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I have been very busy at work, but I read the blogs all the time.
This post here will save you a lot of greaf, pay attention and you will have 100% pulls.

Forget the boxes and shop vac's, just look at the photos.

You will need a vacuum pump, here a 2 choices,knothing else,you can find these on E-Bay


You have to build a platen, look at the photo.
A 1/16 inch aluminum sheet, keep it flat. Dimensions shown will pull most bodies
Under the aluminium sheet is a grillage sheet.
Cut the grillage sheet 1/8 inch smaller than the platen aluminum sheet.


Grillage sheet as shown


The platen block is the same size as the aluminum platen.
Cut a hole in the platen block for the vacuum fittings.


Now study the photo on top of the platen wood block is the grillage,center it on the wood platen block, run a 1/8 inch bead of silicone around the perimeter of the grillage, place the aluminum platen sheet with the predrilled 1/32 holes on 1 inch centers and sandwhich it all together with a flat weight on top. Let this cure, make sure silicone came out from all edges. Leave that alone till the next day. NO LEAKS CAN BE IN THE PLATEN


Additional fitting photo


Now here is the whole thing, A vacuum pump, hose, check valve,and the platen.
You must have the least amount loss for vacuum, a perfect world you can draw knothing more than 28 inches of vacuum, this will not happen with the table top units using a shop vac.
So save time and money do it correctly.


A very simple flip vacuum table, effective and 100% accurate.


Connection from vacuum pump


Drop the platen down on the line up pins


Almost ready


Show time


Lets turn on the heat, get 2 inch sag


Here ya go another perfect body, with a tight draw all the way down flat on the platen, lot of vacuum pull with no leaks.


Look at the bottom PETG is flat around the bottom edges


Not bad


Fresh off the popper


The mold with vent draw holes properly placed very important, dont over look this


The little simplfied vacuum table


A vacuum guage, check for leaks, you must have zero leaks


Please note there is NO VACUUM BOX, only the hose from the pump to the platen, very little draw is needed, and must be air tight.

Ask questions, improve you product, do it right ,do it once, good luck
 

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Phil Kalbfell
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3,373 Posts
Gene nice build of a flip top unit.
I have to agree that a good vac pump is essential IMO.
For any one that does not or cannot build a vacuum box, an alloy project box from an electronics supply store is a great simple start,just needs some holes in the top and a fitting for the hose, some even have rubber seals for the lid.
 

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Joel LeNoir
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952 Posts
Gene.... Very nice. I will be modeling mine after your set up for sure.

One question. What material did you use for your buck? Besides vac windows for myself I would also like to make copies of the kids 1/10 RC buggies.
 

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Hi,

I am not questioning your system but i am trying to understand how it works,
at the moment i fail to comprehend how the holes in the Alu sheet which there are not many work with the holes in your Mold.

Can you please post a picture of the underside of your mold to see how you made that.

Thanks in advance.
 

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Discussion Starter · #5 ·
Maybe this will help to clear things up.

Number one, I showed 2 different vacuum pumps, 1 is a 2 piston and the other is a 1 piston, average use price around $40 to $50 dollars, well worth it.
Ray does well with a shop vac system and has good results.

Now lets talk about the Platen.

The platen is your source to draw vacuum thru, this is why you do not need a box.
The object is to remove quick as possible all the air , the more volume of space you [the box] have the longer it takes. Until you achieve this your hot plastic is cooling and a poor draw will accure.
Go back and review the photos.

Today is how to construct a platen, remember it has to be air tight, otherwords no leaks.

Lets get started.
THIS IS AN EXAMPLE, MODIFY TO SUIT YOUR NEEDS.

STEP NO.1


STEP NO.2 THE ADAPTER


STEP NO.3 ADAPTER SILICONED IN BOTTOM


STEP NO.4


STEP NO.5


STEP NO.6 SAMPLE PLATEN CUT AWAY VIEW AND A FINISHED PLATEN


Go back to previous post and review the whole setup,study it,it is simple.

You do not have to build a complex system, Rays hot plate frying pan appears to heat his plastic just fine, Ray could very easy adapt his hole draw box to a platen, maybe he will give it a try or someone else, you will not need any other heat source.

Now on to the MOLDS.
I use casting resins, [aluminite, cures in 1 minute, but you will need a silicone mold to cast it in], very hot during curing],yes there is a price to pay for this, Ray uses modified plaster with good results for minimal costs, others use other materials, they all have good and bad habits.
I would start with a modified plaster.

Lets take a peek at some molds.
PAY ATTENTION TO THE DRILLED VENT HOLES, YOU NEED THESE SO WHEN YOUR PLASTIC IS DRAWING DOWN OVER THE MOLD SO IT CAN PULL ALL THE TRAPPED AIR OUT OF THESE AREAS, SO THE PLASTIC WILL DRAW DOWN AND FORM THE DEPRESSION. LOOK HOW DEEP SOME OF THESE POCKETS ARE. WITH OUT THE VENT HOLES THE PLASTIC WOULD JUST BRIDGE OVER THE AREAS AND MAKE A DROOPING DEPRESSION.
OTHERWORDS; WHEN THE MOLD IS SETTING ON THE PLATEN, THAT HAS THE 1/32 HOLES DRILLED ON 1 INCH CENTERS AND THE HOT PLASTIC IS COMING DOWN OVER THE MOLD SHUTTING DOWN ALL THE AIR THE VACUUM STARTS DRAWING AIR THRU THE VENT HOLES IN THE MOLD SO THE PLASTIC IS DRAWN INTO THESE AREAS.

JUST STUDY THE MOLDS.

TOP VIEW

BOTTOM VIEW


TOP VIEW

BOTTOM VIEW

THE GREEN STUFF IS A POROUS FOAM, I USE IT TO CREATE A HOLLOW CAVITY IN THE MOLD SO I DO NOT NEED 6 INCH LONG DRILL BITS TO DRILL THE VENT HOLES.

TOP VIEW

BOTTOM VIEW

A CAVITY WHICH IS HOLLOWED OUT FOR THE SAME REASON, ONLY NEED SHORT DRILL BITS FOR THE VENTS.

OK try this on for tonite, wish the thing had spell check;
later
 

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R.E.F.
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1,672 Posts
Hi gene,

As for the draw plate, your 100% correct
I did eliminate the box and have my vac right under and in the box. Just as you show, I attached the vac right to the plate, about 2" from top of plate. Sense, my old vac keeps working, I'll us it until it quites. I can upgrade it as your showing in no time, when I run across a vac pump, it's a done deal and I can retire "Snappy the vac". Thanks for the detailed vac system build/mold process
It should give the fleggling vacer's a good start.
 

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R.E.F.
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1,672 Posts
Hi Gene,

The other question I had was the heating system you are using ? looks like heating element? Before a thought of using the old electric fry pan, I used a heating element but, it didn't heat evenly and some area's drooped to quickly. The electric pan heat's pretty evenly for PETG plastic's, for lexan it doesn't. ?? Any ensight would be helpful Thanks
Ray
 

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Discussion Starter · #9 ·
Hi Ray

Please contact;

Douglas E. Walsh
Vacuum Form
272 Morgan Hill Drive
Lake Orion, MI 48360
(248) 391-2974
or
visit his web site; http://build-stuff.com

I just talked to Doug on the phone,he still has the element kits.

Doug sells a complete heating element that will do well,it comes complete as a kit and very easy to follow instructions.
I have visted Dougs home and he sells everything you need.

Take care and I hope to be making bodies soon.
gene

QUOTE (one27ray @ 9 Jul 2012, 16:19) <{POST_SNAPBACK}>Hi Gene,

The other question I had was the heating system you are using ? looks like heating element? Before a thought of using the old electric fry pan, I used a heating element but, it didn't heat evenly and some area's drooped to quickly. The electric pan heat's pretty evenly for PETG plastic's, for lexan it doesn't. ?? Any ensight would be helpful Thanks
Ray
 

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Phil Kalbfell
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3,373 Posts
One27 ray. Lexan requires a lot more heat and cools much faster. Flip top frames do not work as well on Lexan. A vac former with overhead heating is the best for Lexan. My large machine uses rge element plate from an old pie warmer. My small unit uses 4 elements from a small kitchen toaster grill. Both these set ups have a reflector over the elements to help with the spread of the heat. You could also use elements from a house hold radiator.
 

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Discussion Starter · #13 ·
Z;
To answer your question is, no hooking up a vacuum piston pump to a vac box, I do not think you will be gaining anything.

The whole objective is to pull the least amount air out of a cavity.

Before your vacuum starts to pull vacuum all of the cavity voids of air must be remove before you start to pull vacuum, the more area the more time it takes.

A shop vacuum can pull approx. 3.0hg,piston vacuum pump 26.0hg.

You can revisit the start of this post.

I do not know what you vac box looks like.

Make the platen as shown and fix it to your vac box with the alignment pins as shown in this post,buy a piston vacuum pump, you shoulld be good to go.

Z ,pm me for the number,you can give me a call, I will guide you through this, if you would like.

QUOTE (32deuce @ 9 Jul 2012, 21:09) <{POST_SNAPBACK}>Gene,
Can the vac pump be adapted to a vac box system? I'm having a hard time understanding exactly what I would need to do to my present system short of starting over.
Z
 

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Mike Zimmerman
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1,138 Posts
Hi Gene,
My system works very well for what I do which is PETG. I just thought my next step of improvement would be to tackle Lexan but, looks like I would be better off building a new system for that.
I'll PM you for the number so I'll have it when I get back to my vac projects.
Thanks!
Z
 

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R.E.F.
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1,672 Posts


Ordered the heating element & Booklet today, now I'll need to get a vac-pump.


Gene, have you try a plaster mold on your system ? I wonder how hard the pump pulls down & will it damage a plaster mold ?
I see that you arranged your mold from front to back vs side to side ? any advanged in one vs the other ? I plan on using a smaller plastic area,( like you have) over the heating element. How much heat escapes on the sides ? Could you put a cover over areas not heating plastic/frame ? Have you tried lexan with your system?
Should be fun !1
Ray
 

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Discussion Starter · #16 ·
Ray
Yes I have uesd plaster molds with success, I glue on a thin piece of wood veneer to the bottom of the mold to spread the pressure.
Vac pump source http://www.harborfreight.com/catalogsearch...t?q=vacuum+pump.
Should work fine.
I have done modifications to my system,so when you get started give me a buzz.
The platen has to be correct,very simple.
I pull bodies from any angle,no problems.
Yes I use an arched metal cover to transfer heat to the top of the petg.

This will be a new adventure and you will enjoy this even more.

g;

QUOTE (one27ray @ 11 Jul 2012, 19:27) <{POST_SNAPBACK}>


Ordered the heating element & Booklet today, now I'll need to get a vac-pump.


Gene, have you try a plaster mold on your system ? I wonder how hard the pump pulls down & will it damage a plaster mold ?
I see that you arranged your mold from front to back vs side to side ? any advanged in one vs the other ? I plan on using a smaller plastic area,( like you have) over the heating element. How much heat escapes on the sides ? Could you put a cover over areas not heating plastic/frame ? Have you tried lexan with your system?
Should be fun !1
Ray
 

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R.E.F.
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1,672 Posts
QUOTE (gene/ZR1 @ 11 Jul 2012, 19:13) <{POST_SNAPBACK}>Ray
Yes I have uesd plaster molds with success, I glue on a thin piece of wood veneer to the bottom of the mold to spread the pressure.
Vac pump source http://www.harborfreight.com/catalogsearch...t?q=vacuum+pump.
Should work fine.
I have done modifications to my system,so when you get started give me a buzz.
The platen has to be correct,very simple.
I pull bodies from any angle,no problems.
Yes I use an arched metal cover to transfer heat to the top of the petg.

This will be a new adventure and you will enjoy this even more.

g;

Thanks!

I do the balsa wood on the bottom too, works great ! Do you use a two stage pump ? I have to check with the local harborfreight to see what they have on hand for pumps. I'll give you a call for sure !
Ray

PS happy Birthday Edo
 

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Mike Zimmerman
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1,138 Posts
Hi Gene,
After reading this again I think I am better off building a new system for Lexan. What are the specs of the pumps (HP, CFM, inches of vacuum) and could you put the part #'s in writing? Hard to see on the photos.

Also, where is the best place to hook up the gauge?

Thanks!

Z
 
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