Can you explain more on the different coating you give to the company for testing? like epoxy coated eps?
Foamhack and I are just discussing this at the moment, were trying to stay away from products with VOCs, but I know of one material that could protect the foam but also soften under the heat of the process and become an adhesive between the blank and skin.
Were getting samples together for testing over the next two weeks.
Some of the 2 dozen samples weve put together to go to the factory tomorrow.
Flats, curves and corners to see how the plastic forms and overlaps over relevant shapes.
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EPS, XPS, different densities, different coatings, even pu and pe just for fun.
These will be sacrificial samples to see which combinations handle the heat and pressure of the thermoforming.
Whatever happens we'll learn a lot and get back here to report the results.
Hopefully we'll get a winner.
Foamhacks just collected the finished samples, they had asa and abs pulled on them with some great results.
The lightweight eps held up well to the heat and pressure as well as the pu foam too. Odd that the light and soft eps should be the outstanding performer but ar least it solves what foam to use.
Im still not convinced about what glue to use to hold the shell to the blank, so thats our next area to explore …
Would there be some mileage, in shrink-wrapping compsand constructed blanks?
I thought it might be a way of addressing the issues with lack of skin ridgidity using polycarbonate.
And what of making skin piercing components (plugs/boxes/etc) watertight?
gadgetuk, were considering compsands and the waterproofing issues, no decisions made yetbut lots of robust discussion.
Foamhacks a good theoretical engineer so our discussions go from the basics to the amazing, we whittle down ideas, throw them away and bring in new materials and techniques from industries outside boardbuilding.
Heres some details of the first run of plastics on foam.
Different foams with different surface treatments.
Plastics are ASA, ABS, HIPS.
Some of the samples couldnt handle the heat…
And some did very well.
Almost perfect mirror finish.
Even though its very thin, the plastic shrinks onto the foam and the combo makes for a surface that you cant dent with your fingers.
Another consideration is how the plastic stretches and thins as its pulled around the foam.
This has a depth of 40 mm.
Measuring the thickness of the skin before forming and then measuring the percentage change in several different places.
At** A** …its 85% of the original thickness.
At** B** … its 38%
At** C **… its 38%
I suspect these figures are dependant on the variables of the process and are a guide rather than a rule.
So weve chosen the foam and plastic and were moving onto Round Two.
All thanks to Foamhack for driving all over Sydney to pickup and deliver.
Interesting,
Thanks for the detail!
Hey feraldave
Did the shrink-wrap table sell? What price? New they are around 60k…
Just left that auction…it was said The guy spent more than 3 million of other people’s money and 15 years trying to get the polycarbonate shrink wrap boards to work… Lots of stuff was passed in and going to the dump…
Did you blow then suck?
on deeper pulls, blowing the sheet stretches it more evenly before you suck it down onto the plug.
Im not going anywhere near** that** comment but yes Im aware of the various techniques of thermoforming.
Because of the ‘thin-ness’** **of a surfboard its only a 55mm draw/depth on any side and thats almost halved because its done on both sides and overlaps on the rails.
But it does mean that the shape of the rails will be very accurately contoured.
The next step is to find a glue thats compatable wth the plastic and the foam, Im not totally convinced that a glue is necessary but…
Logically the best adhesive would be a heat activated one so that when the plastic is pulled on to the foam the heat of the plastic activates the glue on the blank and the two are joined.
A water based adhesive rather than a solvent based one is crucial.
And finally something thats one component, easy to apply, low viscosity and cost effective would be perfect too.
Bayer make a range of raw materials called " Dispercoll U " ( DIspersion Adhesive and** Coll**oid ) that are low temp reactive, water based and spray on, but they dont sell them in a ready to go adhesive.
Looking at other temp reactive adhesives, theres a raft of membrane pressing glues used for heat forming vinyl covers to kitchen panels and doors.
And theres a range of polyurethane dispersion colloids for industrial applications that we are testing at the moment too.
Tip: when you call a chemical company and start a sentence with “EPS, ABS, XPS,ASA, colloidal emulsions, membrane thermoforming, latent reactive”…
dont try to explain what you want to the young girl on the switch board.
Ask to speak to a lab-rat in the Technical Department…
.
Hi,
The Illbruck range may have a glue suitable:
Watching with interest
Red
Hi Red and thanks for the tip, funny thing happened with the first batch of disparate foam samples, one of them fused to the plastic in its raw state, that is without any coating so its now a decision whether to go with the new foam or keep looking for an adhesive we may not need or use.
I think we will do a few thermoform runs with this foam to replicate the initial result and also keep searching for the right adhesive just to be thorough.
Im shaping the foam today and we will get them formed next week and let you know when its done.
Just a pic of the foam fused to the plastic shell. The bright pink is the foam thats stuck to the plastic when I peel the plastic away.
The cameras not good enough to show the details too well !
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I found a new forming company and they wanted a few test boards so I whipped up 2 bodyboard shapes, I figure the extra foam thickness will keep it dimensionally stable under pressure and they dont need finplugs before testing in the surf.
Heres the two BBs…
One is EPS because its going to be the cheapest foam to use and the other is XPS because it gave the best performance when formed. The XPS isnt exotic, the two types of XPS we’ve used are called Foamular and Polyboard Enviro 300, both are ‘green’ products, low fire hazard, and $20 per sq metre for a 50 mm board and <** .2**% water absorbtion.
Available in Australia from www.austech.com.au but its made in Dubai so its available worldwide.
The XPS one is a fine grain so it shapes like pu.
Planshape and nose rocker.
Lower rail chine.
Upper rail chine and roll at nose.
And get funky at the tail.I left a lot of sharp corners because the vacuum pressure will smooth them out and I wanted to see by how much.
The boss of the forming company lives up the road so he picked up the boards and will let me know what costs are going to be involved.
The Kydex plastic is $18 for a 1220 sheet and add that to the XPS cost of $20.
Should have results in a day or so…
Any update on this - just read from start to finish and i cant wait to see how it turns out!
We started with a forming company that didn’t follow the instructions we gave them, but took our money.
so now were with another company but they want 340% more to do the work…?!
Seems they already know about the other guys a few years ago who spent millions on doing a similar thing and failed
and now a lot of the big thermoforming companies don’t want to touch anything to do with surfboards… They just say no.
As it stands we do have a new company to do the next experiments but I wasn’t keen to post until we had some results to share.
I don’t know how the other surfboard company managed to scare off all the important thermoformers in Sydney but everyone from the plastics suppliers, importers to formers all know their attempt was a spectacular fail and they have negative interest.
However each test we have done has born positive results so we aren’t discouraged, anyone know a tame thermoformer in Sydney???
i went to the auction…
it wasnt pretty. how much money to you want to spend… the guys had every tool you could imagine to work on the thermo forming, they didnt go to other companys to get anything done, they got the tools and tried it there. all the thermo form companys saw what and how much they did and they got nowhere… not trying to be negative. but when you analize the actual physical properties of the materials you can get an insight into what your best outcome will be. i would have loved to see it work and see both companys be succesessfull in thier endeavours. both the newcastle guys and core fusion gave it a big shot and more than 10 million dollars…
bic have the most successfull working thermoformed boards…