This model is a sign post to be used with my Zebra crossing sign. It has a hollow channel in the middle to hide the wires for the lighting of whatever is mounted on the pole. This needs to be cleaned manually by carefully melting the wax stuck inside.
The pole is 27mm high and 27mm wide, this translates to a 6m×6m
sign post. Of course it is possible to shorten it, mostly because lots of sign
posts on single street are only 4m wide.
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General info on the materials used |
The material for all my models is called Frosted Ultra Detail
by
shapeways.
It is printed in a process called Multijet Modeling (MJM). The model is
printed in layers which are hardened by UV light. There is also a wax like
material used as support material. Most of it is removed directly after
print, but on some models it is stuck inside the holes and has to be
removed before assembly.
At room temperature the
Frosted Ultra Detail
is inflexible and breaks suddenly without
warning. Thinner parts break off very easily, so please handle all models with
care. It gets more flexible when heated, but still breaks suddenly without
prior warning. It is possible to very carefully bend it into a new position
while warm. The
Frosted Ultra Detail
will retain this position when cooled, but when warmed
again it will bend back to its original position.
The material can be cut with a sharp knife. Often small splinters will break off at the bottom of the cut. It is possible to smoothen the surface by sanding, I usually use a nail file.
The
Frosted Ultra Detail
material can be glued together with all-purpose glue and with
super glue. As super glue I prefer the liquid one since it sets so fast. I use
it mostly on parts which I fix in position before gluing. For stuff that needs
adjusting before the glue has hardened I use all-purpose glue.
For painting the
Frosted Ultra Detail
material
shapeways
recommends acrylic paints. There
are some reports in the user forums where models in
Frosted Ultra Detail
started to melt and
smell when painted with non-acrylic paints, so I decided to follow the
recommendation to be on the safe side.
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Cleaning Frosted Ultra Detail |
To remove traces of the support wax and the oil which is used to remove
the wax on the Frosted Ultra Detail
material I use a small
ultrasonic bath filled with water and a drop of dishwashing detergent. I
usually put the models in for 30 minutes with a change of water after
20 minutes when necessary.
Sometimes there is a white powdery stuff on some parts of the surface. This seems to be a mix of the support wax and the material. As far as I know the only way to remove it is by sanding or scraping it off.
Use a small hobby knife to separate the posts by cutting through
the struts holding the 10 poles together. Remove the rest of the struts
either by cutting them off or by sanding the surface.
To remove the support wax I carefully heat the sign post with a
temperature controlled hot air soldering station set to about 60-80°C.
While heating I stick a small (0.15mm diameter) piece of enamelled copper
wire into the channel. I start at the bottom side, since the opening is
bigger. Once the wire is through I repeat the process with a bigger wire
(0.3mm diameter). Then I add a small drop of degreaser to the opening and
push it through with the wire. Finally I spray a bit of degreaser through
the channel inside the model. I also clean off the support wax which has
flowed out of the holes with degreaser.
The sign post is now ready to be combined with my following model:
I usually paint everything after it is glued together as a last step, but it is also possible to paint the pole before assembly.
Zebra
crossing sign