The Google SketchUp Thread

[finescalerr]

Your assignment, should you choose to accept, is to keep us informed of every step. This should be pretty cool. -- Russ

[eTraxx]

Russ. I've been watching the 'guys' produce these fantastic parts using PAP and was envious. Much like the ragged urchin nibbling his crust of bread while watching the wealthy sup at a grand meal. ..

My critter is On18 so this is an experiment to see just how well 1:48 will replicate using the PAP service. I am curious to see the result. I have had one printing from them on a simple object that warped a bit because of the thinness. I'm hoping the sprues will help in that. I have some doubts that the seat frame (front in the blue background view) will print without warping but .. shrug .. we'll see. I'm having fun creating this little critter since every time I do a 'bit' .. I then think of a better way for the 'next one'.

I just looked back at Marc's last printing. His final dimensions were round 1.75 x 1.4. This one of mine is about 1"x.85"x.6" and cost me $28 including shipping.

Here's another view of the model. Theres' a radiator on top. Below that are some poling pockets. Below those journal boxes. Up front is a seat frame. Behind that are coupler pockets and some brackets that fit below the journals.

Yeah. I'm really curious to see how well this comes out.

[finescalerr]

I am going to guess that the resolution will be a problem in 1:48. Havaard had issues with it in that scale and Chuck, in a scale twice as large, still had a fair amount of cleanup. Please post a photo of some parts off the sprue but before cleanup, then again after you sand them.

Aside from any deficiency in the print resolution or issues of strength because the parts are so thin, the fact that you were able to design and draw the parts in 3D means that, someday, you will be able to send them somewhere and get exactly what you want. It certainly won't have been wasted time. And $30 here and there is hardly a fortune to spend on such a valuable education.

I'm watching all these things closely because I want to design and build a 1:32 scale 7 ton Plymouth. I have one 2D side view mostly complete but still haven't used SketchUp enough to do anything with it. As things slowly progress I will start posting and get input from this group about how best to proceed.

Or else I'll just make Marty scratchbuild it for me.

Russ

[lab-dad]

 

Or else I'll just make Marty scratchbuild it for me.

Russ

I thought that was the plan!

Besides by the time we get around to it we'll all have rapid prototype machines on our desks!
And robot girls (in thongs) to do the drawing & assembly!
-Marty

[marc_reusser]

OK...some stuff to share.

This time around I seemed to have several issues and problems with the PAP stuff....some of which was expected, as I was really trying to see how far I could push the process in some respects, and others were just plain weird.

After receiving the parts, and as noted, I gave the whole tree a wash of acetone to clean off the wax....well, a couple of the really thin parts did not like the acetone, and became a bit deformed (top image)...and once dry, the printed parts developed a severe "snowy" condition...as you can see from the 2 images it developed on most all the parts, but it was arbitrary...some parts had it in all sides, some on one side but not the other, and some developed it with funky patterns. I have no idea what caused this...maybe the wax used as spacer when building up the stacked parts, maybe it was a fluke in the process...not a clue ( I may try to contact PAP to see what they say).....mostly it came off pretty easy during the sanding/clean-up process....in some nooks it was harder to get out, and on some parts it reappeared a bit after sanding...but was able to be "killed" once the part was primered (even once the primer got sanded back down it stayed away)....so very strange.






Next issue...and I should have known better after the acetone bath...some thin parts don't react well to thick coats of brush applied solvent based primer. The brake retainer bows had a fair amount of layering texture, and due to their thickness were a bit on the fragile side for excessive sanding, so I thought I would use Mr. Surfacer 500 primer applied from directly from the jar, with a brush, and then a coat of Mr. Color Thinner, to level the surface; would work as a "filler" that then would require only some finish surface sanding.....alas, though....the solvent in the thinner and the primer caused the parts to deform (they will now have to be made of brass).




Lastly....and this was pretty expected.....some of the thin parts are quite brittle (luckily I made extras).  These parts would definitely have been better in PE....or even styrene, which is more pliant. [Cat hair in image added for scale]




But, in the end, despite some frustrations, I think this was a good excercise.
Here are some shots of the finished and pinned linkage (note the piece that broke while trying to shove the styrene rod through for the shot (this has been repaired). The linkage is fully articulated, for ease of installation and final positioning. Once installed it will be glued into a fixed position/form.

[marc_reusser]

Ed,

The parts look good. Looking forward to seeing your results.

M

[eTraxx]

Marc,
Thanks. Hope they resolve well .. at least this will give me a good idea what will work and what won't. I just went and looked. PAP under their FAQ says "a primer is recommended after an acetone or lacquer thinner dip". Your problems with the acetone makes me think that the lacquer thinner might be worth trying. If nothing else .. on the sprues first.

[marc_reusser]

Ed,

Be careful of the laquer thinner as well, as I believe that is the base in the Mr. Color Thinner, I used to thin the primer for the retainer bows...which subsequently warped.  But this could also be because the primer cured over a longer period of time, than it would take the thinner to evaporate by itself. All the parts that had the warping issue on were .010 or less in thickness.

M

[Chuck Doan]

I would definitely contact them. I had an issue with some duplicate parts not being as crisp as the first set. They offered to re-print them in a different orientation and this worked. They were very helpful.

I have seen the frosting, but I haven't had any issues with Acetone so far. Parts left uncleaned will develop a sparkly powder but this cleans off. I have had good results using ACC to repair breaks.

This material certainly has its limitations. I have re-printed a couple of the pump parts so they will be stronger. But none of them would weather a hit.

[eTraxx]

Ed,

Be careful of the laquer thinner as well, as I believe that is the base in the Mr. Color Thinner, I used to thin the primer for the retainer bows...which subsequently warped.  <snip>

That's right .. you said that. RATS!

[JohnP]

My extra PAP parts have also developed synthetic mold syndrome. So it is something with exposure to light or oxygen perhaps, or it could be a byproduct leaching out.

I always start with isopropyl alcohol as a solvent for cleaning, then move to denatured alcohol before hitting the hard stuff. I have to watch it at my day job of electronics manufacturing, some plastics are very susceptible to damage. PAP seems to one of those.

Meanwhile, before folks get too fussy about the rough finish from PAP in smaller scales, I believe one has to decide on the desired effect of the detail parts. If parts like these brake riggings are to create a detailed almost silhouette-like look under a car, then they are satisfactory. If they were to be part of a detailed diorama with car knockers working on a disassembled brake set, then maybe not so good. I think this was worth trying and will look good. My $0.02.

John

[marc_reusser]

Heck I am not fussy about these whatsoever...I am COMPLETELY happy with the results....have been both times I used PAP so far.  These parts are small and fiddely, but I would say 85% of the parts have been cleaned up to be perfectly smooth in surface, and on those, or those areas, that didn't, the remaining surface texture will work just fine with the paint and weathering finish intended.  Some of the grey striation texture that you see on a few parts is where, after sanding, the Mr. Surfacer (from a can) filled in, and leveled out, minor any minor remaining surface texture.

I simply felt I should completely disclose all these issues that I encounter, so that others planning on giving this a try will have an idea of what they could be getting into (I would hate to see a bunch of whiney model railroaders ordering parts from them, expecting some kind of a ready-to-use 3D printing miracle, and when they dont, pestering PAP with complaints, stupid issues and/or refunds....that would be a perfect way to ruin a really good resource).

Marc

[RoughboyModelworks]

(I would hate to see a bunch of whiney model railroaders ordering parts from them, expecting some kind of a ready-to-use 3D printing miracle, and when they dont, pestering PAP with complaints, stupid issues and/or refunds....).
Marc

Whiny model railroaders  Can't imagine such a thing...

On a more serious note though — the "snowy" growth is something of a concern and may be an indicator as to the archival properties of the material. If the condition doesn't return after painting, it would suggest it's some form of environmental reaction, suppressed due to the paint coating. My wheel centers aren't due until the first week of October, but it will be interesting to see how they stand up over time. I will probably paint mine shortly after receiving them, just to seal and isolate the resin from any environmental influences. I contacted my PAP authority on this issue and am waiting to hear if he has experienced a similar problem and if so, what does he recommend.

As far as contacting PAP is concerned about technical questions, that's one area where I've been disappointed in their service. I wrote to them on two separate occasions concerning specific STL file preference settings and have never received a response. Perhaps they're just too busy to answer what may be very simple and rudimentary questions to them, but still... In the end I just winged it using the Cobalt default settings and apparently all was well with the file.

Paul

[marc_reusser]

I decided to drop PAP a note, with an offer to send them images of the issue in question, and I also gave them a link to the post with the photos here. Will let you know what they say when/if I hear back from them.


Marc

[finescalerr]

Printapart is not the only game in town and seems to have its pros and cons. One thing that concerns me is whether the parts will endure over time. Even if you prime and paint them it seems the resin may deteriorate (from what you rascals have reported). And it is increasingly apparent Printapart is generally more suitable for larger scales, with 1:35/32 being about the smallest.

The lesson may be to choose carefully what you ask Printapart to create. While it may provide a solution, it may not always be the best choice. I would expect these issues to resolve as the technology improves.

Every post on this thread has provided very important information.

Russ