Shapeways FM switchers: Cleaning FUD

[DKS]

Especially when that way sucks.

Explain. Exactly what makes it suck?

[bbussey]

Agreed.  Heptane doesn't attack the resin in any way.  Simply soaking the item in heptane will dissolve the wax.  Actually, if soaked in a tightly-sealed glass container, the wax reforms on the exposed glass surfaces inside the jar, leaving the heptane pure.  I've left pieces soaking for days, no matter how delicate, and they've never been damaged, softened or distorted in any degree.  I soak a minimum of 24 hours.  If wax remains present on the parts, they go back in the soup for another 24.

[Sokramiketes]

I suppose I should have been more clear (no pun intended): the surface will naturally be white, owing to the method of depositing the material; in the same way that clear glass can have a frosted surface. If the surface of the RP material was polished, it would likely tend to be clear, but the method used to build the model will always leave a fine-grained irregular surface. Hope that makes more sense.

I'm starting to think Jason is on to something here... if katfudgirl says parts above the wax support structure, that never come into contact with wax, are clear, then how are we sure the heptane isn't affecting the crystal structure of the material?

[Sokramiketes]

Agreed.  Heptane doesn't attack the resin in any way.  Simply soaking the item in heptane will dissolve the wax.

But how are we *sure* it's not affecting the resin?  Because it's not dissolving into goo?  Why can't it be affecting the structure of the material without actually making it all disappear? 

[wcfn100]

I personally feel that solvents are too aggressive for something that can be removed with heat.  I can put a part in hot water and then scrub with detergent and get something that's clean but still somewhat transparent.

Anyone who's removed candle wax from carpet with a shopping bag and an iron can understand where I'm coming from.  There could very well be other ways that we haven't though of yet that could yield better results.  And I would love it if you guys didn't have the tail wag the dog on this and see what she can come up with.

Jason

[peteski]

But how are we *sure* it's not affecting the resin?  Because it's not dissolving into goo?  Why can't it be affecting the structure of the material without actually making it all disappear?

Where does this question lead?  Is anybody complaining that the items dunked in heptane have become brittle, changed or unusable in some way?

[up1950s]

Some Shapeways products have such fine filigree type detail that will  preclude any scrubbing . Many have built these and none have come forward with any reports of change in the properties . Heating may cause warpage or sagging in places . Even if the properties change , and that change is undetectable , ......

[wcfn100]

Anyone try WD40?  I don't have any big pieces to try it on but did test on some building details I had made and it looks pretty good.

Also, has anyone tried sand/media blasting? 

Jason

[Chris333]

You have to think how FUD comes out of the head in a liquefied form and then gets hit with the UV to harden it. Plus just the wax that is around it would make it appear clear like when you look into a fish tank at strange angles.

I dunno I've used acetone and Bestine and got similar results with both with no problems.

Anyways clear or white the surface texture is the problem.

[Chris333]

Anyone try WD40?  I don't have any big pieces to try it on but did test on some building details I had made and it looks pretty good.

Also, has anyone tried sand/media blasting? 

Jason

I have some steel Nn3 hoppers I can play with.


Err wait are you talking about cleaning them with WD40? Everything I have is already cleaned in Bestine.

[DKS]

I personally feel that solvents are too aggressive for something that can be removed with heat.  I can put a part in hot water and then scrub with detergent and get something that's clean but still somewhat transparent.

Anyone who's removed candle wax from carpet with a shopping bag and an iron can understand where I'm coming from.  There could very well be other ways that we haven't though of yet that could yield better results.  And I would love it if you guys didn't have the tail wag the dog on this and see what she can come up with.

Jason

Here's the big problem. Heat won't work because the melting point of the wax and the FUD are too close together. This is a known fact, and many items from Shapeways have been rendered useless because of overheating the FUD, while not completely removing all of the wax. This has happened to parts I've ordered, and it has been reported by others. Hot water and detergent are hardly effective since there is no way to safely scrub all surfaces, not to mention detergent does not dissolve wax. Scrubbing is the last thing you want to do to a delicate model; on the other hand, scrub long enough, and you will partially polish the surface, and that may indeed make it partially transparent. But I will bet my bottom dollar you are not able to remove all of the wax with this method on anything except perhaps a solid cube of FUD.

Now, if you read the literature about heptane, you will learn that wax is one of the very few materials that heptane will dissolve. In fact, as solvents go, it's one of the least aggressive ones known. As for removing wax with a shopping bag and an iron, it's hardly 100% effective. I know, I've tried it. But I have removed wax completely from carpet, clothing and other materials using heptane, and it has been 100% successful, without damaging the material.

Do we know for a fact that heptane is not affecting the FUD? Without extensive tests with sophisticated equipment, no. However, based on the scientific literature available about the known properties of heptane, and based on an awful lot of first-hand experience by myself and many other modelers, empirical evidence (as opposed to personal feelings) suggests it is not harming the FUD. I for one have been using heptane regularly since my pre-teen years, and I have not witnessed it affecting anything other than those substances it is known to affect.

To claim it "sucks" with no factual or even anecdotal information to back it up is baseless and less than helpful. Tell us how many methods you have tried to clean FUD, and be able to demonstrate it was totally clean (try getting the wax out of deep crevices with hot water and detergent--good luck, friend). The evidence is quite convincing that heat is not a viable method. I've tried a number of solvents; the fact that heptane dissolves wax and precious little else is very compelling, plus its ultra-high volatility means it evaporates completely very quickly without leaving any residue of its own.

What other methods are at our disposal? Heat does indeed really suck. Mechanical removal is pointless--there is no way to do so without damaging the surface, and getting at all of the surfaces on a complex shape is impossible. I cannot think of any other viable process besides dissolving except possibly for a chemically reactive process (which dissolving is not).

I for one am satisfied with the performance of heptane. I know quite a number of others who are as well. I'm not saying there is no need to investigate other methods; but until someone comes along with a silver bullet, I assert it's the best option we have. This is not the tail wagging the dog; this is being proactive and finding ways that are effective in the absence of effective recommendations from Shapeways, while other research takes place. What are we supposed to do, stop buying FUD items and wait for the mother ship to tell us what will work? Is there a sillier idea than that?

Anyone try WD40?  I don't have any big pieces to try it on but did test on some building details I had made and it looks pretty good.

Also, has anyone tried sand/media blasting? 

Jason

I see a big cleanup issue with removing all traces of waxy oil from every surface. I'd also question its effectiveness on highly complex shapes with deep crevices. And I'd also be wary that the oil might affect the FUD; recall that we must use plastic-friendly lubricants on our locomotives, else risk damage, since some petroleum products are known to attack plastics. As for media blasting, you want to try that on the door handles of Bryan's burger joint?

[peteski]

If the surface of the part is not frosty white, I will bet my bottom dollar you have not removed all of the wax.

DKS,  If the resin material was normally white in color then it should appear white with or without the wax coating on it.  If the wax makes the object look transparent it is because the resin itself is transparent (not white).  The surface roughness (which scatters light rays) makes the resin appear to be white.  Again, I am talking about the RP pieces I own (which were not rendered in FUD by Shapeways). Those might be different than FUD because I can't melt the resin with any solvents I mentioned in my previous post here. Some of the descriptions of FUD on this thread seem to imply that it is acrylic (which would be easily dissolved by Methylene Chloride).

I'll see if I can take a photo of the White Tower burger building showing the clear parts of the building.

Another sure way to determine if the resin is clear is to take a solid piece of the printed object and sand and polish it.  If it becomes transparent then the resin is transparent. But that will ruin the item.  For me the stipulation that the resin is transparent because is looks transparent with a coat of wax on it is good enough to convince me that the resin is in fact transparent.

[DKS]

DKS,  If the resin material was normally white in color then it should appear white with or without the wax coating on it.  If the wax makes the object look transparent it is because the resin itself is transparent (not white).  The surface roughness (which scatters light rays) makes the resin appear to be white.  Again, I am talking about the RP pieces I own (which were not rendered in FUD by Shapeways). Those might be different than FUD because I can't melt the resin with any solvents I mentioned in my previous post here. Some of the descriptions of FUD on this thread seem to imply that it is acrylic (which would be easily dissolved by Methylene Chloride).

I'll see if I can take a photo of the White Tower burger building showing the clear parts of the building.

Another sure way to determine if the resin is clear is to take a solid piece of the printed object and sand and polish it.  If it becomes transparent then the resin is transparent. But that will ruin the item.  For me the stipulation that the resin is transparent because is looks transparent with a coat of wax on it is good enough to convince me that the resin is in fact transparent.

Peteski, no need to take images to prove your point that FUD is inherently clear; this is accepted. I am not trying to claim that it's white through-and-through (my earlier claim that it's inherently white was poorly-worded, and corrected in a subsequent post). My point is that the RP process is almost certainly going to produce a fine-grain surface that will appear white when perfectly clean; I have not seen otherwise, except on the very rare occasion of a dead-flat surface. If it was possible to produce really smooth surfaces in FUD, then I agree you would see a translucent object, even when clean. Barring that, I will stand by my assertion that residual wax is predominantly responsible for translucency, particularly on complex objects.

Where does this question lead?  Is anybody complaining that the items dunked in heptane have become brittle, changed or unusable in some way?

This is an excellent point. If people were reporting problems with heptane-treated FUD parts, then concerns about using it would be justified. But not using it simply because of a "feeling" that (any) solvent is going to do harm is simply unwarranted. The term "solvent" is extremely broad; by strict definition, H2O is a solvent (water is referred to as the "universal solvent" by some chemists). By the same token, the term "plastic" is equally broad; some are highly solvent-resistant (like acrylic, which you can dip in acetone with no ill effect), while others will melt from a withering glance. In this case, FUD is a pretty tough plastic, while heptane is a pretty wimpy solvent.

[Lemosteam]

I for one would like to see if the blasting method using baking powder works.  Others have also reported minute remains of wax even after soaking, so how does one know the wax is completely removed?  Some level of abrasion may be neecessary, one that has proven to be effective without damaging the product.  Sandblasting may not be practical for katfudgirl, but for us it may be a way to ensure cleanliness.

Katfudgirl, anybody, is there any lighting media that can be shined on the product to see if the wax reacts differently to it than the resin, i.e blacklight or infrared, etc?

[Chris333]

Black light didn't work, just tried.

Also I have sanded parts down till they were clear, but I really don't think anything could come direct from them that smooth, so it's white. Like when you sand paint down it turns a white color, but if you get it wet the white goes away.