How to sand and varnish over hardwax oil coating?

[KariB199]

Hi There,

I recently purchased a Practa 2200 x 600 x 26mm Acacia Timber bench top to use as a desk 

The packaging states that it’s already finished with a hard wax oil coating but it’s still a little grainy and I’m wanting a smoother finish.

I’m wanting to sand and varnish it but am unsure which varnish is safe to use as it has a hard wax oil coating. 
Id like to preserve the colour of the timber and don’t want it to yellow. 
Im thinking about using the Cabot’s Matt Water based Cabothane Clear interior varnish, is this safe to use since it has a oil coating?

If I can use a varnish what brush/roller would you recommend I apply it with

Also wondering which grit sandpaper to use and if I can use a hand sander?

Thankyou in advance!

[MitchellMc]

Welcome to the Bunnings Workshop community @KariB199. It's wonderful to have you join us, and many thanks for your question about coating a Acacia benchtop.

The Practa 2200 x 600 x 26mm Acacia Timber Benchtop is designed to be coated with Hard wax oil. Applying Cabot's 250ml Matt Water Based Cabothane Clear Interior Varnish would differ from the manufacturer's care instructions, so the results would really be unknown. As far as I'm aware, no testing has been done to confirm whether the varnish would be compatible, so I can't give you a concrete answer. However, in my experience, I would be of the opinion that it will be fine. You might like to do a test section on the underside to ensure compatibility. Apply a small amount of the varnish and allow it to cure fully for a few days. Apply masking tape onto the area and then rip it off. If the varnish is not pulled off with the tape then it's a pretty good indicator that coating with varnish will work.

Regarding non-yellowing varnish, Cabot's water-based is a great choice. I typically apply it with a short nap roller, sanding lightly with 320-grit in between coats. To remove the initial grainy texture, you might like to use 240-grit.

Have you considered lightly sanding the benchtop back to remove the grainy timber fibres and applying a Hard wax oil, or are you looking for a varnished appearance?

Please let me know if you have any questions.

Mitchell
 

[JasC0412]

Hi There, 

Have you had any success with applying Cabot’s Matt Water-based Cabothane Clear interior varnish? I'm looking to do the same thing for my new desk.  If so were there any complications?

Please let me know.

Thanks. 

[EricL]

Hello @JasC0412 

Welcome to the Bunnings Workshop community. It's wonderful to have you join us. 

Let me tag @KariB199 to make them aware of your question. It would be interesting to find out if the coating succeeded in staying on. Otherwise, it might be necessary to sand the surface and remove the oil coating in order for the varnish to anchor onto the timber surface. 

If you need further assistance, please let us know.

Eric