Thin layer of epoxy on the mold
Mixed Epoxy and Cotton Flock to fill in around d-nuts and t-bar ridges.
Use black dye otherwise the white color might show through!
Thin strips C/F around the curved
bottom edge of the board (rear and sides) to help "bridge the gap" so
the full sheet lays down better without air bubbles.
Two 24" c/f biaxial from front of the board to strengthen the curved bottom edges so they don't cave in the final bagging (had many cave in from too much pressure and not enough c/f on the edges in the front)
One 22"x12" uni c/f for the front of the board running lengthwise so there are 3 layers on everything
2 - 56x6" kevlar and 1 36x6" kevlar on the bottom of the board to cover everything. The 36 will go in the center in front of the t-bar hole. I put the kevlar in after most of the bottom is already covered in c/f so the yellow doesn't show through. With the c/f runner and center pieces, I lay a few down, then the kevlar, then the rest of them so the kevlar is in the middle.
5 Carbon Fiber pieces (16" x 12") run
at 90degrees to the
length of the board for strength
1 full sheet of 9oz Carbon Fiber
Remaining two 3"x56 strips on the flange sides to help with the release from the mold (will be cut off later)
Bag #1
- Mold
should have the following items before putting them into the vacuum bag
- Peel Ply (puts a rough texture on the surface to help with the next layer to adhere better
· Perforated Release Ply (to suck excess resin into breather material)
· Breather Material
· Put extra breather material at any place that makes a sharp corner. It will help keep air bubbles out of that section
· 4mil painters plastic (keeps anything from coming in contact with the vacuum bag)
· I usually tape the vacuum bag layers to the mold/board/whatever to keep them from folding and causing extra creases. I use the green painter’s masking tape so it’s easy to remove.
· Put extra breather material under the vacuum bag valve or use an old towel
·
Vacuum Bag
- Vacuum for a minimum of 5 hours under heated oven – See pic. The oven maintains a temp of around 135 with the electric heater. My oven is now around 7' long x 3' wide x 4' high.
What I've found is if you have the time, leave the mold sit for about 8 hours AFTER the bagging process to totally cool off. The c/f bottom will pop out MUCH easier if it has cooled for awhile. I usually let it sit while I'm away at work, then after I get home, it pops right out. If you try it right out of the oven, it could take up to an hour to get the c/f to pop out of the mold. This is only for the first bagging, once you get it popped out, the rest of the baggings will be a piece of cake to release.
2lbs 14oz with flange
Carbon Fiber Stringers
4 - 1"x24" curved stringers - 1/8" c/f plate
4 - 1"x12" short spacers - 1/8" c/f plate
2 - 6"x12" c/f plate
2 - 14"x6" Kevlar strips
2 - 14"x4" biaxial c/f
I have tried different types of strings, but the ones that have lasted the longest are made from c/f plates from mcmaster. They are expensive, but when you consider how much the board costs, it is well worth it to at least get a few years out of a board.
I used a metal chopsaw blade to cut the straight portions of the stringers, and a jigsaw to cut the curved. C/F is a pain in the butt to cut since it eats through blades like crazy.
For the foam in between the stringers, I used different widths and then cut them to the correct height.
Once everything is cut, tape the stringer parts together to make one piece. It will make it easier to sandwich between the 2 plates.
Mark the board behind the rear seat tower holes and in front of the front seat tower holes. You will need to line the stringers up so they are not in the way of the bolts going through the board. It should line up with the 3/4" foam pieces.
After everything is ready, spread structural epoxy over the plates/bottom of the board, and put everything together. Use tape to hold it in place inside the mold. Use normal epoxy for the 2 kevlar strips/2 biaxial strips that will hold the front and rear of the stringers to the bottom of the board. (one of each on the front, and one of each on the seat tower section) I used a bunch of pieces of breather to help the bag compress the Kevlar/cf better on the sides of the stringers.
Vacuum bag.
5lbs 1oz with no foam
Once you pull the mold out, fill in areas between the stringers with 2-part expanding foam. I used expanding foam for the whole board - no honeycomb in this board. I'm relying on the stringers to give all the support.
Only do 2ft sections at a time.
100g/100g for rear
150g/150g for middle
100g/100g for front
- expanding foam is too runny and will not work well if you do the whole board. You only need to wait about 15 minutes between sections.
I used plexiglass on the top of the board with 6 vicegrips to hold it to the flanges of the mold. That way the expanding foam spreads out better.
Do not tape anything off. It is impossible to get the tape off after the foam is stuck, so you end up sanding it off anyway.
Put saran wrap or painters plastic lightly over the section of expanding foam so it fills in the gap correctly, then set something flat and heavy on top to allow the foam to expand in all directions. (I used metal plates)
Once foam has hardened, sand to the shape you want.
6lbs 1oz after foam
Put kevlar/Fiberglass pieces 33-39" from the back of the board for binding holes. Rear hole of the binding rail is 34.5" for me.
Top of the board
150/41 epoxy 1.5 hrs
1 full sheet of c/f - 55"
3 15" x 12"
2 14" x 12"
Bag # 3 - do not exceed 20hg or you will crush the 3lb foam
Remove flange – I used a jigsaw, a belt sander and palm sander – WEAR mask!!!
Don’t worry if you now have a gap between the top layer and the sides. That will get fixed with the next layer.
6lbs 9oz after the flange is removed
Drill holes and T-Bar oval!!!
Cut t-bar oval out of finished board, and drill holes for the d-nuts. I drilled two 3/4" holes on the bottom side at each end of the t-bar oval. Then used a cutoff tool to "connect" the holes to make the oval. Did the same to the top, and then just cut the oval out with a knife since the foam wasn't cut all the way through.
Top of the board
150g/41g 1.5 hrs
(3) 6" kevlar strips covering the top and wrapping around the sides of the board at least 1"
1 full sheet of uni c/f (55")
After all layers are wetted with epoxy, position the Kevlar leaving about 1" hanging over the edge of the board. This should seal the board since the 1” lip will wrap around to the sides when vacuumed.
Before bagging, you will need to work with the sides to make sure they lay over the edges properly. Watch the rear because it’s very easy to get the release/perf ply wrinkled behind the c/f which will ruin your back edge. I used tape to tape the release/perf ply so it would not bunch up and cause issues.
Bag #4
7lbs 6oz
Pic of Bottom - uni carbon only
Sand smooth (course, then medium sandpaper) all over the board so the pretty layers will adhere.
Bottom Pretty Layer
Epoxy -125/34
Do the bottom half first.
Thin layer of epoxy on the bottom,
sides, and first few inches of the top.
Cut with sharp scissors after the cloth has been wetted out to leave a nice edge – allow it to roll up the sides and even over the top of the board an inch or so.
After wetting the fabric, cut the back and front sections of fabric so they will lay down well. Use masking tape to tape the perf ply to the board so the fabric lays down nicely with no wrinkles.
Bag #5
Bottom Pretty Layer wrapped over sides and onto top
Top Pretty Layer
Epoxy - 80/21g
Thin layer of epoxy on the Top only
– you will only be covering the top of the board, not the sides.
50" x 16"
Cut with sharp scissors after the cloth has been wetted out to leave a nice edge.
Use perf peel ply only. Use masking tape to tape the perf ply to the board so the fabric lays down nicely with no wrinkles.
Final Bag - #6
9.0 lbs 1.0oz
To get the glossy look:
Sand (120/240 grit), wash with water
Final coat of epoxy (50g/14g for each side)
This will give the board that shiny look you are looking for. Do bottom first, then top.
7lbs 10oz - 1/16 aluminum - 8lbs 13oz 1/8 aluminum Total weight of board when it’s all said and done
Attach bindings to the board with the original binding rails. If the original bindings were tight, you will have to make custom bindings now, since they need to be longer. I used these: http://www.murrays.com/archive/76.pdf (Lightwave adjustable straps)
I used 3/8” allen head rounded head bolts that come up from the bottom to bolt the tower to the board. Then just used locking nuts to hold the tower to the board so it won’t loosen.
