How low do you think one can go on EPS density on a board with glass-cork-glass sandwich skins?
I am thinking about a low density EPS Compsand with perimeter stringers done in a mold with some cork rails...
I would appreciate to hear your experiences, before i start doing test pieces :)
Hope you have been doing fine in the meantime
I would start light at 0.75lb density and increase by 0.25Lb increments if failure occurs. I am predicting 0.75lb will work fine. If that not available start with lowest density foam you have available. Don't bother with test pieces just build the board. Not a fan of built out cork rails if that's what you mean by "perimeter stringers done in a mold with some cork rails". I would have fiberglass between each layer of cork for rails if I am understanding what you are doing correctly
Agree with BB30 on cork rails. I've made several boards with cork rails (not molded), I glued several layers of cork to get about 1/2" width. Cork is noticeably heavier than balsa wood, and it's harder to get a nice cleam smooth finish. If I make a perimeter rail these days, I use either Balsa or XPS (blue Dow foam), usually XPS.
I don't make cork veneer boards, but I do make balsa veneer boards. For .75 lb EPS, I'd use 1/8" thick balsa for better dent resistance. Not sure how that equates to cork. For 1lb EPS, I do a layer of glass, then 1/16" balsa then glass.
I was thinking about the cork rails because its easy to glue on...
Balsa is kind of not easy to obtain in good lengths around here. Only poplar ply basically.
Yeah i know, i went through some old threads researching and saw some beautiful works of yours, if i remember correctly...
Im just worried about the impact resistance of a sandwich on low density eps foam, with which i have no experience...
My Plan was to build something like this:
For another midlength
1. Rocker Slices hot wired from EPS
2. Cut outline
3. Glue poplar ply perimeter stringers
4. Shape the bottom or shape bottom and deck + building up the rails by cork/foam/balsa/etc
5. And this why i was asking... Put on glass - wood/cork - glass on the bottom
6? Build the rails now
6. Some for the deck with exposed cork deck
Something like this for a longboard as well... But probably with a center stringer as well
P.s: Failure is not an option :) Safety first, these are my whole summer boards and i dont want to create too much trash...
Making balsa rails does not need long lengths of balsa. My normal length is 4 feet length but 2 feet would work also. all my panks are milled to 2.5mm thickness. Anywhoooo,I alternate from nose to tail then tail to nose and usually the layered seams of the joined wood in built out rail will be staggered. If the are not staggard I will chop a piece in such a way so the to make it staggered. So I build out nose to tail making rail pieces to use as templetes for cutting additional pieces . Then go tail to nose and use those pieces to make more of that same size. So to add .75 inches of rail to each side of of board.....I will need 12 total of each piece I cut. label, tape joining ends together and i will have six rail pieces alternating every other one where rail seam is. If you really wanted to stagger seam on rail you could make three sectios with no seam matching. I always vac bag the rails also. Only epoxy between layers because I fiber glass board when finished.
First set of pics showing Bending 6 pieces of balsa for the nose. 6 layers on nose because I have 6 layers on each rail. Wet planks in hot water and stuff in 5 gallon bucket. When dry take out sort to work best for situation. tape down, throw in bag and roll out. last pics out ouf bag result on nose.. THESE ARE FULL LENGTH PIECES FOR NOSE
here is the stagering seam on rail build out I was taliking about.
This is what my pieced out rails look like prior to using huck's method of rolling out with a foam brush the rails with epoxy. Roll epoxy on five of the 6 pieces trom right to left. So the far right is piece #6 and far left piece #1. first place 5 on 6, 4 on 5 until 1 is on 2. You now have a rail that will stay dry on the outside of piece 1 and need to get some resin on down side of piece 6. Place on ral of board. this one I had to fit to angled nose piece, tape off and vac bag and roll out. I can do both sides at one time but I was by myself and choose to do one side at a time. Less stressful. last pic out of bag shot tha was not sanded yet. Nose had been taken down 95% to finish prior to rail bagging. Also you need to remember to fiqure out what side gets wetted out with other rail. just dry fit in your mind or for reals.
top and bottom needing some fine tuning of rails in the sanding room prior to glassing. I forgot to mention I hold the rail pieces together with a 2 " length on 1/8" white or beige masking tape you have in your shop to do pin lins with. It is taped on both sides, in the middle, horizontally as in nose to tail direction NOT floor to ceiling.
Wow, another master class. Beautiful work.