Thread: Marbau decking

No,i dont have any idea what has happened,but a belt sander maybe the go,unfortunately.

We have a large marbua deck,marbau posts and top rails,with stainless wires between the posts.
We built it about 6 yrs ago.

I was told to let the timber weather for around 3 months before oiling.

It is under a roof,so not in the weather,the edges cop a bit of rain and sun at times,but the roof does have a 1M overhang over three exposed sides of the deck.
Every three years or so i clean it off with Cabots deck clean,and oil it with Cabots Aquadeck.
Expensive stuff,but the deck looks very good.

Belt sander is too much like hard work. I have a heavy duty Makita one, and it just about drags you along the floor behind it.

I'd put it all through a thicknesser and take just a very light skim off one side (the top) of each board. Use a good quality thicknesser with a spiral helix if you can get one - will leave you with a perfectly smooth finish that doesn't need any sanding.

I've got one in my shed - but I'm a bit too far away. Local Mens Shed might have one if you don't.

I'm guessing the staining is merbau tannins and it seems it can take a few goes to remove by washing. I bought some deck chairs years back and they needed washing with oxalic acid to remove the tannins IIRC. How to Deal With Merbau Wood Stains - Softwoods - Pergola, Decking, Fencing & Carports, Roofing

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When you think about it .... sanding isn't going to work as this will be down in all the grains. So it'll look streaky even if you sand that crap off .... Maybe an electric plane is what you'd need ?

If you plane it you will most likely need to sand it again anyway, you will never get it to look good with just a planer especially being wider boards unless you thickness them which would mean pulling up the boards.
As others have said its most likely a combination of tannins and boards being oiled too early, allowing the boards to grey off before oiling helps with the tannins leeching out.
Your problem also looks like half the deck is getting more weather than the other half against the building, thats why the half in the weather has cleaned up better.
Your best bet would be to sand it back with a drum sander, you can hire them from bunnings or hire shops. If your not confident doing it yourself a floor sanding contractor would do it for you also.
You can do it with a handheld belt sander but be careful not to dig it into the timber, a good quality orbital with a 60g pad will work great also but id sand it with 180-240 afterwards to make it really smooth.
Good luck, lucky its not an overly large deck!
Cheera

Those black markings are the from the fasteners corroding. Gonna get worse unfortunately. What was used?

DL

I have that type of decking and have always used a turps based oil and worked well except second last time when it decided to rain and took a long time to dry.

This time, in my ignorance, I bought top of the range Wattyl Solar Guard decking oil (water based) Wattyl Solagard Deck & Timber Oil 10L | Mitre 10 - well what a disaster - is more of a paint - was drying while applying and despite two coats is very streaky and a normal oil will not be able to be used over the top. It has a hard finish but is really a paint.

Next year when I do my deck I think I will have to get a belt sander to remove the stuff I have now and go back to old style oil not paint. Oil goes on easily where to supposed good stuff is a pain.

Garry

Originally Posted by 101RRS

Next year when I do my deck I think I will have to get a belt sander to remove the stuff I have now and go back to old style oil not paint. Oil goes on easily where to supposed good stuff is a pain.

Garry

The Cabots stuff, water based i use is great,i paint it on and it soaks in like an oil.I give it three coats,has also lasted very well on the steps which are in the weather.
But it must be cleaned well before oiling,with their cleaner.