Core gluing- potential issues?

[MJTennison]

Hi All,

Been awhile since I've posted on here...although I've definitely been able to answer a lot of my questions just by searching on here. Lots of great stuff, especially some of the 'lessons learned' comments and posts on here!

Anyway, I am in the works of building now...built the mold out of MDF, gathered all the materials for the first build (going to vacuum press this first layup), and am in process of preparing the snowboard core.

I glued up (6) 1x2x8 poplar boards, planed them down ~1/16" to get some flat edges, and ripped them to ~5/8" thickness.

I just glued (2) 6" widths side by side, symmetrically about the length (longitudinal) of the 6ft boards, but am concerned about the strength of the 12" core. There seemed to be a very small gap (1/32") about halfway along the length of the board, probably where the clamping force was not sufficient. I was not able to use a jointer on the edges prior to clamping, so they were bowed quite a bit prior to clamping.

Any thoughts on whether this could be a potential issue once I start profiling the core...and even worse, could the core shear once the board is sandwiched between the fiberglass? The 19oz triaxial glass should provide the torsional stiffness necessary to prevent core from shearing/bending, but will this be enough?

Hoping some of the veterans could shed some light on this, in case I need to build up a new core prior to taking it any further...

Sorry for the long winded post.

Thanks!

Merritt

[skidesmond]

Can you see day light through the gap? It may be ok. When you do the layup, epoxy will fill it. make sure you flood that area with epoxy. If I was making the board for myself, I'd still use it.

You could also fill it in w/ a mixture of exterior wood glue and sawdust, pack it in real tight.

[vinman]

i use JB weld putty epoxy for wood to fix any gaps in my wood core after profiling. Unless they are huge they are likely not an issue and as SD said they probably get filled in with epoxy during layup.

[MontuckyMadman]

Nordicas cores are all stapled together little gaps like you mean are of no consequence as long as its not at the sidewall

[MJTennison]

Thanks all for the quick feedback...I am not able to see daylight through core, but will potentially reinforce with additional epoxy and some glass strips if it looks worse after core profiling.

Appreciate the help- getting pretty stoked about printing some graphics and laying this thing up! I'll upload some pictures soon

-M

[petemorgan(pmoskico)]

yeah i agree with the previous fellas' insights. it probably wont be an issue becaues the epoxy should fill the gap. if it was really bad and interferred with sidewall or tip or tail then i might question it.

if you talking like fingernail size crack, and only like 1 or 2 of them, i wouldnt worry.

[twizzstyle]

I have a motto with the stuff I make "It will fill with epoxy". It comes up a lot... You'll be fine!

[MJTennison]

One more question dealing with strength/potential de-lam of board...

I have done a lot of fabric screenprinting in the past, as well as acrylic on poster paper. Seems like most people will use fabric, rice paper, or print directly onto wood/polyethylene sheets.

Are there more delam issues with printing onto fabric or paper, since the epoxy bond is now bonded directly to fabric/paper as opposed to a wood-polyethylene bond?

I am going off of my engineering judgment that the shear strength would be slightly less than a purely wood-polyethylene bond, unless the fabric/paper is highly porous.

Ok, enough nerding out...let me know your thoughts!

Thanks,

Merritt

[chrismp]

paper bonds really well! i use it for all my graphics.

i'm printing on a regular desktop printer (epson 2100) on matte coated paper. usually i coat the non-print side of the paper with white water based acrylic paint to stop my epoxy from seeping through. the reason for this is that my epoxy has an amber tint to it and it dulls the colors of the graphic.

after pressing i coat the graphic with a slow curing clear epoxy to seal the paper. the slow cure ensures that the whole paper is sturated with epoxy to fully seal it. after that it's just light sanding and a couple of coats of two component polyurethane varnish.

[PTTR]

Sorry to hijack this thread.,,but ..

I have been searching the internet for info about polyurethane varnish and my conclusion was until seconds ago that two componet PUs were too hard and would crack?
If you don't mind sharing, what type of PU are you using Chris?

[OAC]

You can even use Biltema's.. ;-)
The trick lay's in the mix and how you apply it. Some exercise doesn't hurt.
Personally I use a 2-comp. from Beckers(you may have heard of..) made for heavy duty stuff. But it seams that nothing can protect a cut from a ski steel edge...
I've tried the expensive stuff from Bassler also

[More]

Well, I sure hope 2 pot is ok, because I've just used an awful lot of it.

[MJTennison]

paper bonds really well! i use it for all my graphics.

i'm printing on a regular desktop printer (epson 2100) on matte coated paper. usually i coat the non-print side of the paper with white water based acrylic paint to stop my epoxy from seeping through. the reason for this is that my epoxy has an amber tint to it and it dulls the colors of the graphic.

after pressing i coat the graphic with a slow curing clear epoxy to seal the paper. the slow cure ensures that the whole paper is sturated with epoxy to fully seal it. after that it's just light sanding and a couple of coats of two component polyurethane varnish.

Thanks Chris- do you have any pictures of the final product prior to board/ski layup?