When you're a carpenter.....

brian_cab · September 19, 2010, 1:04am

or in this case, someone who has made molds and bent things that probably shouldn’t be bent most of his life, everything can be made with a hammer, chisel, plane, saw, file, scraper, knife, torch, lathe, mill, grinder, drafting table, computer, printer and a mold but mostly a mold.

Or, because the real title wouldn’t fit in the subject line how about my very own;

**Resin tints and patterns Rocker Apex What are you working on Show me your shaping bay Constant curve or flat planing area Pics of my home DIY surfboard construction Stringerless build Compsand Unofficial homemade tool **and multi purpose board design

Thread.

So …

We started the year with your typical Outer Banks house on sticks with a laundry room and three houses worth of crap wrapped in tarps. By February the building permit was approved and by summer the majority of pad was enclosed with siding up and doors installed.

Banking, taxes, administration, work, blah diddly blah blah… on to the good stuff.

The heart of the studio that is coming together is a 3’ by 10’ modular adjustable vacuum rocker/shaping/laminting/CNC table comprised of (2) 2’ by 5’ sections(there were to be 3 sections totaling 15’ in length but the wife staked out the room for a ceramics studio add-on).

The goal is to finish the bottom of the deck to better than 80% completion with no further shaping required in the first pressing. Finished laminated mill/cabinet/furniture work is somewhat of an ongoing profession so this is not a stretch. Of course I’ll never get my sacred soul shaper certificate though I’ve got several hand molding and shaping tools passed down from my grandfather that are well maintained and in steady use but eh, I’ll carry on somehow.

The minute the table was even remotely online a new design was put together in CAD

translated to the stations, loaded and brought under vacuum.

The first layup is a rocker proof blank for a project that has been in the works for years awaiting time, money, tooling, etc…

Of course, a celebratory margarita atop a successful pressing of a multi-density blank. This is a modified CompSand/Integral Wave Core/Mystery project so the bottom is skinned right from the get go with 12 oz biax on the 45’s. That is a 6’ 8" by 20" by 2–3/8" skinned blank that weighs in at ~ 5 lbs.

Rough shaping of the topside and rails forms a simple 6’ 6" by 19-5/8" retro test form. A recycled maple/glass sandwich fin is about ready for final glassing - blue tint, the board is going to be called “Tuna”. Before that happens the topside skin and rails need to be hardened up with a layer of biax.

Going to be playing around with differing wraps - 4 mil poly shown here - to get maximum wrap with workability on form details similar to rails that feature tighter radii. As is, the rails were able to be wrapped ~ 120 degrees which isn’t bad and will definitly take care of the skinning material list. To, being able to draw down resin heavy skins like biax and work air/excess resin from the middle to the edges goes a long way towards improving the glass to resin ratio, reduced weight and overall strength.

Next, Quality Assurance. Crap.

Once the roughed blank has been skinned topside the board is freed then table is drawn down again so the curves of the board, table and design may be verified.

This is why you press a proof blank. The articulated substructure was to stiff at the ends which flattened out the curve on the tip. A little tweaking dialed the curve in.

The finished form has been skinned with the final layers of glass and the fin should be wrapped tomorrow. The blank was pressed last Sunday night. The work around the board building has sucked down more time but that will continue to be the case for foreseable future. Meanwhile, the “Tuna” will be in the water this week and version 0.7 or 0.8 blank with the fully formed concave/vee bottom will be in the works. For the near term the goal is a board per week. The CNC rails and gantry for this rig will likely not be ready for 2 months but that is another story for later.

lavarat · September 19, 2010, 3:33am

Nice!

I need to build a bigger ---- new shed for all of my compsand junk.

Since I am a contractor it will be a tax write off, right?

everysurfer · September 19, 2010, 8:51am

More shots of your rocker table. It looks adjustable. When you vacuumed, did it pull the rocker table out of adjustment, or did it hold?

And that margarita sure looks tasty on a hot September night.

brian_cab · September 20, 2010, 12:45am

A few more details on the table;

The table is currently spec’d for a maximum of 7-1/2" rocker* by 33"
width** by 120" length.
The cross stations are set within 5" of the ends and space on 10"
centers so that additional table modules maintain both maximum tip
adjustment and continuous 10" intervals. The length of the table is
supported by a flexible set of stringers set on fixed widths that sit
over the station braces smoothing out curves over the length.

The station T-Slots are built off of reference shelves on the sides. The bottom of the table is a V trough that collects garbage and structurally reinforces the table modules. The vacuum port is raised to attach filters, hoses and other optional devices.

The station cross braces are supported either through dimensioned
spacers in the T-Slots or slot clamps installed to the desired height.

The table sections are over-built with cross and linear support bracing that locks into a leveling cradle. The table is flat to within 1/16" over the surface. Besides the advantage of modular expansion, being able to break down the table and store it aside makes room for parking vehicles and outdoor furnishings when storms are threatening. The honking black hose below is the vacuum port.

Three dimensional forms are developed by installing station profiles on
the cross braces over the length of the table. Curves are smoothed by
the flexible longitudinal stringers overlaying the cross brace supports.

Smooth curves transition over the length of the table. Hard chines -
V’s, ridges, angle transitions, etc. - may be added by splitting the
table surface and adding form elements to the surface that are taken up
during lamination.
Simple hulls, concave and V’s are easily dialed in.

The rocker/camber may be significantly increased by working above the
table

** Working at or above the surface of the table allows a full working
width 36" or greater through the use of extension vacuum platens set
atop the table.

everysurfer · September 20, 2010, 2:03am

Really clever drawing the vacuum down through the table. What do you use to keep the struts in position? I would think it must be substantial, or the vacuum pressure could change their position.

brian_cab · September 20, 2010, 11:15am

Side to side position is maintained by the T-Slot. Downward position is maintained by dimensioned tabs as shown in the Rocker Adjustment Detail pic. As for what keeps everything in position under load?

The vacuum.

Everything - the sides, support shelves, T-Slots, struts, etc. is designed to pull against itself as the table is trying to implode under vacuum.

The table is a working compromise based on but not limited to the following considerations:*****

At sea level, 1 atmosphere is usually measured from 27 - 29 inches mercury which translates to an air pressure of ~ 14+ PSI. A square foot of surface reduced to thin air usually yields north of 2,000 lbs of pressure. The surface area of this table is roughly 100 square feet so drawing down to near 0 atmosphere would put a force of greater than 200,000 lbs of the structure which would absolutely warp the snot out of if not spectacularly implode the table.

Commercial rated vacuum pumps that don’t require industrial electrical service, typically those that draw a low volume down to 27 - 29 inches mercury, are usually rated at a draw down rate of 3 - 10 Cubic Feet per Minute. This vacuum table maintains approximately 20" by 36" by 120" of volume or in the neighborhood of 50 cubic feet. A pinhole can wreck your day and when pressing irregular shapes, my experience has been that pinholes are more common than not. Too, commercial vacuum pumps able to manage those volumes at that pressure are insanely expensive.

On the other hand, commercial blower/vacuum units that draw a few amps are more than capable of drawing 50 - 90 inches of water (typical rating unit for blowers, dust collectors, household vacuums, etc…) which is ~ 3.5 - 6.5 inches of mercury or around 4 lbs per square inch which puts you in same ball park as residential and commercial building specifications that have all manner of handy building references that can tell you how to develop a structure with minimal deflection. A simple wet/dry vac capable of managing this may be had for a few sheckles in exchange for noise and a shorter life span. A durable, quiet commercial grade continuous duty blower/vac capable of handling particulate may be had for less than 100$ - 700$ US. Though a little noisier than a dedicated blower/vac, a Jet Dust Collector will do multiple duties as table vac, hold down clamp and dust collection for well within that price range both used and new.

At only 2 lbs per square inch of pressure differential, something most cheap POS < 30$ box store no name vacuums are capable of, you are putting ~ 4,600 lbs of uniform pressure on a 2’ by 8’ laminated surface so the next time someone tells you to use weights, sand, buckets of water, etc., smile, say nice things then go home and bust out the noisy monster in the corner, some plastic, duct tape and get to it.

If the noisy monster should happen to burn up? Eh, grab a new one on your way back from a sesh with your new board, kayak, boat, ski, skate, dune or other contraption for the perpetually adrenaline and maturity challenged induhvidual.

*****Please feel free to review and suggest corrections to the units and math. Of course, any suggestions aren’t likely to change the very real evidence that all of this works but getting the details correct reduces distractions and helps me when working with others.

Thanks,

Brian

mustkillbass · September 20, 2010, 11:49am

and your point is

afoaf · September 20, 2010, 10:02pm

I showed this thread to my wife. Thank you.

laminate · September 21, 2010, 6:48pm

I’m completely fascinated and inspired. Thank you!

All I can ask for is more pictures and exposition.

brian_cab · September 21, 2010, 8:10pm

The feedback is appreciated.

Updates will be forthcoming periodically.

Just finished foiling and glassing an 8" maple/glass single fin for the yellow board - not investing to much on that first pressing.

Tooling up for a concave to vee bottom on the next pressing which will also be a first stab at an internal preshaped board lamination approach.

Probably have to wait till the weekend given projects in front of that but success, fail or eh the results will get posted up.

tblank · September 21, 2010, 9:32pm

This is like the Sci-Fi version of shaping. Very impressed with the engineering of your table. Well done.

How heavy is that sucker? (The table ) I mean.

f1f859bda2f2a3ab344c · September 21, 2010, 11:30pm

Hey Brian,

Nice table . it looks good…

My rocker table works on the exact same principal, although it’s built differently…

I have 2 commercial / industrial grade vac. pumps connected to the rocker tables deck using flexible plastic tubing and industrial tubing fittings…I’m a plumber / steam fitter / instrumentation piping tradesman, so the “plumbing” of my table was kinda’ easy as well as “free”…

The table features 4 vacuum ports that are located in each of the 4 corners of the table, flush with the deck… These are covered in small triangular pieces of doubled -up breather fabric to stop the ports from “choking” with the bag when the vac is applied…

The 2 pumps are cross connected with a bypass cross over valve / power switch system, so I can draw the initial vac. on the table using the larger of my 2 pumps (approx 5-6cfm) then switch to a quieter smaller hospital style asperator vacuum pump (1.3cfm) to maintain pressure…

My camera is broken, so when I get a new one, I’ll post some pictures of my set -up…

My table is adjustable, although not quite as easy as yours… I’ve sacrificed ultimate ease of adjustment for accurate / smooth pre-planned rocker curves…

I simply use 3 curved rocker templates made out of 3/4" MDF and swap them out for others I have made as needed… I can install a center ‘stringer that gives me single concave, or I can change the outside 2 stringers to introduce V, I normally leave them all the same curve and then shape in any contours as needed after the deck skins are applied and the boards rocker is 90% set in the stringerless blank…The tables deck is a flexible 1/4’ plywood top sheet that attaches to the 3 curved rails… This top sheet has been glassed with 2 layers of 3oz fiberglass and epoxy so no leakage of air can occur…

The 3 rocker curve “stringers” are held down to the flat base of the table using removable aluminum angle iron… The base of the table is a cheap Home Depot door…

Note:

Be careful using vacuum cleaners and other vacuum /dust collectors that are not designed to pull a constant “full” vac. It’s like having a vacuum cleaner with a hose that’s plugged up with debris, and is a FIRE waiting to happen !!

You mention: "If the noisy monster should happen to burn up ? "…

Well, I’ll finish with … " A good understanding household insurance company helps a lot during these times"…;)

You’re not always sitting over a board watching the vac. bag “suck” for a few hours !! There’s usually lots of more important, interesting things to do during that boring time… That’s when an inferior vac system goes bad…

.I have 3 smoke detectors, as well as a 10lb. fire extinguisher sitting in the same room I vac. bag in… There’s a lot of heat and electrical activity going on during this process…

At the very least it will quicly burn out a cheap vac. machine… These vac. machines are NOT intended to do this job, and can in NO way draw a vacuum anywhere close to the 20" to 27" hg. values you mention above… If you want to apply HD skins ,veneers and such, clamping pressures of 10psi. or around 20"+ hg. are required…imho… I’d be scared to bag on skins of any type at less than 12" hg. But that’s just me…

What kind of pump are you using Brian?, you don’t say…

As I said at the start of my post: Nice table… Keep up the stoke, I can’t wait to see your CNC addition…

Not many guys on this site are building surfboards using this method, it’s nice to read about others doing so…

96% of all the wake board style kite board builders I talk to use this method of construction… The other 4 percent use Pneumatic presses capable of tonnes of clamping pressure…

Pneumatics or hydraulics and molds, can you say Aviso…Unless they’re just using bags and molds? can’t be, you can’t vac. bag in those razor sharp “hard” bottom contours…

f1f859bda2f2a3ab344c · September 21, 2010, 11:45pm

I guess I should have intitled my reply : When you’re a pipefitter…"))

f1f859bda2f2a3ab344c · September 22, 2010, 1:52am

Quote:

… If you want to apply HD skins ,veneers and such, clamping pressures of 10psi. or around 20"+ hg. are required…imho… I’d be scared to bag on skins of any type at less than 12" hg. But that’s just me…

NOTE:

I should have qualified my statements above:

I build boards that have 5/8" thick continuous A500 core- cell perimeter rail bands…

When the upper HD core-cell (deck), and the lower HD core-cell (bottom) skins are vacuum applied to the 1.5# EPS core there are no visible voids allowing the compression forces to damage the lighter / weaker EPS core …

If the EPS core is completely encapsulated in HD foam or wood veneers, the vacuum bag pressures can be ramped up accordingly…

If you were to subject “naked” 1.5# EPS to the vac. pressures of 20+" hg, the EPS would / could distort under such compression… This is just my observation’s , maybe the EPS would comform to the design “plan”…

brian_cab · September 22, 2010, 3:00am

Hey Kiterider, sounds like a very involved rig you’re running - certainly moreso than this.

Haven’t yet broken out all the things this little beasty is going to do since it just came online but given constraints flexibility was a must as was price so it just took some time to design it to be good enough and easy to maintain. I’ll be very surprised if the CNC is ready to install before spring given everything else going on but that isn’t a critical path item so of much less concern.

The blower is a no name continous duty low power unit with self cooling venting. In other words, it shouldn’t* melt down. At some point a Busch or other name brand blower/vac will show up at a reasonable price which will replace this one.

Being a pipefitter I’m guessing you’ll have a horror story or two but I’ve not gone without a few which is why this is a rather simple, cheap, relatively low tech affair compared to some of the other messes I’ve gotten into.

Funny you should mention dissimilar density material deformation and too, good line about adding sharp contours.

Later,

Brian

Fingers crossed

brian_cab · September 22, 2010, 2:40pm

Oh, and the unit fully loaded out is probably no more than a couple hundred pounds.

Finished sanding the rails and fin on the Tuna this morning - sokay I guess. Nodda gunna be using that particular foam for the rails again but then the plan never was to go that way - I was just eager to finish the first board off the press regardless how good it turned out.

Just ordered the last part for the table mounted hot wire cutter which will make some of the upcoming cuts more manageable.

Probably going to let this thread rest now till the board is assembled and plonked in the water,

or

The new table mounted foam cutter is ready,

or

The new layup with the contoured/articulated bottom is done,

or

Some combination of the above.

In other words, when I’ve got something to show for it.

Later,

Brian