I'm about to dive into the most extensive diesel kitbash job I've done to date, building an EMD SDP38 out of an Atlas SDP35. One part requires me to rearrange some of the radiator compartment hood doors, and I bought some Cannon doors to do that. The instructions on the back sort of give me an idea how to stick them onto a clean sheet of styrene, but I'm not really sure how I would remove existing doors on the shell and replace them. Has anyone here done this before, and if so, would you have some pictures or guidance on how to do it?
-Peter. Mantua collector, 3D printing enthusiast, Korail modeler.
I've not used the Cannon doors, but have modified diesels to better represent particular prototypes. This E-8 B-unit had many of the original side panels removed, then replaced with sheet styrene, to allow creation of the various intake filters and the screened areas at the top....
For your Atlas SDP35, you'll need to decide what needs to be removed and what must remain.
I'd guess that it would be easiest to remove most of both sides, then cut out (and save) all of the original stuff that can be re-used. You can then create new blank sides using sheet styrene (I'd suggest at least .060" thick), then use solvent-type cement to graft them into place. For the saved parts, cut them from the unwanted portions of the original sides, leaving some extra material on all sides, then file (or sand) them to-size.
To re-install those pieces back into the re-built body shell, drill a 1/8" hole somewhere within the exact area where each part will be located. You can then use this X-Acto saw blade....
in an X-Acto handle, to roughly cut the opening needed. Next, use an appropriate file to to enlarge each opening so that each particular part will be a press-fit, with no gaps around its perimeter. You can then use a suitable brush to apply solvent-type cement from inside the bodyshell, without creating a mess on the outside.The Cannon doors (along with any other styrene parts) can also be added using solvent-type cement.I hope you'll share some photos as you do this work and some of the finished results, too.
Here's an older (from shortly after they were first available) Atlas SDP 35, with a scratchbuilt CN-style "safety cab"....
...and a Model Power FA redone as an FPA4...
...and an FB as an FPB4...
They look a little better painted, though...
Wayne
Thank you for the reply, Wayne. The two major points of this project are moving the entire hood a few scale inches forward on the sill, and then rebuilding the steam generator compartment in the back.
This is what I'm working with on the steam generator end. Everything to the right of the red line on both pictures should match already, sans the radiator grill. The doors to the left of the line need to be replaced to match prototype, and I might have to lengthen the hood a tad if I can make it fit.
I have no drawings of this locomotive to work off of, so I'm guestimating based on pictures and SDP40 drawings, which are somewhat similar. I'd like to keep as much of the original shell intact to help me with that, as I think I'm going to be pretty dimensionally lost without that skeleton. I was hoping there might be an established way of just cutting out the doors and replacing those while keeping the space around the doors intact, replacing one thing at a time while maintaining the overall structure. Do you see a way to go about doing that?
I'm currently bashing some Cannon front end parts to help get the hood shifted forwards.
Da Stumer...I was hoping there might be an established way of just cutting out the doors and replacing those while keeping the space around the doors intact, replacing one thing at a time while maintaining the overall structure. Do you see a way to go about doing that?
I dunno...cutting out the individual doors in order to replace them with the Cannon ones seems to me to be a lot more work than simply cutting out the entire area that needs to be modified, then replacing the removed portion with some plain sheet styrene. This would allow you to easily cement the new doors (which I'm guessing will be different than the original ones, both in their placement and perhaps their size, too) in place quite easily. If you're not comfortable with hacking-up the body shell (if I understand your intentions, all that's needed is to remove the portions that need to be changed) you might be able to file- or sand-away the body shell's existing doors in order to add the Cannon ones, but I still think that replacing that section with new smooth material would make your job easier and more likely to achieve the results you want.When a section of the body shell is removed you can't expect to simply add the new portion and cement it in place...you'll need to not only cut the replacement portions accurately, but also add material to the inside of the body shell in order to reinforce the joints between the new pieces and the original. It doesn't need to be overly thick, as the loco's frame and running gear needs to fit into the re-worked body shell.
I find that a lot of this kind of work can seem overwhelming when you first decide to undertake it, but it usually presents ways to accomplish what you want...some will be very obvious, while others will have you stumped until you get that "AHA!" moment, and it will suddenly become clearer about how you'll need to proceed.Wayne
That is good advice, thank you. With how thick the Cannon doors are (about 0.020"), I think I'll have to cut out some parts and replace them.
What I struggle with the most when working with plain styrene is keeping the cuts and edges square. I can envision cutting out the entire section of doors, keeping the space above and below the doors in place. How can I keep both the cuts on the body and the cuts of styrene to fill the space as square as possible?
Peter, do you have a modeler's miter box? That may be helpful.
I have a miter bix with razor saw and a razor blade miter chopper thing that doesn’t work very well.
Da StumerWhat I struggle with the most when working with plain styrene is keeping the cuts and edges square. I can envision cutting out the entire section of doors, keeping the space above and below the doors in place. How can I keep both the cuts on the body and the cuts of styrene to fill the space as square as possible?
A small modeller's square, like this one that I found in a box of train junk years ago...
can be helpful, but you could also use a full-size square to cut an accurate square from some fairly thick (.060") sheet styrene (I don't mean a square like the one in the picture, but simply a squared piece of styrene). You can then place it on the loco's walkways to make vertical lines (using either a pen or pencil, or the tip of an X-Acto blade). You'd then cut out the major portion of the material to be removed (the X-Acto saw blade in my earlier post works well - simply drill a hole in the material that's to be removed - large enough, of course, to allow insertion of the blade, then work your way around the major part of the material that needs to be removed.
You can then come back with a suitable file to remove the left-over material to the previously drawn lines.
Running a file back-and-forth often results in the file "rocking", which makes it remove material on the outside and inside faces of the cut. When you go to add the plain heavy blank piece of styrene, you should get a decent fit, but with small gaps where the file has removed material that it shouldn't have.Don't despair...when the piece has been installed, you'll need to add a thin-nish (.010" or .015") sheet of styrene on the inside of the bodyshell....cut it a little larger than the blank piece, so that the back of the filler piece is completely covered and overlaps onto all sides of the opening in body shell.Once those joints have hardened, you can easily touch-up any small gaps between the bodyshell and the new piece.For that, I've found that 3M's BONDO Glazing & Spot Putty works very well. It's not expensive, and comes in a tube, and works much better than any of the modelling putties I've used in the past. It also has a very good shelf-life (as long as you replace the cap after use, of course).When the cap is removed and the metal seal pierced, you'll find a fair amount of liquid at the top. It's often recommended that you replace the cap and knead the tube in order to mix the liquid with the putty, but I've for it easier to use a small screwdriver to dip into the tube, in order to lift out a glob of putty, along with some of the liquid. I place it on a small sheet of aluminum, then use the screwdriver to mix the liquid and putty. Next, use an X-Acto chisel-type blade (in the knife handle) as a small putty-knife...dip in into the glob of filler, then smear the putty into any areas where there are gaps or depressions. It will harden fairly quickly, but I usually wait until the next day to sand off any excess putty, using a very fine grade of sandpaper. Brush (or blow-off) the resultant dust, then repeat the process of applying the putty wherever more is needed. Repeat as necessary...repeated thin applications seem to work better than trying to do it in one or two attempts. Properly finished, and painted, the joints will be invisible.
Thank you Wayne, that gives me a good place to start!
Cut out a section of one side of the hood and sanded down the radiator screens. Here’s a test fit of the new doors. I’m going to be using 0.020” styrene as the base because the total thickness of the new section can’t be thicker than the original shell. There is pretty much zero wiggle room over the chassis weight, just barely enough that I could use some 0.010” to reinforce the seams, not really ideal but I hope it works.
Again, this is what the section looks like on the prototype:
The blank section between the last door and the end of the hood is a bit too short on my model. I can’t figure out where the discrepancy lies, but I guess it’s not terribly noticeable. I can’t make the hood any longer or it won’t fit.