Shapeways printout cleaning issue?

[mark.hinds]

Hi all,

I recently received my first Shapeways printouts. Based on advice from these boards, I cleaned them in Bestine to remove residual wax (just in case), and then washed them with a soft brush and detergent. After drying, they have taken on an opaque, white color, instead of their original translucent color.

Can anyone comment on the significance of this color change? I would have been more comfortable had the material retained its original appearance. In particular, does the color change herald reduced structural strength or reduced paint adhesion?

Thanks in advance,
Mark H

[daniel_leavitt2000]

The transucent effect was due only to the wax on the model. Think of having a scratched peice of glass and submerging it in cooking oil. The scratched dissapear though there is no change n structural strengh.

[Chris333]

My FUD stuff turns white as well. Never thought it was a problem though.

[6axlepwr]

I soak my FUD stuff in a 50/50 mix of Simple Green and Dawn dish wasing liquid to remove the wax and oil. Does a great job. The parts become a chalky white in some areas and transparent in others. Paint will stick to them now.

Brian

[mark.hinds]

Thanks for the replies so far. 

So you guys think that despite Shapeways' description below, there is still wax and oil residue on the printouts?  I can see how there might be (given my hit and miss experiences with ultrasonic cleaners), but do we have any addtional supporting evidence? 

<quote from Shapeways>
The printing process used is Multijet Modeling (MJM). Molten plastic is deposited by print head onto platform in layers through several nozzles, essentially a large print head that sweeps across the build layer. As the heated material jets onto the build plate, it instantly solidifies. Afterwards, each layer is then cured, or polymerized by a wide area UV lamp after deposition. The next is applied and layers of thermoplastics builds up.

For overhangs, a support structure of lower-melting wax is constructed that is removed later by being heated. This method of “hands free” support removal allows for highly complex, and delicate applications. The products are printed on an aluminium tray. When printing is ready we place the aluminium trayin the freezer. After that, we get the models from the tray and put them in a basket. That basket we place in an oven to melt the wax away. After the oven we put the basket in a ultrasonic bath with oil to remove all wax rests. After the oil bath the product are really greasy, so we put the basket in another ultrasonic cleaner with water to flush all leftover oil away. Then we dab away the leftover water on the models.

The pros of this technology include build speed virtually independent of part size or quantity. This means that whether a person submits one part or 10, they will all print in almost the same time. 
<unquote>

MH

[Puddington]

Ok; having read 100's of posts on this, I now have to ask....what the H - E Double Hockey sticks does FUD stand for...........?

[bbussey]

Frosted Ultra Detail.  It's their name for whatever the fine detail resin is that they're using.

Yes, there still is some wax residue that remains on the FUD models.  I'm told the melting point of the FUD isn't much greater than that of the wax, so care must be taken with small and delicate details.

[DKS]

I have excellent results cleaning FUD or any other RP plastics with heptane solvent, readily available as rubber cement thinner. Heptane naturally dissolves wax but does not harm plastic, so it cleans very quickly and effectively, leaving no residues, and the parts can be easily painted.

[mark.hinds]

David,

Folloing your previous advice, I also used n-heptane (Bestine).  The result in 100-micron FUD looked like this (models are about an inch long), and the white color is what motivated this thread.  (Sorry that these are 1/4800 rather than 1/160 scale). 

(EDIT:  BTW, these 3D models are not mine; my contribution has been limited to purchasing, cleaning, painting (eventually), and photographing the Shapeways printouts.  The 3D models themselves (of French WWII warships) are created by a guy who goes by the name of Roe Tengco.  His Shapeways store is called "Tiny Thingamajigs".)





MH

[asarge]

I'm trying to place the ships. Japanese, but can;t place which one(s)

[Sokramiketes]

Is the "wax" meant to be removed?  The model looks smoother with the wax in place... if it holds paint OK I'd be inclined to leave it alone. 

[DKS]

You can get it to hold paint with the wax intact if you slather on a gallon. When you completely de-wax it, you can apply a nice light coat. True, it looks a little better with the wax; I imagine it fills in most of the (natural) surface defects. But I'm pretty certain it's not meant to be there.

I have a feeling that the wax is responsible for maintaining the translucency, and when the object is de-waxed, the surface tends to reflect light the way snow does. The object is still probably translucent inside, but the surface turns white because it's totally clean, as opposed to having gone through a chemical reaction with the heptane. One test would be to sand and polish a surface and see if it loses the white effect.

David,

Folloing your previous advice, I also used n-heptane (Bestine)...

Sorry, Mark, I'd missed the reference to Bestine in the original post.

[Dave V]

How does a noob like me go about rendering a 3D design for Shapeways?  Like, say, an H10sb boiler, or COLA tower on the PRR?

[Sokramiketes]

You can get it to hold paint with the wax intact if you slather on a gallon. When you completely de-wax it, you can apply a nice light coat. True, it looks a little better with the wax; I imagine it fills in most of the (natural) surface defects. But I'm pretty certain it's not meant to be there.

I have a feeling that the wax is responsible for maintaining the translucency, and when the object is de-waxed, the surface tends to reflect light the way snow does. The object is still probably translucent inside, but the surface turns white because it's totally clean, as opposed to having gone through a chemical reaction with the heptane. One test would be to sand and polish a surface and see if it loses the white effect.

Sorry, Mark, I'd missed the reference to Bestine in the original post.

Another test might be to dip a cleaned model in Future and see if the translucency returns. 

[mark.hinds]

Another test might be to dip a cleaned model in Future and see if the translucency returns.

Maybe, but Future might not be "wet" enough to completely conform to the rough surface.  Re-immersing it in Bestine might be a better test. 

(EDIT:  Ignore the following paragraph of my original post.  According to Roe, his sprues were hollow, and the whitish center of the un-cleaned sprue therefore was likely trapped wax.)
<ignore>
A further complication is suggested by an experiment I performed Saturday where I cut through a piece of un-cleaned (original condition) sprue.  Viewed in section, the cut surface showed a translucent outer layer, with a whitish core (...).  Does that mean that the material is a wax-impregnated matrix?  Does anyone own a microscope?   
<end ignore>

MH