Re: N4 cabin car


Claus Schlund \(HGM\)
 


Hi Bruce,
 
Bruce wrote: "I butt glued the ends on with ACC. I was a little less careful than I could have been on one end and so there was a noticeable step"
 
I too have used ACC for this type of work. There are, however, two major down sides to ACC. One is as Bruce described - any misalignment causes problems later once the ACC is fully set.
 
The second problem is that, in my experience, the solidified ACC is harder than the resin it is glued onto. This makes sanding any errant ACC difficult to do, because the resin sands away before the ACC does!
 
So I have found the rule is, be super careful when using super glue!
 
Bruce, great work, it is all looking good!
 
Claus
 
 

----- Original Message -----
Sent: Tuesday, November 24, 2020 10:01 AM
Subject: Re: [PRRPro] N4 cabin car

Folks,

N4 progress!  I cut the roof, floor, and ends as marked in the previous post. My suggestion is to cut a little wide and then use something like a TruSander to square the cuts and slowly sand back the right amount.

Floor/underbody - I sanded the two pieces square and then slowly sanded it back until the piece measured 3.995" (29 feet) total length and then glued the two halves together with ACC on a very flat surface. There was no issue with the parts being different thicknesses. I did use a tiny bit of putty on the center sill to fill some slight mismatches.

Roof - I cut outside the 2nd roofwalk support from the cupola on one roof and inside the 1st on the other, basically adding a section on each end. Then I slowly sanded the part with the cupola back so that the support was flush with the sanded end, Then I sanded each end back, being careful remove the same amount from each until the overall length of the roof was 3.780" (27' 5.25"). I did spend some time shaving down the groove where the sides attach to make sure all the resin casting gates were fully removed. There was a slight bit of difference in thickness between the roof pieces but not so much that it couldn't be fixed with shaving and sanding. I butt glued the ends on with ACC. I was a little less careful than I could have been on one end and so there was a noticeable "step". In looking at the roofwalk supports, they were not evenly distributed so I shaved them off. I puttied the joints between roof pieces and then sanded it down. A light coat of Tamiya Fine Grey Surface Primer showed defects, so I used more putty, more sanding, more primer, more putty, and finally more sanding, to make it seamless. 

Sides - I did some experimenting here, and I'm here to say, do as I say, not as I did! 🙂  First, I figured out how long the side needed to be. The body of the N4 measured 34' 1.75" or 3.327" in HO. However, the thickness of the ends (0.050") is included in that, so the side pieces measure 3.227". To begin the process, I cut the ends of the side I was keeping off, just to the inside of the middle attachment for the curved grab iron (5 boards in). Then I cut the ends off the second side just outside the window. This was actually overkill in terms of having enough material. BTW, when I say "cut", I tried both a very thin razor saw and many passes with a hobby knife. The latter is probably better. Ultimately, what you will want is the end piece to be 11 boards, and the center piece to extend 7 boards from the window, or a total of 18 boards from the window to the end. I got too excited and cut the pieces above down directly to the correct length. DO NOT DO THIS!  Cut the sides one board too long on each piece (Cut the end pieces 12 boards long, and cut the center piece 8 boards from the window... or vary this so that the cuts are not the same on each end to help hide them!) and the use the TruSander to sand back one board. Do this carefully, so that you leave a little of the "gap" between boards. On one piece (which you can see in the photos), I had to recreate the "gap" by gluing in a piece of 0.010 x 0.030" strip styrene, puttying, and then rescribing the groove. Note, you'll also want to trim away the grab iron mounting points under the windows as these will not be used. Here, I did have issues with the thickness of the pieces. My ends were thicker than my middles, so I just sanded the ends down until they were the same thickness as the middles. Then I glued the pieces together with ACC. Spraying with primer helped identify issues, which I touched up with some sanding and rescribing of boards. Overall, I am happy with the sides. They may not be perfect, but I think I can make this work.

Regards,
Bruce
Bruce Smith
Auburn, AL


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