Filling cracks

Discussion in 'Woodturning Discussion Forum' started by olaf Vogel, Dec 4, 2016.

  1. Nicholas Licata

    Nicholas Licata

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    Lately, I've been embracing the defects if they can't be hidden. Here is a Japanese Wabi-Sabi example I hammered silver solder to the shape of the cracks hammered them in with CA glue and finished sanding on the lathe.

    wabiSabi1.jpg
     
  2. olaf Vogel

    olaf Vogel

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    Joe, what brand of epoxy do you use?
    The HD version I tried is terrible. The West Systems is good but takesovernight to harden.
     
  3. Mark Hepburn

    Mark Hepburn

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    Joe, I use the five minute epoxy for almost everything. Do you use the thirty mainly for the longer working time or are there other benefits to it?

    Just curious about whether i might want to change what I'm using.w
     
  4. Leo Van Der Loo

    Leo Van Der Loo

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    I find cracks stay cracks, fill them accentuate them or whatever, you can’t make them disappear, so your best bet is to somehow make them look like natural inclusions most times.

    I’ve done the Brass wire stitching in a plate like turning and it worked OK in that piece, but if needed, (but I try and usually succeed to prevent splits) as there are times when the wood itself has some shortcomings that need to be filled, than ground coffee is my usual material to use, tried Epoxy with the materials, but find the restriction of the amount of foreign material that can be added and have it still work not to my liking, especially if one is using something like Copper or Brass powder, where Iwould want to have that material to really show as if it was Copper etc..

    So I use the fine coffee grind and pack that solidly into the opening, and then carefully let CA fill the gaps between the ground material, the outcome of that I do like better than the mixed with Epoxy goo
    Brass wire stitching.jpg
     
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  5. Mark Hepburn

    Mark Hepburn

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    Leo, do you not find if there to be any issues with brittleness using the CA glue? I'm really referring to durability over time. And am I correct in assuming that you use a thin CA glue?
     
  6. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I use coffee grounds where it is appropriate to simulate bark or to add to bark that already exists. I wouldn't consider it for the crack in Odie's bowl because there's nothing about the crack that "barks" at me. Occasionally I will mix coffee grounds with medium CA, but usually I will apply a little medium CA and then sprinkle coffee grounds over it. If I know that I will be building a thick layer then I will sprinkle a heavy layer of grounds and then pack it down with thumb pressure. After that sets, I will apply more CA and sprinkles more grounds on top, but maybe just let it set until dry and then blow or vacuum off the loose grounds. This process leaves a rough textured surface that closely matches a bark inclusion. Lightly torching a defect to darken it before adding the coffee is another useful technique.

    Finely ground coffee mixed with epoxy closely resembles pith wood. I have used fine tipped touch up pens along with an X-Acto knife and needle to draw wood grain.
     
  7. Leo Van Der Loo

    Leo Van Der Loo

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    Yes thin CA usually or add thicker after the initial wetting with the thin CA
    As I have used CA starting some years ago, the oldest piece that I (LOML) still have is an 16 year old Apple bowl we have been using daily as our bread bowl, I remember that the log looked abused/rough, and while turning that bowl I found a small thin bend over nail with a string still attached, and it showed bark had been missing and overgrown, as they say it has character, and LOML Anny does like it, it had several splits or rather separations between year rings,
    I filled all these places with CA and that bowl and the CA is as solid now as it was 16 years ago.
    Old Apple bowl.jpg

    I also made a (what we call a floor bowl, as it is too large for a table) from a Willow burl at that time, as it dried the burl clusters opened up, I left it for a couple of years sitting in our living room, and then filled all these splits with coffee ground and CA, so probably only 14 or 15 years old that all looks just fine, after all it doesn’t have anything to do but stay in the wood, there is very little if any movement in the wood

    Pictures are from when just filled and from 2 years ago.
    Willow burl.jpg

    Willow burl 2014.jpg
     
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  8. Joe Greiner

    Joe Greiner

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    Olaf and Mark:

    I now use Permatex twin-tube; previously used Loctite (from HD). Permatex is supposed to have a two-year shelf life, Loctite only one year. I had a long-running argument with Loctite about placement of the date code; it was on the back of the label and couldn't be seen until opening the package. This all began from a failed connection due to very old product. Permatex had it on the flange extending from the package - alas no longer.

    I had an unpleasant experience with some 5-minute in a structural application, which never fully hardened - might have also been too old. The 30-minute also gives more working time.

    For structural applications, JB Weld is the best I've found; they claim infinite shelf life.
     
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  9. Bill Boehme

    Bill Boehme Administrator Staff Member

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    For years I have heard dire warnings about using CA, but I haven't seen anything that substantiates the claims. I have used it on several medium sized pieces and so far I haven't encountered any problems. However, whether true or not, woodturning lore can have a strong influence on collectors and galleries. Since that is outside my league I sometimes use CA both for repair and as a finish. CA and I have something of a love/hate relationship because every time I use it I manage to get it all over my hands or worse ... my clothing where Mrs B will see it and "gently" remind me of all the things I'm not supposed to do. :D

    I do know some of the shortcomings of CA. It's brittle and loves to chip. Coffee grounds helps solve that problem. I done like using it on long thin cracks.

    I don't like the five minute epoxy because I'm a ten minute woodturner. Also that's not sufficient time for the bubbles to escape.[
     
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  10. Mike Johnson

    Mike Johnson

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    The CA glue does a nice job of pulling itself into the voids, cracks, splits compared to other
    solutions. Starting with the thin on a split and adding medium thickness afterwards the glue
    will quickly settle into the voids and you can add additional glue to the crack as it settles. On
    some voids it helps to seal the back side of the wood piece if the void runs all the way through
    the wall. I will use masking tape to seal one side of the wall or use it to create a dam if the glue
    wants to run out in a direction. I have used thin and medium CA glue in a crack and then pushed
    fine wood dust into the void and re-applied thin CA over the top, after it dries the repair looks like
    a knot depending on the wood type. The dark color woods seem to work best. Turn at a high speed
    and clean up with a negative rake tool and then sand and finish.
     
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  11. Bill Weaver

    Bill Weaver

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    I use quick cure 5 minute epoxy made by System 3 (system3.com) or Woodcraft part number 124270. I love it you can mix whatever in it or just plain ole instant coffee for a dark wood grain effect. I also use it plain with lighter wood area and looks natural. Fills depressions and cracks.
     
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