How to repair rotten Western Red Cedar weatherboards?

Question

As shown in the photo, the surface of the rotten western red cedar weatherboards has been scraped, cleaned, and coated with wood hardener. Bunnings no longer sells this particular weatherboard (I bought it in the past from Bunnings) so I've decided to repair it instead of replacement. How can I fill the surface defect now for the cosmetic purpose? Alternatively, I can leave it as it is and just paint it.

Nailbag · Answer

Hi @reno-abc

If you're after a short term cosmetic repair then following either @EricL or @Dave-1 suggestions will work. Long term which would be my advice is to replace the boards. Though Bunnings may not have that profile, it's very commonly available from most timber yards. Cost/mtr and time is negligible between the two repair process. But one is short term the others if done correctly is decades.

Nailbag

Dave-1 · Answer

Good Evening @reno-abc

I have used the builders bog that @EricL has suggested to repair and bring back to form timber seats. It works nicely and can be sanded and drilled once dry. I would practice on an old bit of timber first to get a feel of how to work the builders bog. (Not the greatest name but describes it well) is all I can suggest.

Dave

EricL · Answer

Hello @reno-abc

Thank you for the update, it's good to know that the weatherboard is not totally ruined. You just need to wait for a nice sunny day to let the board dry off and then you can proceed with the repairs.

Eric