Zio Prudenzio Contest - Gr-950

**Darwin** · #1 05-29-2011, 04:25 PM

Ever since building Zio's snowplow, I've been looking for something "exactly right" to push it. It appears that my quest has been answered by Zio posting the Gr-950. When I saw the number of pictures of the little beast posted on the download page, I figured I was in for another instructionless puzzle....very pleasant surprise to find more pages of construction diagrams than pages of parts, which will make this one much easier. I was finally able to work through the building block that buggered me all winter....warmer weather and some sunshine works all kinds of wonders, both mentally and physically. The current build project should be complete within the next couple of hours....will then get the printer cranked up and start on this one.

**B-Manic** · #2 05-29-2011, 07:00 PM

That's a beautiful engine. I am considering it to pull the Carro L (garitta) I'm building.
BTW bestpapermodels . com has HO scale tracks as a free download Paper model 1/87 (HO) Train tracks | Bestpapermodels.com if you are interested.

**Don Boose** · #3 05-29-2011, 08:19 PM

Looking forward to seeing this. I downloaded this locomotive and would like to give it a try some day. As Douglas says, its a beauty.

Don

**cjwalas** · #4 05-30-2011, 07:28 AM

Really looking forward to following this one as well. I was hoping someone would go for it. It looks like you could have an impressive train with all the cars Zio provides.
Chris

**Darwin** · #5 05-30-2011, 12:31 PM

After the Coke-600 checkered flag waved, I started in on the build. Probably should have waited until morning, but too impatient to start. For those unfamiliar with Zio's design methods, he has a rather unique way of doing parts that are printed on two sides, like the frame pieces. His method works very well, but is very exacting and unforgiving of being a little bit off on scribing the fold between the front and back of the piece. My way of coping with this is to first identify the portion of the part than have the gluing tabs. On the untabbed portion, trim the excess paper away to the outline of the part along the edges where tabs will be located. Once that is done, scribe, fold, and glue the part. When the part is completely dry, check that the folded edge is still straight. (The first of the frame rails I made, I used tacky glue. When about half dried, I noted that the part had badly bowed...looked a bit like a banana. I freaked and immediately reprinted the page, figuring the first attempt was a lost cause. However, once completely dry and after flattening it out, the folded edge was once again nice and straight, so the original part was still usable. The second of the frame rails I used super glue as adhesive, with no distortion of the part at any stage of the process.) When the part is completely dry, place it on the cutting mat so the tabbed side is visible. Trim the part to the outlines, including the internal cutout regions. Kind of reminded me of doing Scherenschnitte when I looked at the pile of little paper bits on the workbench after cutting. Now scribe and bend the tabs. Trust in Prudenzio....if you were precise in locating the fold scribe, the outlines of the untabbed half of the part lie exactly where they need to be in order to fold the tabs.

A complication of this model is that the platform looks like a topo map in the cab area, and requires a whole lot of dryfitting to figure where the folds need to be. As much trouble as it was getting the base shaped, I decided to make the cab floor from bond paper rather than cardstock, figuring it would be a lot easier to get it to conform to the contour of the platform. This may prove to be a mistake, as exacting as dimensions are in one of Prudenzio's kits....but it did make this part of the build go faster. I noted the first fit problem at this point....the cab floor is not quite as long as it should be for an exact fit on the platform...the white region at the cutouts in the platform tell the story. I don't think it's anything a judicious use of black Sharpie won't hide.

After gluing the two frame rails to the platform, I noted that the assembly had all the torsional stability of a wet noodle....to hope to get all wheels to lie on the rails, I decided to make a holding jig to keep things straight during assembly of the major pieces of the model. As a quick-and-dirty approach, I used the "spare" page I printed of the frame rails. I trimmed the rail piece so that the upper edge was flush with the bottoms of the axle holes, and used the fold line for the lower edge of the jig side. The two jig sides were backed with 2mm cardboard (actually, picture framing mat board), then glued onto a base of 2mm cardboard, spaced so that the frame rails would fit between the jig sides. I then inserted pieces of appropriately sized dowels into the axle holes (long enough that there is enough extending past the jig base to attach rubber bands to hold the dowels snugly against the top of the jig sides. And now the build is stalled, as my wife seems to have confiscated the little baggie of rubber bands I thought (foolish me) I had in the stationery drawer. A trip into town is in order.

In the "if I were to do it over" category....when I inserted the first dowel into the axle holes, it revealed my mark 5 calibrated eyeball let me down while assembling the base platform and frame rails. One of the rails is a skoshie bit further forward on the platform than the other, and as a result the entire wheel assembly is a bit catawampus. I don't think it will be enough to be noticible when the model is eventually placed in the diorama setting I plan for it, so am forging ahead (once I buy TWO packs of rubber bands and carefully hide one of them in my modeling stash). If I were to do it over, I would build a more precise jig, with enough of the frame sides to include the entire axle hole, and build the jig precisely enough to guarantee the frame would be perfectly square when the rails are attached (by dowels) to the jig, then attach the platform. Live and learn (and it proves a bunch easier to think of that at 9 am than at 3 am.....).

**cjwalas** · #6 05-30-2011, 12:46 PM

This is already an impressive build. That frame looks like a mine field for any less skilled and experienced modelers. It sounds like you're building this to be extra strong and rigid with the thicker cardboard, which seems immensely wise in the shadow of all the possible warping on a model like this. I'm taking notes.
Chris

**Darwin** · #7 05-30-2011, 12:50 PM

Chris, only the jig is made from heavy cardboard...I'd toyed with the thought of backing the frame and platform with 0.5mm cardboard, but decided instead just to build it as Zio kitted it.

**Don Boose** · #8 05-30-2011, 12:53 PM

This is really excellent stuff! I am saving your narrative and photos for a possible future build, but your description of some of the nuances of Zio models is applicable to all of his vehicle models. I have learned through trial and error some of what you describe regarding double-sided tabbed parts, but still learned some new approaches (I read this thread during a break from fabricating the towing pintle trails for the Carden Loyd tankette and was alternately nodding my head in agreement and saying to myself, "Oh, yeah! That'll help!").

There have been a number of exceptionally interesting (exciting, actually) and informative threads lately, and this is definitely one of them.

Don

**Darwin** · #9 05-30-2011, 01:00 PM

Thanks for the words of encouragement, guys.

**cjwalas** · #10 05-30-2011, 01:17 PM

Quote:

Originally Posted by Darwin

Chris, only the jig is made from heavy cardboard...I'd toyed with the thought of backing the frame and platform with 0.5mm cardboard, but decided instead just to build it as Zio kitted it.

Sorry, my misunderstanding. In my continual search for finding ways of reinforcing Zio's models, I saw answers where there were none.

I'll be interested to see if you do encounter any warping along the way.
Chris