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Author Topic: Kenworth W900A and Fruehauf Dump Trailer  (Read 692 times)

rch

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Kenworth W900A and Fruehauf Dump Trailer
« on: July 05, 2019, 05:34:41 PM »
This is really a tale of two models, but they belong together.

Here in Texas the most common type of dump trailer is the frameless type in varying lengths. In recent decades the half barrel or semi-cylindrical body has taken over but when I was a kid the in 70s and 80s the outside braced type was the dominant style.

In HO scale there are several models of dump trailer with the axles mounted to a heavy frame that stays flat on the ground when the body tilts, but to my knowledge there are none of the frameless type. These frameless dump trailers have the axles attached directly to the body with a thin framework connecting the hitch and bottom of the ram to a pivot point on the trailer body near the middle. I turned to Google to find dump trailers for sale and that's where I came upon many high-resolution photos of a 1979 Fruehauf frameless dump trailer for sale.

I imported the photos into AutoCAD and began making 2D drawings using the width of the trailer body to scale the photos. Once I had the 2D drawings done I began the process of modeling the trailer in 3D. From the beginning I intended to print the model through Shapeways, so I designed objects that are below the minimum thickness threshold to print successfully, which means making some parts thicker than I'd prefer. Still, 0.024" is pretty thin, so the model didn't have too many compromises.








The kit was designed to have the option of building the trailer in the dumping position or in the closed travel position, so the ram was printed in both extended and compressed forms. Unfortunately, with this first draft print I received a couple parts that were warped owing to the very thin cross-section of those parts. The extended ram was one of those parts and it didn't make the cut to be assembled on this model. The dump gate and the thin frame are also warped but neither are too bad. Hopefully my luck will be better on the next one. I'll add some reinforcements to these vulnerable parts for the next print.

The good news is everything fit as designed and if the extended ram hadn't been too warped the model would have easily assembled into that version. I have printed the wheel/tire assemblies before so I knew they would turn out good and they did. I was really surprised at the print quality of the suspension part. All the details I included are there such as brake detail, U-bolts and spring leaves.




I primed the model with Tamiya Fine Surface primer with a couple extra coats on the nose end hoping to fill in the rough texture of the print. It didn't really work that well.






I painted the model with Floquil platinum mist which has a thin pigment grain and looks like aluminum, but in the future I think I'll go with Tamiya's Gloss Aluminum since it will cover better and hopefully help fill in some of the voids in the print. Of course, I could also work the body with a chisel blade to try to knock down some of the visible grain/layers in the print, which are fine to the touch but exaggerated by the Floquil paint. This isn't the finished appearance of the trailer, only the end of the construction phase.










That brings me to the tractors that haul these trailers. Where I live there's a trucking company with distinctive pink Peterbilts on white frames called McRyan Hauling. I first started seeing these trucks in the 90s and they really stood out on the highways. For my 1980s modeling era I decided to take this company back in time and put their paint scheme on Athearn Kenworth W900A cabs.

I know next to nothing about the real trucks. I know trains pretty well, but semi-tractors I just know what I've learned from building 1/25 scale kits as a kid and from looking at photos here (especially the old Hank's Truck Pictures gallery).

Anyway, a few years ago after seeing some Joe Enriquez models I decided to try scratchbuilding frames. I used Evergreen 263 channel with the edges sanded down to round them off a bit and 0.04" x 0.08" strip for cross members. I don't really go too crazy with it - I don't add gussets or rivets - but the little that I do ends up looking pretty good to my eyes, better than the Athearn frame which is what I used on older builds.




I used to have a small collection of Dennis Aust parts such as suspension, lift axles, winches, etc. but I used all that. So awhile back when I was upgrading some Lindberg Ford CL9000 tractors I drew up Ford fuel tanks and suspension based on a nice cutaway drawing I found online. I ended up using those suspension parts on a few other models including these two.

After searching for some fuel tanks, air breathers and steps, I came up with enough information to make some drawings and made the parts. The Holland fifth wheel I already had from a year ago when I was working on the Lindberg Fords.

Around the time I drew up the wheels for the trailer, I also did a few varieties of steel and aluminum wheels, including some duplex wheels for trailers as well as versions with steer and drive hubs. Those are all based on prototypes I found nearby in a neighborhood that has several truck dealerships and repair shops. That area has been gold for me when I'm in a measuring kind of mood!

So to put it all together, I built up some frames to use with some Athearn cab/grille parts I got on ebay for a song. Once I mocked up the cab, steps and fuel tanks on the frame I realized I didn't leave any room for a hydraulic tank so I lengthened the frame. The ugly patches are visible on the inboard side of the frame. They are very delicate but I really need to find a way to minimize the appearance of those. Maybe some etched platform is in order... Lots of Plano photoetch coming soon enough.




Speaking of Plano, Keith turned me onto the Molotow chrome markers. Those things are awesome, though I have learned to paint the parts I want first with a brush to get the crisp lines and edges then come back with the pen to get the pop of the chrome.

So here's where these models are today. Still a ways to go, but they've finally come together.






Hank's Truck Forum

Kenworth W900A and Fruehauf Dump Trailer
« on: July 05, 2019, 05:34:41 PM »

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JJG

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Re: Kenworth W900A and Fruehauf Dump Trailer
« Reply #1 on: July 05, 2019, 11:25:53 PM »
Way to go Ryan, very impressive work you have done so far! I think your idea of deck plates on the chassis to hide the extensions is your best bet, it will give more strength to the lengthened chassis too!

Jim.

rch

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Re: Kenworth W900A and Fruehauf Dump Trailer
« Reply #2 on: July 06, 2019, 06:32:05 AM »
Thanks, Jim. I've used the see-through material before and that's what I had in mind at first, but I think you're right about the solid diamond plate. The frames aren't exactly delicate, but they do twist and bend a bit so I'd hate to sand the splice brace down so much the frame gets weak enough to break. So diamond plate it is.

rch

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Re: Kenworth W900A and Fruehauf Dump Trailer
« Reply #3 on: July 18, 2019, 12:50:12 AM »
I got a shipment of photoetch parts in the other day, so I got to work on the W900A models again. The wire is 0.008" diameter bead wire from the craft store coiled around an airbrush needle. The exhaust heat shields are from Masterbilt Models. The rest of the photoetch parts are from Plano. I snapped these photos yesterday in the Texas sun. I was afraid they were going to melt it was so hot!








JJG

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Re: Kenworth W900A and Fruehauf Dump Trailer
« Reply #4 on: July 18, 2019, 10:15:27 PM »
Looking very good Ryan, details..........makes the difference for sure!! The coiled air lines are something I should add more often, excellent results. Good thing the units didn't stay in the Texas heat long.

Jim

chuckyr

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Re: Kenworth W900A and Fruehauf Dump Trailer
« Reply #5 on: July 18, 2019, 11:44:03 PM »
Excellent modeling skills! 

I have a load of photo etch and aftermarket model parts.Your model shows that you don't have to go ultra detailed to build a top quality replica. The frame looks great.

The final decals should set it off.  You know Microscale has decal sheets with Kenworth, Fruehauf and other truck markings.
« Last Edit: July 18, 2019, 11:55:37 PM by chuckyr »

rch

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Re: Kenworth W900A and Fruehauf Dump Trailer
« Reply #6 on: July 20, 2019, 07:17:50 PM »
Thanks, Jim and Chuck. I have a bunch of decal sheets so I'll go hunting through them for some accessory decals. I printed up some McRyan Hauling logos a long time ago on my inkjet printer. I'll have to see if those are still around and how well they've held up. If they're no good I'll have FedEx Office print some for me. They did my P-I-E trailer decals and they turned out pretty good.

Hank's Truck Forum

Re: Kenworth W900A and Fruehauf Dump Trailer
« Reply #6 on: July 20, 2019, 07:17:50 PM »

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