New deck, DH, foam composite, cheap stuff.

[scratch]

Loooookkiiinnnngggg GooooooooD!!!!!!
As I understand it the pink stuff will not sustain repeated stress from sear loading and that's why it's not used... But who cares?!!! that thing is AWESOME!

[KCcarvin]

How did you get those beautifully cut edges? did you just press it and cut it?

[Bloodstain]

What wood did you use? and how much was the total cost of the build? Im very impressed ;D +rep

[hoch92000]

I didn't notice the responses to this thread. Sorry for the delayed response. Got kind of tied up with the build-off.

Righteous build, man.

Thanks man.

looks sweet, is the poplar notched so the foam fits underneath, or is it just fitted to the sides?

The foam is simply glued to the poplar side to side. The poplar and pink foam are both 1/2 inch, so no planing was required for this. The poplar and pink foam were pre-sanded to prior to glueing such that, when united, there would be a continuous bevel, if you catch my drift.The glue was epoxy. The entire deck was pressed in a vac bag all-at-once. Glass - 1/8"BB - foam/poplar - glass. There was only epoxy between the 1/8"BB and poplar/foam core.

At the minimum, at the truck mount, you want solidity from the top to the bottom of the deck. A notched foam core would leave a little foam through the core at the truck mount site. This would compress over time an fail.

How did you get those beautifully cut edges? did you just press it and cut it?

I ripped the 60" by 60" 1/8" BB to 10" wide strips (really closer to 9 7/8") with a table saw. This created the edge of the deck. The neck and mount area were cut with a jigsaw, then sanded with a belt sander. This is the easiest and cheapest method.

I now have a system using a router with a guide bit and a template to cut decks. So far I have one template, but eventually I will primarily use this method. Works for the shape of the board and the drop-through mount. Much quicker than other methods.

What wood did you use? and how much was the total cost of the build? Im very impressed ;D +rep

The pink foam is cheap: 4' by 8' by 1/2" is about $10 (I think). I used maybe 1/20 of it. About $0.50 ( I had to buy the whole sheet though).

10" by 50" by 1/8" BB: A whole sheet is about $25 give or take. Each sheet yields six 10" wide strips, so $4 (again, I had to buy a whole sheet).

20 oz triax fiberglass, two sheets 12" by 45": It is about $10 for 1 yard of the 50" wide stuff, so let's say about $7 (I did buy 5 yards of the stuff for other decks).

Epoxy: $35 for about 2/3 gallon. Let's say $3 worth.

Varnish: Used automotive 2 part on this, but I don't recommend it. Just use Minwax stuff. A couple of bucks will cover a deck.

Sand: Cheap. For grip.

Also: Tools used were jigsaw, belt sander, drill, sanders, etc. Also used a vac bag system. Ted's will cost $100. A pro system will cost in the $100's to $1000's.

Loooookkiiinnnngggg GooooooooD!!!!!!
As I understand it the pink stuff will not sustain repeated stress from sear loading and that's why it's not used... But who cares?!!! that thing is AWESOME!

Rus, you're absolutely right on. That pink stuff is tough for its weight but it does compress a bit and is easy to tear (poor streng against shear). This deck did eventually slightly fail. In the following pics, you can see little tears in the glass over the edges of the pink foam, about 1" from the poplar runner.
I believe this was caused by twisting of the deck, and indention of the glass into the foam. With these 4 small tears, it certainly has lost some torsional rigidity. I haven't ridden it since.




I will eventually try a light DH/freeride deck again. A couple of changes:I will consider adding a third layer of glass. One that traverses between the foam and the BB layer as well as traversing over the poplar runner. This would create two torsion boxes comprised of the foam split by the poplar runner. Should give more torsionally strength. I would also use a different foam. I've got some new stuff that is really stiff but still quite light. It flexes a bit too.

[Bloodstain]

Rus, you're absolutely right on. That pink stuff is tough for its weight but it does compress a bit and is easy to tear (poor streng against shear). This deck did eventually slightly fail. In the following pics, you can see little tears in the glass over the edges of the pink foam, about 1" from the poplar runner.
I believe this was caused by twisting of the deck, and indention of the glass into the foam. With these 4 small tears, it certainly has lost some torsional rigidity. I haven't ridden it since.




I will eventually try a light DH/freeride deck again. A couple of changes:I will consider adding a third layer of glass. One that traverses between the foam and the BB layer as well as traversing over the poplar runner. This would create two torsion boxes comprised of the foam split by the poplar runner. Should give more torsionally strength. I would also use a different foam. I've got some new stuff that is really stiff but still quite light. It flexes a bit too.

So a stiffer flexy foam should stop the glass cracking so much? (I ask semi obvious questions to learn :L)

[FBD]

i've been dabbling in foamcore building, but taking a break now because i'm about to go to school, but you could shred a SHITLOAD of weight on that thing if you used a lighter fiberglass. you can order 3oz e-glass at 36"x38" sheets for like 6.75 at Fiberglass , Epoxy , Composites, Carbon Fiber - U.S. Composites, Inc. and if you vac three layers on top and bottom of that, that's 22oz lighter than what you're using now. not triaxal, i know, but 3 layers is perfect.

[hoch92000]

i've been dabbling in foamcore building, but taking a break now because i'm about to go to school, but you could shred a SHITLOAD of weight on that thing if you used a lighter fiberglass. you can order 3oz e-glass at 36"x38" sheets for like 6.75 at Fiberglass , Epoxy , Composites, Carbon Fiber - U.S. Composites, Inc. and if you vac three layers on top and bottom of that, that's 22oz lighter than what you're using now. not triaxal, i know, but 3 layers is perfect.

Sorry, woven glass is worthless. It protects but is much less effective for a skin in I-beam construction. The glass I use is three layers of unidirection sewn together. Three ounces of that veil glass would snap mericilessly.

Anyway, this deck weighs under 3 pounds. It is a veritable feather. To lighten it up, one would substitute 6 oz plain weave or twill carbon fiber, and replace some of the poplar stringer with foam.

[hoch92000]

So a stiffer flexy foam should stop the glass cracking so much? (I ask semi obvious questions to learn :L)

Good question.

Ding, Ding, Ding, we have a winner.

Precisely.

[FBD]

Sorry, woven glass is worthless. It protects but is much less effective for a skin in I-beam construction. The glass I use is three layers of unidirection sewn together. Three ounces of that veil glass would snap mericilessly.

Anyway, this deck weighs under 3 pounds. It is a veritable feather. To lighten it up, one would substitute 6 oz plain weave or twill carbon fiber, and replace some of the poplar stringer with foam.

I hear what you're saying. Excuse me but you'll have to understand that I'm pretty cheap haha. Given though, would the foam stringer hold up to tension of regular riding compared to a poplar stringer? if anything, you could use neoprene or volara as a substitute. I found carbon core foam on some composite site a while back, can't remember the link, but match that with carbon fiber and that's pretty light.

how does your board, weight-wise, compare to like the Dee-Lite line from Rayne or other composite boards? Given there's no carbon in it, but if you did use carbon...?

[hoch92000]

I hear what you're saying. Excuse me but you'll have to understand that I'm pretty cheap haha. Given though, would the foam stringer hold up to tension of regular riding compared to a poplar stringer? if anything, you could use neoprene or volara as a substitute. I found carbon core foam on some composite site a while back, can't remember the link, but match that with carbon fiber and that's pretty light.

how does your board, weight-wise, compare to like the Dee-Lite line from Rayne or other composite boards? Given there's no carbon in it, but if you did use carbon...?

You have some very good questions. But you are also lacking in some basic knowledge before delving into foam/carbon constructs. For example, neoprene is the last thing one would use, it compresses. It is flexy which is good, but it can be compressed. Good for a chair. Bad for a core.

To answer these questions, one would need a bit of time. Hate to say it, but you've got to sit down, search through the knowledge here that is laid out, and show some diligence. Start with I beam construction and specifically; what is required of a good core, and what is required of a good skin. You'll be building a Wefunk in no time.

As far as weight: Not sure how much those other boards weigh. I'm sure the specs are on the web site. Those decks are a bit stiffer. Keep in mind, glass stretches a bit and springs back. Carbon, remains quite stiff, and absorbs rather then springs.

[enemy combatant]

Sorry, woven glass is worthless

Absolute rubbish. Triax sometimes is woven (the strands go over and under each other.) You must be talking about woven roving. And triax cloths without a weave have roving and veil like fillers in them to keep them together. That adds nothing to the structural strength and they provide a matrix for a lot of extra resin which just adds weight. They are often used in boat hulls.

Glass cloth is available commercially in hundreds of different weights, weaves, strengths and working properties. And there are a lot of excellent e-glass woven cloths at low weights that have high thread count (helps to keep the resin to glass ratio low) that are quite strong (and are not veils.) Some you might familiarize yourself with are:


1.45 oz.



This place sells e-glass cloth as light as .58 oz. per sq. yd. I really like the 2.3 oz. 60x56 thread count #2113. I use it all the time on typical 7-ply maple boards. A single layer of this on both the top and bottom of a deck can really strengthen and stiffen things up quite a bit. A great fix for heavier riders who find a stock board bending too much. The 3.7 oz. S2 glass they sell is very good too. They also show a 12" wide 4 oz. "Uni-web" S-glass that looks like it might be very interesting to skate builders:
acp-composites fiberglass fabrics



3 oz. #120 is real workhorse and industry standard:

3.16 oz.



Two or three plys of 7 oz. and 8 oz. unidirectional and/or bi-directional weaves can often be layered to result in a stronger layup than the 20 oz. triax you are using:

7 oz. and 8 oz. uni & bi



There are also some new knits that can provide superior strength to woven cloth:

13.4 oz. and 17.6 oz. bi-ax and uni knits



BTW, what is a "torsion box" exactly? Specifically what makes it different than the box construction and square tubing we are all familiar with?

[hoch92000]

Absolute rubbish. Triax sometimes is woven (the strands go over and under each other.) You must be talking about woven roving. And triax cloths without a weave have roving and veil like fillers in them to keep them together. That adds nothing to the structural strength and they provide a matrix for a lot of extra resin which just adds weight. They are often used in boat hulls.

Glass cloth is available commercially in hundreds of different weights, weaves, strengths and working properties. And there are a lot of excellent e-glass woven cloths at low weights that have high thread count (helps to keep the resin to glass ratio low) that are quite strong (and are not veils.) Some you might familiarize yourself with are:


1.45 oz.




This place sells e-glass cloth as light as .58 oz. per sq. yd. I really like the 2.3 oz. 60x56 thread count #2113. I use it all the time on typical 7-ply maple boards. A single layer of this on both the top and bottom of a deck can really strengthen and stiffen things up quite a bit. A great fix for heavier riders who find a stock board bending too much. The 3.7 oz. S2 glass they sell is very good too. They also show a 12" wide 4 oz. "Uni-web" S-glass that looks like it might be very interesting to skate builders:
acp-composites fiberglass fabrics




3 oz. #120 is real workhorse and industry standard:

3.16 oz.



Two or three plys of 7 oz. and 8 oz. unidirectional and/or bi-directional weaves can often be layered to result in a stronger layup than the 20 oz. triax you are using:

7 oz. and 8 oz. uni & bi



There are also some new knits that can provide superior strength to woven cloth:

13.4 oz. and 17.6 oz. bi-ax and uni knits



BTW, what is a "torsion box" exactly? Specifically what makes it different than the box construction and square tubing we are all familiar with?

You certainly have a way with words. Thanks for the encouragement.

The triax I used here, has no roving. It's triax of E fibers. I have used plain weave before, Using up to 3 layers of 10oz to fortify. Plain weaves have significant slack. The uni or triax has worked much better for me. The same deck with triax is stronger than the weave pound for pound. These are my experiences. I have used 3 to 4 oz woven before and it is just not that strong. It tears quite easily. I suppose we each have our own opinion.

[KCcarvin]

say I wanted to make a carbon fiber or fiberglass board JUST out of either of those materials (not together) and a core... with some ply for hard spots where the mounts would go.... would that be feasable... and if so... what cloth would I need to do that... i was looking at a few layers top and bottom of some 6oz plain weave... maybe 3 top 3 bottom of the core... would that be stiff or really flexable?

[enemy combatant]

Thanks for the encouragement.

No problemo. 8) Your build looked sweet in execution. I just wish that I didn't still work for a living and had more time to build more than the occasional board for myself.

I have used 3 to 4 oz woven before and it is just not that strong. It tears quite easily.

I'm quite sure that the skin failures you had with the insulation foam wings on your deck were due to the lack of shear strength in your foam and also possibly to not "prepping" the foam prior to laminating it.

It is a good practice with porous plies like foam or balsa to give them a thin coating of resin mixed with filler the night before laminating them in order to seal them and provide a stronger fabric to core resin bond when they are in the bag. Not sealing them often causes too much resin to soak into the core rather than performing its duty as a matrix for the cloth skin.

[Everett McCord]

good lord thats sexy... to bad it has begun (sp?) to break though

[enemy combatant]

say I wanted to make a carbon fiber or fiberglass board JUST out of either of those materials (not together) and a core... with some ply for hard spots where the mounts would go.... would that be feasable... and if so... what cloth would I need to do that... i was looking at a few layers top and bottom of some 6oz plain weave... maybe 3 top 3 bottom of the core... would that be stiff or really flexable?

You need to look at the manufacturers specifications for tensile and compressive strength and also for the modulus of elasticity of the fabrics in question in order to make ballpark comparisons of different skin materials.

Read this book written for the intelligent layman by the distinguished engineer Andy Marshall, former head of R&D for Hexcell Coprporation:

Composite Basics Book, Andy Marshall, Aircraft Technical Book Company, ISBN-13 9780977489664, ISBN-10 0966454049, Aircraft Technical Book Company, Aviation Books and Video Resources

6 oz. S-glass is readily available at retail stores like TAP Plastics or West Marine (or everywhere online) and is an inexpensive and excellent outer skin material for board building of any sort.

[KCcarvin]

ok here is my proposed layering for the drop through all fiberglass foamcore I'm planning
Top to bottom:

6oz S-glass
------
Biaxial 1708 E-glass
------
((blue board insulation foam))
---------
biaxial 1708 E-glass
---------
6oz S-glass

I figured It was the right combination of multidirectional strength surrounding the core... can't have that moving... and S-glass on the outside to keep it ultralight and thin while maintaining strength.... plus the E-glass uses WAY less resin so will stay even lighter =].

Sound bad to anyone?

oh yeah.. it's going to be 40" long by 9" wide at widest point and will drop through

[hoch92000]

It is a good practice with porous plies like foam or balsa to give them a thin coating of resin mixed with filler the night before laminating them in order to seal them and provide a stronger fabric to core resin bond when they are in the bag. Not sealing them often causes too much resin to soak into the core rather than performing its duty as a matrix for the cloth skin.

That makes sense. I'll have to give it a try. Need to get some filler though.

[hoch92000]

good lord thats sexy... to bad it has begun (sp?) to break though

No worries. I had to try the pink stuff once, to find out why one shouldn't use it in this way.

[hoch92000]

ok here is my proposed layering for the drop through all fiberglass foamcore I'm planning
Top to bottom:

6oz S-glass
------
Biaxial 1708 E-glass
------
((blue board insulation foam))
---------
biaxial 1708 E-glass
---------
6oz S-glass

I figured It was the right combination of multidirectional strength surrounding the core... can't have that moving... and S-glass on the outside to keep it ultralight and thin while maintaining strength.... plus the E-glass uses WAY less resin so will stay even lighter =].

Sound bad to anyone?

oh yeah.. it's going to be 40" long by 9" wide at widest point and will drop through

What is the weight of the biax? 17 oz, I assume.

A couple of issues. I can't recommend the extruded polystyrene foam any more. It is just too fragile. And, I've come across some issues with gas release from the foam.

My issue with the layup, is that the only longitudinal oriented fiber are half the fibers in the S-glass. The biax will provide longitudinal resistence to strength, but at a disadvantage. A -30/+30 may work better here over -45/+45 knitted setup.That biax, I believe, has some chopped mat stuff, which simply adds weight without resistence to stretch. Also, if the biax is 17oz, you're not saving much weight over 20 triax.