Board repair supplies

U2U2U2 · Posted: Sun Jul 21, 2019 5:44 pm Post subject:

This was a Naish 2001era, Titan 109liters. Now about 92l.The nose and tail were both shortened and reshaped, mast track, footstraps, moved, powerbox removed, quads installed. The material for the nose is divinycell foam sheet.Thickest available, carbon overlay to existing top, then various glass and carbon.
Using West Systems 105 Epoxy. The nose rocker could be more. The tail was an experiment , works great with the quads, the tunnels also were, with option to refill, if it exhibited weird handling.This is a really dynamite conversion.
You should under or overlap the layers into existing. Pour foam 8lb would be heavier and much harder to apply. I use it for boxes.
A smaller cut off nose might work, it adheres to the PVC nicely, then carbon, glass on top.

I use a vacuum bag, but it’s not necessary, you can weigh the pieces till they cure.

boardsurfr · Joined: 23 Aug 2001 Posts: 1266

U2U2U2 · Posted: Mon Jul 22, 2019 9:24 am Post subject:

Pour foam, is not designed nor intended as a filler for our use. It is water proof, and fairly light weight. I use 8 lb, on occasion 10. The holes , usually when sanded usually most disappeared , you of course can skim a coat of epoxy and let dry. The pour foam will dry in a very irregular surface, so shaping is required.
Any repair route taken, should have several top layers, carbon, s- glass, glass then
Sanded, 3M Marine putty, sanded, primer, paint.

More than 1 way to bake a cake

Trebor_HI · Joined: 17 Aug 2008 Posts: 26

Rereading the thread, I believe pour foam was brdsurfr's original plan but the pour foam failed to react. Thus, he went the epoxy and filler route instead. And, I do see that he had some problems with the epoxy fill mix melting the Styrofoam. Thought he addressed that by applying a small quantity at a time.

Been considering the pour foam route...but, there is a pretty good chance we'll be moving overseas. Should this happen the leftovers will be discarded. Is it available in smaller quantities?

Any thought on these expanding foams in a can products?

U2U2U2 · Posted: Mon Jul 22, 2019 12:13 pm Post subject:

The PF that comes in cans is to cover areas around windows, cracks, I tried this just to see how crap it would be, it’s really crap so far as hardness goes.
2lb is non structural.Absolute min 4 lb. about 1 qt is normal size, they get measured in pounds mostly.
This is a 50/50 mixture, it’s sets very quickly, if anything too quick, temp effects things greatly.
To pour into a area, it’s easy, like a fin box surround, it foams up like a loaf of bread, you cut the top off with a hack saw blade, then continue the project.
If it didn’t set, something was wrong with a.mixture b. It was past its sell by.
Fiberglass Supply, WA state.
I can tell the difference from 8 lb to 10lb. Minimum for me is 8

DanWeiss · Joined: 24 Jun 2008 Posts: 2296 Location: Connecticut, USA

Trebor, you can spec the exact polystyrene for a match, or buy a $4.00 styrofoam cooler and use that to fill the gap. Mix epoxy with microballoons to form a paste the consistency of runny peanut butter. Glue the new piece in place. Laminate divinicell to that, then go with whatever cloth you select.

U2U2U2 · Posted: Mon Jul 22, 2019 8:02 pm Post subject:

According to the WWW a styrofoam cooler density is 1.00kg/m3.
This converts to .062428 PCF. Pounds per square foot.
The EPS used on a sturdy board is 28kg/ m3 which is 1.74 PCF.
The highest grade used is 32kg/ m3 which is 2PCF.
Most common used are 1PSF to 1.25.

A 1lb EPS blank vs the coolers density is 290 times more weight/ dense.

Real question is what adhesive to glue the kooler part that won’t melt it

boardsurfr · Joined: 23 Aug 2001 Posts: 1266

boardsurfr · Joined: 23 Aug 2001 Posts: 1266

U2U2U2 · Posted: Wed Jul 24, 2019 9:55 am Post subject:

I don’t know what I did on that calculation . You are correct mine is wrong. Way wrong !

Since the density values of EPS core used on Windsurf boards are 1 to 1.5, rare 2, because of addition weight, a difference is huge, in even .5.
I see that you show the value of a styrofoam cooler as 1.2 vs my 1.
Adding micro balloons , West Systems 407, has no effect on curing time for its 105 Systems. Any void in the existing EPS core , a hole or gap, would need epoxy that may melt, both pieces, the heat from when the epoxy cures.
Under an ideal repair, the cooler foam might work, I see no circumstance that a nose repair would benefit form using it, as the more robust EPS already broke.

To both who have mentioned it, my view remains unchanged , but I see now it’s feasible, but it’s not in my recipe book. If worth doing , it’s worth doing right. YMMV.
apologize for mis- information