ATSF semi-lightweight smoothside baggage car builds

[arbomambo]

Fox Valley Models
Designed to fit Rapido cars

[TechnicalATSF]

Hi All

Very happy to see the fabulous results coming from these trucks. I am waiting for my brake disc versions to arrive from Shapeways and will post some photos of the finished product as soon as they are here. @Lemosteam I did not change any dimensions before uploading the files. @arbomambo I think there may be an issue with the Bestine cleaning regime that seems to be US standard for these printed parts. After soaking in Bestine, the printed parts have a white crystalline surface that means that a chemical reaction has taken place somewhere. I have also found that my resin prints (that is what these are) shrink slightly when soaked for a long period - it was annoyingly visible in my B60b prototype prints that I'm working on at the moment - the very thin doors bowed inward meaning that the whole print had shrunk minimally. I have also printed these trucks in PLA and there is no issue with the '540 wheels. Sadly, the detail is not as good.

It's great to see the marvellous photos @arbomambo posted - his photos were the main reason I wanted make these trucks available in the first place.

[Lemosteam]

This is why I don’t soak.  I only clean in Bestine in an ultrasonic cleaner for 20 minutes. None of my many truck designs have shrunk. Believe it or not, ther is a lot of material you can remove from the side frames anyway. It’s spreading the journals that creates the risk.

@thomasjmdavis , yes you may be correct. I confuse the 105 and 107 all the time. That’s when I went and bought these at a train show:

https://www.amazon.com/Deluxe-Round-Assortment-Pieces-BUR-500-00/dp/B0058ECHCC/ref=sr_1_1?camp=1642&creative=6746&dchild=1&keywords=0654207132301&linkCode=ur2&qid=1606576580&sr=8-1&tag=tinylab0b-20

[arbomambo]

I’m very pleased with mine.
In fact, if, indeed, my trucks exhibited shrinkage due to the Bestine soak, then I would recommend the soak.
The trucks match the drawings exactly. They look very accurate under these particular cars. If they were any larger, the spacing would look wrong.
After posting these photos I do see some slight cleanup I need to do on some of the trucks (eliminate some tiny, superfluous ‘flash/material), but this is easily done and even easier to touch up with paint.
Ultimately, these cars will receive slight weathering at the same time most of the other head end cars receive weathering.
I’m very thankful for TechnicalATSF and Lemosteam bringing these trucks life! It’s motivated me to jump back in to my MAJOR ATSF Fast Mail project (the recent article, in the current Warbonnet, on train nos. 3 & 4, has also helped to spur the continuation of the build)

[peteski]

I think there may be an issue with the Bestine cleaning regime that seems to be US standard for these printed parts. After soaking in Bestine, the printed parts have a white crystalline surface that means that a chemical reaction has taken place somewhere.

My observations from cleaning the FUD items are that if the surface was not in contact with the waxy support material, it will not have that fuzzy (as you call crystalline) look.  It might get slightly milky, but that's all.  But any surface that was printed on top of the waxy support material, will appear white and fuzzy.   But what seems to be happening is that the resin surfaces contacting the was surface during printing have a very rough surface.  When the some of partially rinsed (by Shapeways) wax still remains in the rough fuzzy surface, it fills the microscopic roughness, making the part appear to be smoother and less opaque. When Bestine (or other solvent) rinses out all traces of wax, the surface then appears opaque white and "crystaline". But all that was done was to remove all the wax from the rough resin surface.

This is similar to what you would see with any other rough surface and some layer of smoothing substance.  Take some frosted glass.  If you put some water on its surface (or another liquid), that  liquid will smooth out the frosted surface and make the glass appear less opaque.    But the roughness of the dry frosted glass (or dry resin surface on FUD items) scatters light, so they appear opaque.  It is not some crystalline substance that leached out of the resin. You are simply seeing the cleaned fuzzy resin surface.

[TechnicalATSF]

Hi all

I've now had a chance to carry out some measurements. The trucks, as printed have an inside dimension of 12.20mm between bearings. Over the batch of 20 I have there is no measurable difference. I have also measured various wheel sets available from suppliers.

Axle lengths

Intermountain 60051 '540" x 36" come out at 13.95mm (they should be 13.72mm)
Intermountain 60071 High Detail '540" x 36" come out at 13.85mm (they should be 13.72mm)
Intermountain 60072 High Detail '526" x 36" come out at 13.55 (they should be 13.36mm)
Microtrains Standard 36" Wheelsets 00312009 are '536 x 36" and come out at 13.665mm

The nominal dimension these trucks are designed to is 13.72 so apparently the Intermountain '540"'s are a tight fit.

I will measure the Fox Valley sets as soon as they arrive

The Shapeways prints are a wonder of precision printing technology. The latest versions don't need to be cleaned at all but a quick dip in isopropyl alcohol will get rid of any muck on the surface. I'm not a fan of the Bestine soak but the matt surface does seem to be easier to paint after. I have soaked in Brake Cleaner and Ethanol with similar results, with Brake Cleaner providing the same matt surface as Bestine. A quick wash in isopropyl is still the favourite.

The parts as printed fit will accept Intermountain 60051/60071's. However, the precise fit means that there is a minimal rolling resistance, so opening up the hole does seem to help. As @arbomambo suggested, using the small '526 axles helps as they are shorter, particularly if you get paint anywhere near the holes. It seems a shame to spoil a perfect fit, but in the end, anything that works for you, works....

Looking forward to seeing more ATSF Fast Mail items from @arbomambo.

John

TechnicalATSF
https://www.shapeways.com/shops/technicalatsf

[arbomambo]

The detail on my order is exquisite, and the bestine soak didn't affect the detail in any way whatsoever.
I couldn't be happier with these trucks!

[skytop35]

I've been meaning to take this photo for a long time since John was kind enough to send me the new trucks but my camera was having some issues which turned out to actually be a user malfunction. In any case, I got it figured out and took this photo today. Better late than never and thanks again to John for the trucks!