vacuum infusion laminating

[War Whoop]

Something needs addressed there;the only resin would be on the very top surface of the foam in the open or cut cells which I do not think would use over 30 -35 cc’s per square foot the approved structural marine foams are closed cell type ..

I use Airex and lately Core cell all plain sheet form

Here is a picture of some infusion one on top is a piece of a stringer 1” 600 core cell with 8 ply’s 18 oz fabric the piece below is a strake test sample that’s 10 ply’s of unidirectional at the diagonal with 6 -17 oz 45 x45 The reason I will show a picture it had to float across vents. In my free flow bottom.

[War Whoop]

Here in a rough state of fairing you can see where and why for the overkill in the strake sample. this is a 41 foot one off.

[War Whoop]

Another picture of the same 41 I placed lexan (for inside finish and so I coud watch the resin front)across the vents under the strake buildup and infused the lot of it one shot .

[War Whoop]

You asked about foam here is a whole bunch of it this boat is my number 21 one off all of them Foam you can see the chines are built-up and the vents are faired into the bottom which is 2" of A 600 Corecell.here we are preping the starboard side for glass.

[War Whoop]

Another :

[Rod T]

It could well be a characteristic of Divinycell . It would be interesting if any one else has run similar comparison test with other foams.
When I checked with Ian Farrier, he said he was not surprised and that one of the heaviest 31 made was vacuum infused at TPI
Rod.

[Rod T]

Well- knock me down- I was just at the DIAB site - makers of divinycell and they as much as admitted that my findings are correct- They are coming out with an improved foam that will absorb less resin in the surface area. A lot smaller cell structure.

I have fifty sheets of the old stuff in my garage :-(
Rod

[rxcomposite]

Rod T,

I remember one of the Diab representative advising us to spread a light coat of resin on the foam and letting it go tacky before laminating. We were doing contact molding.

The reason given was;
1. The foam absorbs resin
2. We could get a resin starved area if the foam absorbs too much resin.

In vaccuum infusion, the pressure is much more severe, the foam might be taking in too much resin, thus a heavier than expected laminate which some boatbuilders experienced.

[rxcomposite]

Originally Posted by Danielsan

Maybe not the right place?

Somebody knows about Vacuum generators? could they be used?
I see they go -27Hg and about 400l/min.

any hints about this?

greetz,

Hello,

It is just a jazzy name for vacuum pump manufactured by Anver Corp. for intermittent vacuum requirement. They claim it has no moving parts. I think it is a diaphram type. E mail anver.gocomp.biz/1

Nothing beats a rotary pump or a piston pump in terms of pulling vacuum.

Rx

[War Whoop]

Infusion like on big parts; use a positive displacement pump (piston) and a large one at that like a V7 IR on a receiver tank I usually plumb in a small 1 ½ hp Pump in the system behind a check valve between the large pump and the work… this I use to slowly“set” the bag we then rely on “electronic ears” to check entire bag not just the perimeter for leaks the real small leaks are above the human hearing range.. Infusion is 99.9 setup.

[Rod T]

Somebody knows about Vacuum generators? could they be used?
I see they go -27Hg and about 400l/min.



The vacuum generators that I know of are venturi tubes and are useless- You need a big compressor and it runs all the time and you need total seal immediately as they pull no real volumn and only get to 12" Hg

RX comp- Yes it appears that DIAB knows that this is aproblem with their foam- hopefully they will reply to my e-mail

Rod T