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 Post subject: Vacuum bag technique
PostPosted: Tue May 07, 2019 7:08 pm 
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Joined: Sun Feb 17, 2013 4:58 pm
Posts: 1449
First name: Ed
Last Name: Minch
City: Chestertown
State: MD
Zip/Postal Code: 21620
Country: United States
Focus: Build
Status: Amateur
I have never used a vacuum bag before but had a veneering project. I am a hand tool user and found a hand operated vacuum pump. It was cheap - under $30 for the pump and fitting - and worked perfectly for the 4 panels I veneered at 11" X 30". They even have pictures on their website of a set of braces being glued on a top.

1) 30 seconds of pumping and here is what I had. I had to pump 2-3 strokes every 10 minutes with a couple of panels, but a couple were OK after the first pumping. This will depend on the seal you get at any openings

2) a close-up. The texturing is the surface of the veneer which is flamed ash

Made by Roarocket, no affiliation, yada, yada, yada

https://www.roarockit.com/woodworking-tutorials-categories

https://www.roarockit.com/tap-parts.html

Ed


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 Post subject: Re: Vacuum bag technique
PostPosted: Wed May 08, 2019 6:26 am 
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Koa
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Joined: Tue Feb 26, 2008 6:19 am
Posts: 1322
First name: Richard
Last Name: Hutchings
City: Warwick
State: RI
Zip/Postal Code: 02889
Country: United States
Focus: Build
Status: Amateur
I like this technique and have wondered if a simple space bags would work. I just might try it.

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 Post subject: Re: Vacuum bag technique
PostPosted: Wed May 08, 2019 7:00 am 
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Brazilian Rosewood
Brazilian Rosewood

Joined: Sun Mar 30, 2008 8:20 am
Posts: 5924
Hi Ed,
Did you buy the "super pump" or the regular pump? How difficult was it to evacuate the bag?
I made some side laminating forms by thermoforming corian. Presently I use kerfkore and a multitude of clamps to compress the veneer and hold it against the form. Since the laminating form is only 1/2 inch thick it may be possible to fit it in a skateboard bag and vacuform the sides.


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 Post subject: Re: Vacuum bag technique
PostPosted: Wed May 08, 2019 8:33 am 
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Cocobolo
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Joined: Mon Mar 17, 2014 1:27 pm
Posts: 375
First name: john
Last Name: shelton
City: Alsea
State: Oregon
Zip/Postal Code: 97324
Country: usa
Focus: Build
Status: Professional
Clay S. wrote:
Hi Ed,
Did you buy the "super pump" or the regular pump? How difficult was it to evacuate the bag?
I made some side laminating forms by thermoforming corian. Presently I use kerfkore and a multitude of clamps to compress the veneer and hold it against the form. Since the laminating form is only 1/2 inch thick it may be possible to fit it in a skateboard bag and vacuform the sides.


Clay, I have a vacuum press set-up which I use for laminating double tops and backs but for laminating the sides I prefer clamps. I know other people use vacuum for sides but I just don't trust the vacuum to apply the force needed to press the multiple lams on the sides together. I use an inside mold.


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 Post subject: Re: Vacuum bag technique
PostPosted: Wed May 08, 2019 5:04 pm 
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Koa
Koa
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Joined: Mon Nov 24, 2008 12:17 pm
Posts: 1161
City: Escondido
State: CA
Zip/Postal Code: 92029
Country: USA
Focus: Build
Status: Semi-pro
Funny how we all develop our own ideas. I’m the opposite. I don’t trust clamps to give me even pressure to laminate multiple layers in a side. So I vacuum it flat for 2 hrs. Once I feel confident the epoxy is set but not cured I take the sides from the bag and press it into a mold. It cures to the proper shape in a mold.


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 Post subject: Re: Vacuum bag technique
PostPosted: Wed May 08, 2019 8:51 pm 
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Contributing Member
Contributing Member

Joined: Sun Feb 17, 2013 4:58 pm
Posts: 1449
First name: Ed
Last Name: Minch
City: Chestertown
State: MD
Zip/Postal Code: 21620
Country: United States
Focus: Build
Status: Amateur
Clay

It took about 20 seconds of pumping to empty the bag. With the curved/coopered doors there was planty of air space in there, but your sides will have more volume to evacuate.

I sprung the extra $2 for the super pump. I won't be using it anytime soon - you are welcome to take it and the bag to try out when we see each other next.


Ed


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 Post subject: Re: Vacuum bag technique
PostPosted: Thu May 09, 2019 8:26 am 
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Brazilian Rosewood
Brazilian Rosewood

Joined: Sun Mar 30, 2008 8:20 am
Posts: 5924
Hi Ed,
Thank you for the kind offer. I will probably take you up on it. It is always nice to "try before you buy". I understand John's reservations about using vacuum, and he may well be right. The corian molds I have made are only 1/2 inch thick so they may fit in the bag better than the block molds I also use.


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