After dinging the rest of my boards on saturday, does anyone have any suggestions on how to build a ding/rock/reef proof board with resonable board weight?
regards,
Håvard
s-glass and epoxy with a lower weight blank?
Sandwich construction can be lighter and tougher. Or you can just triple 6 oz it and live with the weight.
I want ding proof, not just ding resistant. For the record, one of the boards I did ding was tripple 6oz on the deck double 6oz on the bottom with a fair amount of overlap on the rails, epoxy over EPS. Dinged right on the rail when it hit a rock.
Does sandwich construction make the boards less likely to ding or is it just the glass/fabric on the outside that matters?
regards,
Håvard
Kevlar.
Unfortunately the board has to float… so Dingproof is impossible, unless you know a steel legue lighter than water :oP
Kevlar rails are a good Ding-80%-proof, obviuosly it’s heavy and if you hit rocks really hard it brakes.
Cheers flavio
Spy on Bert!
Quote:
Unfortunately the board has to float… so Dingproof is impossible, unless you know a steel legue lighter than water :oP
Kevlar rails are a good Ding-80%-proof, obviuosly it’s heavy and if you hit rocks really hard it brakes.
Cheers flavio
Isn’t glassfiber/sandwich construction supposed to be stronger that steel at the same thickness/weight? Or is it just better in strength to weight? Anyway, the steel boats seems to ding as well when they hit a rock hard enough…
Kevlar is propably a good idea tho. What about spectra or other polyester fibers?
regards,
Håvard
Quote:
Does sandwich construction make the boards less likely to ding or is it just the glass/fabric on the outside that matters?
Custom sandwich boards are a LOT less likely to ding. In some cases there are near miracle stories of boards falling off roof racks with only paint damage. Some shapers like to jump up and down on them to demonstrate their strength.
I recently saw a 10 yr old Bob Miller custom sandwich board - Bob did mostly custom sandwich sailboards at the time. In 10 yrs of heavy use it has seen only paint damage, and its been washed up on the rocks several times. The sandwich material provides a better backing for the outer glass than the lightweight core foam. Better at load distribution.
A couple of points:
Nothing sticks to Spectra or polyester fibres very well.
Spectra is a high molecular weight polyethylene.
Depends what you mean by strength; yield strength, ultimate tensile strength, compressive strength, bearing strength, sheer strength, impact resistance, fatigue strength (notched or un-notched sir?) etc. Add to this that different materials respond differently to different load rates, UV exposure, water absorbtion, creep, tempreture etc, and it’s impossible to say which is “best”.
If you prioritise your needs (including cost) you should be able to work out the best compromise.
For any given weight Kevlar/epoxy will be the most ding resistant (small point loads) and best in sheer, HT carbon/epoxy will be strongest in bending and tension, UHM carbon/epoxy/nomex core sandwhich will be the stiffest. This last one would also be frighteningly expensive.
Use a lighter weight Kevlar/epoxy (say 2/3rds) vac bagged laminate would give pretty similar flex to a glass board, but be way more ding resistant.
I surf Lower’s regularly. It’s not uncommon for sixty plus people to be in the water. My usual everyday board has always had staggered 4+4+4 top and 4 ounce bottom. I’ve gone 2+ years on the same board with not much more than pressure dings and a couple of rail shatters. But, it’s getting tighter and tighter out there in the lineup. So, I went to S-glass with DHP resin for my most recent board. It weighed in an ounce more than my usual boards. It seems to pressure ding just as easy as the PE boards. And, the other morning my buddy dropped the nose of his board though the bottom of mine while setting it down after a surf. So, much for the ding proof theory. And, I’ve got to keep him away from my boards. The last three major glass dings I’ve gotten have involved him and some stupid mistake.
Even with extremely heavy glassed boards you cannot make a ding proof board. I had a board that was 8oz + 4oz bottom and a 8, 6, 4, top and triple wrapped rails. needless to say i was noseriding on a shallow sandbar and took a HUGE chunk outta the nose. i must have really wailed the bottom as the wave closed out. didnt ever get any dings except for that huge one, and i got some good smacks on the rails etc.
Austin S.
Quote:
Anyway, the steel boats seems to ding as well when they hit a rock hard enough…
Hey you’re not considering mass… and for the steel, i was just joking! 
(think to a full steel board)
Sandwich is stronger, but not undestroyable, undestroyable is an utopia… in any case i say go for kevlar, it’s just difficult to work with it, but once you’ve found out a good epoxy resin you’ll be at half of the work.
Cheers flavio
Any board can be a ding proof board … if you hang it on the wall and never ride it.
A saftey deposit box is better than hanging on the wall
O ’ on the wall it can fall
…ambrose…
where the hard things can stay
and the dings resulting can fray
the end of yer nerves
and the waves of next day
can go unridden by yall
ride it any way
if your workmanship display
the care and the craft
all we portray
appologies to home on the range for not working the rhymes
Haavard
If you are going to go the kevlar route, you had better vac it, it is hell go get bubbles out of, and i would advise a layer of light glass outside, if you touch it with sandpaper it fluffs up. Your only course of action is then to wet out area and cover again with glass!! It is definately not user friendly!! We use it on the crash bows of racing yachts, often carbon on the outer skin, kevlar inside. Maybe you would try glass outer skin, a higher density corecell sandwich core (100kg/m3) with kevlar inside skin, that way you won’t have to sand it!! Should be very ding resistant and not too heavy.
Cheers
Mark
What is DHP resin?
I heard that you only notice the stronger characteristics of s-glass when combined with epoxy as poly resin is the “weaker link” and will take less force compared to epoxy in order to break it. I don’t know what DHP resin is. Is it stronger than epoxy?
as for ding proof board…hmm…would a solid balsa board work?
Rio
“Here you go. Bet you can’t ding this.” The gauntlet thrown, the challenge accepted, the toy has yet to be made that an enthusiast cannot creatively damage. Deuterium? Fire phasers and photon torpedoes to see if it really won’t ding. “Hey, you said it was ding resistant. Don’t I get it fixed for free? Can you give me a loaner meanwhile?”
So last week I had my balsa over EPS sandwich board inside my Subaru wagon. Upside down, it fits over the seats & onto the dash. In a cloth sock made of towel. I was far from home and had no racks. For work, I had to pick up two new lumber racks, front & back, for a work pick-up truck. They are made of heavy steel tubing and look like the one in this picture:
The only way it all fit inside was with the little top ‘ear’ of both racks resting on the bottom of my board. They weigh about 75 lb each, so 150 lb. resting on one little metal spot. 1:15 drive home on poorly paved roads. When I unloaded the racks and then the board, I pulled the sock off expecting a repair would be necessary. Although the board sock was threadbare where the racks had sat, not even a scratch on the board.
This board is made with all epoxy, even the hotcoats. All the glass is 6 oz E. None of the EPS was sealed in any way. A cross-section, where the racks were sitting, would be glass-3/16" balsa-glass-2.75"Eps-glass-3/16" balsa-glass. Its well more dingproof than any surfboard has a right to be.