How to oil new deck with Woodprep on puttied screw holes?

Question

Hi Bunnings,

I applied ‘Feast Watson - Woodprep’ on screw holes and now it appears like a stain. Deck was installed couple of weeks ago and screw holes filled with Earl’s Merbau Putty. I’m planning to apply Cabot’s Deck and Exterior Stain on bolt holes and also where the stain mark from Woodprep area and afterwards apply oil based decking oil. Is this ok or will the stain mark remain. Thanks in advance for suggestions. Thomas

MitchellMc · Answer

Hi @Thyvelikakom,

I thought I'd just add that with any Merbau deck, it either needs to be naturally weathered for several weeks to remove tannins before oiling. Or, the process can be chemically sped up using the Feast Watson Wood Prep. So, you're on the right track, but as Jacob mentioned, you just need to wash the whole deck down.

Mitchell

JacobZ · Answer

Hi @Thyvelikakom,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

The reason you are seeing that shading is because

https://www.bunnings.com.au/feast-watson-1l-woodprep_p0711333

is an acid-based cleaner which is used to help remove the natural oils, called tannins, from the timber in preparation for coating. In the areas where it was used, the chemical reaction has taken place, and the natural oils have reacted as intended. The shading is present because you've only used it around the screws, so the natural oils are more prevalent outside these areas.

If you were to simply oil over it as it stands, there's a very good chance this shading would still be visible. Preparation for oiling a deck is all about getting a uniform surface before application, so from here, I'd suggest you use more of the Woodprep over the whole deck, ensuring you follow the instructions on the packaging closely. This will help to even things out before you apply your decking oil.

If there is still some shading, giving the spots a sand with some 180-grit sandpaper can help to even things out further. Just remember to brush things off if you do any sanding as sawdust will affect the absorption of your oil.

After preparation, check out

https://www.bunnings.com.au/diy-advice/building-construction/decking/how-to-oil-your-deck

for some guidance on the next steps.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob