Topics

One-Piece Cast Resin Box Car Bodies

Rossiter, Mark W <Mark.Rossiter@...>
 

A quick question for the resin kit builders out there.  Most of the kit manufacturers nowadays are using one-piece bodies for box cars, rather than flat wall pieces.  In many ways I view this as a huge leap forward.  My question is what, if anything, do you do with the big blob of resin on the underside of the roof casting leftover from the mold/casting process?  Do you attempt to remove this or do you just leave it alone?  Seems to me it could affect the preferred center of gravity on cars intended for operation. 

Mark Rossiter 

mopacfirst
 

My answer:  nothing.  I've only recently started to encounter one-piece bodies due to my backlog, and frankly I welcome them.  I've actually sold some flat kits when a different manufacturer made a one-piece version of the same car.

But to answer the question, the wall thickness is greater on the one-piece body, as a rule, and I've seen some that had a fair bit of resin on the inside, but not enough to matter in terms of CG.  I put two ounces of weight (fishing weights) in a 40' car, and I think that's enough to overcome the, perhaps, 0.1 to 0.2 ounce of extra resin in the top of the car.  I've weighed several of them, so this is somewhat based on actual data.

I recently took a Dremel to the inside of a one-piece body, one of those where the resin is white, but that was to clean up numerous low nubbies at the bottom edge of the ID that prevented the floor from sitting properly and I couldn't get a file in there.  Did I mention that some of the one-piece bodies also have a ledge at the right point to help the floor sit straight?  That was an issue with some older flat kits sometimes.

Another reason I'm not so worried about extra weight inside the car is that it's common for me to glue a piece of ,125 x .250, or ..250 square, on the inside of the car side at the top to square up the side, while I'm assembling the box.  I'll cement the floor solidly to the bottom edge of the sides later, during final assembly when the floor is painted black and the sides and perhaps ends are different colors but the top edge being straight is the most critical because of the way some car sides of older prototypes meet the roof.

Ron Merrick

Bill Welch
 

I have assembled many one piece body kits and have many still in kit form. I have never seen one with a "big blob of resin on the underside of the roof."

Bill Welch

WILLIAM PARDIE
 

I had a concern with several of the early one piece bodies in that there was a groove between the send and the sides.  This would happen with flat kits if the ends of the sides and the back of the ends were not perfectly flat.  Pn the flatkitsthis was easily corrected.  I gave not bought any of the recent one piece offerings so I don't know if this problem persists.

One piece bodies are certainly a time saver.

Bill Pardie



Sent from my Verizon, Samsung Galaxy smartphone


-------- Original message --------
From: mopacfirst <ron.merrick@...>
Date: 1/3/20 12:50 PM (GMT-10:00)
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] One-Piece Cast Resin Box Car Bodies

My answer:  nothing.  I've only recently started to encounter one-piece bodies due to my backlog, and frankly I welcome them.  I've actually sold some flat kits when a different manufacturer made a one-piece version of the same car.

But to answer the question, the wall thickness is greater on the one-piece body, as a rule, and I've seen some that had a fair bit of resin on the inside, but not enough to matter in terms of CG.  I put two ounces of weight (fishing weights) in a 40' car, and I think that's enough to overcome the, perhaps, 0.1 to 0.2 ounce of extra resin in the top of the car.  I've weighed several of them, so this is somewhat based on actual data.

I recently took a Dremel to the inside of a one-piece body, one of those where the resin is white, but that was to clean up numerous low nubbies at the bottom edge of the ID that prevented the floor from sitting properly and I couldn't get a file in there.  Did I mention that some of the one-piece bodies also have a ledge at the right point to help the floor sit straight?  That was an issue with some older flat kits sometimes.

Another reason I'm not so worried about extra weight inside the car is that it's common for me to glue a piece of ,125 x .250, or ..250 square, on the inside of the car side at the top to square up the side, while I'm assembling the box.  I'll cement the floor solidly to the bottom edge of the sides later, during final assembly when the floor is painted black and the sides and perhaps ends are different colors but the top edge being straight is the most critical because of the way some car sides of older prototypes meet the roof.

Ron Merrick

Tom Madden
 

It's a non-issue. I just dug in the trash and found one of the casting fill tube stubs I remove from Resin Car Works reefer, boxcar and auto car bodies after demolding. Photo attached. I snap these off and they break almost flush with the underside of the roof so there's no "blob" left, but even if I left them on the whole stub weighs only 1.2 grams. That's all of 0.04 ounces. It's 3/16" diameter and 1 3/4" long. No effect on the center of gravity.

Tom Madden

Rossiter, Mark W <Mark.Rossiter@...>
 

Thanks to all who responded to my inquiry, on list and off.  Sounds like it is nothing to be concerned about. 

 

Mark Rossiter

 

william darnaby
 

As a final…or,maybe not…comment on one piece bodies, I have not found them to be a great time saver over flat kits because of issues that I run across.  Your mileage may vary but I have found that it takes time to clean up the bottom edges of the castings as there are lumps and bumps of resin.  I think some of these are vents or risers from the casting process.  I have had to do repair to these areas to get a clean and straight bottom sill on the sides and ends.  One car I assembled this summer had the corner of the sill so badly damaged I had to create a new corner with modelling putty.

 

Another issue is the shelf inside the body being uneven or not deep enough to allow the floor to sit down inside far enough to allow the crossmembers to sit behind the sill tabs.  It sometimes takes a fair amount of scraping with a square edged modelling knife to clean up that shelf.

 

Then there is the issue of warpage.  I have had to install pieces of quarter inch square styrene across the interior of the casting so the sides do not noticeably bow in.

 

Such is the resin world.  And, as I said, YMMV.

 

Bill Darnaby

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Rossiter, Mark W
Sent: Saturday, January 4, 2020 5:08 AM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] One-Piece Cast Resin Box Car Bodies

 

Thanks to all who responded to my inquiry, on list and off.  Sounds like it is nothing to be concerned about. 

 

Mark Rossiter

 

Tim O'Connor
 


I agree Bill.

The sad truth is that not many people can produce perfect 1 piece bodies. But
they are getting better! The RCW 50' SOO box car - no complaints!

Fixing serious warpage is really challenging - e.g. a "twist" in the body. Ugh!

If you've never seen one of Gene Fusco's one piece "Railyard" X58 box cars (or his
other cars) then you've really missed something.



On 1/4/2020 9:16 AM, william darnaby wrote:

As a final…or,maybe not…comment on one piece bodies, I have not found them to be a great time saver over flat kits because of issues that I run across.  Your mileage may vary but I have found that it takes time to clean up the bottom edges of the castings as there are lumps and bumps of resin.  I think some of these are vents or risers from the casting process.  I have had to do repair to these areas to get a clean and straight bottom sill on the sides and ends.  One car I assembled this summer had the corner of the sill so badly damaged I had to create a new corner with modelling putty.

 

Another issue is the shelf inside the body being uneven or not deep enough to allow the floor to sit down inside far enough to allow the crossmembers to sit behind the sill tabs.  It sometimes takes a fair amount of scraping with a square edged modelling knife to clean up that shelf.

 

Then there is the issue of warpage.  I have had to install pieces of quarter inch square styrene across the interior of the casting so the sides do not noticeably bow in.

 

Such is the resin world.  And, as I said, YMMV.

 

Bill Darnaby

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Rossiter, Mark W
Sent: Saturday, January 4, 2020 5:08 AM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] One-Piece Cast Resin Box Car Bodies

 

Thanks to all who responded to my inquiry, on list and off.  Sounds like it is nothing to be concerned about. 

 

Mark Rossiter



--
Tim O'Connor
Sterling, Massachusetts