Thread: Deck and Exterior Timber Oil

Hawk, oil finishes have advantages and drawbacks. The advantages are the speed of application and cost. The disadvantages are; you have to apply it a few times a year (at least), it can take quite a while to dry (a week) it doesn't offer a "shiny" surface and it doesn't really protect the wood very well.

The traditional mixture I use, which is about the same as everyone else's is three fold. A very dry surface will need soaking to "lube 'er up". These first few coats should be 50/50 pure tung oil and mineral spirits (I know you all call spirits something else down there) or pine gum turpentine. Apply this mixture over the cleaned, raw wood. Do this once every other hour, for a whole day. The following day switch to a 70% - 30% mixture of oil and spirits and apply at least 3 more coats. At the end of two days you've probably saturated the wood fairly well and now you need to "lock it down" with sealing coats. A few more coats of oil/spirits at 70/30 plus, which has a few ounces per gallon of "Japan Drier" added to the mixture. This drier will speed things up. You can skip the drier and use straight tung oil (no spirits) but you'll wait at least a week before it's tack free.

Tung oil is the no holes bared best at this protection. Linseed is the cheaper, not as good, 20th century alternative.

After all this work getting the wood soaked up and coated with oil, you'll be applying maintenance coats every 3 months in most climates, more as you get closer to tropical weather. If I use traditional oil finishes here in Florida, I need to apply a coat every other month to keep it in good condition. Since you're in Adelaide, you'll probably need to apply additional oil every other month if she sees much sun light.

Top this all off with the fact that the wood will eventually darken and burn from UV damage anyway. Not as fast as with linseed oil, but pretty quickly. All oil finishes need to be stripped off, from time to time, to get back to a lighter color and knock down the thick layer of dried oil on the wood.

I personally have little use for these types of coatings unless it's a traditional build and this type of finish is the only thing acceptable. For your handrails I'd strongly consider a good quality spar varnish or spar polyurethane. These form a much better moisture barrier and a hard film coating, that have real UV inhibiting filters in it, to protect the wood. These will last much longer and protect the wood much better.

Endeavour Oil is another good product to use , but you MUST do it regularly...don't be lazy or the wood will suffer and have to be redone all over again. It is very easy to use, I simply do a wet sand down with 360 before application , apply from a nice rag, and it takes less than an hour to do the rails on a 40 footer.

Use a hand squirty bottle to apply the water, same as you do when wet and dry sanding big jobs.

A big sponge can be useful with wet sanding. Just put it uphill from where you are working and water will trickle down over the area you are working for several minutes clearing residue and keeping everyting wet so it doesn't stick to the hull before you are ready to wash the area off.

MIK

Marine Spar Varnish is made for that task
I use the Feast & Watson brand on the wood fittings in my tinnie... has protected them really well so far. Not sure how well it would bring old timber back to life colour-wise (I have only used it on new timber), but it makes a good final protective coat

Hawk,

Just going back to your original question, the linseed oil will make the wood go black (as you now know), it is boiled linseed oil that is used if you intend to use linseed oil, but NOT on the boat. Boiled linseed oil is great for rifle stocks etc that get handled and sometimes bumped a bit, it accepts small dents without showing and can easily be re rubbed (by palm of the hand) as required.

I assume that your boat now has black ugly wood on board. Start by cleaning off the exterior with a solvent rag, then let it dry thoroughly and then use an oxalic acid mix with a surfactant (degreaser is fine) to clean down the wood again. Then let it dry and sand off the top wood grain. This is the only time that you would sand down the actual wood when varnishing as it is a destructive process, something that we usually avoud like the plague. After the wood is sanded, again use the oxalic acid mix to bleach the wood and hiopefully it will be about clear by then. Make sure that you always wash off the work when finished. When dry, a light sand with 240 or 360 fre cut paper, and you can apply the first coat of your desired finish.

In Adelaide you can finish bright if you like, it lasts quite well there (I lived in Adelaide for 4 years once), so that is the prettiest finish. If you still want to go with oiled finish, then ask around the marinas about Endeavour oil, I have used it extensively, and as long as you regularly do it, the wood stays clean and nice, let it go and you will be sorry again. It has to be redone at least 3 monthly intervals, I would recommend 2 months. Very easy to recoat, wash down with 360 w & d hose off, let it dry and apply with a rag, very fast to do and lovely result. It takes about 2 to 3 hours to do the normal plastic boat trim on a 40 footer (one coat).

Quite a few years ago now there was an article in Wooden Boat magazine in the USA about a a traditional cruiser with white hull and varnished upper works and the owner was fed up with varnish bubbling and blistering in the sun and so he decided to experiment with a Dutch product called Sikkens Cetop HLS. He believed that the durability of this product was based on the fact that it "breathed" and therefore, there was no blistering with moisture getting under the finish to cause the blistering.

Well, I then used this stuff and the results are pretty good. OK, it's not quite like varnish in the sense that it's not really high gloss but subsequently Sikkens brought out another product called TGL+ which is high gloss, and they state that this product has similar qualities to Cetol HLS. It is used with a coat or two of Cetol HLS under it, by the way.

I have used TGL+ but the boat I've used it on is still not finished, so apart from sitting out in the sun for quite a few hours when I'm working on the boat I can't really speak for it's longevity.

But, my experiences with Cetol HLS have been really positive,

There was a Bolger Micro built in Montreal by a Peter Lenihan?, called Lestat some years ago and all the bright work on that boat was done in Cetol HLS and it looks just great. Many years later the brightwork on that boat is still looking terrific - well, from the photos that I have seen on the net, anyway.

The cabin decks on my Michalak Scram Pram have been done in Cetol HLS followed by TGL+ and a photo is included in this post:



GregF

-you can build up a nice bright finish the same way,several gloss coats over an initial satin coat or two,very easy to apply and maintain.Ian Oughtred is a big fan of this for complete hulls,certainly looks good on my gunwhales.
Cheers,
Dave.