what do the home builders use for their vacuum bags....do you make your own or buy...and if you make them how, and how much vacuum pressure do you use


thanks

t

I have always bought construction grade polyethylene film wherever I could find it. E.g. Home Depot in the U.S. Then I have taped the bag together or used silicone based window fitting goo to seal it up. Cheap and good enough if you are careful. Buying a professional vacuum outlet to connect the bag to the pump is a good idea, but there are alternatives.
How much pressure? As much as I can get without starving the laminate for epoxy or crushing the materials in the bag.

What do you plan to do and what is your budget <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

I made my own vac table from a double thick glass fume hood door with sandwiched wire mesh. Then I pulled carbon and foam down into my new tool (rudder half)- and broke the new table. I was using a home built pump- a free, discarded automotive AC compressor driven by an old electric 1/4 hp motor via a belt. CRAK- it said! <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />
Turns out my tool wasn't flat enough, and had a 2 inch wide 1/2 inch deep groove down the middle of the underside. Stupid man! Pump plenty strong enough.

I had already pulled too much vacuum on my foam core rudder being used as a plug and swelled it. DOH!

I have an official vacuum pump, not sure what pressure it operates at, doesn't seam to be bone crushing vacuum. I use 4 mil poly. Peel ply, doublestick foam tape for sealing, and a polyester fill material to absorb exess resin and maintain a space for the vacumm to operate in, I get from Fiberglass Supply in Bingen, WA at what seems to be reasonable prices. The pump came with a piece of clear, soft plastic tubing, maybe 3/8" i.d., that has a bunch of slashes cut into it at the end. This end is inserted into the bag and sealed with the tape. Been workin' great, have had a bit of practice.


Dave

What is the difference between an official vacuum pump and an unofficial one?

Are we feeling a bit cranky today Phill? I sense a streak of catsailor.com overexposure <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />

To answer your question, I would have to say that it's all in the head of the owner.

Hi All

At Boyers, the sealing tape was called 'Black S##t'. That was the common name for it in the workplace, 'Matt, throw down a roll of .....'

It was a black mastic tape, it was like Blu Tac almost, came in a roll and sandwiched between plastic.

The actual vacuum bag was just a clear poly film that was already sealed down both edges, just had to seal up the ends, and around the outlet.

Regards

Matt

Rolf,
Cranky? Not me- too much like hard work.
But you have to agree that Fuzzy got a good deal.
How much do you think he paid for that tubing?

so is there any info around for a newbie whos wanting to learn the art of vacuum bagging... idiots guide to everything lol

I'm sure you will get basic information from where you buy consumable suplies for V/B. West System also put out a worksheet on it.

If you have any particular questions you my get answers here?

Not aware of any books dedicated to Vacuum bagging as there is not all that much to it. However if you are going to do any kind of building Gougeon's Book on Boat Construction is a pretty handy bit of basic reading.

Try here for starters.
http://www.gurit.com/core/core_picker/download.asp?id=141
Just remember peelply and PVA, you can not live with out them!!

thanks this will be a good starting point....

Nice 'copter shot Jason. Here's what they look like in Los Angeles. Note the inversed paint scheme.
Dauphin helicopter

Close up attached.

GARY

yeah this was one of 2 shot i got... heres both... and i see what you mean about the paint...

they were doing practice... dropping guys in the water... let me tell you it was VERY hard to sail with the rotor wash