Wood treatment, what do you think?

[Jedadiah]

OK Guy's here's the deal,

walking around the DIY shop and i ask my Mrs to get me some Linseed oil. She comes back and asks if i need boiled or raw?

Now it's your turn, do i want boiled or raw? Whats the difference?

And to cap it all off, she asks if Teak oil will do instead as we already have this at home?

Well, will it?

By the by, it's all to do with treating wood scales. Your advice and experience would be very much appreciated!

 

[Shinken]

You want the boiled variaty, What wood are you treating?

Danish oil is another option and if you have lots of knives you wish to treat CCL is the best

 

[Snufkin]

You want the boiled variaty, What wood are you treating?

Danish oil is another option and if you have lots of knives you wish to treat CCL is the best

You want boiled, and mixing it 50/50 with turpentine (not turps sub) will help it to penetrate the wood better.
I tend to use danish oil alot these days though.

 

[TheGreenMan]

Jed,

During the last few weeks I’ve been using a good quality (Robert Sorby) Danish Oil on some birch handled Moras. And I’m very pleased with the results. I applied about six, rather generous coats (with about 12 hours between each coat), to the handles with a very soft-haired artist’s brush, and the build up of resins in the Danish Oil have produced a highly sealed finish on the wood, that provide a very good grip even when with wet hands and handle.

I found that the thinner finish produced with a traditional wipe on with a cloth, leave for ten minutes or so, and then wipe off the excess with a cloth, method was leaving the handles feeling a little slick (not so good on a knife without a finger guard).

A cold pressed, organic boiled Linseed Oil, is worth consideration for a food-safe finish, as would be an organic Tung Oil (you could also use a high quality citrus oil, such as Orange Oil, to use as an alternative to turpentine as a food-safe solvent to aid deep penetration of the wood – Tung oil needs to be flooded onto the wood for deep penetration, rather than applied to the surface in relatively thin layers, like Danish or Linseed would be).

And Linseed and Tung don’t contain any resins like Danish, so the layers build thinner and slower.

Incidentally, Camellia oil is a non-drying, food-safe finish that can be applied to carbon blades to help prevent rusting (it’s used to oil the blades of Japanese kitchen knives).

Best regards,
Paul.

PS: the reason for using boiled Linseed as opposed to raw Linseed, is that the boiled type dries faster.

Word to the wise - Linseed oil can in some circumstances cause spontaneous combustion of cloths or rags used to apply the finish. I used to make paints that contained high levels of Linseed, and I can confirm that rags that became soaked in Linseed did at times become very hot, and I do mean hot. The rags should be laid out flat to dry before disposal in household refuse.

 

[JM]

I use home made "danish oil" obtained by mixing pine rosin to boiled (and boiling) linseed oil. I find it often better than tung oil, as it does not give a plastic grip, but a good grip.

Before:

After: (two days soaking)

 

[TheGreenMan]

Beautiful work on the handle, JM. And useful information too. Thanks.

Best regards,
Paul.

 

[JM]

You're welcome, I collect the resin from a sick or wounded pine, it is quick to make one kg this way.

The following must be done in open air:

Then heat small quantities of oil and throw 1/3 to 1/2 resin in it, bring to boil, heat until the resin has dissolved, take care, because wild pine resin, even if hard, contains good amounts of turpentine which takes fire easilly (that is why you do 300 ml at a time, not more, 300 ml burning can still be blown away...) When resin is melted, filter into a cloth to remove bits of bark an other incrustated (and bow boiled) ants

Then make a few tries and find the concentration you want, for me it is arround 1/3.

When applying it is thicker than linseed oil, but if applied slighly warm it regains some fluidity. It dries in a few days for thin coatings, 3 weeks max for long soaks.

When cooled, it forms a kind of white colloidal suspension that sinks into it, but wich can just be ignored. to avoid the suspension it is needed to dillute more.

As I said, it smells good, penetrates well, seals the wood in one application two at most, hardens the wood locally, gives a good grip. Only down effect is that it attacts dirt, and gives a die effect, so you must let it dry before use, and even then it will darken in time, gathering dust.

Pine resin also dissolves in alcool (better than in oil, actually), and can be applied as an oil using this solvant, drying in less than one hour then.

 

[TheGreenMan]

Very useful post, JM. Thanks again

Best regards,
Paul.

 

[Jedadiah]

Thanks fella's,

your experience and advice is very much appreciated.

Greenman,

i'm very interested in the 'organic' oils you mentioned, particularly the tung oil. I thought that Tung oil was poisonous but if it is recomended to be used for handles that will be used for food prep then it can't be can it?

When you said it needs 'flooding' do you mean it would be better to sit the handle in a bath of this oil for a period of time? If so, how long? Are there any suppliers you could recommend? Is it suited to particular types of wood? I intend to use different types of wood for the scales i will be making, i'm actually going to be using Leopard wood for the present project but i also have a Mora with English walnut scales at the moment that could do with finishing.

My intention is to make bushcraft knives that can be used for food prep so organic certainly seems to be the way forward.

Thanks again.

 

[TheGreenMan]

I’m finding organic tung oil difficult to source. Organic linseed oil is easier to find in the UK (flax oil). The product below is described as ‘pure’ therefore it should contain no thinners or chemical driers that might make it harmful if ingested. It’s recommended for wooden work surfaces in kitchens, and it can also be used on wooden chopping boards used in food prep. So I think it’s safe to say it’s ‘kosher,’ so to speak.

http://www.agwoodcare.co.uk/show_product.php?id=87&gclid=CPjzlpbHposCFQrlQgodtEBijA

‘Flooding’ a finish is primarily a method of finishing wooden floors with PURE tung oil, where one starts with a highly diluted coat of oil for the first application, and with each session (day), increasing the proportion of oil, which is then waxed when fully hardened. As a general principle, many thin coats are better than fewer thick coats (probably because the oil has to oxidise and harden. If a thick coat is applied it will take much longer to harden, and may even remain sticky – something like the deliberately over-thick coats I put on the birch handled Moras as described in post #4 - and this may allow dirt etc to become embedded in the surface, which is probably not what we’re looking for in a food-safe finish).

If you wanted to try a ‘dunk’ method, if you’ve got any spare wood that you’re going to use for the knife handle, you could try submerging it into a 1 part oil/2 parts solvent mixture for say, an hour, and wiping it off, and then saw it in half just to seen if it has penetrated right to the core. If is has, then wait for a few days to see how it manages to evaporate the solvent and harden off the oil.

Usual method:

The principle at work is that liberal, multiple coats are applied so that the oil/solvent mixture is absorbed deeply into the wood and until a glossy coat is sitting on the surface and stays on the surface for around 30 minutes or so. If you have any dry spots appearing on the wood, then you need to keep applying the mixture until the wood has a glossy film over the entire surface and keeps that glossy finish for around 30 minutes. Then any excess mixture is wiped off the surface. This is then left to dry for around 12 hours.

Next day you start the same process as described above. If on the first day one started with 1 part oil to 2 parts solvent (which is recommend to aid penetration of dense woods), then the second day it should be 1 part oil to 1 part solvent. On the second day you should notice that the glossy stage is reached a little quicker. Again, when the glossy stage has been reached and it stays glossy for around 30 minutes, wipe off the excess. Leave for twelve hours to dry.

Third day, same routine.

If on the fourth day the wood is still absorbing oil, keep following the routine until the wood will absorb no more oil.

Now it needs to be left for about a week to allow the oil to harden off (oxidation process). Then you can buff it to a soft sheen with a soft cloth, and if one were finishing a floor one would wax and buff it instead.

These are general principles only, and the actual method will probably vary according to the density of the wood, the wood’s own natural oil content etc.

It’s probably best to follow the manufacturer’s instructions for the first time you use the oil.

A noteworthy point is that one should use an oil that is described as ‘100%’ or ‘pure’ Tung oil, as there are other types of Tung oil used for wood finishing that will contain chemical additives that may not be food-safe, which will require a different method of working and give a high gloss finish, which would not be wanted for this kind of use.

Now then, the Citrus Solvent. Slightly more difficult to get hold of in the UK! I’ve used Pure Orange Oil that can be bought at food stores to make orange tarts (orange version of the classic Tart au Citron…but I digress! ) it looks the same as the Orange Oil Solvent, but personally I’d stick with the stuff that’s known to be the right stuff to use, albeit more difficult and expensive to obtain (but hey, whoever said that bushcraft was easy, and an inexpensive hobby? ).

The only supplier that I know of that sells small quantities of both Tung Oil and Orange Oil is in Germany:

Lignea Chinese Tung Oil, 1 liter:
http://www.feines-werkzeug.de/product_info.php/info/p207_Lignea-Chinese-Tung-Oil--1-liter.html

Orange oil, 250ml/1 litre:
http://www.feines-werkzeug.de/product_info.php/info/p297_Orange-oil.html

And they have organic Linseed too (this one is ‘sunbleached’ which will dry quicker than ‘raw’):
http://www.feines-werkzeug.de/product_info.php/info/p209_Linolja-Swedish-Linseed-Oil--1-liter.html

+ shipping to the UK @ 17.00 EUR


Have fun!

Best regards,
Paul.

 

[TheGreenMan]

Here’s a URL for lateral thinkers and/or those who take wooden flutes into the woods, be they made of Leopardwood, or not:

http://www.flutes.fsbusiness.co.uk/oils.html

By the way, I put my money where my mouth was and ordered some of those oils from Wolfknives. They’re so nice, it’s all I can do to stop myself drinking them. Incidentally, postage to the UK from Germany was 4.95 EUR which is pretty good value for a parcel around 4kg.

I’ve oiled several knife handles (various - dunked for 2 to 4 days), and no disasters so far. Although, I have to say that in terms of durability and hardness of finish (if one were using a wood of low-ish density), then a homemade ‘wiping varnish’ such as JM described, would be the way to go.

Best regards,
Paul.

 

[brancho]

I used danish oil and soaked my last knife overnight wiped of the excess and buffed it with a soft cloth as dried over a few days.
The results were great.

I do not think you need to worry too much which finish you use as far as food safety is concerned as the oil will be dried before use IMO.

 

[TheGreenMan]

Yep, as I understand it the food-safe thing is a bit of a ‘red herring’. Even if you use bog standard boiled linseed oil with metalic driers, once the oil has cured they are locked into the film and rendered harmless, unless you actually eat the handle.

But I just like mucking around with the fancy stuff

Best regards,
Paul.

 

[Sickboy]

Read this post with interest as i'll be using a wood handled knife as soon as mines put together, but i have a question that probably doesnt warrent another thread, do you need to treat stabalised wood? I would assume not as it's inpreganated with epoxy etc but was curious none the less

 

[Squidders]

nope... stabilised wood needs no treating... left alone, it'll probably outlast the blade

ps. I use danish oil on mine and i'm a handle licker

 

[TheGreenMan]

nope...ps. I use danish oil on mine and i'm a handle licker

Homemade, or 'off the shelf', Squidders?