Shapeways: Bring your creativity to life in 3D http://www.shapeways.com/forum/index.php Shapeways: Bring your creativity to life in 3D Read density data from data sheet http://www.shapeways.com/forum/index.php?t=rview&goto=59401&th=12203#msg_59401 http://www.shapeways.com/rrstatic/material_docs/mds-strongfl ex.pdf says:

Bulk density EN ISO 60 0.45 g/cm³
Density of laser-sintered part EOS method 0.93 g/cm³

So the density of a printed part is 0.93g/cm3. Correct?
Why this difference for the bulk density? The bulk density is the density before the material is processed?

I want to make a part that will be inside water but almost floating.
]]> shapeyou 2012-12-31T10:26:54-00:00 Re: Read density data from data sheet http://www.shapeways.com/forum/index.php?t=rview&goto=59402&th=12203#msg_59402 The bulk density is for the loose powder before it is sintered. If I understand correctly, the powder is laid down in the printer under vacuum before being zapped by a laser, hence a more dense printed part.

Paul
]]> stop4stuff 2012-12-31T11:03:32-00:00 Re: Read density data from data sheet http://www.shapeways.com/forum/index.php?t=rview&goto=59445&th=12203#msg_59445 this post.
Basically, for Nylon (White Strong and Flexible) solid material is 0.93g/cm3 while trapped material is 0.45g/cm3.
So it floats anyways...

]]> Magic 2013-01-01T15:07:54-00:00 Re: Read density data from data sheet http://www.shapeways.com/forum/index.php?t=rview&goto=59462&th=12203#msg_59462 http://www.shapeways.com/model/329987/density-test.html) is 0.98 and the data sheet says 0.93.
.
I worry a little about this because I want to tune a part to have the water density, not to float (almost floating, the expression I used). And there are little metalic weights I need to append to that part. So I need to make calculatations with precision.

Can someone tell me if the porous PA 2200 absorbs water or other liquids? If it absorbs water the density will change. And that's a problem because I need to use it inside water.
And what type of varnish do you advice for this material?
Thank you]]> shapeyou 2013-01-02T09:31:24-00:00 Re: Read density data from data sheet http://www.shapeways.com/forum/index.php?t=rview&goto=59464&th=12203#msg_59464
As water density varies with temperature (the principle behind the Galileo thermometer) you'd need to fine tune your just floating parts in situ to the temperature of the water you are using.

Several coats of a Spray on acrylic paint or varnish would make an effective waterproff seal - expect the first couple of coats to soak into the model and leave each coat to fully dry between re-coats.

Paul
]]> stop4stuff 2013-01-02T10:24:09-00:00 Re: Read density data from data sheet http://www.shapeways.com/forum/index.php?t=rview&goto=59508&th=12203#msg_59508 stannum 2013-01-02T19:45:32-00:00