Vacumn forming & Sandwich construction

[johnmellor]

Bert -

Fascinating stuff!

I hadn’t thought of a contour mat but I can see that in principle, it wouldn’t be that hard for the guys who assemble boards for Surf Tech to “fine tune” or customize existing shapes with the use of similar devices. Slide in a deeper concave, move the vee around a little or add a horizontal wedge to tweak the rocker? I can imagine that with a finalized board design that you intended to replicate in quantity, you could probably combine a rocker table, bottom contour and vent sheet all in one? Probably save a lot of time by not having to fine tune the bottom shape on each blank by hand?

I think you’ve blown a few doors off posting this method.

[glennshotwell]

Bert,

Thanks so much for sharing. This is great stuff. Is that 1/8" h80 for the bottom, and 1/2" h60 for the rail?

This guide will be a BIG help for my board project. For one I was thinking, having never made a board this way, of doing the rails in a separate bagging session. I am seeing now that would have been an unneeded extra step. And what weight/ounce glass is that? Also E or S glass?

Also I’m curious, since balsa has such better physical properties than PVC foam in all aspects except for waterproof, will this rail give the board enough stiffening as perimeter stringers? Would laminating a couple of layers of foam on the rail (thinking the epoxy between the layers would stiffen), or maybe even putting a rope or strip of glass or carbon between two layers help bring the foam rail up to balsa strength? I was thinking to achieve balsa strength maybe even a layer of very light carbon or s-glass between two rail laminates. But this would definitely make final shaping harder. I guess if you’ve got the time anything might be possible.

You’ve helped bring more stoke back into my love of surfing.

[Bert_Burger]

this is old sckool for me now , thats why i dont mind passing it on , but these techniques , really opened the doors to me ,in the sense of leading me to another level …so i figure it should get some of you guys out there up to speed and at least competitive with moulded imports …

i get frustrated when i see millions getting pumped into the development of new technologies , coz the guys spending the money have no idea how far behind they really are …im not knocking development , but from my perspective i see grand claims getting made through the media , i think to myself , "man thats gonna cost them " i see dodgy product getting released and unsuspecting buyers lap it up only to get burnt …anyway ill leave that one there … ive got plenty to say on that subject , that could be another thread …

yea john , there is so many possibilities with vac forming , and completly customisable …

before i continue ill answer your questions glenn …

yep 1/8 h 80 bottom , 1/2 h 60 rails …

that glass is 2 oz e , this board will be for me so im milking it all the way , if it was a guy off the street it would be 4 oz e , not that i would build a board this way for someone , this is purely a swaylocks dedicated project , to familiarise everyone with vacumn forming …

as far as foam v balsa rails for stiffness ,

your deck and bottom skins do most of the work as far as stiffness , thats why i havent done wood rails im trying to make it flexier to counteract the thicker sandwich …plus i dont want to show how i do my rails …

i will lose spring tho , by not using wood , thats why its going to be a super small wave groveler designed to be surfed flat in soft mush …

you can do all of that stuff you mentioned , it will depend on the overall thickness of your rails and board in general as to how much or little flex/stiffness you want or desire …by moving layers around you can really achieve so many different characteristics in performance and not even have to change the shape …

thats why i want more people to understand sandwich construction , so then finnally crew will understand why my shapes work so well even tho they shouldnt if appraised by conventional wisdom …

ok back to the subject , now youll notice the whole job in the bag , bag taped for a seal and the rail pieces sitting wide and high nothing is where its supposed to be …

ok i cheated a bit , i didnt use the little pump ,my big pump was running and i had a spare connection , so i hooked it up to the radiator hose on the bag …now you can see the bag has pulled vacumn , everything is tight and pressed against everything else , the bag has formed the rails tightly against the blank , the blank and rails are being pressed tightly against the wet d cell im running about -30 kpa which is 300 grams of pressure for every cm2 , so this job being about 2 meters x half a meter , means its recieving about 3 tons of weight spread evenly over the job holding everything in place …

heres the whole job being pressed , you see the rocker bed doing its job , in the first place the rocker is computer designed , your off cut simply becomes the bed to ensure you have the correct rocker , even if you dont get your foam cumputer hotwired , its important to keep the offcut in good condition if your home hotwiring …its also possible to use the opposite offcut ,the deck one , if you use that one you can customshape a bottom before adding your d cell , itll take a bit more work to get your rails on cleanly , plus you have to be very careful when bagging the deck , coz you cant use the bottom bed in the same manner …

its funny ive got all this stuff in the back ground i dont want seen , so if you see the same backgrounds from different angles its because im moving blanks around in the background as coverups , coz im working in my vac form room , if you saw some of the background stuff and these basic principles , im sure a few crew in similar fields would put 2 and 2 together …dont want any snakes and frogs looking in , hehe …

continued,

[Bert_Burger]

ok now its the next morning , board out the bag all the pieces locked together …

now its into the shaping bay , rip off the excess d cell with the jigy , and clean up the outline with a sanding block …

heres another angle on the single into double in a single …without taking one stroke with a tool …if i was still building boards this way , i could put that exact same concave on any board , length, width , outline , or rocker …hows that for keeping control of your variables …

and this was long before shaping machines were even invented in polyurethane construction …from working with these concepts in the past , its showed me how valuable a shaping machine is as a learning tool , because without control of your variables , its mostly random guesswork and chasing your tail around trying to isolate particular performance enhancing characteristics , it can be done its just takes a lot longer , i suppose its typical that the early board builders even tho they learnt about shape , it just took alot longer and it was harder than it would be for a new modern day shaper to grasp the same principles of design because of having access to computer aided designing tools and shaping machines , plus still being able to consult the early board builders as well …

so all you young up and comings out there have got it made from a learning perspective …

and here comes the shape ,

[Bert_Burger]

traditionally , its near on impossible to shape a piece of 3/4 lb eps , its just like shaping a floppy sponge , but now you have something rigid with the h60 rails and bottom already pressed on …

ive fully scooped out the deck ,under my feet would be barely an inch thick , this contruction allows you to explore shapes which are impossible in conventional construction ,so now a whole new world of shapes opens up as well and more effective ways of designing specific boards without having to make comprimises on shape because of being locked into design parameters , which are bound by current construction techniques , how high can a 36 year old 100 kilo surfer boost , when your average grom is struggling for speed in the same waves ???

below is a quote from a 40 year old plus surfer , hes working with similar principles and dimensions , also breaking ground with variables of a unique nature based on common concepts …

Quote:

I’ve boosted more

airs in a session than I’ve ever done before and I can’t break it yet. I’m

basically freaking right now. I’m building another one today with different

flex.

---

ok i will leave it there , this board is in the bag at the moment having the deck pressed on , so theres more to go now , but i will save it for tommorow …

regards

BERT

truman finds his way into another world soon , after being locked in for all those years …

[daddio]

When the explorers first came to the new world the native people couldn’t even SEE the boats anchored off-shore. It was the shamans that started to see (know) and then show others that there was even SOMETHING there. The first look at your pictures made no sense at all, but then I tried to just relax and let it be… It came to me just like a small wave lapping at my ankles - or so I thought, cause after that little wave pulled back I was totally covered - dripping wet! WOW! Thanks for sharing, Bert… (signed Truman and son)

[kenz]

Great stuff Bert! I like the way you wet out your fiberglass…nice and neat.

I’m particularly fascinated by your contour mat. What exactly is going on there? Is it depressing the foam to put in the concave? Or is it just forming the whole sandwich to the shape of the contour mat?

[J.Troy]

Great stuff Bert!!!

Im Having trouble getting my brain around those techniques…

[haavard]

Bert, thanks for sharing. I can see even from the little you’ve shared so far why you’d want to keep a few secrets. It opens up some wild posibilities. Keep some of your secrets, I think you’ve earned it.

Few questions:

Did you just tape with 2" masking tape around the edges of two plastic sheets for the bag? Won’t the paper leak or does the edges of the plastic kind of seal themselves with enough vacuum? I guess you don’t use a gauge either, just let the holes in the bag keep the vacuum at a resonable level?

What’s that contour mat made of? I guess I figured out how you made them…

You don’t seal the the EPS with anything prior to putting the glass/sandwich material on?

regards,

Håvard

[markyv]

Thanks Bert

I and many others will be endebted to you for a long time, this really is the spirit of swaylocks, long live custom board builders!!!

[meecrafty]

meenotcrafty…ucrafty

Ok Bert, after a few reads its starting to come together in my head but I’ve got a few questions.

You start with a styrene blank with rocker built in, d-rails with rocker built in…does the rocker bed reshape the sandwich?

If so, what keeps the new rocker in shape after baggin? I mean its all flimsy superlight weight stuff and I could see how the whole thing just flexes out of control after youre done.

???

Did you really fold a 7ft long x 2ft wide sheet of glass into something that fits into a soup bowl? Then saturated it with a teeni-tiny bit of epoxy, then uraveled the whole thing without destroying it? So what’s next? Ya gonna pull out a rabbit out of that little bowl?

BTW, the last few pics on your last post aren’t showing up…dont know why.

[J.Troy]

Quote:

meenotcrafty…ucrafty

Ok Bert, after a few reads its starting to come together in my head but I’ve got a few questions.

You start with a styrene blank with rocker built in, d-rails with rocker built in…does the rocker bed reshape the sandwich?

If so, what keeps the new rocker in shape after baggin? I mean its all flimsy superlight weight stuff and I could see how the whole thing just flexes out of control after youre done.

???

Did you really fold a 7ft long x 2ft wide sheet of glass into something that fits into a soup bowl? Then saturated it with a teeni-tiny bit of epoxy, then uraveled the whole thing without destroying it? So what’s next? Ya gonna pull out a rabbit out of that little bowl?

BTW, the last few pics on your last post aren’t showing up…dont know why.

Im thinking Bert is gonna pull an elephant out of the bowl…I still havent figured out the process Bert is showing us but it mast have taken years and alot of $$$$$$$ to refine what Bert is doing there…unreal work there.

[louis]

thanks burger.

i used the same technics back in he day on snowboard making.

instead of pvc it was ptex and core and so…

i feel stupid that i never though about doing surfboards this way, made so many snowboard.

oh well, i hope this will fight the chinese invasion.

so my question is: is the board flex better than surftech board? the first picture of the blanks have rocker.

could you actually put flat eps foam?

thanks a bunch.

Louis

[bluejuice]

I’m exited I just rushed out and took some pics of my pump, It’s an old fridge compressor the only one I’ve had for about 9 years I keep it topped up with car oil and run it for about 8 to 10 hours at a time.

Here’s hoping the upload works

[bluejuice]

OK that worked after a few attempts ita a bit small. Heres a pic with a diagram showing how I recycle the oil.

As the vacuum pump is running and gets hot the oil in the compresser and comes out as a mist this is collected in a can, I have another tube in the can that picks up the oil when it condenses back into a liquid. this oil is then sucked back into the pump along with air from the can and I use a valve to adjust this mix into the incomming vacuum line which allows me vary the amount of vacuum.

[bluejuice]

I have limited pics at the moment but will put them up as I do a new board I’ll also only post sailboard pics as the mals I do are very similar to Berts construction and I don’t think he wouldn’t appreciate that info on the net. The divinicell boards have the outline cut out and I only shape the bottom, I then tape a thin plastic painters drop sheet to a table and laminate the glass on this I then lift the wet glass from the plastic lay it on the bottom of the board, trim it, put the div that has been cut to the outline on top hold it in place with masking tape put it in the bag, When it’s dry I reshape the rails and deck, I cut the deck div then use a heat gun to bend it around the rails. Here’s a pic of a shaped blank with div bottom on carbon and glass cut to go under deck div and pre bent div ready to be laminated and go int the bag.

[Bert_Burger]

ok guys i see some questions , i will answer any at the end , as most of them get answered as we go , i already see some clever deductions being made , and its yes to most of them …

ok so youve seen the shaped deck , once thats done , lay your board deck down on a sheet of divinycell and trace around your board , then cut out the shape with a blade …

so now you lay glass on your d cell , cut to shape and put some extra patches in the heavy traffic areas …

now do your resin work directly onto the d cell , for the whole bottom which was a rectangle i used 150 grams of resin ,but just for the deck with less area and working directly onto the d cell i used 240 grams … the foam sucks extra resin , but that helps support the deck better …

continued ,

[bluejuice]

This pic is the board in the bag before I put it on the rocker jig which I the weight down. The div deck is taped down with packing tape then a strip of shade cloth is put over then it’s put in the bag. I don’t have any fancy disk attachments like Bert I just poke a hole in the bag put in the thin reticulation tube cover with blue tac and then some tape to hold it in place. For the ends of the bag I just scruntch up the plastic and twist it like a plastic bag of fruit from the shops, Then wrap some masking tape around it.

[Bert_Burger]

now , get your wet sheet of d cell and place it on your deck , a few bits of masking tape to keep it in place so it doesnt move as your sliping it into the bag …because the bottom contours are already pressed into the bottom of my board , at this stage its possible to press them out again if you dont support the shape youve made , so while its not visible , the contour mat is taped to the bottom of the board … this time around you dont need the firm flexible sheeting underneath the board , that was only there to ensure the whole contour mat lefts it imprint in the bottom of the board , without a hard base behind the contour mat , you would get a softened version of your contour mat as half the mat would get pressed into your rocker support bed , which is only soft foam …

this is your last chance to do any rocker tweaks or curve modifications , in this case im pressing a 6-8 onto a 7-3 block so i want a little more cosmetic nose flip , just a simple wedge under the nose will do that …

once this layer is formed down and resin sets , the curves will be set in concrete , no way you can change anything after that , at the moment the board still has enough flex to be pulled into a slightly different curve …

as an example , if you get a few sheets of veneer or paper cardboard or even playing cards , bend them into a curve , then press tightly at the ends as if youd glued them together and try to bend them the other way , for something to flex it needs some shear movement , you can glue 2 flat sheets of something together and it will still move a bit and spring back to its original shape a bit , but glue 3 sheets together and it stays that way forever …

now its back in the same bag , under vac , you can clearly see the deck being pulled tight onto the board and the board being tightly pressed into the bed

heres another angle on that wedge under the nose tweaking the nose rocker …

continued,

[Bert_Burger]

now its out the bag every thing is set , the deck skin is still a little messy , at this stage its ready for a tail piece to be added , unless youre doing a super tight pin , most of the time the tail section needs to be added later , you can see ive cut my tail ready to add some d cell …now its quite clear where everything is as far as cross section is concerned …

heres the finished shape …

and another angle …

continued