Nail-holes filler for merbau decking

Good day,

I'm refreshing my merbau deck - stripping all the boards, planing, sanding, cutting away cracked/rotten end and then re-arranging with what's left.
The issue that I'll be left with lots of old nail holes mid-board. While I don't expect it to have a significant impact on boards' life span, it's visually unpleasing so I think to fill them with a putty.

I'm finishing it with Cutek CD50 + colourtone which get sucked into wood and doesn't create any film. Hence the putty needs to have colour close to merbau or accept stain very well. And of course it needs to be fit for outdoor decking purposes with regards to sun and rain.

I also want to cover screw heads with the same putty - CD50 doesn't, again, create film so the stainless still heads will be catching on the eye which I'd rather avoid.

I did a quick research and there is seemingly little info on the subject. One thing I found is Earl's MulTfill which says its for exterior use and even come in merbau color (i'm not fussy colourmatch too much - it will never be perfect).

Any other recommendations?

Thank you in advance.

Rather than using wood filler how about wooden plugs?

Old fashioned recipe "Painters Putty" or "Glaziers Putty" will last probably longer than the modern "fillers." It wont look as good as the tinted "fillers" but has stood the test of time in many old homes.

Save your saw dust in a jar and mix it with an exterior grade glue (like pva) or even mix it with your finish if you are using one that will dry, I have found Cutek to be a very good finish but will not be able to mix dust with that finish you would have to use glue.

As someone with a LOT of merbau decking, I don't reckon anything will hold. Decking cops an absolute flogging from the elements- both thermal and moisture expansion/contraction. If you must go down this path, use something flexible that doesn't set hard. Maybe black Sikaflex Pro?

Dunlop 310ml Coloured Silicone - Travertine - Bunnings Australia

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Originally Posted by Mobyturns

Old fashioned recipe "Painters Putty" or "Glaziers Putty" will last probably longer than the modern "fillers." It wont look as good as the tinted "fillers" but has stood the test of time in many old homes.

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Can you share the recipe please?

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Originally Posted by Camelot

Save your saw dust in a jar and mix it with an exterior grade glue (like pva) or even mix it with your finish if you are using one that will dry, I have found Cutek to be a very good finish but will not be able to mix dust with that finish you would have to use glue.

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That's an idea! My deck is covered and with side walls (like a balcony) so doesn't get that much rain. Wouldn't cover screw heads with it (or I'll curse a lot if I ever need to clean the head to take the screw out) but fixed with my favorite Weldbond glue it should work.

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Originally Posted by Chief Tiff

Rather than using wood filler how about wooden plugs?

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I'll have to work out how to make about 1000 plugs first. I love my deck but that's too much :)

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Originally Posted by aeroden

Can you share the recipe please?

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I haven't made any in a long time now. Traditional glaziers / painters putty was made from raw Linseed Oil (though boiled can be used), whiting (calcium carbonate / calcite / limestone powder) and in some cases Zinc Oxide was also added. You basically add the Linseed Oil a bit at a time to a quantity of whiting and knead until you make the putty the consistency of "bread dough." It will keep in a sealed jar for months but won't keep as long as commercial "putties." You will find that making the putty a bit on the wet side will make it easier for hole filling, and dry firm mix for glazing.

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Originally Posted by aeroden

I'll have to work out how to make about 1000 plugs first. I love my deck but that's too much :)

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The plugs don't have to be fancy. We used to rip slivers of matching wood then simply drive them into the hole with a flooring hammer, like driving a wood nail. Use a framing chisel inverted (bevel down) to trim off excess.

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Originally Posted by Mobyturns

The plugs don't have to be fancy. We used to rip slivers of matching wood then simply drive them into the hole with a flooring hammer, like driving a wood nail. Use a framing chisel inverted (bevel down) to trim off excess.

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Wouldn't plugs absorb moisture through the end grain over time and start to stick out from the board?

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Originally Posted by aeroden

Wouldn't plugs absorb moisture through the end grain over time and start to stick out from the board?

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Nah; wood doesn’t expand along the grain very much at all. Across the grain is a different story… Any subsequent sticking out will be caused by the decking board shrinking as it gives up moisture but this will be measured in fractions of a millimetre.

How about traditional wooden plugs to cover the screws; and tapered plugs hammered into the nail holes? One company used to make a pointy tapered drill bit that you drilled into a blemish, then took a dowel of your plugging timber and put it into a pencil sharpener to get the matching taper. Bit of glue, wack it in and trim flush.

I don't know what the real answer is, but I'd suspect glued pegs is it.

If you were to make plugs, which strikes me as the best idea so far: DFM A2 Steel Dowel Plate 17 Holes MADE IN USA (Metric 17 Holes) : Amazon.com.au: Home Improvement

Drill the hole to something consistent, such as 5mm, cut strips of an existing board, bang them through this plate and glue the resulting dowels in with something like Titebond 3?

As for poking up with shrink/swell over the years, when one oils the deck the end grain will suck that juice in real fast. Regular maintenance might help?


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Originally Posted by Chief Tiff

Rather than using wood filler how about wooden plugs?

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I’m just in the finishing stages of a Deck for a client, would you like to quote for 700 ish screw holes too be timber plugged [emoji6][emoji6].

An it’s a small deck !!.

Cheers Matt.

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Originally Posted by Chief Tiff

One company used to make a pointy tapered drill bit that you drilled into a blemish, then took a dowel of your plugging timber and put it into a pencil sharpener to get the matching taper. Bit of glue, wack it in and trim flush.

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Still do!

Here is a local - Wooden Nails – Japanese Tools Australia

Here is an Ali vendor on some end-mills that might do in a pinch: VACK Carbide Ball Nose End Mills 3.175mm 4mm 6mm 8mm .... I did see some tapered drill bits on Ali, but can't seem to find them today. Will update if I do :) A-ha! It was Xtorque from SydneyTools! Sydney Tools - countersink-bits-wood


I've found nails are easy to make in some volume, but a little time consuming. One uses dowels (either lengths bought or made in a plate as in my other post) and use a drill and a jig on a sanding disk to shape them... let me find a picture.

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Originally Posted by Simplicity

I’m just in the finishing stages of a Deck for a client, would you like to quote for 700 ish screw holes too be timber plugged [emoji6][emoji6].

An it’s a small deck !!.

Cheers Matt.

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If a client is prepared to pay for it then they can have whatever they want. :D

Dad was a registered builder up until the mid 1980's. What we hated was a client who would want PC items listed at minimum but actually achievable $$$$ values to get a loan then want to "upgrade" to higher end appliances during the build. Dad would warn them up front but most could never understand that any variation over a PC item was at their cost. Every single variation by the client was signed for in a "day book" then billed as additional sums. So many arguments over that caper! Dad insisted that for fixed appliances that they pay the additional sum to the supplier before any appliance was installed.

Close… but the specific item I was thinking about is no longer made :(. It was Veritas’ “The Plugger”

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Originally Posted by Simplicity

would you like to quote for 700 ish screw holes too be timber plugged

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Certainly; I only charge a dollar-fifty per hole plus mobilisation costs to & from Bundy, providing that suitable plugging material is provided by the client. You might need to loan me a hammer. And a sharp chisel. And another sharp chisel in case I hit one of the screw heads with the first one.

:D

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Originally Posted by Chief Tiff

Certainly; I only charge a dollar-fifty per hole plus mobilisation costs to & from Bundy, providing that suitable plugging material is provided by the client. You might need to loan me a hammer. And a sharp chisel. And another sharp chisel in case I hit one of the screw heads with the first one.

:D

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Sounds fair an reasonable,I be in touch,[emoji6][emoji6][emoji6] maybe.

Cheers Matt.

Thank you very much for your valuable inputs. woodPixel - I'll definitely add that dowel banger tool to my wishlist.

I think at this stage I'll go with that Earl's merbau-tint putty mainly because I want to finish this project while it's still warm enough here in Melb to apply Cutek :)
It also the easiest one to undo/replace should something go terribly wrong with it (and again, my deck is more like balcony - covered and with waist-height side walls). I'll definitely post some pictures when I'm done and hopefully more in 12 months to see how it fares.

While I have your attention:
* What should be recommended gap size between boards? Couldn't find any references for 70x19mm merbau. For 90mm they recommend 3-4mm which sounds a bit too small. My wood is seasoned (I'm reusing the wood that was on the same deck before for the most of it). On my other deck (same materials) the gaps are around 4.8-5.5mm. Should I go with 5mm?
* Would 50mm screws will be enough? Or better 65mm? (My joists are some kind of old softwood, 50mm wide: Deck joist - Album on Imgur)


Thanks again for all your wisdom.

If your joists are in good condition with no rot from the previous holes then 50mm should be OK, but you will need to go deeper if the fibres are soft and have started to rot. I use G-Tape on top of the joists before laying the boards. Also I bought some deck clamp attachments for my Irwin type clamps from Bunnings, see link for how they work Quick Tip: Clamping Deck Boards With An Irwin Mod || Dr Decks - YouTube

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Originally Posted by Camelot

If your joists are in good condition with no rot from the previous holes then 50mm should be OK, but you will need to go deeper if the fibres are soft and have started to rot. I use G-Tape on top of the joists before laying the boards. Also I bought some deck clamp attachments for my Irwin type clamps from Bunnings, see link for how they work Quick Tip: Clamping Deck Boards With An Irwin Mod || Dr Decks - YouTube

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Joists are still solid. And yeah, g-tape all the way! : Joists with g-tape - Album on Imgur
50mm it is then.
If I become paranoid I'll mb put 65mm on the ends of the boards.
Another thought for 50mm is if in the future I will need to replace a board, I can then switch to 65mm screws for it.

And I'll be going with 5mm gaps after all.