Need advise on cutting plastic locomotive body to use on rotary snow plow

[Lone Wolf and Santa Fe]

    I need advise on cutting a plastic locomotive body. I have a Athearn blue box rotary snow plow which I want to kitbash into a more prototype looking unit. The rear of the model has part of a boiler protruding from it from when it was steam operated. A few decades ago these plows were converted to run on electricity using traction motors from an old B unit which is permanently coupled to the rotary plow. When the shops did the conversion they removed the boiler and mounted a door from a F7B unit on the rear.
    I have a couple of old F7B shells to use to make the conversion but I’m not really sure how to cut the ends off or where exactly to cut them. I plan on cutting the rear off of a B unit and also cutting the rear off of the rotary plow and then glue the rear of the B unit onto the rotary.
    I have an exacto knife set which includes several blades. There is a serrated one which looks similar to a small hacksaw blade. I was thinking about using it. What do you think?
    Then the question is where to make the cut. Do I cut the shell about 1 or 2 millimeters from the end leaving the entire end intact? Or should I just cut off the inside part of the end without touching the side of the shell?
    If anyone has done anything like this I would like your advise. Thanks.

[doctorwayne]

I wouldn't cut the ends from either, as it's unlikely that the curve of the B-unit's roof is the same as that of the rotary plow.
Instead, cut the door and doorframe from the B-unit, leaving some excess material on all sides, then use a file and/or sandpaper to neatly remove the excess.
On the plow, remove the smokebox front - it was a snap-in detail, and should snap-out, too.  I don't have an Athearn rotary plow to which I can refer in order to detail what needs to be done next, but I would first cut a hole for the F-unit door:  centre it from side to side and at the required height, but make the initial opening smaller, both in width and height, than the prepared door, then carefully file the opening to the proper size.
Once the door and frame has been cemented in place - use solvent-type cement, not ca - you can decide how to finish whatever is still showing on the back of the plow from the removal of the smokebox front.

If there are holes from the former clips, it's preferable (and easier and stronger) to fill them with plastic rather than putty.  To do so, strip styrene (Evergreen offers an almost infinite variery of sizes) works well - as I recall, those holde are either square or rectangular. 
Otherwise, if the holes are round or not too big and could be drilled-out to become round, you may be able to plug the holes with sprue material left-over from a kit.

To use either sprue, or rod or strip material, square or rectangular in cross-section, the round hole should be about .003" smaller in diameter than the filler rod, or a couple of thou smaller in both dimensions than that of the square or rectangular strip-material filler.
Use a small brush to apply solvent-type cement to the end and circumference of the filler material, then to the walls of the hole and then re-apply cement to the filler.  Next, force the now-softened end of the filler material into the also softened walls of the hole.  Allow the joint to fully harden (overnight is preferable) before cutting off the excess material, then use a sharp, chisel-type blade in your X-Acto (bevelled-face on the work surface, so that it doesn't dig-in), and finish with a file and/or sandpaper.  Once painted, the plug should become an invisible part of the material in which it was installed, and also totally suitable to be drilled, even where the plug and original material touch, if you need to add grabirons or other details.

An alternative to plugging holes is to simply "plate-over" such distractions with thin styrene sheet material....once painted, it won't be all that noticeable.

Wayne

 

[hon30critter]

doctorwayne

it's unlikely that the curve of the B-unit's roof is the same as that of the crane.

Hi Wayne,

I'm not sure I understand the reference to a 'crane'. Did you mean 'plow' or is there something that I don't understand about rotary snowplow terminology?

Thanks,

Dave

[mlehman]

Lone Wolf and Santa Fe

I have an exacto knife set which includes several blades. There is a serrated one which looks similar to a small hacksaw blade. I was thinking about using it. What do you think?

I like the small hacksaw blades for cutting in close around details. But for larger cuts, I prefer to get a razor saw of some sort. The longer length and stiff backing make it easier to get a square cut.

As Wayne advised, leave extra material and then file to fit on both sides. Don't rely on the saw to get you there on the first cut. Also remember to factor in the size of the saw's kerf as it cuts.

[RR_Mel]

I kitbashed my Athearn snow plow by cutting out one section from the center using a Atlas snap saw.  I cut and removed a section between the rivets to shorten it.  I cut both walls then scribed a cut line on the roof between the two wall cuts.  When the cuts were complete I sanded both sections using a full sheet of 120 grit laying on a flat surface, sandpaper fixed to the table and moving the sections for a perfect fit.  I used Testors liquid plastic cement to attach the sections together.  The seam is very hard to see even knowing where the cut is.

 

 

 

My Athearn F7B snail is powered to push the plow, not prototypical but I like to be able to move them on their own.  I also powered the rotary blade with a small motor.  I control the blade motor on/off and headlight from the F7B snail decoder.

 

 

I’ve kitbashed several diesel shells using the Atlas saw.  For added strength I cover the seams on the inside with .02” Styrene sheet with Testors Liquid Cement, that also helps alignment. 

 

I had pictures of my snowplow kitbash but I didn’t keep backups and they were lost in the Goggle crash three or four years ago.

 

 

 

 

 

 

Mel

 

 

My Model Railroad   

http://melvineperry.blogspot.com/

 

Bakersfield, California

 

I'm beginning to realize that aging is not for wimps.

 

[doctorwayne]

Thanks for spotting my mistakes, Dave.  When I saw your post, I realised that I do have one of the Athearn rotary plows, so dug it out a few minutes ago to look at the holes into which the smokebox front snaps.

There are four rectangular holes, with the laterally-centered top and bottom ones a somewhat loose fit for Evergreen .040"x.100" strip styrene, while the mid-height left and right holes are an equally loose fit for .080"x.100" strip material.
The left and right holes may be the only ones needing to be plugged, as the new hole to be cut for the door may take care of the other two.

To plug those holes, I'd first cut some .005" sheet styrene into short strips equal in width and height to the openings, then use solvent-type cement to affix a piece of the material to the top or bottom of the openings and to one side only of the same openings.  Let the joint cure overnight, then use  short pieces of .080"x.100" strip material, prepared as outlined in my earlier post, and then jam them into the holes.

I've corrected the references to Athearn cranes (must've still been thinking of the recent thread on wreck cranes), and truly do appreciate your comments, Dave.

Wayne

[Lone Wolf and Santa Fe]

Thank you all for your comments. I found them all to be very helpful. I've been a little scared to do this and I'm glad I waited. I know you guys all do some very fine work and knew you would come through.

doctorwayne

I wouldn't cut the ends from either, as it's unlikely that the curve of the B-unit's roof is the same as that of the rotary plow.
Instead, cut the door and doorframe from the B-unit, leaving some excess material on all sides, then use a file and/or sandpaper to neatly remove the excess.

That is exactly why I asked. Thank you once again.