[img_assist|nid=1063773|title=|desc=|link=none|align=left|width=333|height=585]
Hi Guys,
Another build thread. Let me start by saying that I welcome criticism, especially on this one. I’ve done some stuff differently than most, and would really like input on everyones thoughts on my methods. Including those “That’s nothing new, Somebody else did ot that way back in 1962”
[img_assist|nid=1063775|title=Level Racks|desc=|link=none|align=left|width=571|height=321]
A clean shape starts with level racks. If the top of the racks are off, setting a level on the top of the blank won’t give you a true read. Preventing a twisted shape can be done with reading the level on the deck.
[img_assist|nid=1063776|title=level deck|desc=|link=none|align=left|width=573|height=322]
The basics of this one is a U.S. Blanks stringerless Red.
that turned out very nice!
+1…
I like the color, rich, yeah that’s it…
Your reflection in the gloss coat looks true… That’s a good thing…
[img_assist|nid=1063780|title=Rocker Stick|desc=|link=none|align=left|width=359|height=640]First step is figuring out your deck and bottom rockers.
For right now, I’ll leave the design part out of it, but there is a definite mathematical method for doing it.[img_assist|nid=1063781|title=Radius Formula|desc=|link=none|align=left|width=640|height=415]
Like I said before, this one is stringerless, with a divinylcell deck.
Trying to build a stringerless board without anything stiffening it during glassing and shaping is really a pain. Its really too floppy, and when you try to glass it in standard racks, gravity is going to alter your hard work. Most use the rocker table to hold it steady.
I went a different way. I figured the most stressed area, and most prone to damage part of a board is the deck. A reinforced skin fixes that. Maybe the divinylcell skin that others used for impact strength would also function to stiffen the board during shaping and glassing. So, to a point, the skin makes the stinger redundant.
[img_assist|nid=1063782|title=Cutting the Outline|desc=|link=none|align=left|width=640|height=359]Here’s the sheet with the template drawn into it. The outer dashed line is the boards template, the inner solid line is where to cut. Sheet metal scissors do this easy.
Divinylcell is really too porus for a light laminate. The holes are going to suck in too much epoxy. To keep the weight down, “spackle” it with a slurry of epoxy and microballoons. Then while still wet, lay out 2 oz. fiberglass cloth over the slurry. Trim to the outline.[img_assist|nid=1063783|title=2 oz over skin|desc=|link=none|align=left|width=640|height=359] In this picture, the cloth is over the slurried skin, but the cloth hasn’t been wet out with epoxy yet.
I got a little ahead of myself. At this point, the deck and rails are shaped, but not the bottom! The deck rocker is pretty critical, but the bottom rocker is key. With a full thickness blank, you can come close to accurate, but the real step is in the vacuum bag.
[img_assist|nid=1063784|title=Shaped deck, taped for cutlap|desc=|link=none|align=left|width=640|height=359]Here’s the deck, taped for a cutlap. The white goo around the masking tape is more microbaloon slurry. A little extra to hold down the skin. I’ve done it before without the extra slurry, and the edges can lift up a little if you don’t
Nice board.
Greatest compressive stress is on the deck. Greatest tensile stress is on the bottom.
If you only had one piece of Carbon Cloth, you would put it on the bottom because carbon fiber has very good tensile strength rather than compressive strength. Relative to fiberglass, carbon cloth has much higher tensile strength.
I guess I should let you finish your build process before we start with questions, but I'm wondering what the thickness is on your d-cell. That's going to influence the stiffness of the finished product quite a bit.
Build thread! Yeah! Love 'em. I’m watching.
[quote=“$1”]
The basics of this one is a U.S. Blanks stringerless Red.
is that there lightest foam?
cheers huie
1/8" d-cell on the deck only. I did the Bert Berger d-cell top and bottom before, and absolutely it was too stiff.
[quote=“$1”]
No, Orange is their lightest foam. but just a little lighter than red. I went to Fiberglass Hawaii and asked for a second stringerless 6-10 A in either Red or Orange. They had the Red available. The only flaw in it was a bubble that was outside the template, and it was only $50.00.
Compressive, vs tensile, vs impact. The skin gives impact strength, but since the blank is stringerless, the flex is slightly more than a regular stringered board. It is noticeable on a hard bottom turn, or cutback.
No point in adding carbon to the bottom, as I dont usually impact the bottom of the board, and it would add the stiffness that I’m trying to avoid.
In my very limited experience, stringerless, S cloth, no d-cell deck, and S-cloth at 2 1/2" thick, with my size and weight had a little too much flex, especially in the tail where the board is thinner.
[img_assist|nid=1063786|title=|desc=|link=none|align=left|width=640|height=359]
So here’s the board in the vacuum bag. Again at this point, the deck and rails have been shaped, but not the bottom.
The deck rocker is held by the lumber rocker stick. Once it is cured, expect a little spring back of the blank. What I mean is that the sandwiched blank will be stiff enough to be easy to finish shaping,but won’t hold perfectly true to the rocker stick.
That’s why I haven’t shaped the bottom yet. I want the bottom to be perfect to my design, and the only way to be exact is to shape it after.
[img_assist|nid=1063787|title=In the bag|desc=|link=none|align=left|width=640|height=359]
Once you pull it from the bag, the next step is to take down the 1/8" step at the edge of the d-cell. A tip is to run masking tape on the white foam deck, next to the d-cell. because your rail tops are finished at this point, you don’t want to scuff them up as you feather the d-cell down. The masking tape protects them