EPS Plywood Fun Gun

Ok. I always found the step by step threads the most interesting (ie Robbo, Oldy and lpcdefg). So this will be my contribution. I was thinking to wait until I was done in case I make any huge mistakes (this will be my first vac bag attempt), but we learn from our (and others) mistakes right?

The board will be a So Cal winter board for when the beach breaks max out and I head over to Palos Verdes Cove. I’m a shortboarder but the Cove is mostly longboarders so I’m making something I hope will get me in early with the big boys and still turn with some resemblance to my 6-4 thruster (see the “Mush Gun” thread).

I was going to go to 9-0 but then I saw Daniel Hess’s beauties and decided I would try a poplar ply construction. So, ply being 4’x8’ I went to 8-0. Here’s my hand drawn template sketch. It says 20 1/2" wide but my template came out 21 1/4". Probably better wider. Also, I’m taking it out of an 8-6 blank so the rocker will be “relaxed,” more long board like, for the generally mushy waves at the Cove.

I was also inspired by Greg Griffin’s swallow tails.

Nah, don’t go much over 20 1/2 in the width maybe 20 7/8 but no more. Make sure you pull the nose in, but you don’t need to hyper thin it out. Tail rocker is crutial, don’t make it too flat or it will be super fast, but stiff. do something like 3" ±… make it 2 7/8" thick but thin out the rails so you can set em. Nose rock? I like some like 6" for a big board. You go too flat you’ll catch the wave, but out run sections. Its best to set up the board (my opinion, ala Jim P, and Bill T. I learned via trial & error) with solid tail and nose rocker, and set the fins fairly straight with little cant 4%. Use the pro Box with the variable inserts. You’ll be happy with the results.

Resinhead, back from the dead.

Thanks Resinhead. I made a full paper template of the 21 1/4" and it did look wide. I was riding a 7’-8" x 19" last winter that turned just fine but couldn’t catch waves outside with the 9-0’s. So maybe 20-1/2" being a full 1-1/2" wider will be enough. I do like to turn hard on the rail.

I was thinking more like 2-3/4" thick, seeing as how it will be a 1 lb EPS core and I don’t want the infamous “corky” feel. Also, I have to carefully adjust the shape- no dome in the flip- to accomodate the bender ply (limiting the compound curve problem).

I should mention that I have a folder with a bunch of shapes that I liked as prototypes for this project and a few of yours and a few of Keith Melville’s are in there. Thanks.

I hate to say this but from our experience large single sheet are hard to vacuum to the deck where you have compound curves.

We’ve been using 1mm bamboo to 1/42-1/62 thick hardwood (cherry) sheet veneer over EPS and you really have to spend the time to push out all the air bubbles as you pull your vacuum into the lock position.

Helps to have two sets of hands to vacuum a deck with large panels.

I don’t know how anything as thick as ply will be like working with cause we’ve only done really thin veneers…

Bottoms are no problem based on the way the curves go but decks are a little tricky.

taped or glue together strips seem to flow into the deck curves alot easier some how…

This is just a heads up from my brother any my experience but then we probably don’t know what we’re doing anyway…

But be prepared…

And best of luck

I kind of like poplar too with it’s greenish tinge in the grain…

Haven’t seen any ply made of it by I’ve been using blocks of it for nose and tail block material along with knotty pine instead of using expensive Koa…

I think Daniel Hess uses a mold to make his popular bending ply skins then puts them on the already shaped frame-rails. The details are a little fuzzy, but they are beauties.

Great outline, Looks like it will turn well. What type of fin setup will you be going with. If you are going quad you should think about moving the whole fin cluster forward to keep the board maneuverable. I’ve been doing this on all of my guns and it gives them a bit more turn.

How do you plan on bending that ply around the rails? The vacuum pressure to get them to wrap will most likely crush the 1lb. EPS. Thining out the top ply to 1/16th with a door sander will allow it to flex in those compound curves.

http://hesssurfboards.com

Here’s the full paper template. You can see from the tail that it is not a true gun- a 14" tail is pretty wide. The other thing you can see in the photos is what I learned from my boatbuilding experience- “fair” curves- no flat spots or bumps. From the nose you can see why I made the swallow so small- lots of curve in the hips.

Thanks for the input Daniel. Imitation is the sincerest form of flattery- I got sucked into this whole vacuum mess after I saw your boards and fell in love. If this project fails miserably I may be up in the Bay area next summer!

Thinning out the bender ply! Why didn’t I think of that! I could basically taper it thin by the rails and in the nose and leave it full thickness under the stress points.

I was going to go with a thruster set up, just because it is what I’m familiar with. I’m attracted to the quad just because of the buzz going on about them, especially with regards guns. Maybe I’ll have to do more research.

Hi Llibel,

Have you ever thought about soaking the ply in some water or solvent for a period of time to soften it up? then vacuum it to bend and then dry up the wood? Might work, but Daniel’s suggestion might be better.

Cheers,

Rio

llilibel03, just my two (euro)cents about your wood template: once you have cut it out, you should erase the pen line and true the curve by eye. I find that the pen line interferes with your vision when fine-sanding the curve.

I did the first test of my vac system- 1 hp compressor, venturi vac generator, and hefty trash bag with masking tape. Low tech, low cost.

I shaped a little piece of packing styrofoam and was going to see if I could bend some ply around it. I used luan which is stiffer than bender ply and the curve on the piece of foam is probably more acute than any I will have on a 8’ board.

My first run failed- woops! No breather cloth. The bag just sucked into the hose. I then used some high tech breather (paper towels) and that solved that problem. You can see the ply bending pretty well in pic #4.

My second problem was that after the initial pressure built up in the compressor wore off, the airflow of the little compressor was not enough to keep the vac up (down). Little by little the vacuum dissipated and the bag loosened. I have a valve installed on the vac line to cut it off, but the bag wouldn’t hold the vacuum.

So my low tech low cost solution failed. I am now actively looking for a used vac pump on ebay, one that can run continuously and hold the vac. Any suggestions on specs?

Also, OT, do some ebayers scam by putting low prices and then gouging you on shipping? I’ve seen some pumps for $9 but then shipping is close to $50. Others coming from the same distance will have shipping at about $15-$20.

first of all get a better bag

good one aren’t that expensive

secondly used a faster curing glue like GG or 5 minute epoxy so you can leave the pump on for a shorter period and get the glue to cure. them heat cure will bagging to speed up the curing process even more.

You got to work damn fast

but it can be done

joewoodworker has some decent pumps but real vacuum pumps cost $ no matter what.

If you are real cheap

then go build a large 2foot deep sand box outside in the sun.

fill it with 1/3 of the sand

vacuum bag your board with what you got then place board in bag into box and cover with the rest of the sand.

let it cook for 24hour (just like imu-ing a pig)

and then dig your bag out

repeat for the other side

the heat and the sand pressure maintain the pressure in place of the vacuum

sounds silly but even Bert’s done it that way when it was called for…

How about this one? It’s a Gast 1/6 hp. Says it pulls to 27" hg and is rated for continuous service. I only need 10" to bend to ply according to my test. Also, more than 10" and I’ve read you can crush the 1 lb EPS.

The bag was a 3 mil trash bag just for the test. I have a roll of 4mil for the actual bag. I’m going by Bert’s vac bag thread where he uses masking tape (or “multi purpose adhesion stripping” as he calls it).

I’m not sure about the hole in the sand technique. I live in a condo. The HOA may not like it if I start digging in the garden. I don’t know how the local Parks and Recreation Dept will react to my digging a hole in the sandbox across the streeet, or the Department of Beaches if I go down to the beach and start glassing surfboard there.

The other alternative is to sell the condo and buy a house…but in my area that is definitely not the cheaper alternative!!!

So, what do you think of the ebay pump?

Pump looks good…but be wary of corroded parts…might be more of a hastle…replacing them

as for your 1st bag attempt and losing pressure, do you have a one way valve (check valve)

because the vacuum releases its pressure…it’ll hold it for a while then all of a sudden, pressure will dissipate. Check valves are cheap, alot of people use them for aquariums so check your pet store or marine aquarium store…if you do have a check valve, make a reservoir system it’ll help hold pressure for longer. Go to home depot and use their pre cut pipes, I realised you don’t need to use PVC. PVC is very expensive.

Cheers,

Rio

Dont’ know what you mean by reservoir. If I get a check valve where do you locate it? Just before the hose attaches to the bag?

Hi Llibel,

-for the check valve, you want to mount it as close to the inlet of your vacuum as possible.

-here’s a picture of a vacuum set up taken from Joe Woodworker. The white tubes are the reservoirs and they hold “extra” vacuum so when vacuum escapes, the reservoirs supply the needed vacuum.

you can check out other pumps & setups at: http://www.joewoodworker.com/veneering/welcome.htm

Cheers,

Rio

A resevoir is just a large tank that gets vacuumed like everything else. Because of the volume of the vacuum you build up it takes longer for it to leak out and thus longer to get to your restart pressure (assuming you have an automatic pressure regulator) giving your pump a longer break inbetween runnings. Of course it also has to run longer when it’s building that vacuum though.

I got an expensive pump system from a friend and the resevoir is in line right after the pump. Mine looks like a big air compressor tank. Just a T fitting going into it with line connected to both sides of the top of the T. Sometimes they are large sealed PVC tubes that people build themselves.

I don’t have a check valve and I don’t think my pump needs it. It doesn’t release pressure after it stops running. Probably a good idea though, couldn’t hurt.

That was before I did some repairs so don’t try to make working sense of this picture. Red tank is the resevoir.

Here’s my hacker set up. I still have to mount it all on a board so I can attach it with some 2x4s to my vacuum bag travel case on wheels(big construction site tool box) where I keep all my bagging stuff.

My traveling compsandosystem…

The pump was acquired from and set up by CMP I just bought all the components like the 10 gallon compressor tank which Charlie reverse engineered into a vacuum reservoir.

His setup is permanent in shop mounted on his racks so he uses long PVC tube 4’-5’ long tubes.

Get a good gauge and a good switch.

I bought a red plastic check valve from joewoodworker they’re pretty cheap he also has a nice switch which is nicer than using vice grip pliers to pinch off your hose.

A pretty fugly setup but she’s done going on 30 compsands so far including Uncle D’s wedding board with many more to go and no major disruptions so I think I got my money’s worth.

Oh yea she’l run all night long with no problems other than the noise and we can pull two bags at once with a t-joint at the reservior…

Thanks CMP you’re the best!

garbage bags and a vacuum cleaner work great… attached pic shows it all. That’s my little brother in the bag…

Wow Redthorn!. How did you get those compound curves?

Now my new dilemma. I hard a hard time locating bender ply in my area. I didn’t want to drive or ship. I finally found a local wholesaler. I had to buy through a retailer and then go pickup (ostensibly for the retailer). I get there and the guy shows me the stack of bender ply and to my horror they were totally without visible grain- just a plain cream color. I got into this whole vac bag world because I wanted a wood board.

I ask the guy if I can look through the stack, but being a wholesale place with only forklifts running around he said, “Normally we don’t let our customers do that.” He shrugged. Then he was called to the phone. My luck. I quickly looked through the stack and about 5-6 sheets down started to see some grain showing. I didn’t have much time so when I saw what looked like a considerable amount of grain I pulled it out.

You be the judge. Should I use side 1, which I like because it has more grain, but the grain kind of ends in a blob, like it was a stain or something; or should I use side 2 which has less grain. I was leaning to side 2 because I thought I could use the “stripe” like a stringer, but actually I won’t be able to center it.