Repairing a Cracked 1/4" Plywood Fin?

[jmmome]

Cracked a fin upon landing this 45 pound rocket- it still feels quite sturdy, but flexes a bit compared to its neighbors.

What are best practices to repair a crack like this?

Thanks!

 

[Voyhager3]

Maybe try gluing it back together with wood glue, then putting a layer of glass on it. I really don't know though, just a thought.

 

[David Schwantz]

syringe and epoxy. Inject into crack, cover with plastic wrap, clamp flat and then refinish.

 

[jmmome]

syringe and epoxy. Inject into crack, cover with plastic wrap, clamp flat and then refinish.

Thanks!!! Hard to believe, but I've never cracked a fin before.........

 

[David Schwantz]

I like to use finishing resin for this as it is thinner making it easier to inject and soak into wood. It also gives you more working time.

 

[jmmome]

I like to use finishing resin for this as it is thinner making it easier to inject and soak into wood. It also gives you more working time.

I have some of that- will use it. Thanks for the tip!

 

[T-Rex]

Thank you @jmmome for starting this thread.
I have a couple plywood fins that delaminated at the corners due to a hard landing. Will have to consider injecting epoxy and clamping.

 

[jqavins]

Only because it's this rocket, I suggest the following:

If you can, push the fin to one side or the other enough to open the crack slightly without causing more damage. Insert something in the crack, as thin as a toothpick, or maybe even half a toothpick. Then, once it's glued up, it'll be ever so slightly crooked, as befits this particular rocket.

 

[sriegel]

And if you have an odd surface crack after the repair, cover it with a strip of posterboard glued down firmly. Then dot the edges of the strip with Gorilla wood glue and let dry. Awesome simulated rivet effect.