Quantcast

Need help repairing cracked fin fillet

The Rocketry Forum

Help Support The Rocketry Forum:

Balsa Bob

Well-Known Member
Joined
Jan 18, 2009
Messages
706
Reaction score
2
On a recent flight of my Super Big Bertha the parachute shredded and it came in pretty hard... hard enough to crack one of the fin fillets. The fin itself is fine, and the actual joint between the fin and the BT remains rock solid. It's just that the glue fillet (Elmer's) has cracked through the paint job. The original finish looks great and I'm hesitant about sanding down to the bare wood. Anyone else have this problem? Repair suggestions would be appreciated.
 

gpoehlein

Well-Known Member
Joined
Jan 18, 2009
Messages
3,555
Reaction score
8
That depends on how large the crack is. One thing you might try - pack the crack with baking soda and wick in a little CA. When it is set, sand the fillet lightly, trying not to scuff anywhere else. I'd touch up the paint with a brush - if you used rattle can paint, you can spray some onto a pallet like a pie pan and use that to touch it up with a brush.
 

Balsa Bob

Well-Known Member
Joined
Jan 18, 2009
Messages
706
Reaction score
2
Thanks for the response. The crack is narrow (hairline) but lengthy. I thought of CA, but didn't consider trying to fill the crack first. Problem is I have to really rock the fin to get the crack to open even a little. The trick will be keeping the CA off the BT and inside the crack.
 

blackjack2564

Crazy Jim's Gone Banana's
TRF Supporter
Joined
Jan 18, 2009
Messages
8,960
Reaction score
1,095
Location
Savannah Ga
I have used CA to fix cracked fillets. Taped both sides of cracked fillet with the easy remove blue masking tape to keep the mess to a minimum.

Yes you have to force the crack open, then apply the Ca and when you release the fin, the excess will come out. Having an extra set of hands near by, with a q-tip or corner of a paper towel to sop up the excess, will make for a neater repair.
 

Balsa Bob

Well-Known Member
Joined
Jan 18, 2009
Messages
706
Reaction score
2
Sounds like a plan. I'll let you know how it turns out. Thanks, again.
 

gpoehlein

Well-Known Member
Joined
Jan 18, 2009
Messages
3,555
Reaction score
8
If the crack is that small, a bit of thick CA will probably do the job by itself. If you do it right, you might not even need to sand it. Touch up the paint and you're good.
 

Balsa Bob

Well-Known Member
Joined
Jan 18, 2009
Messages
706
Reaction score
2
I corked off last night before attempting the fix... I'm gonna get some toothpicks and try the CA thing this afternoon.
 
Top