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My LOW budget Vacuum Switch

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Old 03-17-2018, 07:23 AM
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Vettster
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Default My LOW budget Vacuum Switch

Just thought I'd post this here in the hopes it may help other builders entering composites fabrication. I can't take credit for the idea. I found a picture on the net with no info, but that was all I needed. It works very good and is KISS! Keep It Simple Stupid

I'm getting pretty good at the bagging with regards to a perfect seal.. though I still have to occasionally check it and give it a pump once or twice. It's kinda nerve racking when you're trying to relax and watch a movie etc, so I decided to use a switch. I didn't want to go with the expensive electronic switches that you can only get from the US and pay a fortune in shipping + duties, taxes and waiting for a week or more...so I made my own for $5. That was the cost of the 15a 125v switch.

The syringe has a spring inside. When vacuum hits 8 bar the spring is compressed releasing the switch and turning off the pump. When/if it loses vac (5 bar)the spring pushes the plunger out which activates the switch starting the cycle again.

The only tricky part was the switch. I don't have a lot of experience with electronics, but I knew that I didn't want the switch to turn on or off so slowly that it would arc and burn out the switch. A simple chat with the electronics salesman set me up with what is called a "momentary quick switch". It builds up pressure and then snaps to the on position and same for the off.

Hope this helps someone.

Trevor

Last edited by Vettster; 03-17-2018 at 07:26 AM.
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Old 05-27-2018, 02:58 PM
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Smile low budget vacuum switch

very cool idea I am going to build one myself
thanks for sharing
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Old 05-27-2018, 03:32 PM
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Your welcome. The only thing I would change is to use a 20ml syringe instead of the 10ml syringe I used. The small one is a bit to sensitive.

Have fun!
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Old 05-30-2018, 06:21 AM
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I built my own rig.some time back. For a cheap pressure sensitive switch I scavenged the vacuum advance unit off an automobile distributor. They come with a spring. built in.

I reused a micro switch and a relay from my junk box. The vacuum advance unit was a spare I had for my classic car as the diaphragms do fail

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Old 12-10-2018, 03:52 PM
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That's an awesome neat idea, thanks for sharing.
I was going to build one, an purchased ez vacuum instead, when I learned I need the vacuum switch.
I don't think I can get that kind of "quick switch" here, now I am thinking using a switch to activate a relay
Any idea of sealing the DIY vacuum tube sealing ? Right now I just pucture a hole, insert the tube and give some aquarium silicone glue, which gives me trouble after a few jobs.
My only Idea is to ask a friend to lathe a nozzle with a base that I can insert between the plastic tarp.
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Old 12-10-2018, 10:18 PM
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Whisky29, Check with the supply houses that support composite fabrication. There is a neat little fitting that has rubber washers, and a threaded section that goes in the bag. I've used caulk before, but once I got the "Ez Vac Bag Connector" I never went back to caulk. There is another handy item for sealing the bag that's a little hard to explain. It's a rod, that presses into a "C" channel. Over the years I used a lot of poly film bags, but once I starter using nylon bagging material it was a huge improvement.
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Old 12-12-2018, 05:37 AM
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How do you control the 8 bar/5bar on off points? Is it the position of the syringe and the power of the spring? I'm just trying to follow this. Thanks for an explanation.
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Old 12-12-2018, 06:03 PM
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Originally Posted by GREG DOE View Post
Whisky29, Check with the supply houses that support composite fabrication. There is a neat little fitting that has rubber washers, and a threaded section that goes in the bag. I've used caulk before, but once I got the "Ez Vac Bag Connector" I never went back to caulk. There is another handy item for sealing the bag that's a little hard to explain. It's a rod, that presses into a "C" channel. Over the years I used a lot of poly film bags, but once I starter using nylon bagging material it was a huge improvement.
Thanks for the information. I should have but it back then
So basically its a nozzle with flat base with rubber that hold the plastic in a channel with rubber as well? I wonder if oring would work,
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Old 12-12-2018, 06:30 PM
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Whisky29, I was talking about two different items. The Ez Vac Bag Connector is the connection from the pump to the bag. The rod and "C" channel is to close off the opening to the bag. The rod is used to force the bag into the "C" channel to seal the bag.
Fiberglast Products has a number of videos on their web site to demonstrate the use of these tools
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