Pre-coating scraf joints...?

8:1 scarf-joints in ply hull panels expose a lot of porous end-grain.   Would it be useful (or otherwise) to pre-coat the scarf surfaces with unthickened epoxy: allow to cure overnight: lightly sand: then complete the joint with thickened epoxy?   I seem to recall having read this somewhere as a sort-of belt-and-braces approach to these important structural joints.  Are there any important do's or dont's in doing this?   Advice welcomed...

 Lol from Oz

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RE: Pre-coating scraf joints...?

I've never had any problems just pre-coating the open grained joint with unthickened epoxy and allowing it to soak in while I prepare the thickened glue.  I've also tested this method on scraps and the plywood always breaks before the joint - and that's before the fibreglass is applied.


RE: Pre-coating scraf joints...?

Coat the joint with straight unthickened epoxy and let set for 5 minutes to soak into the end grain. Recheck and apply more epoxy until dry spots no longer appear. Before the resin sets up, mix and apply your thickened epoxy cell-o-fill mixture and clamp in position for 24 hours.

Remember to tape both sides of the joint with clear plastic packaging tape for easy clean up.

RE: Pre-coating scraf joints...?

Scraf...!!!  OK, goddit, dunnit - the scarfs to hull panels and sheer clamps are looking good.   Quick hardening of epoxy today - 30 deg C = 86 deg F!   Tomorrow - mark out and loft hull panels...


Lol from Oz 

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