Just curious if you guys are using a Holding tank with your Vacuum pump ?

My small one for RC airplanes will handle a mold the size of a board quite easily.
It has a Beer keg for a holding tank & takes a bit to empty the air.
I placed a check valve & a adjustable vacuum switch between the pump
and the holding tank.

There's a relay that goes from the switch to the pump. If you can get a mercury
relay because there Way more reliable; or clean the relay contacts every month
so Ya won't loose a part in your mold.

So-- the switch is adjustable from 3 to 29 Hg. if your using a light foam then
set it at a lower setting.Using Honneycomb then set the switch to a higher settting.
It will come-on when the tank goes below the setting
by a few Hg, then turn off when the desired setting is hit again. This makes the
pump run for only a few minutes each hour if you took care of all your leaks at the mold.

I posted this because i know of at least a hand full of guys that just let their pump
run all night ! (That's just silly)

Bille

yep i use a resivour (dog)

here's my home made vac pump set up using fridge pump and lpg bottle. I don't use any switches. i just work a good seal around the vac bag then suck down to full vacuum turn the pump off and the resivour holds the vacuum for a good while before i have to top up with the pump. I generally only suck down until the resin goes green.

Two things --plummet-- ,why the $50 is worth it for the adjustable switch; not
counting the idea that now your part stays under vacuum till the resin is cured
& the pump only runs 5 minutes every Hour :

** different type core materials Really want different Hg settings.
if using bamboo or wood core,in lu of foam the setting will be WAY higher.
That re-fridge pump Ya got will suck 20Hg; i have one near the same on top of my beer-keg.

** you can pre make 50K carbon uni for board stiffeners by placing a .5oz plain weave Glass
with peel-ply, on either side of then sucking down. when cured just trim the sides & place
under your glass, (they bend to shape easy cause their only 0.003" to 0.005"thick)
depending on how wide you spread the carbon fibers. Or use a Uni Carbon with binders
attached, then sand the edges flat later; but Don't forget the peal-ply !
The straight cuts under the glass look real professional. Other parts that have
no core can also be done at "near" Max that the pump can deliver.

On another note :
Ya can place a garden hose or small diameter tube on the exhaust from
the pump, and keep the fumes from the part outside of your
work aria by running the tubing out a hole in the wall. Works good in winter
when Ya wanna keep the temp at 77+ degrees while waiting for parts to cure.

Bille

your right an adjustable switch will be nice.

The parts i've made recently. My carbon fibre landboard truck housings were all carbon with a bit of pvc core. but there was no tension by the way of plywood layers so no need to hold vac until full cure.

ps that switch is harder to get hold of in nz. tried to find one in the past and it got too hard.

But my creative juices are flowing again and i have a bunch of boards i want to build.

wave tt
wave mutent
another landboard
longboard skateboard

but its rolling into summer so my any building will be put on hiold for thw winter months. i have far to many kites to fly, bikes and skateboards to ride in the mean time.

If you order a switch from the link i supplied then be certain
to get a relay as well.
** I got my relay at Radio-shack, it's a cheap contact relay.
but i clean the contacts every 50 hrs or so with emery-paper.

I used a Brass, (check valve) from Home Depo out of the plumining deparment
to keep the vaccume from running back out of my pump.

Every part i make, i spray a shot of WD-40 into the check valve,(it has a threaded top),
that shot of spray will lubricate the Pump & it's seals !! (important)

When does the Lil grommet get a Kite ?

Bille

that pic is a couple of years old not. thats my oldest girl whose now 7. and she has a 1.2m kite. she's not yet too interested in flying it tho.

Off topic but the Author won't mind :

I did this & it's FUN !
A way Ya might try to spur interest is to use your kiteboard in
light wind. Tie a rope to one of your surfboards about 20ft long
to the back or your harness.
Put a life-jacket and a helmet with a face-guard on your daughter.
then tow her at just over the planing speed of your kite-board.
The kid will have a Blast !!

Bille

What is the link? I didn't notice it.

Thanks
Alan

Here is the adjustable switch :
http://www.acpsales.com/Vacuum-Switch-3 ... Range.html

& you'll Need a relay :
http://www.acpsales.com/Relay-for-Vacuum-Switch.html

Be sure to "Clean" the relay contacts with 600gt wet& dry sand-paper
at Least every 50hr of operation !!!!!
Don't Forget ...

Bille

Hello All:

Would someone mind emailing me a circuit diagram for setting up the system (with vacuum switch and relay) for a 220-240V system? I am very interested in how to connect all the relay plugs correctly.

Thanks in advance,

Reuven