72 replies to this topic

[Gene/ZR1]

Pappy

1. Tape off all holes on the platen outside of the mold, to direct all vacuum to the underside of the mold.

 

 

2. Plug the 4 holes in your mold,  shown in green.

3. Drill 1\16" holes, 12 each (or smaller holes) at locations as shown in red.

 

 

regards; gene

[Pappy]

Thanks Gene, I will do that.

[Pappy]

Hi Gene,

 

I did what you recommended and it worked good but not any better than what I'd been getting before. I got dimples up on the headrest but you can put a little dot on them and they'll look like Zeus fasteners. I'm getting good usable bodies either way. 

 

I've been working on making more molds but not having much luck. I've been trying some Dura Rock plaster I had, but I need to order some Smooth-On mold making material. It's a hard flexible rubber that works really well. I had some but it was at least 15 years old and it only has a very short shelf life.

 

Stay tuned.

 

Butch

[Gene/ZR1]

Hi Gene,

 

I did what you recommended and it worked good but not any better than what I'd been getting before. I got dimples up on the headrest but you can put a little dot on them and they'll look like Zeus fasteners. I'm getting good usable bodies either way. 

 

I've been working on making more molds but not having much luck. I've been trying some Dura Rock plaster I had, but I need to order some Smooth-On mold making material. It's a hard flexible rubber that works really well. I had some but it was at least 15 years old and it only has a very short shelf life.

 

Stay tuned.

 

Butch

 

Check all your vacuum connections and anywhere else for leaks, 

You can send me a body and I will cast you a mold.

g;

[Pappy]

Hi Gene,

 

The dimples are from too much suction. I filled in the holes next to the headrest with bondo and I'm going to re-drill them. The drill bit wasn't running exactly true and wobbled out the hole a little at the top which showed up on the body.

 

I'm going to send you a resin body that we use that you can make a mold out of and one of my PETG bodies for you to play with, but I still want to make my own molds, it's the only way I'll ever learn.

 

PM me your address.

 

Thanks

 

Butch

[Martin]

Hey Gene, thanks for taking the time to share your knowledge and skill. It occurred to me that this would be a good time to revisit my attempt to recreate my favorite 49year old race car.

I have bought every Mclaren body  known to man. But no match. So a while back I repaired the beat up original body and started modifying a resign body with a mind to have it vac-u-formed once it was the same proportions as the original .Now I feel the correct approach is to make a silicone mold of the original and then make a new plug, and go from there.

What mold material would you recommend? I do not want to damage the original  body so I'll set it on a clay base, Is there a particular clay  that will work well with the rubber mold material?

I know it is not a thingy (which i do have a passion for) but thought it best to ask if you think this body is doable?

Thanks in advance for your advice.

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[Gene/ZR1]

Hey Gene, thanks for taking the time to share your knowledge and skill. It occurred to me that this would be a good time to revisit my attempt to recreate my favorite 49year old race car.

I have bought every Mclaren body  known to man. But no match. So a while back I repaired the beat up original body and started modifying a resign body with a mind to have it vac-u-formed once it was the same proportions as the original .Now I feel the correct approach is to make a silicone mold of the original and then make a new plug, and go from there.

What mold material would you recommend? I do not want to damage the original  body so I'll set it on a clay base, Is there a particular clay  that will work well with the rubber mold material?

I know it is not a thingy (which i do have a passion for) but thought it best to ask if you think this body is doable?

Thanks in advance for your advice.

 

 

Martin;

You should be able to make your vacuum mold without problems.

 

Best clay

Silicone Compatible Modeling Clay

Also mold release friendly.

Special synthetic clay that will not contaminate silicone rubber. Use for containing flow of RTV during mold making and for making simple molds. (Place a little #80966 Industrial Talc on the part and press it into the clay. Then carefully remove the part and pour resin into the cavity). 1 lb.

 

Mold silicone

OOMO 3O

 

Resin

QUICK CAST

[Pappy]

Gene,

 

Where is the best place and the best way to buy PETG. I've been buying it in 2' x 4' sheets on the Ebay.

[Gene/ZR1]

Gene,
 
Where is the best place and the best way to buy PETG. I've been buying it in 2' x 4' sheets on the Ebay.

US Plastics in Ohio
Call them!
Buy Vivak 4x8 foot sheets, make sure you tell them to roll it in a tight tube and keep the length to 4’-1” ,confirm the shipping costs, order up to 5 sheets, shipping should be around $15.00

Gene

[Pappy]

Thanks

 

I mailed a box to you Monday morning, you should have it by Friday.

[Gene/ZR1]

Thanks

 

I mailed a box to you Monday morning, you should have it by Friday.

 

Thanks

 

I mailed a box to you Monday morning, you should have it by Friday.

Pappy

The box arrived yesterday, your mold is very good  , I will photo post on suggested modifications on your mold so bodies will come off the mold easier and other modifications in prep for a silicone mold cast.

 

regards; gene 

[Pappy]

Gene,

 

I took the plywood off the bottom of my mold and put a piece of teflon on it. I pulled a body but had a real hard time getting the mold out and it got a little fold in the plastic right on the front of the nose. I was able to sand it off so it looks alright but in some places the plastic feels kinda thin. I think I might have heated the PETG too much and made it a little to soft. Could this possibly have been my problem with the fold and getting the mold out?

[Gene/ZR1]

Gene,

 

I took the plywood off the bottom of my mold and put a piece of teflon on it. I pulled a body but had a real hard time getting the mold out and it got a little fold in the plastic right on the front of the nose. I was able to sand it off so it looks alright but in some places the plastic feels kinda thin. I think I might have heated the PETG too much and made it a little to soft. Could this possibly have been my problem with the fold and getting the mold out?

 

Pappy

 I took your resin mold and sanded it smooth, I infilled the cockpit using Klean Klay, (blue),this clay is over 10 years old, you can use it again and again.

 Next I elevated your mold on a clay platform. Look at how the clay is placed and contoured to direct the PETG to areas around the mold. This will eliminate the adding wood to elevate the mold.

Do it once, do it correctly and be done.

 In the photos you can see that when I'm done and cast the silicone female mold then when the resin is poured I will have a completed mold for vacuuming, only thing left is a few vent\draw holes to drill.

 I will finish this out and pull a few bodies and send you a ready to use mold and try it on your vacuum table.

 You can use this as a guide for other projects.  

 

 

 

 

 

The clear body you sent me, the PETG was way to hot.

 

regards; gene

[Pappy]

That looks great, Gene. Can't wait to see how it turns out. 

 

I used clay like that to smooth out the plywood but never thought about using it in place of the plywood, or to fill in all the big gaps and the cockpit. 

 

The body I just pulled I heated the PETG hotter than the one I sent you so now I know I'm getting it way to hot.

 

Thanks much

[Pappy]

Gene,

 

I'm thinking of making a new platen and frame to pull one body at a time and not waste so much material. What do you would be the minimum size sheet of PETG I could use?

 

I'm thinking maybe a 5" x 7".

[Gene/ZR1]

Gene,
 
I'm thinking of making a new platen and frame to pull one body at a time and not waste so much material. What do you would be the minimum size sheet of PETG I could use?
 
I'm thinking maybe a 5" x 7".

Pappy
My cut petg plastic is 8”x11-1/2”, that includes the clamping frame.
This size you can make 2 of your bodies at once.
No waste of plastic.

Regards g.

[Gene/ZR1]

I was asked this question; How do you drill a vacuum \vent hole in a mold and your drill bit is to short?

 

 

[MattD]

Try these.      https://www.ebay.com...BcAAMXQMmJRJBq1

[Gene/ZR1]

I was asked this question; How do you drill a vacuum \vent hole in a mold and your drill bit is to short?

 

The last thing you don't want to do is snap or break the drill bit off in the mold, cause you won't get it out!

 

Use this method, floral foam is cheap, get it anywhere, you will save drills bits and casting resin.

 

A #58 wire drill bit approx. 1-1\2" long. After you chuck the bit it will be to short to drill the vacuum \vent hole in the mold.

 

Typical  #58 wire drill bit approx. 1-1\2" long

 

You can see the drill bit alone will not won't be long enough.

 

So get some floral foam        example; https://oasisfloralp...1003:3100003026

 

Take a draw blade and you can press the blade and cut the floral foam. Cuts like butter, regular foam will leave little aggravating crumbs of foam sticking to everything . 

 

Cut you floral foam filler box out plug to fit your mold.

 

Use large wood flat craft toothpicks to set the floral foam filler box out plug to the depth for your project. Use rubber bands to fix your floral foam filler box out plug from floating and moving when you pour your mold resin.

 

After your resin cures you can dig out the floral foam filler box out plug as shown.

 

Another example using floral foam.

 

This was a deep box out, shown with a 26D to size up the cavity

 

regards; gene

[Gene/ZR1]

Try these.      https://www.ebay.com...BcAAMXQMmJRJBq1

 

Matt

The bit size should less than 1\16", or a no.58 bit is  0.042 or smaller.

g.

 

 

[Gene/ZR1]

E-mail question; Can you pull more than one body at a time.

Yes with common sense.

 

Have a look;

 

Load them with equal spaces

 

Heat up the plastic, turn on the pump

 

Bingo you have 4 Jello or chocolate molds or 4 each 0.15 cent bodies 

 

 

[Martin]

Love the Vac forming process to that end I have saved these vacuum pumps.

Gene my question is do these look like a good basis for a small 8"x12" vac-foming machine?

Thanks for all your sharing of the process you have already given.

 

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[Ivan B]

I have been looking into doing somebodies but wanted to know if this vacuum pump would be good enough.

Not sure about the specs. 

 https://www.harborfr...pump-61245.html

Thanks for any advise.