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Thread: Linseed Oil Putty/Seam Compound Definitive Recipe

  1. #1
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    Default Linseed Oil Putty/Seam Compound Definitive Recipe

    In researching traditional seam compound recipes I came across this specification which does not seem to have been posted here before. It may be useful to someone.

    S.I. No. 241/1950 - Standard Specification (Linseed Oil Putty) Order, 1950.


    http://www.irishstatutebook.ie/eli/1.../made/en/print
    - Chris

    Life is short. Go boating now!

  2. #2
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    Default Re: Linseed Oil Putty/Seam Compound Definitive Recipe

    Interesting reading, thanks.

  3. #3
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    Default Re: Linseed Oil Putty/Seam Compound Definitive Recipe

    interesting indeed, ...
    that 1950 Republic of Ireland should be using metric weights and measures, 20 years before England Wales Scotland, yet no apparent allegiance to Europe yet.
    That there is no apparent distinction between raw, refined and boiled Linseed oil , when there are significant differences in other fields where linseed oil is used,
    And hey, what's gold size...? I know, I work in this field, but it assumes everyone else is party to this highly specialised area. It's a mordant for gilding in signwriting on glass, but not much else . Where's Jay Greer. he should know
    'C'est la vie' say the old folks it goes to show you never can tell

  4. #4
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    Default Re: Linseed Oil Putty/Seam Compound Definitive Recipe

    Quote Originally Posted by jonboy View Post
    interesting indeed, ...
    that 1950 Republic of Ireland should be using metric weights and measures, 20 years before England Wales Scotland, yet no apparent allegiance to Europe yet.
    That there is no apparent distinction between raw, refined and boiled Linseed oil , when there are significant differences in other fields where linseed oil is used,
    And hey, what's gold size...? I know, I work in this field, but it assumes everyone else is party to this highly specialised area. It's a mordant for gilding in signwriting on glass, but not much else . Where's Jay Greer. he should know
    The tests for compliance will have been done in the Irish equivalent of the UK's Laboratory of the Government Chemist, hence the use of SI measurements.

    Nick

  5. #5
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    Default Re: Linseed Oil Putty/Seam Compound Definitive Recipe

    So the chalk that is used will be like French Chalk ie something like Soapstone? Not like the chalk you use for writing on a blackboard?

  6. #6
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    Default Re: Linseed Oil Putty/Seam Compound Definitive Recipe

    The specification addresses the component materials of the putty variants, as well as the testing methods and benchmarks to verify conformity.

    The relative concentrations - mass and/or volume - of the component materials, nor the processing steps to blend these together are excluded, so it would seem that the recipe part goes missing.

  7. #7
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    Default Re: Linseed Oil Putty/Seam Compound Definitive Recipe

    I made my own red lead putty to pay the seams below water on my then 112 year old Kauri planked yacht.
    There was nothing to scientific regarding quantity ratios, I just went with what looked and felt (consistency) right.
    I was not even sure it would work but, I thought that some red lead must be better than none at all.

    IMG_0492.jpg

    As you can see by the label, the red lead content is quite high.807 gms/Litre.
    Mixing the above oil based paint into linseed putty resulted in a rather runny mixture.
    This mixture was then thickened with a wallboard repair powder which mainly consisted of calcium carbonate (chalk).
    I mixed the powder in and kneaded it by hand until the desired consistency was reached. This was determined by the putty mixture not sticking to my chemical resistant gloves.

    IMG_0993.jpg

    The seams above the new planks were payed before work on the new planks had begun.
    This was to allow the putty to skin before painting. The paint helped to stop the putty and planks from shrinking to much.
    Just to note, the hull is made up of two skins. The inner planks run at approximately 45 degrees.
    Before fitting the outer planks, a thick paste made from the red lead paint and linseed putty was liberally spread over both adjoining surfaces of the planks to alleviate voids.

    IMG_3424.jpgIMG_3425.jpg

    This is the result when first hauled out, 16 months after relaunching.
    The boat had been out of the water for 18 months prior to launch so some squeeze was expected.
    Small crustaceans and some other small grub had feasted somewhat on the seams close to the waterline, lower seams were unaffected.
    So the lead content was maybe to low (they are not dead...yet) and the linseed oil content was maybe to high (nutritious).
    The squeezed putty, which was still reasonably pliable, was removed and any spots retouched with more red lead putty.
    The second time the boat was lifted ,12 months later, there was no sign of any seam damage or since on subsequent lift outs.
    Janet has been in the water for 5 years now. The putty finally stopped any significant movement about 18 months ago.
    The hull does not leak, there was a small one forward initially but that stopped after 6 months. Somewhere up in the rudder trunk does though. Will get to that one day.

  8. #8
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    Default Re: Linseed Oil Putty/Seam Compound Definitive Recipe

    Nice run down Mike1902 on your experience with DIY putty, applying it to the underwater seams and observing/tending to it over a 5 year span. So retouching does work !

    On my motor cruiser, the hull seams above-the-water-line are the ones that call for attention due to squeeze out accompanied by tell-tale signs on the overcoat (paint).

    This could be due to my boat living substantially more on the hard than on the water

    IŽd like to add : I am currently redoing the above-the-water-line hull seams, with bees-wax/linseed oil - 50:50 (mass) amalgamated in a double-boiler - subsequently mashed with a filler composed of 70% Titanium Oxide and 30% Whiting, with a dash of red-led primer poured in to achieve the desired consistency; the seam putty has recently skinned and the seams have never felt so silky smooth to the touch !

    The red-lead primer applied over the skinned seams has adhered more firmly, hopefully the subsequent coats and the overcoat will as well.
    Last edited by carioca1232001; 11-09-2020 at 08:08 PM.

  9. #9
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    Default Re: Linseed Oil Putty/Seam Compound Definitive Recipe

    Mike, I have to say that I think that's the best post I've ever seen on traditional seam compound. Excellent information. And a nice looking planking job too! Now I just wish I could see the rest of your boat...
    - Chris

    Life is short. Go boating now!

  10. #10
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    Default Re: Linseed Oil Putty/Seam Compound Definitive Recipe

    Quote Originally Posted by carioca1232001 View Post
    Nice run down Mike1902 on your experience with DIY putty, applying it to the underwater seams and observing/tending to it over a 5 year span. So retouching does work !

    On my motor cruiser, the hull seams above-the-water-line are the ones that call for attention due to squeeze out accompanied by tell-tale signs on the overcoat (paint).

    This could be due to my boat living substantially more on the hard than on the water

    IŽd like to add : I am currently redoing the above-the-water-line hull seams, with bees-wax/linseed oil - 50:50 (mass) amalgamated in a double-boiler - subsequently mashed with a filler composed of 70% Titanium Oxide and 30% Whiting, with a dash of red-led primer poured in to achieve the desired consistency; the seam putty has recently skinned and the seams have never felt so silky smooth to the touch !

    The red-lead primer applied over the skinned seams has adhered more firmly, hopefully the subsequent coats and the overcoat will as well.
    I was told a number of years ago by a very experienced boat builder not to worry to much about the finish on the hull after a recaulk and putty, especially if the boat had been out of the water for a while and had dried out somewhat.
    "It is going to move" he said, "give it a couple of seasons and let it settle down". No truer word spoken.

    IMG_2493.jpg

    That's exactly what happened. The photo above is just before the first lift out 16 months after relaunch.

    IMG_0485.jpg
    The putty in the seam shown is just your regular linseed putty.
    This is what it looked like initially when first payed.
    The hull had been completely recaulked and was primed prior to putty application.

    IMG_1018.jpgIMG-1563 (1).jpg

    The above left photo is what the hull looked like pre relaunch after about 14 months on the hard. As you can see the planks are quite obvious, the seams are exaggerated a bit by the light angle.
    The above right photo was January this year. The seams have now blended in after finally stabilising, which allows a better finish to be achieved. This was the third hull paint in since launching in September 2015.
    I have used normal Alkyd primer and paints on the hull. There has been no bonding problems anywhere.
    When Janet is hauled out next, I plan to give the hull the wet and dry treatment and finally get that finish I want.
    Last edited by Mike1902; 11-10-2020 at 03:43 AM.

  11. #11
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    Default Re: Linseed Oil Putty/Seam Compound Definitive Recipe

    Quote Originally Posted by cstevens View Post
    Mike, I have to say that I think that's the best post I've ever seen on traditional seam compound. Excellent information. And a nice looking planking job too! Now I just wish I could see the rest of your boat...
    Thank you Chris.
    I plan to write a thread here on the forum one day about Janet's makeover but a dinghy is taking up my time at the mo.
    Here's a few pics from the past five years.
    Cheers,
    Mike.

    FullSizeRender(10).jpgFullSizeRender(13).jpgIMG_3920.jpgFullSizeRender (66).jpgIMG_3922.jpg

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