My latest vacuum forming machine and a silicone mold

[Anonymous]

Here's my latest vacuum forming machine I use to make coil shells. This is the fourth I have built and by far the best. I added a second 6CFM pump and built the table in a way that there is an absolute minimum of air to evacuate. This latest machine is fast, so fast I don't even have time to use the reserve tanks.
<img src="http://www.coilbuilders.com/pics/vac1.jpg" alt="" />
Here's a closeup of the table.

 

[Anonymous]

Here's the part I wanted to mold, its a set of wings for a coil shell I machined on the cnc mill. I wanted to be able to duplicate this part quickly and cheaply so I purchased some liquid silicone for mold making and that stuff is super.
No smell like the tubes of stuff one might buy at the local Home Depot. This is a deep draft part with no taper at all but you can do that sort of thing with liquid silicone. Its not cheap though, about $130 a gallon ouch!
<img src="http://www.coilbuilders.com/pics/milledwings.jpg" alt="" />
Here's the mold.

 

[Anonymous]

something that you would buy although it's probably better built than anything you could buy!!! <img src="/metal/html/smile.gif" border=0 width=15 height=15 alt=""> Amazing workmanship!!!!!!! Way to go Charles!!!!!!!!!!! Good Luck with it!!!!
HH
Beachcomber

 

[Anonymous]

[No message]

 

[Anonymous]

Questions...
Couldn't figure out your vacuum hook-up... what's the big canister to the right, the primary tank? Are the blue tanks the reserves?
What material are you casting in the mold? Then, how are you attaching the ears to the shell?
Are you still using quartz heaters?
The table set-up doesn't make sense... can you post a pic or two that shows how it works?
I'm in the process of walling off sections of my basement to separate my metal lathe & milling machine from the woodworking stuff. As soon as I get this done, I'll start building my vacuum machine. I bought the same Robinair, think I need the 2nd pump?
- Carl

 

[Anonymous]

Hey Carl,
1. That big tank to the right is a combo vacuum/pressure tank. Its not used for vacuum forming, I use it to degass resin and for pressure casting. For example I just poured a liquid silicone mold the other day, that stuff is very thick, I think they take some liberty calling it "liquid" and so by the time its mixed theres a bunch of air trapped in there e.g. a zillion air bubbles form. But place the resin in the big tank, draw it down to 29 inches of vac for about 2 minutes and presto all the air is removed. NOTE: It will expand about 4 times is normal size during this process so be careful to use a large container else it will create a big mess. The other use is in pressure casting, if you want to cast a part in resin and ensure there are no air bubbles, you place the part in the tank and connect an air compressor and pressurize to about 60psi. That crushes any air bubbles to microscopic size. Again safety note, these pressure tanks are ASME rated and one should not exceed the labeled rating else the top might explode off and create a new skylight in your house or worse.
2. I use urethane resin for the molds for the vacuum forming machine. They make urethane resins especially for mold making. I cast the wings out of urethane also and fix to the shell with plastic cement.
3. Yes I'm still using the infrared quartz heaters.
4. Not sure what you are asking on your next question...are you talking about how the sheet is raised and lowered? Or are you talking about the vac table itself? The mechanism raises and lowers the sheet straight up and down via the big white bar handle across the front. I wanted that to be a one handed operation so I could work the reserve tanks with the other. Course now I don't need them lol.
The table...I started with a 21 inch slab of solid 1 inch thick polyeth. In previous vac tables it seemed impossible to get the table sealed completely, there was always some leakdown. At 29 inches you can pull air even through sealed solid oak. No leaks now, it holds 29 inches. I milled a recess in the center of the table deep enough for the perforated aluminum sheet plus a underlayer of 1/2 inch wire mesh. This creates a very small air space to evacuate. Finally the seal, I had been casting silicone seals using tubes of silicone, this time I saved myself a lot of time and purchased a 20.5 inch silicone o-ring, 1/4 inch and milled a groove in the table for it. I drilled and tapped two holes under the table for the pump hoses and thats it.
I would recommend a 2nd pump if you plan to form ABS and especially to eliminate the need for reserve tanks though you still might need the tanks for deep draft parts like say something 4 or more inches tall where there will be a lot of air trapped under your sheet to evacuate.

 

[Anonymous]

I can see how the bottom part works but how do the heaters work and do you have any pictures of the part where the plastic sheet fits

 

[IsmaelY]

Where's the Photo's, followed this from Geotech forum still no photo's....

 

[Ron SDakota]

n/t

 

[Buddy (TX)]

Nope its not just you... I do not see any pictures either... keep checking but still have not found any.

Buddy(TX)

 

[Rick(ND)]

You dont see a picture is the post was made in Nov of last year. I think after a while the pictures are taken off to save space.

 

[Carl-NC]

Yup, Findmall deletes pics on a regular basis.

Charles also cross-posted some of his pics on the Geotech forums, where uploaded pics are *never* deleted. However, a few of the threads have pics linked in from other sites that no longer exist.

- Carl

 

[Mr.Bill]

The problem with the photo posting is where he has the photos stored.

www.coilbuilders.com/pics/vac1.jpg

This is what I got when I checked on the photo address.

Not Found
The requested URL /pics/vac1.jpg was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

It's the same for the other photo also. The photo wasn't posted here so it wasn't deleted here.

Bill C.

 

[Carl-NC]

...in this case, Charles did link to external pics. Sorry 'bout that.

However, it is true that Findmall does delete images after a while, greatly diminishing the value of some posts, especially in the technical discussions. It would be far, far preferable not to do that.

- Carl

 

[Mr.Bill]

The photo's don't get deleted here, at least not tech. one's. There is no one here going about deleting photos, at least not unless there nasty ones.<grin> I have read a few post by others mentioning the same, but there miss-informed, and spreading miss-information. If one were to take a look at the properties of the red X that appears, you would see where it was stored. If the photo was deleted, there would be no trace of it being there.

---

What you may have noticed since the new forum, none of the photos on the old forum could be brought over. There was nothing that could be done. So perhaps that's what your referring to ???

Also, just like in Charles case, a great deal of the photo's, and tech. papers were not stored on Finds forums, so Finds has no control if other forums choose to stop the photos stored on their forums. With your forum, most leave their post on your forum pages. That's not always the case here.

With the old forum when files got corrupted, sometimes batches of files needed to be removed. If they were such a post in the middle of this, they would have gone also. This new forum is a bit more secure.

Later

Mr. Bill

 

[Charles (Upstate NY)]

I store the pics on my own server and link to them rather than uploading them to Findmall and as someone had guessed I delete older pics from time to time to make way for new ones hence the broken links.

I'll post some newer pics for those who may be interested.