Restoring a red cedar spa

[ajmuzza]

Hi guys,

wondering if you may be able to assist. I have an old spa which is clad in what i think is red cedar. i sanded and stained it with a cabots outdoor furniture product last year. looked kind of ok but a year later it's pretty ordinary. see pics attached. just wondering what is the best way to bring this back. Thinking of a diluted hydrochloric acid solution to try and clean the timber (no idea what the black is) then a sikkens semi solid stain.

any thoughts or observations would be appreciated.

cheers

andrew

[auscab]

Try some Oxalic acid first. Its sold at Bunnings now .

[aldav]

The timber is almost certainly Western Red Cedar. It's a timber from the East Coast of the US, not to be confused with Australian Red Cedar.

[Xanthorrhoeas]

Agree with both of the above. The black is most probably a mixture of oxidisation of the timber and resin as well as quite possibly some blue-green "algae" (not regarded as an alga any more but that is what most people know it as, if at all).

I have also purchased the oxalic acid on eBay as a white crystalline powder. If you aren't confident mixing it you can buy ready-made solutions under various trade names such as Dekswood, from most paint shops, though its much more expensive that way it is certainly more convenient.

If you want a natural-look oiled finish you could look at a marine oil called Deks Olje (available from Whitworths) that you put on wet-on-wet until the timber is saturated. I have found that lasts best out of all the uncoloured decking oils. Any timber out in the weather needs to be re-coated about every six months if oiled, though the pigmented oils can stretch that out to a year. Exterior paints will easily last 10 years, so are the lowest maintenance.

David

[Pete57]

We have spa with similar looking timber. It was my parents so fairly old. Last year I sander to bare timber and coated with marine varnish from Bunnings. Time will tell how long it lasts.

[China]

I have only ever use Aussie clear on my spa after 10 years still looks good

[Xanthorrhoeas]

Hi China,

What is Aussie Clear? Is it an oil or a polyurethane - other? How exposed to the weather is the spa? The exposure and UV levels make a huge difference to the longevity of a finish. My boat has a simple marine varnish inside (paint outside) but it is almost always enclosed with clears and canvas, so very little UV. Still needs refinish after 5 years!

[China]

It is a oil I have used it twice in ten years and yes my spa is semi undercover https://preschem.com/products/timber-protection/aussie-clear/