Re: [bolger] Gluing plywood sheets
-snip.
and then you can bleed a little air in. Also, if you go to the
junkyard or maybe the auto parts store you can get one of those
vacuum
operated diaphragm actuators (don't know real name, but you see them
in air intake where they close a door to route intake air around
exhaust manifold when it's cold). These actuators can be set up
against a spring to operate a micro switch to control pump. You can
get away without much of a "storage tank" if you leave the pump on.
How to you store vacuum, anyway? I guess I should know, I've had bank
accounts with lots of financial vacuum in them at times. Don't use a
55 gallon drum, anyway, it'll collapse (no, I didn't do it, I know
better than that, but I saw the aftermath). If you get a bell jar you
can use it for a tank and also to debubble epoxy mixes (carefully or
it'll bubble over).
> =========to
> To do it right you need a pump, storage tank, regulator and switch
> start and stop the vacuum pump just like an air compressor.Actually, you can just leave the pump on unless you are doing foam,
and then you can bleed a little air in. Also, if you go to the
junkyard or maybe the auto parts store you can get one of those
vacuum
operated diaphragm actuators (don't know real name, but you see them
in air intake where they close a door to route intake air around
exhaust manifold when it's cold). These actuators can be set up
against a spring to operate a micro switch to control pump. You can
get away without much of a "storage tank" if you leave the pump on.
How to you store vacuum, anyway? I guess I should know, I've had bank
accounts with lots of financial vacuum in them at times. Don't use a
55 gallon drum, anyway, it'll collapse (no, I didn't do it, I know
better than that, but I saw the aftermath). If you get a bell jar you
can use it for a tank and also to debubble epoxy mixes (carefully or
it'll bubble over).
> snipsnip
> ========
From: "Lincoln Ross" <lincolnr@...>
You can lay up the whole thing at once if you can get it to
stay in place.
To do it right you need a pump, storage tank, regulator and switch to
start and stop the vacuum pump just like an air compressor. You
can use a vaccum cleaner to do the inital pull down and then
use your vacuum system to finish the job.
There are two cheap gadgets one uses air the other water. They
cost about 20 bucks but they use a LOT of water or air.
It will work great if you can tape and seal the bag on the inside edge
of the hull or have some excess hull to use to seal the bag too. Then
you cut the hull down to size after bagging.
Vacuum bagging will build the lightest strongest layup of
any method suited to low production. I don't think any
composit method will beat it on strenght to weight ratio.
The only draw back it is not suited to high volume production.
Gordon W5RED
G. C. Cougergcouger@...Stillwater, OK
www.couger.com/gcouger
"You miss 100 percent of the shots you never take." - Wayne Gretzky
> >----------
> > I usually only leave the vacuum on for 4 or 5 hours with System 3,
> fast
> > hardener.
>
> I like to use really slow epoxy when I'm doing something that will
> take a while to get just right so I don't have to hurry.
>
> I'd be careful using a shop vac and not leave it
> unattended. I
> > had one catch fire once from the wiring overheating. Also, have a
> back up
> > as they do burn up some times. Kurt Hughes, who has done a lot of
> vacuum
> > bagging for Cylinder Mold construction where the whole side of a
> hull up to
> > 40 or more feet long is bagged together of 2 or 3 layers all at
> once, says a
> > shop vac will last 20 sessions.
You can lay up the whole thing at once if you can get it to
stay in place.
>=========
> If you're going to do such a big hull, you can afford a real pump,
> which will pull pretty hard and still last a long time. Probably a
> few hundred $. I'm sure there's some cheap gadget that will do.
> For instance there are valves you can put on your compressed air
> supply that will pull some vacuum. Very cheap, not very efficient.
> You can still use a shop vac or similar for the initial pull down.
To do it right you need a pump, storage tank, regulator and switch to
start and stop the vacuum pump just like an air compressor. You
can use a vaccum cleaner to do the inital pull down and then
use your vacuum system to finish the job.
There are two cheap gadgets one uses air the other water. They
cost about 20 bucks but they use a LOT of water or air.
>========
> snip
> > No, bagging wouldn't work well for adding layers to a framed hull.
> >
> > Gary
>
> I'll bet if you have a layer of epoxy on the existing wood you can
> use
> the existing hull as one side of the bag and make it work just fine,
> assuming it's airtight.
It will work great if you can tape and seal the bag on the inside edge
of the hull or have some excess hull to use to seal the bag too. Then
you cut the hull down to size after bagging.
Vacuum bagging will build the lightest strongest layup of
any method suited to low production. I don't think any
composit method will beat it on strenght to weight ratio.
The only draw back it is not suited to high volume production.
Gordon W5RED
G. C. Cougergcouger@...Stillwater, OK
www.couger.com/gcouger
"You miss 100 percent of the shots you never take." - Wayne Gretzky