FUD FXD forming small crystals after time?

[peteski]

So this whitening effect of acetone and other harsh solvents might be actually stripping the TEG-DMA out of the FUD, leaving the a more brittle urethane shape with more pronounced frosting (not crystals). 

But even rinsing the FUD-printed items in Heptane or Naphtha (which is what I normally use) does not affect the surfaces which were not printed against the wax.  Those surfaces remain translucent and have semi-gloss surface.

[Chris333]

Is 35watts good enough for an ultrasonic cleaner?

Thinking about getting this one unless there is a cheaper one:
http://www.sunpentown.com/uculcl.html

[narrowminded]

Corn oil?

... and mention of spongy crystals forming on EX-200 (clear stuff?) if warm parts are cooled rapidly such as cold water or blown dry with air instead of just letting cool for several minutes in normal room temperature.  I wonder if there's any similarities in material that are surfacing here? 

For cleaning it seems that they DO like temperature of 130 to 140F for their various procedures, just above the melting point of the wax.  They don't mention any use of volatile solvents.  Nothing more than warmed corn oil and warmed dish soap and rinse water (+130F).  This was just from a quick scan of the link.  More thorough reading and understanding is warranted.

[narrowminded]

Is 35watts good enough for an ultrasonic cleaner?

Thinking about getting this one unless there is a cheaper one:
http://www.sunpentown.com/uculcl.html

That one is pretty small.  Make sure those dimensions will work for you.  I don't know about the frequency but suspect any agitation will assist even if not ideal.

I have a unit with heater option that goes for about $80 and is available from a number of vendors including Harbor Freight.  It has a useable tank size of 9 3/4" x 5 1/2" x 3" deep.  The heater temp limit is fixed at 149 degrees F so maybe a preheat and then shut off manually. 

I have minimal experience washing printed parts and haven't always used the heater but in light of the above recommendations I will be investigating that further and will likely use it when cleaning printed parts.

[Chris333]

Here I thought it created heat as it vibrated (or whatever).

The HF cleaner is 160 watts.

[narrowminded]

Here I thought it created heat as it vibrated (or whatever).

The HF cleaner is 160 watts.

It does but not rapidly nor to the temp indicated without running it way too long, if it could even get that hot just from the ultrasonic effect.

[SandyEggoJake]

Corn oil?

Corn oil.  It is highly unsaturated, so when warmed to above the melting point of wax, will act like a sponge.  And there might be a secondary benefit; Corn oil is rich in Vit E.... a potent antioxidant.  Perhaps squelching some of the residual free radicals?  Who knows...

[thomasjmdavis]

Since I don't have decals for it in the drawer, I have decided to run an experiment on a DT-6-6-20 shell I have.  I bought the shell a couple years ago (I could look it up on paypal, I suppose).  Not long after that, we moved, so any work was put off for a while. I used Simple Green to clean it (the local art supply was out of Bestine at the time, and was unable to get more until recently- and I try to keep volatile solvents out of the house in any case)- several hours, followed by toothbrushing, which seemed to get rid of 75% of the wax, then 2 additional 24 hour soaks until I had all the surfaces "white" vs translucent.  Sat it on a table in the sun for several days for any additional "UV curing" necessary.  It then went back in the drawer for a year.  This summer, short bath in Simple Green, toothbrushed, cleaned with dish soap, and a final short scrub with 90% alcohol for any fingerprints. I gave it 2 coats of Model Master acryl gray primer, followed by 2 coats of MM acryl gloss black.  Model Master acryl is a water based or water borne acrylic.  On the referenced Shapeways blog on the crystal problem, several commenters raised the possibility that the problem could relate to chemical interactions between Bestine or other solvents, and the FUD/FXD/FED material.  Since almost by accident, this model has not been exposed to any of those, I figure it is a good test subject.

It went into my "decal queue" waiting until I had a big enough decal order to make it worthwhile to pay shipping, and so, essentially, has had 3 months, in black paint.  To date, no evidence of crystals or flakes on the exterior.  I am going to let it sit for several more months, to see if it grows crystals.  If not, I will strip the current paint, and try to do a better job removing the printing artifacts (every single flaw shows up under gloss black), and then finish the model.  As I am currently in the early stages of layout construction (working on getting together passenger station trackage on a module in my office while working on a remodel of the basement), it will be a while before I need a transfer loco, and will save me putting in hours of work on zebra stripes if the thing "crystalizes." 

[Lemosteam]

It does but not rapidly nor to the temp indicated without running it way too long, if it could even get that hot just from the ultrasonic effect.

Mine gets warm after ten minutes and hot after 20. It does not have a separate heating element.

@chriss333 that's a nice unit for the price but you might want a bigger tank for passenger cars and the like.

[Chris333]

Mine gets warm after ten minutes and hot after 20. It does not have a separate heating element.

@chriss333 that's a nice unit for the price but you might want a bigger tank for passenger cars and the like.

So the Stillwells are coming? 

[Chris333]

Guess I can spring for the Harbor Freight model...  if I use a 20% off coupon 

Maybe even fit a VW carb in there 

[narrowminded]

Now that the subject has been broached and Chris' next step will be to actually use the thing, would this be an OK time to share some of those experiences?  

I have yet to fill the parts cleaner tray directly with a soap or cleaning solvent.  I have used mine mostly to clean intricate machined parts that I want to assure are clean inside and out.  Instead of putting the cleaning agents directly in the machine tray I have put them in glass jars.  The jar is then placed in the tray that has been filled to about the minimum fill line with just water to transfer the action to the jar.  I have used mineral spirits, alcohol, dish soap, or rinse water this way.  This has allowed for ready changes of the cleaning agent without using a fill and/ or full clean out of the machine between changes.  I do save and reuse the solvents until such time as they are deemed useless.

I have questioned whether this method, parts in a sub container, might tend to dampen the cleaning action but it seems to work fine and I haven't tried otherwise for a fair comparison.  I have cleaned only a few printed parts in the whole time I've owned it and while they seemed to come out fine...     

[Chris333]

I saw a few videos where they did the same thing, but with a plastic baggie instead of a jar. The idea is to keep the dirt out of the cleaner.

[nickelplate759]

I do something different with my ultrasound cleaner, but for the same reasons (to keep the basin from getting contaminated). I fill the basin with tap water.  Then I fill a small jar with my cleaning solution, put my part in the jar, and the jar in the water.  I use this for paint stripping. Haven't dared try it with Bestine, as the machine has a bunch of warnings about flammable liquids.

[wazzou]

I saw a few videos where they did the same thing, but with a plastic baggie instead of a jar. The idea is to keep the dirt out of the cleaner.

I'd be worried a plastic bag might melt.