Vacuum Problems. Please help

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#1

Hey guys,
After many frustrating attempts and hours lost I need some advice.

I can’t get my vacuum pump to pull ANY vacuum. I am using a rotary vane pump which uses oil. When the pump is connected directly to the vacuum gauge I pull at about 22 with ease.

Once I have the tubing on a mould I can’t pull any vacuum at all. Once I was able to pull some vacuum, but I wasn’t able to measure the amount I pulled.

My questions are:
Does baggin tape go bad? Am i using the wrong type of baggin tape. I mean yellow purchased from Airtec, BUT it is years old, close to 4 years now.

Is my vacuum bag the problem? I didn’t see any holes or any wrinkles at all. I have experience with vacuum bagging but, For some reason I just can’t get things to work

I have tried vacuuming a flat panel on a piece of aluminum and sitll had no luck pulling a vacuum.

Where can I purchase one of those vacuum fittings that the vacuum tubing connnects directly to? I know I can order one. Id like to try and find somewhere local to buy one.

My workshop is in my dads machine shop in Burbank, CA next to the airport. Home is in Tarzana, CA. Help please

#2

are you using breather?

#3

I’ve experienced the same problem a few times. Pump gauge says it’s pulling 28hg but i could easily pull the bag away from the mold.

It sounds like you are not acieving full vacuum under the bag. Possibly your vacuum line is being sealed closed by the bag itself, this can happen. I think that is why Hojo asks if you are using breather. Breather being the white polyfil looking stuff that looks like a white blanket. If you wrap your vacuum line ( inside the bag) with this breather material you should be able to pull full vacuum on the mold.

Also if you are not infusing the mold, You should cover the lay up/stack with this white breather. Wet lay up, I always use the breather. Always make sure there is breather wrapped around the vacuum hose inside the bag.

#4

did you get it working ???

#5

NO. I called airtech and they said that the baggin tape can in deed go bad. Since my baggin tape has been sitting for a few years, it is likely that this happened.

I’m going to order some new baggin tpe to try this. And Im goingt o get one fo those fitting that u poke a hole in the vacuum bag instead of running the tubing directly into it.

#6

I need some help deciding on the best vacuum connector for my setup.

I am currently running my vacuum tube from my pump into my bag. I don’t want to do this anymore. I’m concerned that I have leaks from the area where the tube enters the bag.

I was looking at fiberglast.com stuff
http://www.fibreglast.com/showproducts-category-VacuumBaggingEquipment-19.html

The vacuum connector and the thru bag connector. I don’t think I want to use air hose, but the plastic vacuum conector seems cheap and not durable enough to do the job.

I was looking at Airtech’s: https://www.airtechonline.com/htm/defaultIE.htm
And the problem i see is: most vacuum connectors attach with a male end, using this connector a female end is needed.

What are you using and where did u buy it from?

Also:
In terms fo baggin tape from Airtech’s site: https://www.airtechonline.com/htm/defaultIE.htm

This stuff seems pretty cheap. Have you used this before? I have only used airtech’s 200y: https://www.airtechonline.com/htm/defaultIE.htm

But for the same price, you get twice the amount of material…

#7

Skip the fiberglast and airtech conectors. Buy the ones at USComposites. Ive used them all. They are all the same, USC is way cheaper.

For tape I use yellow tape called “Tacky Tape” which a lot of boat guys use for underwater repairs. Its good stuff. Best sealing tape Ive found.

Tried the grey tape, very disapointed, left it a long time ago. The black tape is too thin, and falls off its backing way to easily.

#8

I use the black and grey, love it :smiley: It’s not an oven cure tape though to the best of my knowledge.

The yellow is awesome tape, BUT it’s pricey.

#9

I just did a small test panel and pulled 22in. Im going to push for 25in.

My atm gauge says I am at about 28.8in Hg so how is 22in Hg in comparison? Is this good, bad decent?

Is this good enough for vacuum infusion? I dont want those pin holes to show because of a weak vacuum.

Also, what would be the best vacuum someone could buy. I was looking at the Robinair vacuum pumps. They have a 6 CFM for $330 but a 10 CFM for $850+ why so much more for not such a big jump in CFM rating?
What will these pumps pull in terms of pressure? What kind of pumps pull 30in Hg? I have only heard of these

#10

Can u send a link? I searched their site and couldnt find any fittings on there

#11

Hate their ordering process, but they are really quick on following through with orders. Looks like they raised the price since last time I bought them. They used to be $18.

Heres the link.

http://www.shopmaninc.com/vacuum.html