My EPS build snapped testing flex.

So here is one for all you people that actually know what they are doing to giggle at point, figures and generally take the piss, as i got a good chuckle out of it.

 

Why is that you can punch as hard as you can an EPS (H grade) epoxy construction board with double six glass job and barely dent it, but lay it on the ground and step on it upside down and the little beauty snaps, the glass creases and the foam snaps?I will refrain from further amusement, but just when you think the board is bullet proof.

 

 

 

A few tid bits.

 

  1. the rocker was bent and laminated in so the board was i guess under stress.

 

  1. would this happen if i stood on another boards bottom?

 

  1. What can be done to rectify this as i have a great eps shape i have just finished and am wanting to glass.

 

The board went well too, just to rub salt in…

 

 

That is too funny.

Sorry mate but i reckon the look on your face would have been priceless.

H Grade EPS is very dense and much more prone to snapping than say SL or L. Especially if it's just hand laid up without skins.

My advice would be don't stand on the fcuking thing out of the water. Test the flex while riding it is probably a better solutions.

Would love to see the video. Hahaha.  Yeeewww!

Not standing on it out of the water…you got me…

 

in terms of glassing is three anything i can do? Using less dense say SL and L comes with its only little set of problems.

 

I think surfblanks here we come. i just love the lightness and floatation of EPS though, Im sure there is an eps guru there, that may be able to impart of course after they finish laughing… 

Hey rakeflip

Stringer ? If no stringer I think you have the answer. Also what rocker and where did it snap ?

I have done SL grade with corecell rails and skins and stringerless that you can bounce on all day. These were fish and hybrid rockers though.

Cheers

Mooneemick

Snapped right in the middle, It was a fish rocker near flat tail but a fair amount of nose lift maybee 4 inches.

 

Looking back it was probably not the best glass job. And the board wasnt going to be surfed after this next one was made, and well i was just testing how much torment the board could take…

 

As long as I dont get this board out in the water and it snaps.

If you really want to stick with EPS go with the Marko blanks. Shapes nice and surfs well.

I've used SL, L, M, H and VH in heaps of different types of constructions and the Marko 2.2LB is about the same as the H grade but is moulded instead of cut from a billet.

The Last board I did from a marko blank i used 3 x 4oz deck and it was super light and super strong. 6'1 x 18 1/2 x 2 1/4.

Surfblanks pink is nearly as light and finishes beautifully and is a brilliant white when finished with Midgets Bright UV resin, Where as all the epoxies I've used cant come close to that whiteness.

Personally the crispness and pop of a pu/pe just feels right.

If you glass the next one the same as the first one it should be plenty strong just maybe dont jump up and down on it on the footpath.

Good Luck.

 

Daren

just shocked me that it broke so easy…i doubt it would in most surfing conditions though…

Put in a stringer or stringers (rail) and hotwire the blank to the right rocker.

A stringer will give it some strength and you can control the amount of flex by using different materials and thickness.

You can even just laminate a 4 oz strip down the center.

Hotwire the blank from a block. That way you are not stressing the blank when its sitting idol and will give an even flex in both directions.

Bending the foam is already stressing it one way so it wont flex much in that direction, if you know what I mean.

If you are still having doubts, I would follow Entity's advice, go with surfblanks.

A lot easier to work with and an exellent end product (depending on shaping and laminating skills of course)

But a lot less to go wrong than with EPS/epoxy

Cheers

[quote="$1"]

If you really want to stick with EPS go with the Marko blanks. Shapes nice and surfs well.

[/quote]

Ok Daren, now where did you get Marko blanks from.

I tried to source them ages ago when I was trying to get RR and couldnt get them.

I have now got RR, but Marko?

What give?

Where?

Cheers

 

double 6, both sides.

really?

good wet out.?

assuming it buckled on the side your feet were on....

did the foam remain stuck to the glass, did the glass pop up, pop in or just crumble?

 

 

that should be a good start.

i doubt the core density is really the main factor here.

(but the actual density of H grade is..?)

punching the board is mostly an indicator of impact strength or local compressive strength. (which is not how you broke it)

how thick is the board?

core thickness will have a lot to do with flexural strength (proportional to thickness squared).

stringers will also contribute to flexural strength and buckling resistance.

length of board and weight of buckling force ?

shit happens.

sorry,

-bill

 

 

 

[quote="$1"]

[quote="$1"]

If you really want to stick with EPS go with the Marko blanks. Shapes nice and surfs well.

[/quote]

Ok Daren, now where did you get Marko blanks from.

I tried to source them ages ago when I was trying to get RR and couldnt get them.

I have now got RR, but Marko?

What give?

Where?

Cheers

 

[/quote]

 

I got them through Nigel at isurf in Sydney.

I don't know if he has a lot of them but every time I've wanted one he's had them.

Lenny also has moulded EPS blanks as well and they shape and surf well also.

I may be going back up in the near future if you need something just let me know.

It was forced agaisnt the way the rocker had been set. so the board flexed when force was exerted on the deck, but failed and snapped when force was put on the bottow so agains the rocker, a fair amount of force at that.....still surprsing.

 

great impact strength though.

 

In hind sight the laps wernt big enough and there was some straight joins in my deck patch that could of made for a defiete weak point.

 

very happy with my shping skills just have to turn my attention to glassing better. my rocker set perfect on the next board but what i think i will to mimick a stringer is run to paralle cuts down the board, set the rocker o my table and fill my grooves with a fibreglass cloth, q'cell slurry in it and let it set. then

 

It was forced agaisnt the way the rocker had been set. so the board flexed when force was exerted on the deck, but failed and snapped when force was put on the bottow so agains the rocker, a fair amount of force at that.....still surprsing.

 

great impact strength though.

 

In hind sight the laps wernt big enough and there was some straight joins in my deck patch that could of made for a defiete weak point.

 

very happy with my shping skills just have to turn my attention to glassing better. my rocker set perfect on the next board but what i think i will to mimick a stringer is run to paralle cuts down the board, set the rocker o my table and fill my grooves with a fibreglass cloth, q'cell slurry in it and let it set. then glass

 

It was forced agaisnt the way the rocker had been set. so the board flexed when force was exerted on the deck abd the rocker sprung back, but failed and snapped when force was put on the bottow so agains the rocker, a fair amount of force at that.....still surprsing.

 

great impact strength though.

 

i just would hope in most surfing conditons it wont snap easily..

 

In hind sight the laps wernt big enough and there was some straight joins in my deck patch that could of made for a defined weak point.

 

very happy with my shping skills just have to turn my attention to glassing better. my rocker set perfect on the next board but what i think i will to mimick a stringer is run to paralle cuts down the board, set the rocker o my table and fill my grooves with a fibreglass cloth, q'cell slurry in it and let it set. then glass double 6 ontop and single 6 bottom.

 

should i step back to M grade eps than the H to allow a little more flex in the core?