vacuum

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#1

I have just bought a vacuum pump. It is my first. So its not the best but hopefully it will do to get me into infusion. yes i have had vacum bagging experience and my main mistake was my bag was always to tight an i did not pleat it so i was bridging on sharp corners

it says it will pull a maximum of 10Pa. Or 0.002953006

Am i right in thinking that is what would be left in the bag? I am 2 to 4 metres (6.5 to 13 ft) above sea level.

So am i correct in thinking that i will be able to pull 29.997046 which is enough for infusion.

Depending on size of pattern being infused?

#2

there really has to be a standard set for vacuum, or an ACCURATE conversion!! It’s hell trying to find a vacuum pump when people are rating them “Hg, micron, and torr…all on teh same site!
Anyway, if the conversion you did IS 29.9"hg…yeah, that is definitely enough for vartm. Per research and experience, I would never go below 28”. Both my pumps are around 29.5".

#3

Yea pressure units are very annoying. Theres Torr, Atm, Inches of Mercury, Centimeters of Mercury, Inches of Water, Centimeters of water, Pascals, Psi. Anyhow a regular atmosphere is 101,325 pascals. Your vacuum pump can reduce the pressure to 10 pascals.

My cheap harbor freight vacuum pump only pulls to 62 cm of mercury or 24 inches. It’s not the best but I’m able to make some pretty good experimental parts with it.

#4

Yes it is confuseing. I did read that 30inhg was 100% vacuum so if I took 10Pa which is 0.002953 which is what would be left in the bag from absolute pressure then I in theory should be pulling around 29inhg or there abouts.

Maybe I am way of the mark?

#5

From what I know and from Riff said I’m pretty sure you’re correct. What model pump are you getting?

#6

Its by a company called actec

Air displacement is 3cfm
Ultimate vacuum is 10Pa
Power is 1/4 hp

#7

Brainstorm - did you ever get that pump? It’s one of the one’s I’m looking at to build my own veneer press on the cheap as I’m allergic to the high prices charged for bespoke presses.

On the face of it this looks like it would do the job. Your arithmetic looks OK to me.

Or is there a better/cheaper solution? I don’t need a total vacuum - something better than about 20 ins hg would be fine i.e. better than a 70% vacuum. Any ideas?

Sorry to throw a load of questions on my first post but would appreciate some help. Thanks.

Roger

#8

yer i got it!! only done 2 small parts. as still learning. tbh tho real test is when i do a large part. doos seem to be a good little motor tho

#9

Most of the time I write down vacuum levels in percentages. That is the only unit that seems to work globally…

These small pumps will do the job sufficiently. They migh produce some smoke, but that’s it. Nothing to worry about.

#10

yes i have noticed that