Vac press table?

hegan · Post by **hegan** » Mon Sep 02, 2013 6:56 pm

Been thinking about this, and done some searches on here and on the web. Found some stuff out on the web but on here not so much. Has anyone ever tried making a vac table press something along the lines as this in the video.

Just up scaling it to a work bench size and using a real pressing vacuum. Has it worked for anyone that tried it?

sammer · Post by **sammer** » Tue Sep 03, 2013 8:04 am

You mean like this...

Mine using PU vacuum membrane with just a thru fitting.

and this...

OAC's Using a rubber membrane and a proper vacuum table.

Grabbed the image from here if you need more info.
http://www.skibuilders.com/phpBB2/viewtopic.php?t=2531

OAC's rubber membrane is a better way to go. Both the Nylon and the PU membrane hold the shape after pressing. Ok if your pressing the same shape over and over.

sam

OAC · Post by **OAC** » Tue Sep 03, 2013 8:59 am

I switched to silicon membrane pretty quick after that. It has delivered 30+ pairs without any trouble! Still going strong!

I use "paper bakelit" on the table.
Both the silicone and bakelit can take 250 - 300°C

I had plans renewing the whole set up, but it delivers so good!!

This is how it looks nowadays, wall mounted(for storage purpose) and everything:

Jibber · Post by **Jibber** » Tue Sep 03, 2013 10:06 am

What is the max. Vacuum you can pull with this setup?

Thanks, Christoph

twizzstyle · Post by **twizzstyle** » Tue Sep 03, 2013 10:30 am

The max vacuum you can pull with ANY vacuum setup is your local barometric pressure (14.7psi at sea level on a standard day). If you want more you need an autoclave (or a high pressure weather system!

)

hegan · Post by **hegan** » Tue Sep 03, 2013 1:59 pm

Ok I see that the vacuum pumps from under the table instead of making a hole through the pu or silicon. I might be taking that road because after making a few pairs and having some bad luck with the holes through the bag ripping and letting air out I'm done with that method.

hegan · Post by **hegan** » Tue Sep 03, 2013 3:51 pm

Ok just downloaded sketch up, so go easy on how bad this draw up is.

But this is the idea I'm working with.

The inside of the box with a support in the middle that has air holes drilled in it. Make it air tight by using plumbing sealant along the seams, inside and outside.

The hole is the location of the valve.

And the top with holes drilled in it.

I'm thinking of making a frame like the ones you guys have done, maybe with oak for extra weight.

sammer · Post by **sammer** » Tue Sep 03, 2013 7:47 pm

Your base is going to need more ribs.
14psi doesn't sound like much but it will break the bottom panel of your base at the worst possible time.
I broke a 3/4" panel by leaving about 11" unsupported.
The panel just sucked up into the void and broke 1/2 way thru the press cycle.
Luckily my epoxy was just about at gel stage when it happened.
Surprised me 'cause I'd pressed a few pairs before it finally failed.

When I finally make a vacuum hold down I'll probably router a pattern of channels into a bottom 3/4 mdf sheet and then laminate a 3/4 sheet with matching holes onto the top. Have to seal it all with pu or shellac or glue.

I think that's what knights has done here.

sam

OAC · Post by **OAC** » Tue Sep 03, 2013 10:20 pm

Don't overdoing it! No need for an extra "chamber", just make the valve go thru the table.
If you're not going to use heat you can use av sheet of PVC or some other plastics. Just to seal the table.

OAC · Post by **OAC** » Tue Sep 03, 2013 10:23 pm

...and no need for channels on the top either. It's better to have them, or just one, under the mold instead...if any.

Jibber · Post by **Jibber** » Wed Sep 04, 2013 10:41 am

twizzstyle wrote:The max vacuum you can pull with ANY vacuum setup is your local barometric pressure (14.7psi at sea level on a standard day). If you want more you need an autoclave (or a high pressure weather system! )

Not any setup is really airtight. For normal vacuum bagging 80% is ok. I use vacuum infusion to build my kiteboards and there you need a perfect setup. Therefore my question...

For the other stuff I agree with OAC. Keep it simple otherwise you will get problems to seal everything.

Cheers Christoph

deepskis · Post by **deepskis** » Wed Sep 04, 2013 12:44 pm

Here is an old pic of my setup. Very simple and effective. Keep it as simple as possible!

hegan · Post by **hegan** » Wed Sep 04, 2013 4:27 pm

Ok I think I will just make a normal mdf table and use this plan from joe woodworker http://www.joewoodworker.com/veneering/ ... -press.htm . cant get much simpler than that.

OAC · Post by **OAC** » Thu Sep 05, 2013 1:06 am

Just make the frame sturdy! I started with the one like JW, but it was a little weak for the pupose. I know sammer had some issues aswell. I ended up with rectangular steel tubes.

dvollebregt · Post by **dvollebregt** » Sat Sep 07, 2013 1:15 am

I'm also thinking about building such a table. What kind of vacuum pump do you use?

Ski Builders Forum

Ski Builders Forum

Vac press table?

Vac press table?