E33, E44, EF-3 Electrics in FUD (Shapeways)

[peteski]

Havingfuntoo:  you might be over thinking this.  The resin is quite resistant even to much stronger chemicals than naphta and the way it is printed seems to bond even the smallest cross-section items quite well. The ultrasonic cleaners used for hobbyists (like me) are very low power cleaners probably designed for cleaning delicate jewelry.

As far as naphta and heptane is concerned, you are correct, they are similar (but different): both are petroleum distillates.

[muktown128]

From a chemistry perspective, you are better off using heptane to remove the wax.  The chemical structures are simlar (long chains of carbon-carbon bonds), except the heptane is shorter (only 7 carbon atoms).  Naptha is a reasonable alternative, but won't dry or flash off as fast as heptane.  All of the materials would be considered non-polar. 

The glycol ethers are based on a different chemical structure and is more polar because it contains oxygen atoms.  I would not consider it to be as effective in dissolving wax because of this difference.  You also want to be a little more careful dealing with the glycol ethers.  Glycol ethers based on ethylene glycol have a higher health hazard than ones based on propylene glycol.  Consulting the MSDS is a excellent suggestion when working with any chemicals you are not familiar with.

Scott

[eagle5473]

This is another project that Rich from the UK site has been working on.

Aaron

[jmlaboda]

"This is another project that Rich from the UK site has been working on."

How 'bout a link?

As for the type it appears to be a Pullman Bradley American Flyer coach, but likely accurate for the Bangor & Aroostook, Boston & Maine and New Haven.  If accurate it could be something very worthwhile.

[DKS]

As far as using alternative solvents, I've tried acetone in addition to heptane, and surprisingly the acetone did not attack the RP resin. Of the two, my choice would still be heptane, as it evaporates the fastest by far, and has the least objectionable odor.

Then I tried MEK (Methyl Ethyl Keytone), hoping it might produce a softening effect to reduce the stepping. Interestingly, MEK had virtually no impact on RP resin. But I say "virtually" because I detected an ever so slight increase in tackiness of the resin surface, suggesting to me that there was a subtle but potentially desirable reaction. With repeated applications and some gentle rubbing, I was able to smooth the surface to a small degree. It's a difficult and tedious process, but early tests are encouraging and I believe it's worth further study.

Of the three solvents, though I will still return to heptane for wax removal, for the same reasons cited before.

The MEK test was very quick and sloppy, but the results have encouraged me to try the technique in a more controlled fashion, so stay tuned for additional posts on this topic.

[peteski]

Hmmm David, if you add all the chemicals you tried and which I have tried and posted my findings few posts earlier (if anybody bothered to read that), we have both confirmed that the resin used in RP is pretty resistant to solvents.   I also hoped that I could soften the resin (but if you want more details, you can just read my earlier post).

[eagle5473]

the link is pn page 1

[jmlaboda]

"the link is pn page 1"

Is there a link for the coach?  It is not shown in his list of items available.

[eagle5473]

http://www.rmweb.co.uk/community/index.php?/topic/49622-general-electric-e33-e44-e40-and-gf6c-in-n-scale/page__st__50


Not yet released to Shapeways for purchase yet.   Sound like all his work will be in the next few months

Aaron

[BCR 570]

It is neat to see pictures of these Shapeways models.  I was shown some PGE cabooses a few weeks ago and was impressed with the results.  I have ordered several as well as a pair of the GF6C electric locomotives.

Tim

[screeh]

It is neat to see pictures of these Shapeways models.  I was shown some PGE cabooses a few weeks ago and was impressed with the results.

Who is doing the PGE cabeese, Tim?  I'd be interested in seeing how they look...

[Lemosteam]

Going back to the cleanup, solvent and "stepping" discussion, has anyone tried to mitigate the stepping/surface quality using an air eraser?  Wonder if the aluminum oxide would knock down enough of the high points to improve the surface under the paint?

[daniel_leavitt2000]

It would only work if there was no surface detail. Anything on the model such as rivets would sheer off before the stepping was mitigated.

[Lemosteam]

Ahh but we have a custom rivet solution do we not?  Coming from one who has modeled rivets in CAD, these can make the CAD model much larger in size and complexity than may be necessary.  Maybe that is a reasonable tradeoff if the sandblasting helps to smooth out the stepping...

[BCR 570]

Who is doing the PGE cabeese, Tim?  I'd be interested in seeing how they look...

They were commissioned in HO and N Scale by a member of our PGE-BCR Modellers Group and rendered by the same gentleman who has produced the various electric locomotives.  I am not yet sure how they will be made available; when I am I will announce something here.

I am currently field testing a new resin kit produced from 3D masters and can confirm that sandblasting does indeed help to reduce the stepping characteristic of curved surfaces.  If you understand the printing process, it is apparently also possible to manipulate the build orientation to your liking.  This also helps with quality control, which at the moment is dependent on builld orientation and accrdoing to some has been inconsistent.

This is very promising technology and Shapeways have done a good job to make it accessible to hobbyists such as our crowd, but they are not at the forefront of the industry and there are other firms doing the same work at a higher level, albeit for more money.


Tim