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Thread: Could I cast this in Bronze?

  1. #1
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    Default Could I cast this in Bronze?

    I think I'm going to set myself up for doing some casting.

    So, could a fairly capable person, who is new to casting, make this winch stand?

    I need two of them, and the quoted prices for new make my eyes water. How would I pattern it and where would the parting line be? The hollow curve of the standing part is what is giving me concern. How would you do it?


  2. #2
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    Default Re: Could I cast this in Bronze?

    Might be easiest to put the parting line along the centre line so you have two symmetric halves.
    It really is quite difficult to build an ugly wooden boat.

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  3. #3
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    Default Re: Could I cast this in Bronze?

    And the concave face of the vertical bit can be flat or convex.

  4. #4
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    Default Re: Could I cast this in Bronze?

    Yes, a relatively easy job.

    If you are thinking of getting started with bronze casting I'd suggest joining a forum called Alloy Avenue.
    http://www.alloyavenue.com/vb/forumd...casting-forums
    '' You ain't gonna learn what you don't want to know. ''
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  5. #5
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    Default Re: Could I cast this in Bronze?

    How easy Peter? I currently have the same style of thing made of galvanised steel, which is fine, but I have a set of self tailing winches I want to fit, which I think are a bit big for the present mounts.

  6. #6
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    Default Re: Could I cast this in Bronze?



    If you look at the top surface you can see a light line half way across at right angles to the coaming. That is the parting line. The pattern would be split along that line ( continued all the way around). There would be a taper from the parting line to the edge ,I would make the pattern about 9 mm thick at the parting line tapering to 6 mm at the edge with all the taper on the underside.

    Imagine the pattern being withdrawn from the casting sand, there must be no obstruction and the pattern must be very smooth.
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  7. #7
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    Default Re: Could I cast this in Bronze?

    Makes sense Peter, but what about the leg it stands on? Do you think it has concave hollow? I think that would look nice, but maybe it is actually flat on that inner face and uses the outer curve as draft.

    What provisions should be made to prevent warping the angle between the leg and the top platform? I've heard that such things have a tendency to contract in as it cools, maybe making the angle more acute?

    Thanks for the help. If its plausible, I think I'll gear up and give it a go.

  8. #8
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    Default Re: Could I cast this in Bronze?

    There is a way of casting any shape or curve you want on the inner faces but as it uses core it isn't anywhere as simple, especially for a beginner. The outside curve in the photo is just the required taper.
    '' You ain't gonna learn what you don't want to know. ''
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    Default Re: Could I cast this in Bronze?

    I'd go a little heavy on the thickness of the flanges for fine-tuning where they meet up with the boat. As thin as it appears, getting the mold fed properly is going to be interesting, see Jim Ledger's work on casting shells for his blocks. Also getting the pattern out of the sand cleanly will take some doing, there is a lot of surface area for the sand to stick to. Playing around with the sand might help. You want it sticky enough to stay together but not so sticky that you can't get the pattern out. Please do cast it, I want to see how it goes.
    Steve

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  10. #10
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    Default Re: Could I cast this in Bronze?

    Looks like there is a parting line at 45 degrees right by the screw head on the leg also, indicating a mold that is made up of more than two parts.

  11. #11
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    Default Re: Could I cast this in Bronze?

    This thread on the casting forum seems to be a gold mine of info for a beginner like me.

    http://www.alloyavenue.com/vb/showthread.php?2469

    The thin walls and large area seems like the greatest challenge with this part.

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    Default Re: Could I cast this in Bronze?

    I need two, if you want to make a production out of it.
    R
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    Default Re: Could I cast this in Bronze?

    John,

    Looking at those thin walls, I'd be tempted to make a pattern of the piece out of styrofoam.

    Display foamboard can be had in various thicknesses and you could probably find some that is about right. Glue the sheets together to get the shape you want, including risers and vents, then just pack the sand around it. No need to take it apart and remove the pattern, just pour the bronze in. It's hot enough it should effectively vaporize the foam and leave a hole the size of the pattern. Then you would clean it up in the normal manner once it has cooled.

    I'm pretty sure I have seen youtube videos of this operation.
    Alex

    "A man who is not afraid of the sea will soon be drowned, for he will be going out on a day he shouldn't. We do be afraid of the sea, and we only be drowned now and again" Aran Islands Fisherman

  14. #14
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    Default Re: Could I cast this in Bronze?

    Pay close attention to the lead angle to the winch, that is the fussy bit to avoid overiding turns.
    (The first set I made were wrong and I had to remake them- 7 is what I remember)

  15. #15
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    Default Re: Could I cast this in Bronze?

    not to discourage you from a project,
    but the Spartan Marine catalog lists these in five sizes from $120 to $340 each..
    if you needed a smaller size, doesn't seem too out of line


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    Default Re: Could I cast this in Bronze?

    Quote Originally Posted by J.Madison View Post
    Makes sense Peter, but what about the leg it stands on? Do you think it has concave hollow? I think that would look nice, but maybe it is actually flat on that inner face and uses the outer curve as draft.

    What provisions should be made to prevent warping the angle between the leg and the top platform? I've heard that such things have a tendency to contract in as it cools, maybe making the angle more acute?

    Thanks for the help. If its plausible, I think I'll gear up and give it a go.
    If the leg warps a few degrees, the pattern should be made with a more obtuse angle to allow for it. An experienced foundryman might know how much to open up the angle. Since it will probably take a few tries to get it right anyway, I would start square and see how much the first one(s) changes.

    A pattern with a hollow back on the leg is not coming out of the sand. I know enough about cores to shut up and send you to someone else.

    Lost foam has been mentioned. Once again. This video confirms a number of my suspicions and seems helpful. https://www.youtube.com/watch?v=HwzUutlb204
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  17. #17
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    Default Re: Could I cast this in Bronze?

    That part would be a be a simple weldment.

  18. #18
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    Default Re: Could I cast this in Bronze?

    and a simple casting.
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  19. #19
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    Default Re: Could I cast this in Bronze?

    I could make the largest size from Spartan work, Rig Rite has them as well, but what I actually want is even a little bit bigger. 2 of them would be pushing $700, which is more than I can put toward this part. I'll make it from wood if needed. But for less than that I think I can get set up to cast, and there are many, many more parts that I need cast, so I might as well start to learn it now. I'm encouraged that Peter thinks it would be simple. I'm going to dive into the research.

    I'll be in touch!

  20. #20
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    Default Re: Could I cast this in Bronze?

    Spartan Marine is a division of what used to be Cape Dory Yachts (now Derecktor /Robinhood). I used to build the Cape Dories and we hated those things, first installing them (they often needed repeated grinding to fit) and then stubbing our feet on them. We begged the production people to change to simpler wooden pads for the winches. No go.
    If I had a dollar for every girl who found me unattractive, eventually they would find me attractive.

  21. #21
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    Default Re: Could I cast this in Bronze?

    A couple of things here, I would make a pattern and have it cast, the foundry will soon tell if something needs changing. I have had quite a few things cast for my boat from my own patterns. I think the foundry told me that lost foam was good for iron and aluminium, but not bronze. The leg I would make round or elliptical in an athwartship orientation for toe protection, not too thick for casting reasons and there will be a loss of for/aft strength.
    the invisible man........

  22. #22
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    Default Re: Could I cast this in Bronze?

    The toe stubbing hazard is certainly worth thinking about. My galvanised steel winch pads now that I think about it, are mounted only to the cockpit coamings. Just a big angle bracket, with a diagonal brace.

  23. #23
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    Default Re: Could I cast this in Bronze?

    Quote Originally Posted by Phil Y View Post
    The toe stubbing hazard is certainly worth thinking about. My galvanised steel winch pads now that I think about it, are mounted only to the cockpit coamings. Just a big angle bracket, with a diagonal brace.
    That would put a big strain on the coamings .
    '' You ain't gonna learn what you don't want to know. ''
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  24. #24
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    Default Re: Could I cast this in Bronze?

    Quote Originally Posted by PeterSibley View Post
    That would put a big strain on the coamings .
    Yes I would think so. They are not much beefed up on the inner face, but seem to have done OK for the last 40 years or so.

  25. #25
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    Default Re: Could I cast this in Bronze?

    I'd say they are remarkably well built to have withstood that for 40 years !!
    A winch mounting like the one pictured makes a very effective coaming brace .
    '' You ain't gonna learn what you don't want to know. ''
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  26. #26
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    Default Re: Could I cast this in Bronze?

    I want them as much for a coaming brace as for a winch pad. My coamings are not fastened such that they could withstand winch loads on a bad day out, especially because the weather winch will be used to set up the runners.

    I prefer the bronze over the more normal stack of wood purely for looks. There isn't a laminated anything within sight on the boat. I will go with wood if I can't get bronze to work. If you think these are hard on toes, you should see all the big galv eye bolts I have on deck! Oh- and the 50 lb fisherman style anchor.

  27. #27
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    Default Re: Could I cast this in Bronze?

    I took the CWB bronze casting class twice, there is one coming up in March: http://cwb.org/classes/bronze-casting/

    Well worth the time, especially if you can take it at the Camas Beach facility and rent one of their cabins.
    Steve

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    R.D Culler

  28. #28
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    Default Re: Could I cast this in Bronze?

    I'm not much of a classroom kind of guy, but that is seriously tempting. Its the pattern making and mold making that I would like more instruction on.

  29. #29
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    Default Re: Could I cast this in Bronze?

    I'm not big on classrooms either but this was very hands-on, first thing we did was fire up the kilns so they could get hot while we talked about molds. Pounding sand and pouring by lunch as I recall.
    Steve

    Boats, like whiskey, are all good.
    R.D Culler

  30. #30
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    Default Re: Could I cast this in Bronze?

    Who is teaching the CWB bronze casting classes these days, Steve? I haven’t kept in touch with them at all, I’m afraid. I left most of my gear behind with them, though. But Cama Beach is worth a visit any which way.

  31. #31
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    Default Re: Could I cast this in Bronze?

    I recommend ANY course, it would be a lot easier than trying to learn everything from Youtube videos and magazine articles as I did.
    '' You ain't gonna learn what you don't want to know. ''
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  32. #32
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    Default Re: Could I cast this in Bronze?

    Well I signed up for the CWB bronze casting course. Should be a fun way to spend a weekend!

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    Default Re: Could I cast this in Bronze?

    My brother and I were planing to but a new baby came Thursday and I suspect SWMBO won't be keen on me leaving for a week. Would have loved to meet you Mr. Madison.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
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  34. #34
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    Default Re: Could I cast this in Bronze?

    1054.jpg1055.jpg

    Sure you can. You don't even need to use cores. Alex (Pitsligo) loves these. You can design the pattern so that it can be molded and withdrawn using only a following board as support.
    Chuck Hancock

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    Default Re: Could I cast this in Bronze?

    1056.jpg1057.jpg1059.jpg

    The following board in this case is also the parting board for the flask.
    Chuck Hancock

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