Hi @nagumuthu,
Thank you for your question about matching your merbau post with an oak door.
My suggestion is to box out the post using 110 x 19mm 2.4m DAR Tasmanian Oak and then coat it with a clear sealer such as Cabot's 1L Gloss Exterior Clear Timber Finish.
This project is quite involved and would require a track saw or table saw to make angled rip cuts along the length of the Tasmanian Oak to create seamless mitres.
If you did not have access to these tools and weren't comfortable with their use, I'd suggest contacting a finish carpenter for their assistance.
It's certainly possible to paint the post to match, but unfortunately, if you were to paint, it would cover the timber grain, losing some of the beauty of the timber.
If you wanted to paint the post, I'd suggest heading to your local store's Paint Desk and picking out some colour cards to take home and match up to your door. Once you've chosen your colour, head back to the store and speak to the team at the Paint Desk so they can mix up a suitable external paint in the colour of your choice.
Let me know what you think and if you have any further questions, please don't hesitate to ask.
Jacob
