing stove heater to soften the plastic and the air gun to heat the corners of the sheet on the other side, to make sure everything is evenly warmed. Then I flip the hinged frame 180 degrees over onto the mould. I made a breakthrough when I realised that even flipping the sheet too quickly made it chill in the air draught, and gave me results a little like yours, Jaak. Now I turn it over gently, with the heat gun playing on it all the time it's in motion, and it pulls down like a dream (mostly).
Using an oven and transferring the sheet to a separate moulding box has always looked like a very difficult way to do things to me. Timing! Heat mould, heat plastic, all in closest possible proximity to each other, drop plastic over mould the instant you get 'even sag'- a smooth reflecting wrinkle free bowl in the plastic sheet. I have a lamp casting a low light on the plastic as it softens to watch the surface closely. Try not to move the plastic any distance through the air from heat source to mould. It will chill. You will get stretch marks, pocky surfaces, localised thin spots, all the dreaded diseases of vac forms that my rubbish bins are full of.

Heating the mould? Ray say nay I say yay. You takes ya choice, buddy. Don't ask me to fight; Me & Ray are tight.

Now I have to go and vac form some chocolate moulds for my daughter. Careful what you're letting yourself in for Jaak.
 

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R.E.F.
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Hey Jaak,

As John pointed out, you have two idea's, to heat or not to heat, both are equaully valid methods, it's really an individual choice which you will evential gravite towards as you mold more. So now you know both methods work. I did omit some other reason why I don't preheat my molds. Which I'll mention to you as you develope yout talents, but for now trail and error will help your learn curve. Again.. the key is Timing & speed of application- the quicker you get the heated plastic on the mold, ( of course your vac is on/running before you apply the heated plastic.) Like I said earlier, it only take me less than 15 seconds to mold a body and if I got everything right, I don't need to reheat areas with a heat gun an vac again. Sense your using a oven to heat your plastic, I would guess your mold time is much longer. As John already mentioned, plastic will cool really quick as time go's on. But.. don't get discourage, organize your space and do some dry runs to get your timing/placement of plastic down. I know you can do it
you have already taken the first step

Let us know how it's going. I love chocolate


 

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Also, you might have your heat too far from the vacuum. Just moving the sheet plastic 6 feet from the oven to the former can cool the sheet some.
I have used the stove top with much success by placing the vacuum box just to the right of the stove.

I hold the frame over the hot burner until the plastic sags down smooth, flip on the vacuum, and drop it over the mold.

Disclamer: I am not the professional body former Ray or John are. So listen to THEM! But I have managed to pull window glass, bubbles, detail parts and such for the last 20 years. Full bodies are very difficult for me and I've only done a few bodies successfully.
 

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Slot-A-Holic
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Thanks again for all your opinions and advice


John,

I love to hear every bodies opinion criticism or advice,
i was thinking of drilling some holes but i received and seen bodies that where at least as difficult as mine.
Therefore i wanted to try solve the heat issue first to see how it would come out then.

The-ray,

I have been working on my timing and how much i heated up the parts,
moved the vacuum box closer to the oven (next to it)
Results to follow

John tx,

I had the heat gun to close at previous attempts,
and i listened to youre explanation what caused No1 to fail, so this time i heated up the sheet in between No1 and 2/3 and 4.
with a 3 cm drop i put it on the vacuum former i had moved to box closer to the oven too.

The-ray,*post 2

I again heated the mold but noticed 2 problems,
1 my mold kind off went downhill, number 2 wait for the mold to cool off or else you will ruin your (maybe) perfect pull.

Jairus,

I moved it closer this time and with success.

Attempt No5 and CosmiC is born


(mold was damaged and i didn't want to fix it until i got the pulls proper, and i tried to remove the mold to fast not letting it cool of enough causing a little fold on the front
)

But the pull was perfect, all details (imperfections) are clearly visible









I want to send some of you guys a copy of CosmiC but it may take a while before i can get a clean version out of the door,
of course you can re-pop as much as you like to sell or give away.
 

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Stranger Things 2
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I've never had the inclination or time to get into vac forming but know from a mate who did his own HO and 1/32 pops that it's both fun and frrustrating at the same time ... cudos to you for giving it a go.


I'll keep watching this thread with interest for your progression, I'm sure time will show excellent results .
 

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R.E.F.
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Hey jaak,

I see that your mold have given up some surface matterial, preheating a plaster mold will do that. You can still save the mold by adding some plaster to surface and rework.

In a post here by Gene, he gives you the nuts & bolts of vacing 101, he has a really nice top of the line system, worth the investment once you get the basic down. I plan on redoing my systyem like gene's some day! I'm still using my original beginners system, total investment of less then $20 bucks, why ? because I still get 100% perfect pulls everytime. As gene mentioned, a good vac makes your job much easier and I'm sure you could pull lexan with it. John & gene both do a more involve mold making process to create a mold, they both are really good at it, but it is more expensive to do. Plaster being the cheapest method vs resin, etc. With that all said, here are some pic's on how to achieve a good looking body with a less expensive system. One thing we all have in common is, the cost of plastic !! that depends on how big a surface area your using. The end product is a finished plastic slotcar body, how you get there is up to you.

this pic shows the total system and it's simplicity



A pic of the mold sitting on the plate, side view. notice the vent holes drilled into mold- very important to do.



front view of a bat-ray flexi version



view of the heating system



view of the drooping plastic, about 1 1/2" to 2" if you can see the difference?



finished body with mold out.



body sitting on a frame



There are some noticable differences/philosphys in how I do my thing vs others, basical they all work. Hopefully these threads will give you some insight into the process of vacing and the Fun of making your own " thingie " bodies

If you need additional info let me know ! Now go vac some stuff
 

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Nice post Ray.I am a fan of low tech/lowbucks achievement.

Do the holes in the mold go right through to space on the bottom of the mold?
Do they have have vacuum?
Do they leave an impression in the finished body?

TIA

munter
 

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Hey Jaak! Congratulations! A proud moment. Welcome to the brotherhood. We will send you instructions for the secret handshake later....

The thing with heating the moulds- I don't know if Bro' Ray does this, but I add plaster polymer resin into the plaster mix. It's basically PVC glue, which makes the plaster set extremely hard. I have moulds made out of this that have popped 200+ bodies, and been in and out of the oven every time. They don't seem to deteriorate much, beyond a little touch up now and again, mostly because I drop 'em because they're so hot... But I even invested in a pair of mitts, so that problem is solved too.
Thing with plaster of paris is that it comes in many, many various grades, and if you're using standard builder's plaster, it really won't be up to the job. It's crumbly, and forms a surface skin which will break away over time. Then there super fine, super-hard dental plasters, which are brilliantly good at taking detail and incredibly durable, but the problem is trying to drill the vent holes in it. Can't be done. Well, I couldn't find a way of doing it.

The stuff I use all the time now works well enough for me; Basic Alpha super fine casting plaster, mixed with Tiranti plaster polymer. Within a couple of days of casting, it stays soft enough to drill holes, make minor corrections, etc. but pop it in the oven for a day on low heat and it will turn to stone. For lexan moulding, I heat the moulds up to 130 degrees. And it's essential to do that. For PETG, I find that it's necessary only to take the chill off. I pop the moulds in the oven at low setting for 20 minutes, when they come out they're lovely and warm like your pet hamster, and they seem to pop and take detail much more happily than a room temperature mould. But then maybe it's warm enough where Bro' Ray lives all year round. Us Northern Europeans need some helps.

Keep poppin', Jaak!
 

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Slot-A-Holic
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Thanks John,

I will delay any further progress for the moment as i will need to move in around 1 a 2 Months,
after that i will make a version that i can use a hinge,
I wanted CosmiC to be Swiss-born made by some Dutch guy


Also will need to rebuild a track again after the move.

I had a look at Gene's Vacuum former but i can't comprehend how he can create enough vacuum with the amount of holes it has,
and how it can be that the holes in the body actually create a vacuum without lining up with the other holes in the sheet.

EDIT:

After reading more about Vauum forming i made up my mind,
i was considering making a hinged version but now reading somebodies comment i may choose not to do that.

It seems that the best solution i think,
one thing is sure i will build a new machine.

Probably a combination of gene's non box version with pump and a overhead grill,
which i will raise the sheet too and when it has the right amount of drop i will lower the sheet on the vauum table,
also making sure it will not overheat and heating up the mold wont be needed either
 

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Jaak, I really think that for PETG moulding, the hinged box method is by far and away the most efficient and simple. Vacuum cleaner, hinged box, electric hot plate. Done. The only reason to get more complicated with overhead grills and such is if you plan to do a lot of lexan moulding. Then life does get a lot more tricky: higher temperatures, shorter working time and so forth. Get the PETG working sweetly, then decide if you need to invest in Lexan forming gear.
That's my advice.
Have to say though to be honest, my advice has caused a great deal of trouble in the past.
 

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Slot-A-Holic
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John,

I greatly appreciate your advice and will never use that against you,(or anybody else)
at the moment i am taking every bodies advice into account and will from my own ideas what i think will be the best way.

In no way can i ever blame anybody for the choices i make


I think the differnce in building a vaccum former with overhead heating is as complicated to make a hinged box version,
so why not make it and have more options in the future.

My decision is not final yet but i am forming a nice idea how to make it.

Using those drawer side bearing thingie whatchyamaycallit's to raise and lower the sheet,
Holding it at the proper height with a clamp or pin.
Make a fixed frame to hold and overhead heater (possible my double sided Grundig grill upside down) on which the bearing sliders will be mounted on the vertical pilars that hold up the heating source.
And a solid table base a la Gene style with the double piston pomp he recommended.

The only difficult part will be finding the sweet spot of what distance it should be from the heating source.
 

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R.E.F.
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Hey Jaak,

You will find holes in just about every body made lol. The holes go threw the mold to an air chamber/open area in back of mold above the vac , aids in drawing plastic into detailed areas on your mold. As for overhead vacing systems, Brain is the man with the expertise. I use a good grade of plaster and if I want it rock hard ,I add Durham water putty-yellowish poured, once dried you can heat it and mold away. John, I could never wait 20 minutes to heat a mold LOL. OMG what would I do while I was waiting
Well Jaak, it's a personnel choice on how you want to do it, remmber ! have fun doing it, good luck!!
 
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