Vacuum Bag Help

[Seadog]

I'm giving it a try. Will be re-coring the hatches if I can get this right.

Have the West System Vacuum bag kit.  On my test piece it looked like

the suction created under the rubber suction cups prevented the air from

being drawn out with the vacuum.  Tried putting a small wooden block

under the edge of the cup to keep it off the bottom panel.  That worked

pretty good but I'm sure there is a better way.  Any suggestions?

[JimCt]

There's a bleed mat that should go into the bag to act as a channel to fully evacuate the air.  Same principle as the Food Saver bags.  Ask your wife... she may be familiar with the Food Saver set-up.

From their site:

Do I have to use the FoodSaver® Bags? Can I vacuum package in other plastic bags?
To vacuum package with the FoodSaver®, you must use the FoodSaver® Bags. They are specially designed to be strong enough for vacuum packaging and the waffle pattern in the bag is a patented design that makes sure air does not get caught in pockets around the food.

[warthog5]

Jim's right, but I do it a little different.

The laminate is laid with resign. You don't have to totlly saturate the glass, but don't starve it. [you will learn with practice] Usually you start with more resign than will be needed.

On top of this goes peelply. On top of that is a layer of bleeded cloth. the excess resign will come thru the peelply and be absorbed into the bleeder cloth. The peelply and bleeder cloth get thrown away the next day. [One shot deal]

Now where the vac port comes thru the bag. I take a piece of bleeder cloth aprox 18in square. I fold it into a 4in X4in square.

This get's laid on top of the sheet of bleeder cloth that covers the laminate and where the vac port will set.

This allows air to travel thu and it acts to stop excess resign from being sucked into the Vac Port.

Look close and you will see the extra square of bleeder cloth. It is squished down due to the vacuum.

[Seadog]

Thanks guys!      

Wart - it's hard to see in the picture but do you put the

vacuum cup right over the laminate and not off to the side?  If it is over

the laminate does it leave a depression of the cup underneath?  I tried a

raw piece of 1/4 kleg under the vacuum cup but I like your way better.

[Seadog]

Forgot - one other thing - is 6 mil 'visqueen' ok for the outside layer?

[warthog5]

5mil will work fine if you don't have a bunch of weord shapes. IE just a basic flat panel.

You can use thinner stuff, like 2mil or 3mil.


Let me see if I understand you correctly.

You put a piece of Kledgecell under the vac port on top or to the side of the laminate?

Air can't flow like that. It would be the same thing ,just about as sticking your hand over the vac port and expecting it to pull air around it.

Air will flow thru a pile of bleeder cloth.

Sometimes the port is off to the side of the laminate, but most times it's sitting right on top of it. This is due to usually not having enough room to have it off to the side.

Yes it can cause a slight depression. Try to keep your vac at 15hgin. the depression usually happens when the pressure get's in the neighborhood of 20hgin. You can start getting a resign starved laminate at that pressure. Not Good!

[warthog5]

Here's some pixs for you. Some on the laminate and some off of it.

http://www.classicmako.com/projects/xshark/bw14.htm

http://www.classicmako.com/projects/xshark/bw5.htm

[Seadog]

Closed cell foam - can't draw air thru it - got it.





Here's a shot of the first draw on a hatch.  It was right at minus 5" Hg.

Came out OK, but needs to be fine tuned.  Hatch is 18.5" X 13.5".

The schedule was 2 layers 17 oz DB, 3/4" Klegecell core, two more layers

DB. then 6 oz cloth finish.  2:1 epoxy resin.  It almost seemed like the

cloth didn't need to be wetted out - the vacuum might have drawn out

enough resin from the laminate underneath to soak the cloth on the way

out.

(That's one of 2 eight points I got last season)

[warthog5]

Look's real Good.