Build a Vacuum System to Dry Boards

[Beasho]

Needed to make a carriage for all the gear.  Cut up an old wooden crate that had been floating around the garage for years.

Decided NOT to fully glue the Condenser tube.  This was probably a good thing because I doubt any drain spout could keep up with the amount of GOOP that collects at the bottom.  Nasty yellow biology and Salts.

The pressure fit of the condenser tubing still appears to hold enough vacuum.

[Beasho]

With the mobile rack I can more easily position the board for the sun around the house.

After another day in the sun, and an overnight with a space heater on the nose, pulling the vacuum through 2 holes on the nose and with 2 x 11/64" holes in the tail/mid section I am down to 19.90 lbs.   

Progress report as follows:

[Beasho]

Energy and Flow Rate are key at this point.  From the Board Lady:

"Evacuation of water occurs primarily due to evaporation, which requires energy to cause water molecules to mobilize; and air exchange, to carry off these mobilized molecules. For this air exchange, we can generally only offer a 5/16" diameter vent fixture. That's less than 1/10th square inches, to evaporate moisture out of the approx 30 liters of air that is free to move in the EPS channels of a 100 liter board. The resulting evaporation rate is dismal, to put it mildly, hence the length of time required.

Think of a wet towel: you hang it up on the line, with a dry 75 degree breeze flapping it about, and it will be bone-dry by nightfall. But bunch it up, throw it in the hamper, and it will still be wet next week. Little surface area, little energy to mobilize the water molecules, little air flow to carry them off."

https://boardlady.com/waterintheboard.htm

[Beasho]

PS:  When using a Vacuum to pressurize ding repairs:

WHAT IS THE BEST SUBSTRATE TO ALLOW AIR TO FLOW BELOW A LAYER OF PLASTIC THAT ALSO APPLIES AN EVEN PRESSURE DISTRIBUTION ON THE BOARD?

[PonoBill]

If you keep the vacuum reasonable and don't squash it, any open cell foam will work well. EPS is fine.

[Beasho]

EPS?  Sounds like it would be a thick application.

I tried to tape down a sheet of plastic vinyl - as in cover for hard copy report.  I punched 5 holes in the vinyl and bored a hole into a cheap suction cup. 

The vacuum appeared to semi-seal the vinyl along the center and NOT all the way to the perimeter.   This was a test on a random FLAT section of the board .  Next attempt would be to place on some sort of curve and insulate the vacuum layer from the resin maybe with clear packaging tape or plastic wrap??? 

Putting a sheet of paper towel seemed to do the trick of getting the vacuum distributed under the entire sheet to the edge of the tape.

I am only a neophyte here.  Any suggestions would be great.

[jrandy]

The standard vac bag layup:

core, glass, resin, perf ply OR peel ply, breather matt, bagging film with edges sealed with mastic.

Peel ply (silicone treated nylon) soaks up extra resin and creates a re-bondable surface. Perf ply (plastic with small holes) only bleeds a little resin from the laminate into the breather.

The breather matt is not 100% crushable so there is room for air flow out of the bag through the pump.

-Beasho, your choice of on-hand materials was pretty good short of buying from a composites store.-

I have a thread called 'a little vaccum bagging' that might help:

https://www.standupzone.com/forum/index.php/topic,32181.msg359640.html#msg359640

[surfcowboy]

Breather material is just cheap poly quilting filler that you can sport from a fabric store. That or any old fleece blanket that you've got or buy from Walmart/target for $5-$10.

[PonoBill]

Sure, breather ply will work. I use EPS a lot for flat vaccum bagging because I can salvage it from packing material and it applies even pressure edge to edge instead of being hard on the edges and soft in the middle.

[Beasho]

Slow and Steady seems to be working.

Down to 19.4 lbs --> Targeting 18.4 lbs

Running the pump continuously with small space heater (~ 200 Watts) pulling 18 inHG. 

The board lady suggested that THROUGHPUT would be necessary.  I have 2 holes in the bottom of the board 15/64" and ONE at the top of the board.

It appears as though the weight is dropping at a rate of 1/10 lbs per day for the last 5 days.  Just 1 lbs left to go.

I may plug it up sooner and/or use Pono's silver tape for temporary seal-up on the holes to allow for Surfing and then draining overnight.  The waves have been big which has prevented me from needing the smaller foil board.  I have been happy with my 7' 4" board in waves that have been continuously 8 to 10 to 14 feet or more on the buoys. 

[stoneaxe]

Great to see the progress....sucks that it takes so long but your patience is paying off.

[PonoBill]

I have temporary aluminum tape repairs on my !7 V1 that are five years old. After you'd gone to all that trouble to lighten up your board it would be a shame to do a conventional repair which can easily add a pound.

[Bean]

A conventional repair should not add any additional weight unless you simply scab on a patch.

[PonoBill]

A conventional repair should not add any additional weight unless you simply scab on a patch.

Certainly, if you are super careful, table-wet the cloth, do everything just perfectly, it might only be a bit heavier than the original skin, but it will be a LOT heavier than a couple of piece of aluminum foil. And if you do the standard ding repair as practiced by any number of pros, you can double that added weight. Try it some time. I've compared a standard repair to just taping with aluminum tape numerous times. I don't use it because I'm lazy, or I don't have the materials, or I don't know how to fix dings. I do it because it works very well and it's the lightest way to get the job done--as long as you don't care about cosmetics.

[Bean]

Aside from making the board look like a Duct Tape Invitational wannabe, tape does not address structural damage.  For instance a simple rail ding will be the most likely place that a board might snap.

One key step in keeping the weight off in a repair is building up the foam before you laminate.  A heavy repair is also an invitation for a snap because it creates a hard spot (can act as stress riser).

For temporary ding repair, I bet the aluminum tape would work great.  I like to use vinyl stickers.