Sunday, September 4, 2016

Series: Colorizing 3D Prints #12 - Colorizing with Chalkboard Paint

Before talking about a project that was a LOT of fun, I have to tell you where I got the idea.

Cathy Parlitsis of Stamps and Scrapbooks is a person that creates wonderful mixed media and paper crafting tutorials and videos.  Her site and YouTube channel are well worth exploring.

I came across this video, where Cathy re-purposed some candy canes and blackboard ornaments to create some very cool food identifiers for a pot-luck dinner.

Working on the principle that no cool idea should go unappropriated, the idea came to me that a great 3D printed craft project that would involve colorizing 3D prints might be a personalized mini-chalkboard.

My first attempt involved creating and printing all the elements... chalkboard area and personalized hanging frame in a single printed object.   But, of course, since I am masking challenged, that turned out to be more trouble than expected with the chalkboard paint finding its way into unwanted areas.

3D Printed Chalkboard - First Draft
I was able to clean it up a bit; but, clearly there had to be a better way to do this project.  Plus, after proving that the chalkboard paint would work on a PLA surface, I really wanted to make the design to be more personal for the person for whom it was intended.

So, the design was broken into two pieces.  The first piece, the chalkboard, was beveled to fit into the back of the second piece, the frame, which was expanded to make room for a name..

Inlay Trick #1 - Bevel Inlay Edges

While the chalkboard piece is inserted from the back, it is still essentially an inlay.  Inlay is another way to put two different color prints together.  The inlaid piece must fit into the host piece and there are some tricks to making it work more easily.  The 3rd Gen Cube on which this project was printed has some differences in the size of borders and holes from the specified design when printed.  We can make allowances for that; but, by beveling the inside and outside matching edges we know that the piece will fit even if our compensation estimates are off.  If the edges are straight and we miscalculate by even .1mm, we might have to reprint the object. The beveled edge gives us a little margin for error.

Beveled Edges Widen the Margin of Error in Fit
Inlay Trick #2 - Resize (Expand) the inlay object when using it to cut the inlay channel or hole.

The trick in making sure the insert fits correctly is to use the inlay object to define the hole or channel into which it will be inserted.  But, first, we resized the chalkboard by 1mm in the X and W directions.    We do this because, typically, holes get slightly smaller and pegs (inserted objects) get slightly larger when 3D printed.  Resizing the chalkboard ensures that the design of the hole will be 1mm bigger all around.  But, when printed the opening of the hole will actually be a bit smaller.

After the hole is cut, we return the chalkboard to its original size for printing.  I added 1mm to both the height and the width.

Then we print each object separately.  With an independent chalkboard, colorizing it with chalkboard paint is easy and requires no mask.

For now, the frame remains uncolored.  But, should we desire to add some color, it would be a lot easier than with a single design.

Once the paint dries, the pieces are taped or glued together.  Since we may want to colorize the frames, for now it is taped.  But, because, this was printed in PLA, clear fingernail polish would be the glue of choice when we turn to that option.  Here is the result.

Mini-Chalkboard Colorized with Chalkboard Paint
It's easy and fun.  Of course, I had to make two, with two granddaughters.

One single style black board and 2 new style chalkboards
The new two-piece style is better in every way.  There is no danger of paint slipping under the masking as can be seen in the top sample.  Names are added to the Master Design just before the object is saved for printing, allowing each one to be personalized with a unique name.

It can be hung using a suction cop attachment on a window or a small stand could be printed to hold it on a desk.  In any case, I know they are going to be surprised and pleased the next time we see them!

Thank you Cathy!!  I loved your original idea and it turned out to translate very well to 3D printing!

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