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 Post subject: Flattening back sets
PostPosted: Sat Feb 23, 2013 9:40 pm 
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Brazilian Rosewood
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Location: Canada
I have a few back sets that are less than flat. I sometimes used the house oven to flatten these out, 220 degrees, plywood on top and bottom and rocks on the plywood for weight. Worked alright but smells up the house and generally makes a bit of a mess. While perusing our local government auction site I saw this unit:

Attachment:
Press 1.jpg


Attachment:
Press 2.jpg


It is called a dry mount press. Used in photography and things like putting transfers on to t-shirts (that is what some research told me). The table of this press is 17" by 21", just right for backs! So I bid on the press and won it, thinking that it should work well. I paid just over $100 with taxes and fair bit more to have it delivered from Vancouver. I replaced the cord and tried it out. Here are the results:

A birch set I recently cut. Kind of wobbly even after drying in a press fixture with three cross supports.

Attachment:
Birch 1.jpg


And once pressed, here is the results after about a half hour in the press. Heat is only on the top plate of this press so the pieces needed to be turned.

Attachment:
Birch 2.jpg


All in all I'm quite happy with the results and this will really help salvage wood that would otherwise be a problem. I think these things are reasonably available at various auction sites. It weighs about 250 pounds as well!

Hope you find this useful!

Thanks
Shane


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 Post subject: Re: Flattening back sets
PostPosted: Sat Feb 23, 2013 10:01 pm 
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First name: Darryl
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Nice idea Shane.

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 Post subject: Re: Flattening back sets
PostPosted: Sat Feb 23, 2013 10:24 pm 
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Koa
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I recommend that this should not be used on wood that has any wax on it. When heated, the wax will flow like water into the wood and never come out. It will compromise glue joints later.


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 Post subject: Re: Flattening back sets
PostPosted: Sat Feb 23, 2013 10:24 pm 
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Koa
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I recommend that this should not be used on wood that has any wax on it. When heated, the wax will flow like water into the wood and never come out. It will compromise glue joints later.


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 Post subject: Re: Flattening back sets
PostPosted: Sat Feb 23, 2013 10:28 pm 
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Brazilian Rosewood
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wbergman wrote:
I recommend that this should not be used on wood that has any wax on it. When heated, the wax will flow like water into the wood and never come out. It will compromise glue joints later.


Sure hope you aren't speaking from experience Bill! But what you say is very true, you wouldn't want to use any heat on waxed sets until the wax is gone.

Shane

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 Post subject: Re: Flattening back sets
PostPosted: Sat Feb 23, 2013 10:48 pm 
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Koa
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Unfortunately, yes. I stored a bunch of wood in the attic that heated up enough for the wax to flow.


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 Post subject: Re: Flattening back sets
PostPosted: Sun Feb 24, 2013 4:14 am 
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Koa
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What's wrong with that? The wax won't penetrate very deep into hardwood unless the whole lot is under pressure. 2 or 3 tenths of a mm with a Hand Plane and it's all gone.


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 Post subject: Re: Flattening back sets
PostPosted: Sun Feb 24, 2013 7:48 am 
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Brazilian Rosewood
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I have heating blankets that are 18 by 24 to flatten the backs. 20 min at 250 and that usually takes care of things. Though , if you don't control the humidity well in your storage area you are not going to keep them flat. I store all my higher end wood pressed and keep my regular wood on a stack with weight.
It is amazing how much a piece of wood can move by humidity.

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 Post subject: Re: Flattening back sets
PostPosted: Sun Feb 24, 2013 8:24 am 
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Koa
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Joined: Mon Dec 18, 2006 9:42 am
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Location: United States
"What's wrong with that? The wax won't penetrate very deep into hardwood unless the whole lot is under pressure. 2 or 3 tenths of a mm with a Hand Plane and it's all gone."


Not true. Once completely liquid and on hot wood, the wax flows like water, alcohol, or any other solvent. If you plane or sand it, you may get to a point where you do not notice the wax, but it is still there.

I you dip cold wood into barely melted wax to seal the ends, then the wax hardens imediately and does not flow in that situation. If you take wood sealed with wax and heat the whole thing up past melting, you are asking for trouble.

Use something that does not contain wax to seal ends.


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 Post subject: Re: Flattening back sets
PostPosted: Sun Feb 24, 2013 9:48 am 
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That's a really cool repurposing of some photo equipment. I actually used one of those quite often in college.

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 Post subject: Re: Flattening back sets
PostPosted: Sun Feb 24, 2013 11:13 am 
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Brazilian Rosewood
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looks like a veneer [press used by marquetarian furniture makers in spain.


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