Boiled linseed oil inside flotaton chambers

Discussion in 'Materials' started by minno, Sep 24, 2015.

  1. minno
    Joined: Aug 2014
    Posts: 90
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Canada

    minno Junior Member

    Hi all

    couple questions about BLO

    will boiled linseed oil work inside flotation chambers?

    will it dry (or whatever it does) if the chamber is sealed up?

    Will silicone stick to oiled wood?

    Minno
     
  2. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 489, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    What are these chamber made out of? Why oil the inside? Why use silicone anywhere except on a port or light seal?
     
  3. Petros
    Joined: Oct 2007
    Posts: 2,936
    Likes: 148, Points: 63, Legacy Rep: 1593
    Location: Arlington, WA-USA

    Petros Senior Member

    boiled linseed oil cures by absorbing oxygen molecules into the polymer matrix creating a cross linking of the polymer chains. As long as it does not run out of O2 it should cure, but if it has a solvent or thinner in the mix it will have to outgas as it evaporates.

    Boiled linseed oil is the tough base of most oil based paints, but by itself has no UV resistance, nor it is fully waterproof, and is typically slow to cure. It will also not prevent mold, it could even feed mold spores. Note that it really cures by cross linking with oxygen, it does not "dry" (evaporate solvents).

    I would think anything you put in a sealed compartment would need to be vented, except perhaps epoxy. Epoxy has no uv protection anyway, but inside a chamber that may not be an issue. BLO is much less costly of course, perhaps if you add japan dryer to it it will cure faster and sealing it up will not affect it. You could mix up your own low cost finish that is mold resistant, cures fairly fast, and would work okay if out of the sun light.
     
  4. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 489, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Japan drier will help to a get BLO to cure, but the addition of a vehicle will help, such as mineral spirits or gum turpentine, though as pointed out, it'll need to outgas the vehicle.

    On plywood this is a waste of time and very little protection can be offered. Inside a chamber, it's unlikely UV will be an issue, but paint would be a far better choice, in every way you look at it.

    I use tinted epoxy inside of chambers or places I'll never be able to or it will difficult to get again. Inside air chambers during construction you can easily paint, before the last side goes on, but typically to get in there again, you'll have to use a 6" deck plate or something, so anything short of low yield hand grenade full of paint, just will not do. This is why I use tinted epoxy. The material inside the chamber needs to be coated anyway (usually) and this will likely be the last time it ever sees any color, so . . . The epoxy will live a lot longer than paint and waterproofs the insides too.
     
  5. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,401
    Likes: 1,026, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Boiled Linseed oil ? I reckon if I went looking for that, I'd just get a blank look from the sales people these days ! I think raw linseed oil is still available here, which is the one used in putty, and to keep wooden tool handles etc from cracking. It is highly penetrating and readily migrates into the timber grain. In my limited understanding, the boiled variety was more used as a pigmented gloss finish. Linseed oil has always seemed to me to attract mildew, it loves the stuff ! However, back in the distant past when it was the basis of paints, the pigment (white lead) seemed to keep it at bay.
     
  6. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 489, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The only difference between raw and boiled linseed oil is the impurity content and some metallic driers. Raw linseed is just that, smashed flax and takes weeks to dry. Boiled linseed generally will cure in 24 hours, unless it's really humid. Boiled can help paints gloss retention and flow out properties and it's commonly used to polish wood, once a significant build up is present. It turns blackish gray with UV exposure and really doesn't protect anything well. Unless a traditional Dutch oil coating is what you're after (in which case tung oil is far better), there's no good reason for linseed oil on anything. Not that it can't be used, it's just not the best or even close to the best thing available. The cheapest paint will work better.
     
  7. philSweet
    Joined: May 2008
    Posts: 2,487
    Likes: 280, Points: 83, Legacy Rep: 1082
    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    Actually, there is a difference. Heating the stuff for a few hours-days will convert it chemically into "stand oil". Boiled linseed oil has a percentage of this goop in it. It provides a glossy elastic finish. The driers are catalysts and ph buffers - white lead is one catalyst, but needs something to raise the ph a bit.

    BLO is basically crappy Alkyd paint. The epoxy I use is about the same price and isn't flammable <edit. so I looked it up, technically, it is not flammable, it is combustible>>
     
  8. minno
    Joined: Aug 2014
    Posts: 90
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Canada

    minno Junior Member

    Hi All

    I'm building a pair of outriggers out of coroplast on a wooden frame at the moment and thought I'd use some BLO I have on hand for the frame as well as inside a flotation chamber on my sailboat, never thought of mildew, guess I'll use paint and give it time to cure.

    silicone is one of the few things that'll stick to coroplast, I'll be using it as a sealant in the outriggers.

    minno
     
  9. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,401
    Likes: 1,026, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Linseed oil paint (I'm told) was often helped to dry in a convenient time with the addition of the drier Terabene, but apparently that created a coating that went too brittle over time, and was inclined to crack too readily, when used over exterior timber. And produced a vast amount of dust when it then needed to be sanded !
     
  10. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,401
    Likes: 1,026, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Eating Linseed oil (flaxseed) is all the rage these days, but it doesn't taste that good !
     
  11. Petros
    Joined: Oct 2007
    Posts: 2,936
    Likes: 148, Points: 63, Legacy Rep: 1593
    Location: Arlington, WA-USA

    Petros Senior Member

    Raw linseed oil takes many weeks to cure, back in the day they used to "boil" it in a pressure cooker that altered the chemical make up of the hydrocarbon chains allowing it to cure when exposed to oxygen. They do not boil it any more, it is too costly, so they add chemical "dryers" (such as Japan Drier), which are typically metal compounds that also sever to accelerate the curing (or absorption of O2 into the polymer matrix).

    You should NEVER consume boil linseed oil because likely it has the heavy metal and cheimical dryers in it rather than actually being boiled.

    The faster the mix cures, the harder and more brittle the finish becomes. A slower curing finish should be less brittle and hold up longer on a wood surface. But takes longer to cure.

    It is still used as the base for oil based paint, but it has a lot of other compounds added to it to make it a much better product. I tried mixing my own once, and gave up on it. The finis took a log time to cure, and it was "fuzzy", very dull and rough. the least expensive commercial clear oil based finishes were far easier to use and gave a much better finish than any homemade concoction I could develop. One of the good things about big companies, they have whole RnD departments that work this stuff out and than have their factories mass produce near ideal mixtures of these compounds at very reasonable prices.
     
  12. hoytedow
    Joined: Sep 2009
    Posts: 5,814
    Likes: 376, Points: 93, Legacy Rep: 2489
    Location: North of Cuba

    hoytedow Carbon Based Life Form

  13. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,401
    Likes: 1,026, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

  14. minno
    Joined: Aug 2014
    Posts: 90
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Canada

    minno Junior Member

    ever try cod liver oil?

    minno
     

  15. hoytedow
    Joined: Sep 2009
    Posts: 5,814
    Likes: 376, Points: 93, Legacy Rep: 2489
    Location: North of Cuba

    hoytedow Carbon Based Life Form

    It is better than castor oil!
     
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.