# Forum Home Renovation Decking  Sanding before oiling deck

## nat1

I Need to sand merbau deck as have tried to clean old spa n deck finish that has gone blotchy .I used intergrain reviva to clean. Just wondering whether to use a hired drum sander or use an orbital or belt sander.I have had no experience with the drum sanders. I will be using intergrain ultradeck for the new finish.Any ideas appreciated.

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## nat1

May have answered my own question.Using the reviva /pressure cleaning has mostly removed the old finish except in some spots and around the edges (eaves protected). I think I need to gently sand, so a drum sander may be a bit harsh.Maybe I need a rotary sander and an orbital for the edges?

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## ringtail

Have you tried napisan ? Sanding a deck should be the absolute last resort. Its a massive PITA and puts a square edge on the decking boards which looks un natural. With the napisan, wet the area, apply the napisan solution, keep the area wet, give it 15 mins and then scrub the bejesus out of it, then pressure clean.

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## nat1

Thanks for the tip re napisan. What would be the solution strength for the napisan?

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## nat1

"1/3 of a container to half a bucket of water 
very scientific... dont mess with what works i figure" 
Found an old post from utemad........Maybe i should read more before asking questions!!

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## ringtail

Ahh, but how big is the napisan container and how big is the bucket ? I used a 20 lt bucket to which I added half of the biggest napisan container. Warm - hot water works best. Be careful aswell, the napisan is very alkaline and turns the deck really slippery. Pressure wash very, very well.

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## nat1

Will be trying the Napisan first, cheers ringtail......

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## ringtail

I wish I could take the credit, but I am merely a convert, turned by other pioneers on the forum. Good luck

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## jimj

I am sorry to crash in on this discussion and Ringtail I follow all of your advice as it is always great and spot on. However Napisan ( active ingredient sodium percarbonate) is an alkaline solution which is designed to disolve dirt and oil . Spa&Deck is an acyrlic and wont remove the coating. There is a stripper that is very hard to source and even more of a hassle to use than sanding. I can only recommend having the timber sanded. I would suggest having someone who sands daily just sand it then Nat can do the coating. Sanding will bring up the newest and brightest timber to recoat. Chemicals can only achieve about 60% of the same result (in my opinion). 
If you have never used a large heavy walk behind sander you can cause quite a bit of damage. Most sanders hired are drum sanders that have been fairly beaten up. The abrasives that you use are just as important and they sell you fairly crap abrasives with the machine. You still will have the problems of sanding the edges. They will generally hire you an edger which will tend to leave unwanted swirl marks. I use a 90kg Lagler hummel belt sander for the main body of the deck and finish my edges with a Festool 150 rotex sander and specialist abrasives because they work.  
Good luck 
jimj    restore-a-deck.com.au

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## ringtail

I guess you are spot on jimj, again. I guess that is one definite pro of using an oil based product though. Been an optimist ( read not wanting to sand ) I'd still give it a go - its only 10 bucks and a bit of time. But if sanding is required, take jimjs' advice and get a pro ( insured and licenced) and do the finishing yourself. Maybe you could go on a roadtrip jimj ?

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## nat1

Thanx guys. Sanding was my original thought for the removal.Just wondering if i should use the intergrain ultradeck or try traditional oil when the timber is ready.I have read a lot in these forums and i know Jimj uses a lot of Spa n Deck. I obviously let my deck go too long before recoating.I am also concerned about when and how to recoat in the future if the water based products penetrate and seal the surface of the timber.Surely I wont have to sand before every recoat? Any thoughts on recoating?

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## nat1

Have just read a big chunk of 'Cleaning and oiling your deck thread", there is a lot of great info there. I think i will stick with the intergrain ultradeck (already purchased but not opened yet). Looking back 4-5yrs when I 1st oiled my deck with S&D ,I realise that a few mistakes were made (I only know how to learn one way). The deck was drying whilst applying,then I remember rain soon after doing the job,A few years of direct sun and rain and presto 5yrs down the track the deck looks crap.
Ok,I will get it right this time,how hard can it be.
1) Prepare timber as to best knowledge
2) Use best product as to best knowledge
3) Maintain timber (recoat) at the perfect time in the future??????

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## jimj

I think you have worked this out fairly well. Probably the several biggest mistakes I see made is coating the decking without preparing it to the best state it can get to. After sanding if you hose it down with water and it looks stunning with all of the timbers true colours showing the timber is now ready.
If you recoat the deck and it loks patchy from whatever method you used in preparing it will look blotchy with a new coating as the coatings are designed to let you see some of the timbers grain. If you don't want to see the grains people use solid acyrlic paint(yuck). Virtually every manufacturer states in their maintenance paragraph says annual maintenance or earlier may be required. I tell my customers here(Sunshine Coast) that 3 coats will generally keep most foks happy for 12-14 months but I recommend 4 coats for totally sun exposed decks and that usually keeps folks happy for 15-16 months. In saying that I still say that they should inspect and recoat if needed annually. As long as you recoat before the patchiness starts it will recoat very well. I recommend 2 coats on the recoat. 
The other MAJOR mistake is coating the deck when the timber is too HOT. I know from November-April I can't coat from 9am to 3pm on full sun exposed decks. I do all of my coating in bare feet so I can feel the wood temperature. The wood can be warm but not hot as it will flash dry the product. When I am coating after sanding I have to organise my day to accommodate the temperature. Is it a slight inconvenience? I guess it is but I can say I have seen a lot of decks that were coated by both the homeowner and professionals who wore shoes and coated at 12 pm and it is just a mess.
If you keep up the coating annually you will not need to resand each time. I think you will find both aquadeck and ultradeck are water based products as is Spa&Deck. If a product cleans up with water and not turps it is a water based product. All will need the same approach.
I can honestly say no product lasts 5 years in full sun. If there is one out there that does I would like to become a shareholder in the product.   
Good luck
jimj         restore-a-deck.com.au

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## nat1

Gee, I wonder where you can get technical support for recoating decks from somebody who actually does it for a living? Here of course.
Well I tried to clean again with S&D Powerlift and Napisan in separate areas to prove outright that the deck will be sanded.Neither products lifted the old S&D.Looks like sanding.
I also spoke to Flood Support and was told that I possibly could feather in the new coats without sanding. I said that sanding would put my mind at ease, and the tech support said it would be my decision.
Thanks again to Jimj and others for assistance.

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## jimj

Nat, 
The thought of trying to feather Spa&Deck in my mind would be next to impossible and I use the coating on virtually a weekly basis. If I have the concept of feathering correct in my mind you would stain from the bad area up to the good and stop once in the good area. This would leave a distinct dry line and look terrible. With Spa&Deck you need to start at one end of the board and continue keeping a wet edge until you reach the other end. 
If you want to give me a call I am happy to explain over the phone the technique I use in coating. I think it would work with the other coatings you are considering. I would just have it sanded by someone who sands for a living and the coating and maintenance should be easy. 
jimj    0409260205

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## ringtail

Yep, have to agree. Sand that bad boy. I bet you will never let it get like that again eh.

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## nat1

Being an owner builder and fanatical DIYer , I decided to hire a drum sander for the deck.Used 40 grit then 60 to finish. The edger I hired was a bit of a mongrel but did the job.Will be taking the swirl marks out with my Ryobi orbital around the edges.
I am very happy with the result ,looks great,nice and level. Did take a while to get it flat.Only used a couple of sheets.The screws into my steel joists where a real bitch.A few snapped and heads flogged when driving down.They are a real pain to remove when they snap.Stop whinging, it is looking good.That was 55m,now just another 55m out the front to go.Then cleaning process and ready for coating.
The pro's certainly earn their money.

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## jimj

Great news and I am sure will be very happy with the final outcome. As much as everyone dreads the thought of sanding it is by far the best way to prepare. Once you have it sanded you can hose it down with fresh water throw the nappy san mix on for 10 minutes.You will be amazed at the amount of oil,dirt and tanin that shows up. Give it a rinsing and then when dry you are ready for coating. After that it is just the maintenance to keep up with. 
Any before,during and after photos will help others in the forum see what this method does. 
I am 75% through sanding 120m2 deck that is totally black-grey left untreated for 12 years. Not much fun but it is shaping up pretty good.
Now you know why I use a Festool Rotex random orbit on my edges. I wear out a set of very good knee pads every 4 months. 
jimj

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## nat1

Ok, I finished sanding, then I cleaned with the napisan mixture, I also cleaned again with an oxalic acid based deck cleaner to brighten the timber.I am now ready to oil.Hope the weather holds up. 
Before sanding, and after sanding /cleaning pics..........

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## jimj

Well done! You have prepared it to the very best level that you can. It will now coat to the best finish that the coating you use can offer. I am certain when it is all completed you will be delighted with all of the effort you put in. 
jimj

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## nat1

Decided to use Intergrain Natures Timber Oil Merbau tint.
The first coat sucked the oil up and left a purple tinge when drying.After the second coat went down I wiped off excess and once dryed it is a nice deep claret colour.
It was easy to apply especially on the merbau stairs and posts.
Will post pics soon.

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## nat1

Pics of oiled deck, stairs before oil and after....

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## bexi

I just finished putting my 2nd coat of oil on my new decki have built.
I started building the 42SqM deck in July and finished the construction a couple of months ago but procrastinated too long before oiling it and seeing as half the deck is undercover and half is out in full sun, it had noticeably gone grey outside. 
So i tried the napisan thing which did nothing.
I really didn't want to sand as i knew i would ruin the deck with a big walk behind sander (no experience) and didn't want to spend a couple of weekends sanding with a belt sander.
.... Well, i had no other option so I belt sanded the whole thing!
Mongrel of a job but reward is great....

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## nat1

Nice deck Bexi, sometimes sanding is obviously the only way.Probably the right decision to use the belt sander for that size deck. The drum sander I hired actually was quite easy to use once I got the hang of it. It was the hired edger that was a bitch of a thing to use. Either way the edges had to be done on hands & knees. My total decking front and back was about 110sqm so I really had no choice.

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## andyr

Just to chuck a spanner in the works, what if your deck has been nailed with a dome type nail? Sanding is not really an option!
Andy

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## jimj

If your decking has been nailed with dome headed nails to prepare it for recoating you have 2 choices. 
1. Use chemicals and highpressure water cleaning to prepare the wood surface.
2. Punch the nails nand sand.
I only punch nails and sand as this provides a better preparation ( my opinion) prior to coating.  
My only wish:  No More Dome Headed Nails as they only cause grief to many home owners 
My other wish: stainless steel countersunk screws 
jimj   restore-a-deck.com.au

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## andyr

Cheers jimj, I've taken the first option and it worked very well when I used a decent Karcher. Appreciate the advice, I tend to hesitate when I'm unsure. 
Thanks again
Andy

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## jimj

It is always pleasing to hear that your effort has been rewarded with a result that makes you happy. 
Well Done! 
jimj

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