Most common rails on TT boards are ABS rails. ABS strip is bonded to core or in some cases ABS sheet is bottom sheet of the board. Can anyone explain me is whole bottom sheet needed and if not than preffered width of abs strips.

I used ABS for the rails on my board. I was making a ply core but if I was to use foam I would follow the same route as I did with the ply.

What I did it shape my ABS to the final shape of the board and made the rails down the side about 40mm wide and at the tips I went to around 6 inches. The middle was filled with a ply to fill in the gap. If you take a look at the images here http://blog.brettschumann.co.uk/2008/06/step-5-assembly-part-2.html you shall see what I mean.

I see what you mean, but is extra weight worth it. I mean ABS is not a core material and is not soaked with resin so your sandwich construction has 2 different "core" materials that have fairly different physical behavior. Basic idea is, does ABS add anything else except weight?

To be honest, I have no idea. I just copied manufactured boards with regards to the rails. The ABS is pretty flexible and I don't think would add any benefit to the board in terms of flex. The idea of the abs is to add a nice impact absorbing edge to your board. I is pretty light and I would say lighter than the ply I used. I know that in a nobile board, there is ABS, honey comb, Foam and wood as well carbon and glass. I imagine each of those materials have their strengths and weakness and I guess when all put together make a pretty neat board. Other than that I cannot comment to much on it.

actually, abs side walls can give a good absorbing but the main reason to use abs side walls is that it keeps water or humidity from getting into the core as well as giving u a lot of flex wich u would'nt have if the fiber went all the way over the edge.

think of it as two thin metal plates glued together, they still would have a lot of flex

but if u welded a vertical piece between the two flat pieces (Like an " I beam")
the metal woul'nt be flex at all

why use abs, cause its flex, its water tight and it sticks better to epoxy then pvc

What i mean, is there really any difference between those two strategies?

weight and no matter what, your fiber will always have a better bond to your core (wood or foam core) then to pvc or abs


and a full plate of pvc must be stiff as hell!!!

that was the answer i was waiting for.
Than what width of ABS strip is enough. And i noticed on some production boards, ABS at the end of the board is significantly wider.

the abs dosnt need to be that wide

and yes a lot of companies put more abs at the tip . some companies put two smal strips on the sides and larget plates at the tips ( u can change the thickness)

i dont know what width they usualy use but for my home made boards, i use about one inch wide
if u used wider strips, i had problems keeping the strip flat (to stiff)

anyways, hope im helping u and not confusing u

crystal clear
Thanks for tips.