Nylon Rope trick

Remembering back to my days doing Chemistry A-level, I recall the Nylon rope trick and wonder if it has relevance to RepRap.

Nylon is formed by putting two liquids in a jar, which do not mix and one of them is heavier that the other, so they form two layers in the jar. But where they meet Nylon forms.

Now the formation of nylon rope is not of much use, but if a thin layer of one of the liquids is deposited on the surface, and then a similar thin layer of the other liquid is deposited on top of that, the whole lot will turn into a layer of nylon. Repeat and you have a solid object.

This does not require heating, and as far as I remember the liquids are not toxic or difficult to handle. I suppose also that one could mix the two liquids as they were being deposited, but the danger there would be that they would mix in the printing head and that would gum things up. As I recall the nylon forms quite quickly.

The only real difficulty would be knowing how much material you had deposited, i.e how much up the design your next layer came. But with experiment that should not be too much of a problem if the liquid can be dispensed in a controlled manner. I would guess that a thin spray would be the easiest way.

Now my memories of chemistry are limited, and I do not recall if there are other plastics which can be formed in the same way.

David

Hi David,

it should be possible, to print thin layers of both fluids separate with a conventional color-jnkjet-head, when filling the fluids in the separate chambers - they will intermix on the surface only. But you have to deal with embedded water too, so heating or curing could be needed too.

For this i ordered the book "Inkjet-Applications" by Matt Gilliland ( [www.amazon.com] ), but didn't realized this until today - hope to do this in the next months ...

My favorite for inkjet-enhanced 3D-fabbing is "Selective Inhibition Sintering", where i print simple salt-water on a powder-surface and heat the surface, until the dry powder melts together and the wetted lines/areas stay separate ...

Viktor

I remember this as the PU-foam trick I've seen some twenty years ago at the Chemistry section of Deutsches Museum, Munich. Take a few mililiters dialcohole and a diisocynid (sp?) - and you get polyurethane.

For first tries use a large container you don't need anymore! The chemical reaction also produces CO2 making foam out of the PU filling the container.

Problem here is to guard the height of the foam.

Howie

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