Making a pyramid anchor...how to?

Discussion in 'Watercraft' started by James Waggoner, Jan 23, 2010.

  1. James Waggoner

    James Waggoner Active Member

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    Anyone know a do it yourself way to melt and mould a pyramid anchor?

    I have a couple anchors that are either too heavy or have the wrong base.

    So what do you think?

    James.
     
  2. shawn k

    shawn k Member

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    James
    I am guessing you went to a store and saw how much an anchor costs.
    Ask this question on Ifish. Theres a couple of guys on there that can help you.

    My 2 cents is its not worth the effort. If I was going to build my own anchor I would build one out of truck tire chains. they are harder to lose.
     
  3. Old Man

    Old Man Just an Old Man

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    Is the cost of the lead going to be more that the price of a made one?
     
  4. James Waggoner

    James Waggoner Active Member

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    A guy on Ifish said he would help me out, but at this time he didn't have a the right mould; he only had pyramids with the square base instead of the triangle base.

    As a far as the stores, they are expensive and I usually only find the square base pyramids. I need the triangle (four sided) pyramid for the anchor nest built in to my boat.

    I have the lead, in the form of two anchors, one is a 35# anchor (The right type of anchor just too heavy), the other is a 25# anchor that works very well (Wrong style to fit in my anchor nest). I figured, if I knew how to melt it, I could make a mould out of concrete or something. The other option was to take the 35# anchor down to a shop and have them cut it down to size.

    James.
     
  5. floatinghat

    floatinghat Member

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    James, I would guess for a single time use you could just make a mold from a backer board used for tile jobs. They have this thin stuff that is smooth, you could shape it to the size and shape you want. That said, lead is nasty stuff be careful.
     
  6. Derek Day

    Derek Day Rockyday

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    if you have a plane you could take the 35lb anchor down yourself. Otherwise, go to the library and find a book on saillboat/yacht building. They have sections on pouring keels, so you could just translate the lead keel pouring into anchor making. Shouldn't be too difficult. But I think that mock one up out of wood, cast it in concrete and pour the lead into the concrete mold would be about the approach you'd want to take. If you do it, post process pics, I'd be curious to see how you did it.
     
  7. jeff bandy

    jeff bandy Make my day

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    I have a pile load of lead sitting around. maybe we could have a pouring party. The way I see it is, the mold is the easy part. the hard part is melting the lead and pouring it. I know this has been covered here before.
     
  8. Franko Manini

    Franko Manini New Member

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    Hey Guys,

    New to the forum, but I thought I'd chime in on this one. I've made a mould that will pour up to a 35lb anchor. It is SUPER easy to make, but requires the ability to make long straight cuts on steel plate, and welding or brazing. If you can do these things, it's a breeze.

    The mould itself is 4 triangles, each taller than they are wide (isosolese, not equilateral triangles). I recommend that you lay out the triangles on cardboard and cut them out before you start cutting plate. That way you can customize the shape of your mould to whatever you like, rather than doing the math. Once you are happy with the shape, cut the four triangles out of plate. I used 0.125" plate, because it was handy. Using relatively thick plate is better than thin since it will reatain heat (heat a mould before you pour to burn off any water) and cool more slowly resulting in a more homogenous pour. Thick plate, to a point, is also easier to align and join. I set up the triangles on plate that was about 6" wide, and 4 feet long. I set my metal cutting bandsaw to the appropriate angle using the cardboard triangles as a template, cutting the full width of the plate. After one cut, I flipped the plate over, and cut the corresponding angle resulting in a traingul piece of plate. Repeat until you have 4 sides to the mould.

    Weld or braze the sides together, and after they have cooled, check your work by filling the moould with water. I use steel bracket to hold an eye-bolt in the lead as it gets pured. Remember that you need a bracket that will push rather than suspend the bolt into the lead, because it will float as the lead is added.

    Puring is a pretty easy process. Weigh out the lead prior to melting so you know what weight of anchor you will end up with. Preheat the mould, secure the eye-bolt, and pour to lead into the mould at a consistent rate. Let the mould cool in ambient air. NEVER use water to cool a mould, a steam eruption could result splashing molten lead into your crotch and other sensitive areas. I pour when I have time to let the moulds cool to the touch. If you tap the anchor out too early, it will crumble.

    If you plan on batch pouring using one mould, you may want to take the time to scribe lines on the inside of the mould so you know how much lead to pour to get an anchor of predetermined weeight. This way you can melt all your lead at once and pour several anchors.

    A cool thing that I did, was that I told our fishing club memebers that I would pour them an anchor if they brought enough lead for two anchors. So now I have a bunch of anchors and lead free to me! I sold a few too ;-)

    Happy pouring!

    Frank.
     
  9. James Waggoner

    James Waggoner Active Member

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    This is exactly what I was thinking to make a mould. The backer board sounds like a viable option as well, the concrete solutions just seems stronger and easier to make....bucket of concrete and a wooden pyamid anchor to push into the wet concrete to create the mould.

    About melting...can I just get big steel or aluminum pot from goodwill and put it on a propane burner? You know the big burners used for camping.
     
  10. Riverman

    Riverman Member

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    Hey Franko... how about a picture of the mold.

    OK I have it now, a 4-sided triangle.
     
  11. Kirk Singleton

    Kirk Singleton Capt Kirk

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    I am up for a pouring party if anybody has the stuff. I have 30 lbs of lead.
     
  12. Riverman

    Riverman Member

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    I found this info on the net, but what size triangle is needed for a 20# anchor?

    General guidelines for anchor use:
    5 lb: lakes only or use as second anchor
    12 lb: 8' - 10' boats in moving water
    20 lb: 12' - 14' boats in moving water
    30 lb: 14' - 18' boats in moving water
     
  13. Trout Master

    Trout Master Active Member

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    Ever think of makng a sand cast mold? Alot easier then some of the other's. Do you have the equipment to melt and pour it?
     
  14. jeff bandy

    jeff bandy Make my day

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    Boy that is really general. All depends on; type of bottom, boat, current and scope.
    (scope=amount of line/angle from boat to bottom)
    My big anchor is a combo lead/chain at 45lbs. I have a 14' Al. boat with a lot of rocker so she pulls purity hard at anchor.
    My thinking is the less I drag, the less chance of snagging.
     
  15. James Waggoner

    James Waggoner Active Member

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    Lead is 6.55 oz per cubic inch. Therefore to make an approx. 20# triangle base pyramid anchor the base would be a 6" equalateral triangle with sides projecting to an 8" high apex, yields 19.45#

    Simple formula is Volume of a Pyramid: 1/3 X [Base Area] X Height = Volume Base Area: (Triangle)1/2h X Base = Area, (Square) Base X Height = Area

    To figure out any pyramid anchor size, just take the deisred weight in pounds, convert to ounces and divide by 6.55 (the per cubic inch weight of Lead) to get the cubic inches of volume needed, next take the Pyramid volume equation and and plug in the volume and fill in one of the varibles to figure out the unknown.

    Hope this is correct...if I'm wrong someone please let me know.

    James.
     
  16. Ryan Mills

    Ryan Mills New Member

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    It should be 6.55 oz per cubic inch. Though it might be easier to use 0.41 pounds per cubic inch.
     
  17. James Waggoner

    James Waggoner Active Member

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    Yes, cubic inch! nice catch. And 0.41 lbs per cubic inch would save a couple of steps in converting pounds to ounces.
     
  18. James Waggoner

    James Waggoner Active Member

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    Whats a sand cast mold? And "NO" I don't have lead melting equipement but I do own a propane burner and some old pots.

    One thing I did find during my internet research on melting and molding lead is: Lead melts pretty easy, and if you don't try to boil it, it doesn't let off toxic fumes; by the way there is a pretty large temperature window between the two so this doesn't seem to be a huge worry. One cautionary tip I found on several sites was to be sure the mold is moisture free, as the hot melted lead could cause it to explode sending hot lead and mold fragments all over.

    James.
     

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