PU with MDI

Here you go

Steve Caves in North Bondi. ph 361 563 9283

mongrelsurfboards.com or email: mongrel@stx.rr.com

His site will show blank sizes etc…can fill you in on glassing experience. etc.


here’s another good aspect of MDI Homeblown foam…the cell structure in uniform throughout. So unlike Clark Foam you can strip from top or bottom w/out worrying about softer foam as you progress toward the center. At least this is what has been stated about the foam. I am just moving into the glassing stage this week w/HB blanks and I will be adding info as I go along (being a shape to shine guy in the new era in order to pay my mortgage).

There are other foams that have this deeper into core feature…or are hard yet resilient…notably Surfblanks (developed by midget Farrelly in Oz…called Teccel in Brazil, also in South Africa and now in U.S. coming out of Carpinteria while produced in Ensenada.

A big eye opener for me was to read Ben Marcus’ “Great Foam Forum - the post Clark World” in Surfersvillage.

Just shaped one today very hard. I’ll let you know how it glasses. Much harder than everything else I have shaped.

“One” meaning Homeblown MDI or Surfblanks?

Get out the hard block and open coat 40 grit…go from there…it will feel like sawing.

Homblown seems to be even harder than the Surfblanks. I have to get a drum. Shoulders are getting quite the workout!

You’re girlfriend thinks you should stick with the sanding block:)

I’ll try the bevel one I use on her!

I went to Fiberglass Hawaii (Ventura) yesterday…unfortunately one of my two Clark Hitachi full size planers (not the Pro Model PSB20 or whatever they are) doesn’t have the same drum size that will take the carbide drum…is there one in existence for the longer Hitachi??? Do carbide blades work…or even still around…or am I destined to try sanding some of this new foam with a belt sander (wow, talk about squirrly).


For a drum/shapers barrel, try Foamez in Westminster. If they don’t have one that will fit, try down the street at Surf Applications(Bruno Surfboards). If you can’t find one that fits your particular planer you may want to consider buying a new planer already fitted with the drum. I know that is an exspensive choice, but with the variety of blanks out their it will pay for itself in the long run. Otherwise do what I do; powersand. Use the planer(slow and easy) to bring the bottom and deck down to thickness, then use a hard or medium disk and your Milwaukee to get rid of the ridges, cutlines etc. Band the rails with the planer(slowly). Then blend with the sander and a soft disk. Finish it off by hand. The sander cuts down on planer and hand sanding. Before I started doing this I had to keep the spackle handy to fix all my tears. Surfblanks turns into a beautiful end product. But unless you are using a machine to pre-mill they will take more time than US Blanks and any softer foams that may be out there.

“When have you e-v-e-r seen a board split lengthwise down the middle?”

Hi Deadshaper -

I’m reading this thread with interest. It has a lot of info.

Regarding the board splitting down the middle… I did see that happen once at Swamis during a big swell in '82 (?). It was the year some piers were taken out by the big waves.

I remember the kid with the board and commented “Weird. Never seen one break like that!”

He said, “No sweat, I’m TEAM!”

It was a Nectar board that split down the stringer from the nose, then across at the fins.

That story is just for reference… I know how boards normally break and you are correct that the deck usually buckles across.

Aloha Bruce. I just read up on you in the Shaper Tree, hope your back in the water enjoying surfing.

I’m new to all this and was interested in your comments about stringerless EPS and glass. I just glued up a 1.7 lb. Marko stringerless blank with 3mm unidirectional ply to make my own perimeter stringered blank for a 6’5". It went a bit rough but I ended up with a good blank for my first try at adding stringers. I just shaped the board and wished that someone had been filming when I ripped the tip of the nose off on the first pass with the planer. Seems 3mm stringers don’t like to be planed sideways with almost no foam on either side, go figure?! After some choice words I glued the nose back on with some quick set epoxy and pretended that it never happened.

Any way sorry to ramble but with all your experience can you tell me for such a flexi blank what would you recommend for a glassing schedule? The board is for me and I’m 6’3" 195lbs. and I’m generally very hard on boards. I don’t mind it a bit on the light side but don’t want it be disposable. I know that I should have gotten a higher density of foam to begin with but my initial plans changed from a corecell bagged hybrid to something a bit more traditional glassing wise. Also could you give me your opinions on 6 oz. S glass vs 6 oz. warp? From my limited experience I’m thinking that the warp might be better for the bottom for the longitudinal flex and the S might be better for the deck for compression.

Last question. I’ve been reading up on Syntex/Xynole cloth. Whats your take on the stuff? I’m using epoxy so it sounds like it might be at the least a very good material for a deck patch instead of S or E cloth.

Quick question–why does biofoam need epoxy? Is it really that much heavier/softer?

I have a biofoam blank in the garage, and without weighing it, it seems to be about what I remember a Clark blank weighed. I skinned it & cut the outline and it seems harder that a typical blank. Combined with the finer foam, I’d think that it would soak less resin for a lighter board.

Any ideas?

Yeah…I’m hip on the power sanding. Ned (McMahon) and I had discussed using a disc on the Homeblown foam…it is consistent but prone to tear when you wanna zip along like the old days…

…just picked up some U.S. Foam and my first batch of Surfblanks. Hey let’s face it.if it’s soft like Clark was…you can just whang thru it pretty mindlessly. The harder foams don’t want to let you do that but Farrelly’s philosophy of his foam being for the surfer over the shaper is evident…I certainly don’t have a bitch with a better more durable product for my customers.

I s’pose I better take a good look at Klingspor again for the highest grade abrasives…and Plesunkas’ stuff.

By “perimeter” stringer do you mean parabolic (the new buzz word of this era)? Define.

Otherwise…the term pretty much says ‘other than a center I beam approach’.

As far as Warp vs S2 glass you will find that S glass has improved flexural, tensile (impact) capability as compared to other reinforcements. Actually S2 glass is an exotic, not glass. Regular E glass is the weakest glass and originally came from insulating electrical wiring (that’s where the “E” came from).

We know S glass comes out stronger and lighter ounce for ounce. As far as warp glass, it is expressly designed for the warp/weft (aka fill) advantage. Two thirds of the glass strand runs on the warp while S2’s usual weave pattern is 50 warp/50 fill. I would expect the S2 to have better resistance to compression, esp. with fixed cell blanks. But EPS has memory so the resistance to denting (energy management) is a different dynamic altogether. Pre-stressing rocker also is a factor to consider.

A lot of people aren’t aware that S2 is available in S2 warp. I haven’t used it but I bet it is a killer terrific product. Killer price too…expensive.

Getting back to your approach…use of unidirectional glass is longitudinally the strongest approach I could imagine you could take w/out use of an I Beam of some material (wood, PVC, Aluminum, compressed cockroaches, etc.) I used some uni on glassed on tri fins…man what a difference. A challenge to work with though…100% one direction…fishing rod stuff ya know…like uni directional carbon…let’s go marlin fishing!

As far as the other materials you mentioned for the deck patch (one of the many synthetic exotics out there), I’m not up on the ones you mentioned. There’s a lot of that stuff that is extremely promising that is difficult to get…I played with a bit of Spectra back in the mid 80’s…they were using it in jockey’s vests to protect against horse’s hooves penetrating the vest on fallen riders…very light, extremely strong. We also used MPV (modified polyvinyl) earlier than that, but the supply dried up…I was told it was all going to Korea in the making of athletic shoes? It was said that is what the “Pirates of the Carribbean” boats at Disneyland were fabricated with. Arrrrrrrrrrrrrgh!

I have two 1.5 EPS longboards I’m doing for a friend this week…very different boards (stingers) because he rides so far forward on 9’0"'s…won’t move back…was sticking on cutbacks unless going Mach 4 so this is what I developed eons ago.

They’re a trip…fins way up too and very small fins that everyone thought he’d spin out with…never happened. In fact he downsized the rear fin even more (like 4" or 5")…board hauls ass…as they should because they are about as finless as you can have with directional stability…the V, edeges & concaves help too. The new boards only have an epoxy glue line for a reference point, instead of a chalk line etc. . The guy surfs Point Arena. Big snap potential…esp. with such a long fulcrum.

I’m glassing these with 6 oz warp glass with generous double laps on both sides. I’m running additional 6 oz warp down the center top and bottom about 6" wide…I’m hedging on the center strips and thinking maybe I just run some additional 4 oz warp on the rails. These boards are pretty thin so I told him he has to be aware that they will surf unreal but probably snap at some point. I could run carbon down the center but how stiff do I want? Carbon sounds like a cannon being fired when it snaps (heard my friend’s mast go in Maui…loud!).

Updated 12/22: I didn’t go with additional cloth down the centerline…chose to layup addtn’l warp on the rails (see stagger lapping in the stringerless longboard thread). Boards have been surfed in double & triple overhead…incl. a freefall and reattach recovery at the bottom of a wave resulting in NO DENTS and NO STRESS CRACKS.

So on your board…which is short, you could reasonably glass with all 6/4 & 6/4…all things equal right? That’s just my two cents worth. You could do 6 warps and 4 oz 50/50 direct sizing full length underneath for some impact, or you could use S glass stomps for heel dents or you could criss cross 4 oz warp for the same stomp effect but your flex pattern might go wacky…or we all might hail you as the new Einstein for doing it that way.

Update #2 - 12/22: I am currently sourcing MPV (Modified Poly Vinyl and Impact glass in place of S2 cloth…more later. For MPV see thread “Does Anyone Remember MPV?”)

I just reread your post…“uni directional ply”…thought you meant uni-directional glass. Still my take is pretty much the same. Reinforce the rails extra like what I’m doing on the stinger LB’s.

You DON’T need epoxy on the BioFoam (Homeblown) blank.

Epoxy is widely acknowledged as stronger than polyester resins, but there are excellent polyester resins that have been around for many years.

MDI (BioFoam- Methyl Phenyl Di Isocynate)) is not as soft as Clark or U.S. Foam…both TDI (Toulene Di Isocynates)

Biofoam has a noticeably finer cell than the Clark or U.S…it is also noticeably harder, tears if you plane quickly and has a more sawing action when using a sanding block. The finish shaped blanks feel heavier than Clark or U.S., but can glass out lighter. This is due to less resin absorption into the blank.

The resin absorption on soft blanks can be countered by using UV activated polyester resin (or a hot batch of catalyzed resin) and presealing the blanks…you can use microballoons (Q Cell) in that presealing process. This was a regular practice for EPS blanks up until the recent introduction of super fused EPS. In fact you can also elect to use heavier cloths in the layup, then squeegee out very dry and come back with a Q cell hotcoat to fill air in the dry laminate. This is not cosmetic by any means but can yield a strong light board.

People place too much inmportance on the resin and not enough on the cloth. For the most part, resin is brittle and is not the structural reinforcement for the blank. In a sense, resin is like concrete which is another plastic (yes, really).

On a general consumer product I was working on, I was trying to drastically reduce the weight of a half pipe molded product with a hole in it (to hold dog bowls and potted plants up off the floor). The concrete was just too heavy for what I wanted and the hole made the unit want to crack easily. I sent my mold to a huge concrete company in Arizona that does shopping malls with concrete architectural features. My units were weighing in at 27 lbs. at the time.

They said they could only do what they could do and that concrete has to be certain thicknesses in order to have strength. I disagreed with them.

Then I told them to think about a highway overpass (bridge). Bridges have all that rebar in them to handle the weight of vehicles. “Well my form is like a bridge”. I told them to put long fibrous strands through the mold and to treat the concrete like window dressing, like icing on a cake - the concrete surface need only be smooth where visiblle to the eye (not the underside). They had special concrete that could cure in 5 minutes…they had a 180 lb. guy stand on the form about 10 minutes after pouring and releasing it from the mold and to their amzement, it held up fine!

They were blown away. I wasn’t surprised. Weight reduction 60%.

Mahalo, Mahalo!

Thank you for taking the time to answer all my questions. I especially enjoyed the cockroaches comment lol, I wish I could round a bunch up and make them into a stringer or foam.

By perimeter I meant putting a 3 mm stringer on each rail. I think that it is a tad smaller than an 1/8" and I placed them about 2 1/2" from the outside rail edge. The stringers terminate at the nose and at the tail tips. I’ve been hearing about blanks from Marko that are pre stringered like this for months but I can never get one, so I made my own. I’ve also been reading about how boards flex, what makes them break, and how they feel as they are ridden. The idea of putting a stringer on each rail sounded like a good idea, at least for ride feel so I wanted to see for myself what it was about.

I have 3 years of experience making custom vac bagged kiteboards so I like the idea of trying new and old types of materials in different ways to make a better riding and longer lasting board. I really appreciate the information about the cloth. Brian Hinde at Fiberglass Supply used to take the time to explain to my inquiring mind about the different types of cloth and there is nothing like experience.

I got all impatient the other night and I ended up glassing the bottom of the board. I went with 6oz. S with an extra wide lap and a 4oz. E fin/tail patch that is cut in an extreme V shape. The V is deepest inbetween the fins and the tops go way up onto the rail stringers for extra support. I’ll probably go full 6oz. warp deck, 3/4 6oz. S, and a 4oz. S stomp patch for the tail all with deep V shapes just to see I can feel any difference.

I had a kiteboard builder tell me once that he did a board with 6oz. warp and he ran the cloth 45 degress to the center line one on each side and then one down the middle. Said it was the strongest most flexible board he ever made and the biggest waste of cloth. I use double bias biax for my kiteboards and it is great stuff for allowing flex but only goes as light as 12oz. Wish they would at least make 4 and 6oz. in the 45/45 degree bias. I think that it could be used in conjunction with the warp for some interesting results.

The Sytex/Xynole is going to have to wait. I have to order it from Florida so that will be for another project.

Thank you again for your time and knowledge. I’ll post some pictures of my efforts once I can convince my daughter to let me use her camera again.


Kiteboarding’s cool…what the hell ever happened to windsurfing? I still have my gear.

is anybody out there?

Never windsurfed but it’s the same thing. The high speed and the power in the surf is like having revenge on every single crappy day of surf that you ever endured.

Riding more like a surfer with little surfboards has been a super with the new bow kites.

Here check it out. http://www.kiteforum.tv/component/option,com_videos/task,show/id,634/Itemid,30/

Yeah, I grok.

We used to drive the road to Jalama and be all bummed out when we came over the hill and it was blown to smithereens. Then in the 80’s we just saddled up with our surfsailing stuff along with our surfboards and had the choice. Then the world got more high tech and we just got the bouy reports and the surf cams and all the forecasting that makes you feel like you landed on another planet.