How can I repair a waveboard that was run-over by a car?

[kite_hh]

I am on the final stretch, but I have a problem with the rails. My epoxy just runs off and doesn't stick to the rails. Hence I do get a nice layer on top to cover the structure of the carbon, but the rails do not have an adequate layer on them.

What is the solution here? Fast curing (5 min?) epoxy? Some other trick?

[BWD]

If epoxy sticks but runs off too thin and/or leaves drips = resin too thin and/or wrong technique, try using tape and board position (rail up maybe?) to control flow. Can also be simply resin viscosity too low. 600+cps is better for top coats. Other tricks - apply resin at higher ambient temp so it gels faster or let resin sit in pot as long as you dare before applying it. Also, you can warm the resin base in warm water bath or briefly/gently in microwave (eg <5 seconds for an ounce. If more heat needed only increase by one second steps).

NEVER HEAT HARDENER.

Most boat and surfboard epoxies work best at temps 75-80F. Use hotter if you dare and lower temps if you are filling a void and need to avoid exothermic heat build up from cure, or need to make sure resin has enough time to flow before gelling.
Your repair looks great so far.

[faklord]

Something like this might be another solution?
http://www.easycomposites.co.uk/#!/resi ... owder.html

[kite_hh]

If epoxy sticks but runs off too thin and/or leaves drips = resin too thin and/or wrong technique, try using tape and board position (rail up maybe?) to control flow. Can also be simply resin viscosity too low. 600+cps is better for top coats. Other tricks - apply resin at higher ambient temp so it gels faster or let resin sit in pot as long as you dare before applying it. Also, you can warm the resin base in warm water bath or briefly/gently in microwave (eg <5 seconds for an ounce. If more heat needed only increase by one second steps).

NEVER HEAT HARDENER.

Most boat and surfboard epoxies work best at temps 75-80F. Use hotter if you dare and lower temps if you are filling a void and need to avoid exothermic heat build up from cure, or need to make sure resin has enough time to flow before gelling.
Your repair looks great so far.

I am almost certain my technique is far from elaborated.

Unfortunately I am not able to change the surrounding temperature. But I will try to make even more use of the tape and let it sit a while before applying. Thanks!

Today I went to buy some new epoxy. I had intended to buy a real fast curing one (like 5 minutes), however the sales person (they also do board repairs) convinced me, that the epoxy I have been using is just fine and that I should instead use several layers each spread by about 3 hours.

Another option would be Aerosil, which is what @faklord suggested. However, he would go with several layers, since the aerosil will influence the viscosity but will also likely make the resin less see through.

I will probably go for the layers, though I am worried to get the mixture right every time. I guess at some point I will need to just go for it.

[kite_hh]

I am on the final stretch. The last coat of epoxy is on the board and currently hardening.

Right now it seems the finish is good (as in clear and even) enough to spare me the final sanding and polishing part. (Do I need to put varnish on top? Or is epoxy just fine?)

However, I did get a slight difference in levels on the bottom where I taped it off. It is far from being a millimeter of difference, so it is in the mikrometers.
The red arrow on the picture points at the edge. Everything to the right has a layer of new epoxy, while everything to the left is the factory original of the board.

Do you think this will have any (noticeable) difference in the feel of the board? Sure, it doesn't look perfect and it doesn't feel nice touching it, but the overall hassle of sanding and polishing is quite high If it rides fine (which I will hopefully test on Sunday), I might just leave it as it is.

Theoretically I am aware that some turbulences will occur due to this edge, I just don't see that there really is any laminar flow at that level on a kite board with all the speed and constant white water being hauled under the board. So, what do you guys think?

[kite_hh]

Ah, well. It is not over until it's over.

I read up how to drill through carbon fiber to get to the leash plug. Everything I read said use a drill, which I then proceeded to use. Bad idea. It went through the epoxy no problem, but once it caught the carbon things got nasty. The carbon fiber was pulled up with the drill and ripped my fine layers of epoxy around the hole with them.

Disaster.

My advice: Do NOT use a drill. My situation may have been special since it was only one layer of carbon and it was hollow below that layer, but I sincerely advise against drilling. My next attempt will be with a sanding drill. This way I won't rip up other material.

It really should have been my first choice.

So I filled the leash plug with wax and now once again I am waiting for the epoxy to cure, before I get my second attempt to free the plug.

Almost done... almost.

[kite_hh]

The repair of the repair turned out to look decent enough for me not to be sad anymore.
I am now eagerly awaiting the first test drive.

[kite_hh]

The first test ride worked out totally fine. It did not show any sign of weakness and rides nicely.

Slingshot says it weighs 3.54 kg. Mine shows 3.63 kg on the scale (with wet deckpads, without fins). I unfortunately did not weigh it before the repairs, but it sounds fair enough that I put some grams of epoxy on this board and the pads may hold some water. This means that hopefully all cracks have been sealed and the board is not taking on water.

Thanks for all the great help here!