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The William K. Walthers Corporation has filled a major void in model railroading since they began shipping their HO scale blast furnace kit in the summer of 1996. Despite its compressed size, the finished model bears a convincing resemblance to the structure that has symbolized the iron and steel industry for the past century. Now virtually anyone with kit building experience who wants a pike based upon steelmaking may build that type of layout.
Many of us want to improve the rudimentary appearance of the 'vanilla' Walthers Blast Furnace (which I'll refer to as the 'WBF' from this point onward). The kit provides an excellent starting point for replicating an iron smelting facility in miniature, but anybody who has examined a prototype blast furnace quickly realizes there are infinite opportunities for upgrading the HO model. Writings of Dean Freytag* and others, scale blueprints by Mike Rabbitt*, and a set of videotapes by Jeff Borne*, all provide ample information on how to convert the WBF into a world-class structure; however, finding the time necessary to tackle all of these projects may prove difficult. If you are "time challenged" yet want to have a blast furnace that can be uniquely identified with your own pike - and not just another out-of-box kit - this article is for you.
* See details in "Additional Resources" section.
I have not yet found any technical names for the gas uptake pipes that run between the bell platform and the downcomer on all post-WWII blast furnaces. Since I plan to refer frequently to these pipes, I want to establish a few single-syllable words describing them.
Looking sideways at a modern uptake pipe configuration, it's easy to imagine a small child's drawing of a person minus the head or arms. For lack of any better terms, the twin lower pipes will be called the "legs" and the larger, single upper pipe, the "neck." The wishbone-shaped piece from the WBF kit containing both the lower legs will be named the "wye."
The two-letter suffix "-OD" refers to the Outside Diameter of any scale model tubing used in the upgrade project.
Visit any HO layout with a blast furnace on it, and you can quickly determine if it came from the Walthers kit. Figure bf_old_layout_bw_text.jpg shows four of the 'signature' features of an out-of-box Walthers kit.
First, the downcomer pipe appears very narrow. While this may have helped Walthers increase sales of their kit to N scale modelers, it poses a problem for HO enthusiasts who know what a real blast furnace looks like.
Second, I have never seen open handrails on the bell platform of any prototype blast furnace - they are always covered with solid sheet metal (I admit, I'm not sure exactly why).
The third obvious Walthers trait is the gas uptake pipe configuration. Since the WBF replicates a structure of the post-WWII era, the uptakes on each side combine in an inverted wye, resembling a headless body with legs. On most real-life furnaces, the quadruple bottom 'leg' sections rise approximately 1/2 of the overall height of the top piping from the bell platform. However, the legs of the WBF ascend to 3/4 of the uptakes' total height. Mind you, there is absolutely nothing incorrect about this - it simply is another Walthers spotting feature.
Fourth, perhaps the most recognizable characteristic of a WBF is the topmost junction of the uptakes with the downcomer. Viewed directly from the front or rear, it resembles an inverted 'U'. While there are indeed prototype structures built this way - figure B_Zug_SIG.jpg shows an example - 90% of the prototypes I've seen have their downcomers joined to an inverted 'M' piping arrangement.
Anybody reading this article could undoubtedly point out more examples of how to recognize a WBF on a layout. However, to keep this presentation brief and manageable, we will focus only on the four listed above. Regarding smaller details like stairs, walkways, and valves, I do not plan to discuss them or include them in photos of the finished models - I defer that topic to the masters (Freytag, Borne et al.).
As with any modeling project, you will first need to gather the necessary tools and supplies [glue, tape, etc.]. Not every tool is needed for every style of conversion, but I am listing them all together here to conserve space.
Figure bf_kitbash_001.jpg shows what I used in kitbashing the WBF, including:
* Dremel Moto-Tool (with 1/4-inch cutting/grinding bit)
* X-Acto (or compatible) razor knife
* Rail cutters
* Precision needle-nosed pliers
* X-Acto (or compatible) razor saw with miter box
* Quick-Grip clamps (set of 2)
* Rubber bands (dozen)
* Ruler
* Fine-point permanent marker
* Medium-coarse file
* Sandpaper, 50-grit
* Protractor
* Plastruct PlasticWeld liquid cement
* J-B Weld slow-setting "steel" epoxy
* Pin-vise (with various sizes of miniature drill bits)
* Jewelers' screwdriver set
* Machine screws, size 0-80 by 1/4-inch
As for the various Plastruct and Evergreen materials, these will be listed according to whatever conversion style they are used in.
Materials Needed:
* Evergreen plain sheet styrene, .020-inch thickness (1 sheet)
First you will need to cut a sheet of .020"-thickness styrene into a 1/2-inch wide strip. Next, hold the strip beside each of the seven octagonal sides covered by the handrail (the eighth side adjoins the skip boom) and mark their lengths using a fine-point permanent marker; now snip off each marked section using a pair of rail nippers. Figure bf_kitbash_015.jpg shows the bell platform and the seven strip styrene pieces laid side-by-side. NOTE: the sides are NOT all the same length.
The bell platform I used was leftover from a previously kitbashed WBF and had been cannibalized, so it was missing its handrails. Therefore I needed to pre-attach my panels to each other in alternating sizes (see figure bf_kitbash_020.jpg), wait approximately 5 minutes for the PlasticWeld to congeal, then pick up the string of attached panels and bend them into an open-sided octagon shape (see figure bf_kitbash_025.jpg). I then placed them gently onto the bell platform with the open section straddling the skip hoist bay (see figure bf_kitbash_030.jpg), lining them up correctly and cementing them into place.
If your bell platform still has its handrails, you can simply glue the individual panels to their corresponding-length handrail sections.
NOTE: This section will only describe the downcomer's lower-end construction. Top-end cutting and fitting instructions vary with each different top piping arrangement, so they will be covered separately.
Materials Needed:
* Plastruct 1"-OD tubing (2 15-inch sections)
* Plastruct 45° elbows for 1"-OD tubing (2)
* Plastruct tube cap for 1"-OD tubing (1)
Hopefully, the cast house and dust catcher on your WBF kit have been assembled and the furnace stack mounted to the cast house floor. If not, you will need to complete those tasks (using the Walthers kit assembly instructions) before proceeding to the next step.
If the original downcomer pipe is still attached to your dust catcher, you must remove it; cutting may be required if it was cemented, otherwise it should simply slide out.
Some delicate preparatory 'surgery' may be necessary on the top end of a fully assembled WBF. For starters, the frame and handrails of the explosion valve maintenance platform need to be removed - a pair of rail cutters may prove very useful for doing this. Some breakage will probably occur, so just save the pieces in a re-closable plastic sandwich bag for later repair. Next, using an X-Acto (or compatible) razor saw, cut the floor of the platform into separate halves. Now carefully sever the tops of each gas uptake just below the bend, so that you will have what resembles a pair of 90° elbows (see figure bf_kitbash_032.jpg).
At this point you should be able to completely detach the downcomer's center 't' junction from both sides of the gas uptake system. If this junction was cemented you will need to cut it.
Once the old downcomer is removed, take one of the 15-inch sections of 1"-OD tubing and carefully ream the inside surface at a steep angle (see figure bf_kitbash_033.jpg), so that it will fit tightly over the top of the dust catcher. Label this end "bottom" with the fine-point marker. Next, take each 45° 1"-OD elbow and shave off the joint 'ribbings' with an X-Acto knife; this will enable the elbows to fit reasonably snug into the tube, yet remain loose enough for twisting and adjusting - very important for final assembly. Take each shaved elbow and test-fit it into an un-reamed end of 1"-OD tubing, making sure you can twist them with minimal effort.
Having verified that the elbows can be repositioned easily, set aside the two elbows and the reamed section of 1"-OD tubing; now take the remaining tube and cut off a 2-inch length. This will become the topmost end of the downcomer. Set aside all of the other downcomer-related tubes and fittings; you will not be doing any more work with these until after you have assembled your customized top piping system.
Enlarging the Downcomer: Part 2 (Applies to all 3 conversion examples)
NOTE: Before doing the work described in this section, your gas uptake piping assembly MUST be completed to your satisfaction. Please skip to one of the three uptake conversion examples before continuing with the downcomer enlargement; if you do not plan to modify your uptakes, refer to the paragraph titled "Downcomer Top 't' Junction" in the B Furnace - US Steel Zug Island section.
With the top piping assembly attached to the furnace stack on the cast house, you will be ready to do the necessary positioning and measuring to cut the correct lengths of 1"-OD tubing for the downcomer.
Start by noting the current location of the dust catcher: if built according to the original Walthers instructions, it should straddle the track used by the slag cars. Regardless of where you choose to position it, the dust catcher plays a vital role in determining the lengths of pipe you need.
Take the piece of 1"-OD tubing that you reamed earlier, and place the modified end over the top of the dust catcher. Next, attach a 45° elbow to the other long section of 1"-OD pipe. (NOTE: You may want to enlist another person to help you stabilize the furnace topworks before continuing with the next step.) Now connect the same elbow to the downcomer's top segment, and pivot the long upper tube until it intersects the lower vertical section - hold the two pieces together there.
With your free hand, grab the unused 45° elbow and place it beside the intersection of the two pipes; make sure the vertical member (on the dust catcher) is in plumb. Mark the positions where each pipe would fit into the elbow, and make the cuts accordingly. You now have all the pieces you need to finish assembling your downcomer (figure bf_kitbash_052.jpg).
A recent trip to Detroit, Michigan with the Railroad Industries SIG yielded a gold mine of prototype blast furnace photos. Of the three examples highlighted in this article, one is the 'B' furnace at the United States Steel (formerly National Steel) Great Lakes Works on Zug Island; the other two are the 'C' (a.k.a. "William Clay Ford") furnace and the partially-dismantled 'A' (a.k.a. "Henry Ford") furnace at Rouge Steel in Dearborn. I chose to include two from one facility to illustrate how different furnaces can appear even on the same property. One other feature common to all three examples is that, like the WBF, they each contain only two explosion valves at their summit (most prototype furnaces have a third valve in the center).
Bear in mind that these are NOT exact replications of the corresponding prototype - I am focusing only on how their gas uptake pipes are configured.
Each conversion project will be discussed in ascending order of complexity.
My reason for including the 'B' Furnace is the resemblance of its upper downcomer junction to that of the WBF - an upside-down "U". This makes it (for me, at least) the easiest of the three conversion projects, so I'll discuss it first.
Materials Needed:
* Plastruct stub-in tees for 1"-OD tubing (2)
* Plastruct 3/4"-OD tubing (1 15-inch section)
* Plastruct 9/16"-OD tubing (1 15-inch section)
* Evergreen strip styrene, .020-inch thickness by 0.25-inch width (1 strip)
* Evergreen 1/4"-OD styrene tubing (1 piece)
Looking at the photo of the 'B' Furnace in figure B_Zug_SIG.jpg, we see much shorter versions of the lower uptake 'legs' than those found on the WBF. Our goals for this kitbash are to (1) complete the top section of the downcomer and (2) shorten the 'legs' and lengthen the 'neck' sections of both sides of the gas uptake arrangement.
NOTE: You may wonder why I use a lower-case 't' to describe the point where the downcomer connects to the uptakes. Take a look at the piece cut from the old downcomer with its 45° bend attached, and that is exactly what it resembles!
First you'll need to cut a pair of holes through the center of the 2-inch piece of 1"-OD tubing that you cut off earlier. To do this, you will use the two 1"-OD stub-in tees on a temporary basis - in other words, don't use too much cement! As shown in figure bf_kitbash_035.jpg, place each tee opposite each other on the 2-inch length, just slightly off center; be sure to also view the alignment of the tees along the crosswise axis (figure bf_kitbash_036.jpg) to ensure they face each other straight-on. Apply a tiny amount of PlasticWeld to the joints, only enough to keep the tees from slipping out of position, and wait 10 minutes for the glue to solidify. Next, use a fine-point permanent marker pen to trace around the inside of each tee where it touches the 1"-OD tube (see figure bf_kitbash_037.jpg). Now, quickly pull off the tees; a 3/4" circle remains on each side of the tube, marking where you will cut out holes for a 3/4"-OD tubing segment (see figure bf_kitbash_039.jpg). Using a Dremel (or compatible) rotary tool with a 1/4" cutting bit, cut out the center of each circle as shown in figure bf_kitbash_040.jpg. When the holes have been cut, try inserting a piece of 3/4"-OD tubing all the way through both holes. Keep enlarging the holes until the 3/4" OD tube fits snugly within each.
Next, cut off a 11/8-inch long section of 3/4"-OD tubing and insert this through the two holes in the 1"-OD segment. Attach a 45° elbow to the longer end (you did remember to position the pair of holes off-center, didn't you?); now you have a 't' junction for the top of your new downcomer (see figure bf_kitbash_050.jpg). With your razor saw, cut off the shorter side as close as possible (preferably within 1/8") to the 3/4" holes. Place a Plastruct 1"-OD tube cap on the freshly-cut end, then place the 3/4"-OD cross section of the 't' between both of the 90° uptake elbows that you cut off earlier. The original (uncut) ends of the bends have flanges to keep your new 't' junction aligned, but do not cement these together yet. However, with the 't' properly positioned, you should now re-attach the two halves of the explosion valve maintenance platform. A small rubber band may be used to keep the uptake elbows pressing firmly against the 't' member.
You are now ready to proceed to the second objective of the 'B' furnace imitation project: making the lower 'legs' shorter and the upper 'neck' taller. The first thing you need to do is trim the excess plastic from each of the two "wye" sections - 1/2 inch from the top and 1 inch from each "leg." Figure bf_kitbash_081.jpg is a cutting diagram for a wye with its 90° bend already sheared off the top. The darker area denotes what will be used, while the faded areas show what to discard.
The next step is to cut two (2) 25/8-inch lengths of 3/4"-OD pipe and two (2) 3-inch pieces of 9/16"-OD tubing (see figure bf_kitbash_090.jpg). These are the extended necks' visible outer pipe and the inner dowel, respectively.
Despite Walthers' claim that the tubing of their blast furnace kit is "fully compatible with Plastruct," I have not found this to be the case. The outside diameter of their tubing usually falls in between two consecutive sizes of Plastruct, so a bit of additional work is required.
The 9/16"-OD dowel tube fits nicely into the top bend and into the apex of the inverted wye, but not inside the slightly wider 3/4"-OD tubing segment. Therefore, to keep the outer Plastruct tube properly center-aligned with its Walthers mates, we need to add a pair of .020" rings near each end of the inside tube. This is done by taking a piece of .020"-by-.250" Evergreen (or compatible) strip styrene, pre-winding it (figure bf_kitbash_095.jpg), and wrapping it around the 9/16"-OD dowel tube. Each winding must be positioned so that it will be 'hidden' slightly inside each end of the 3/4"-OD tube (see figure bf_kitbash_100.jpg). Trim the excess strip, then cement the ring with PlasticWeld and let it sit for 10 minutes. Figure bf_kitbash_105.jpg shows a finished dowel tube beside a corresponding outer 3/4"-OD segment, alongside a combined pair lined up for connection to the elbow on the top and the wye on the bottom.
You will need to taper the outside edges of the 3/4"-OD tube at each end where it joins its slightly narrower Walthers mates, to eliminate (as much as possible) the width difference. A fine-grain file should do this job effectively. "Before" and "after" images of a tapered tube are shown in figures bf_kitbash_110.jpg and bf_kitbash_120.jpg, respectively. (Later, once all of the pieces have been permanently fastened into position, you may cover the joint with a thin layer of J-B Weld "steel" epoxy cement, which sands nicely and does not shrink.)
One slight modification is needed to the bell crane frame: It needs to be narrowed to make it fit between the two thicker 'neck' uptake columns. Although I originally thought I would have to partially disassemble it, shorten the cross members and re-cement the separate sections, I soon realized that I could simply grind away the horizontal beams where they adjoin the pulley axle (figure bf_kitbash_130.jpg); this area will be obscured by the uptake columns and therefore not easily visible.
Now you should be ready to rejoin the four uptake legs to the bottom elbows near the bell platform. Cut four pieces of Evergreen (or compatible) 1/4"-OD thin styrene tubing at a length of 1/2 inch for dowels, place these in each bottom elbow, and slide the legs over them - but do not cement them until later. A photo of a preliminary assembly of the modified pieces appears in figure bf_kitbash_135.jpg. Please note that when this picture was shot, the 3/4"-OD 'neck' pieces were still not tapered and the downcomer piping was not yet cut to fit the cast house and dust catcher.
To paint the structure, I bought two aerosol spray cans of Rust-O-Leum primer - one black, the other rusty brown - from my local hardware store. First I applied a coat of black, and after allowing 10 minutes for it to dry, I covered it with a very thin 'dusting' of rust brown. Please note, it is very important to have the component pieces connected to each other during the painting operation - this prevents mismatches of color.
Figure bee_model.jpg shows the final assembled, painted model. (Finishing work on the downcomer pipe is covered in the section titled "Enlarging the Downcomer: Part 2" near the beginning of this article.)
The 'C' Furnace is one of two active blast furnaces of the three still standing at Rouge Steel in Dearborn, Michigan. (Rouge's inactive 'A' furnace will be discussed later in this article.) It represents the most common downcomer/uptake pipe junction configuration: an inverted "M" when viewed directly from the front or rear.
Materials Needed:
* Plastruct stub-in tee for 1"-OD tubing (1)
* Plastruct 3/4"-OD tubing (1 15-inch section)
* Plastruct 9/16"-OD tubing (1 15-inch section)
* Evergreen strip styrene, .020-inch thickness by 0.25-inch width (1 strip)
* Plastruct 45° lateral tees for 3/4"-OD tubing (2)
* Plastruct 90° female-to-male elbow for 3/4"-OD tubing (1)
* Plastruct concentric reducers, 3/4"-OD to 9/16"-OD (2)
* Evergreen plain sheet styrene, .020-inch thickness (1 sheet)
With its uptake-to-downcomer junction pipes at a 45° angle (see figure C_furnace_front_clip.jpg), the 'C' furnace lends itself nicely to the use of Plastruct tubing and fittings. On this conversion project, we will eliminate the 2 stock uptake elbows and replace these with slightly longer, un-bent 'neck' pipes, each capped with a concentric reducer. The top downcomer segment will be impaled by a modified 90° bend, which in turn will connect to two modified 45° lateral tees that branch-off from the uptake 'neck' pipes. One additional task will be to cut out a small rectangle of sheet styrene for the explosion valve maintenance platform - that is, unless your original platform was not glued to your furnace.
First you'll need to cut a pair of holes through the 2-inch piece of 1"-OD tubing that you cut off earlier. To do this, you will use a 1"-OD stub-in tee on a temporary basis. As shown in figure bf_kitbash_150.jpg, hold the stub-tee firmly on the 2-inch length with your non-writing hand; with your writing hand, use a fine-point permanent marker pen to trace around the inside of the tee where it touches the 1"-OD tube. Upon pulling off the tee, a 3/4" circle remains on the side of the tube, marking where you will cut out one of the holes for the 3/4"-OD 90° bend.
Unlike the 'B' furnace example discussed in the previous section, the second hole will NOT face directly to the other one - it needs to be at an angle. To locate the optimum spot for the second hole, place the stub-tee opposite of the circle you just traced, then move it back until its tapered outer edge 'points' to the closest point of your circle; position the point approximately 1/4 inch from the circle (see figure bf_kitbash_155.jpg) and trace another circle as you did the first time. As shown in figures bf_kitbash_157.jpg and bf_kitbash_158.jpg, the holes line up on the vertical axis but not on the horizontal axis. Now use a Dremel (or compatible) rotary tool with a 1/4" cutting bit to cut out the center of each circle as shown in figure bf_kitbash_159.jpg. Once the holes have been cut, try inserting the 3/4"-OD 90° elbow through each. Keep enlarging the holes until the elbow can be pulled completely through.
As I hinted earlier, the 90° bend and the two lateral tees need to be modified in order to make the downcomer junction fit between the two uptake neck pipes.
First, sever the male-end dowel from the 90° elbow; then cut off approximately 1/16" from the same end. (Figure bf_kitbash_162.jpg illustrates a "before" and "after" comparison of two elbows.) Next, you must gouge out the inside of the castrated male end so it will resemble a female end (see figures bf_kitbash_163.jpg and bf_kitbash_164.jpg) - this allows the insertion of connecting dowels on both ends. To make the dowels, cut two 1/4-inch length rings of 9/16"-OD tubing (see figure bf_kitbash_172.jpg).
The 45° lateral tees also need to be shortened. To do this, cut off the male end to where only 1/16-inch of outer surface remains past the point of the upper opening; figures bf_kitbash_167.jpg and bf_kitbash_168.jpg show "before" and "after" comparisons of stock and modified lateral tees, viewed at different angles. Then insert the 1/4-inch dowels into the formerly-male ends of each tee, with roughly 1/8-inch of dowel protruding (see figure bf_kitbash_173.jpg). Cement the dowels firmly in place with PlasticWeld and wait 20 minutes. After the glue has sufficiently hardened, use the cutting drum on your rotary tool to grind away any of the excess dowel that would prevent a snug fit of the lateral tee to a 3/4"-OD tube.
Ensuring A 45° Downward Slope
Insert the 90° elbow through the two holes in the 1"-OD downcomer top section, then try to pivot the longer end downward on the elbow to a 45° angle, with the elbow perfectly vertical - i.e., the way it would appear when mounted between the two gas uptake neck pipes. Until you can position the downcomer top at 45 degrees, mark the spot where the elbow is obstructed, then remove the elbow and grind a tiny amount away from the marked area of the circle; re-insert the elbow and repeat the above steps described in this paragraph.
Once you have confirmed that your downcomer can be sloped downward at a 45° angle, you may snap-on the lateral tees via the dowels (see figure bf_kitbash_180.jpg). However, you must NOT apply cement at this time - later adjustments may be needed.
As a final clearance check, place your semi-completed downcomer top assembly between the narrow 'legs' of the uptake wye (see figure bf_kitbash_181.jpg). It should fit loosely, with approximately 1/8 of an inch gap; if it does not, your junction assembly is too wide to fit between the uptake neck pipes you will build in the coming section. Shorten the 90° elbow as described above, in tiny increments, until the 1/8-inch clearance gap is achieved.
Now it's time to build the new gas uptakes. Start by cutting two 13/4-inch lengths of 3/4"-OD tubing; then cut a pair of 9/16"-OD tube segments, also in 13/4-inch lengths, for the dowels. You will also be using the two 3/4"-to-9/16" concentric reducers.
In the 'B' Furnace chapter, I described how to compensate for the uneven interior diameters of the Walthers tubing and the Plastruct tubing that need to be connected. The 9/16"-OD tube fits perfectly into the top opening of the wye, but is too narrow to grip the inside of the adjoining 3/4"-OD Plastruct tubing section. To correct this deficiency, you need to wrap two rings of Evergreen .020" by .250" strip styrene around the dowel. (For detailed instructions on this procedure, refer to the section titled "Overcoming the Walthers Compatibility Gap.")
With the bottom end of the dowel tube inserted into the apex of the wye, there should be just the right amount of clearance for the male end of the reducer to fit into the top of the 3/4"-OD neck tube. Figure bf_kitbash_185.jpg shows the separate finished components on one side, and a completed neck pipe attached to a wye on the other.
Now that you have all of the pieces ready for final assembly, a dilemma emerges: The parts have to be held together somehow, but if you cement them, you risk locking them permanently into an incorrect position. Here's where machine screws come into play. Two locations immediately come to mind where machine screws would be very useful: the downcomer/elbow joint and the two neck-pipe/lateral-tee joints.
First, center the 90° elbow in the downcomer segment and hold it vertical; then, orient the downcomer pipe at a 45° downward slope. While holding the subassembly in this position, grab a pin vise with a .075" drill bit and drill a hole through the bottom of the downcomer and onward through the 90° elbow. Then, after carefully removing the drill bit, insert a .080" machine screw into the slightly-narrower hole and tighten it with a jeweler's screwdriver until the screw head is barely visible (Caution: Do NOT over-tighten!). Your downcomer is now locked into position until you remove the screw.
Now drill a .075" hole approximately 1/8-inch from the end of the long side of each 45° lateral tee, followed with a .080" machine screw. (HINT: You may want to further ream the hole at the outer surface so you can counter-sink the screw head.) Figure bf_kitbash_200.jpg shows the downcomer top subassembly at this stage.
Finally, you need to drill a hole at a 45° angle into each uptake neck pipe, so you can attach the lateral tees using the screws you inserted just a moment ago. But before you start drilling, you must locate the optimal connection spot. Do this by sliding the lateral along the neck pipe until the topmost point of the downcomer is slightly below the level of the top visible end of the concentric reducer. Then, using the pre-existing hole in the lateral tee as a guide, drill the angular hole into the neck pipe (see figure bf_kitbash_220.jpg) and insert the machine screw.
With your uptake neck pipes firmly attached to the downcomer, you are ready for the final assembly of your furnace. But first, you will probably need to install a new explosion valve maintenance platform. To do this, cut out a rectangle of Evergreen .020" sheet styrene, 1 inch wide by 3 inches long. Dab some syrupy, dark-colored paint onto the extreme top ends of the two concentric reducers, carefully set the rectangular sheet upon them, then gently lift it off without any sideways movement; the two circles mark the places where you should cut holes wide enough to slip over the dowel ends of the reducers (see figure bf_kitbash_210.jpg).
An unpainted version of the assembled topworks is shown in figure bf_kitbash_240.jpg with a mock-up downcomer.
I used two aerosol spray cans of Rust-O-Leum primer - one black, the other rusty brown - for painting. First I applied a coat of black, and after allowing 10 minutes for it to dry, I "dusted" it with a very thin veneer of rust brown. Please note: it is very important to have the component pieces connected to each other during the painting operation - this prevents mismatches of color.
Figure C_model.jpg shows the final assembled, painted model. (Finishing work on the downcomer pipe is covered in the section titled "Enlarging the Downcomer: Part 2" near the beginning of this article.)
Rouge Steel's retired 'A' Furnace is another example of the inverted "M" design of downcomer/uptake configuration. Unlike its sister furnaces, however, the pipes leading from the uptake neck to the downcomer are nearly perpendicular (see figure A_furnace_rear.jpg), not diagonal. Because of this, you will not need the 90° elbow or the two lateral tees that are used in the 'C' furnace model.
Materials Needed:
* Plastruct stub-in tee for 1"-OD tubing (1)
* Plastruct 3/4"-OD tubing (1 15-inch section)
* Plastruct 9/16"-OD tubing (1 15-inch section)
* Evergreen strip styrene, .020-inch thickness by 0.25-inch width (1 strip)
* Plastruct concentric reducers, 3/4"-OD to 9/16"-OD (2)
* Evergreen plain sheet styrene, .020-inch thickness (1 sheet)
As on the 'C' furnace model, we will eliminate the 2 stock uptake elbows and replace these with longer 'neck' pipes capped by concentric reducers. Two 11/4-inch lengths of angle-cut Plastruct 3/4"-OD tubing will be inserted into each side of the top downcomer segment. Each 1-inch angle cut, in turn, will be rounded on the lower end and cemented to the uptake neck pipe. You'll also need to construct a new explosion valve maintenance platform.
First you'll need to cut a pair of holes through the 2-inch piece of 1"-OD tubing that you cut off earlier. To do this, you will use a 1"-OD stub-in tee on a temporary basis. As shown in figure bf_kitbash_150.jpg, hold the stub-tee firmly on the 2-inch length with your non-writing hand; with your writing hand, use a fine-point permanent marker pen to trace around the inside of the tee where it touches the 1"-OD tube. Upon pulling off the tee, a 3/4" circle remains on the side of the tube, marking where you will cut out one of the holes for the 3/4"-OD uptake connector pipes.
The second hole will NOT face directly to the first - it needs to be at an angle. To locate the optimum spot for the second hole, place the stub-tee opposite of the circle you just traced, then move it back until its tapered outer edge 'points' to the closest point of your circle; position the point approximately 1/4 inch from the circle (see figure bf_kitbash_155.jpg) and trace another circle as you did the first time. As shown in figures bf_kitbash_157.jpg and bf_kitbash_158.jpg, the holes line up on the vertical axis but not on the horizontal axis. Now use a Dremel (or compatible) rotary tool with a 1/4" cutting bit to cut out the center of each circle as shown in figure bf_kitbash_159.jpg. Once the holes have been cut, try inserting a 3/4"-OD tube into each. Keep enlarging the holes until the tubing sections fit easily into them.
Using a razor saw with a miter box (figure bf_kitbash_062.jpg), cut two 11/4-inch sections of 3/4"-OD tubing; both ends should be at a 12° angle and parallel to each other (see figure bf_kitbash_242.jpg).
Ensuring A 45° Downward Slope
For each 11/4-inch segment, insert the tube through one of the two holes in the 1"-OD downcomer top section, then try to pivot the longer end downward on the connector tube to a 45° angle, with the connector positioned the way it would appear when mounted to an uptake neck. Until you can position the downcomer top at 45 degrees, mark the spot where the angle-cut tube is obstructed, then remove it and grind a tiny amount away from the marked area of the circle; re-insert the connector tube and repeat the above steps described in this paragraph.
You need round the lower end of each connector pipe in order to joint it properly to the uptake neck; i.e., you must convert them to 12° lateral tees. The following is a technique I learned from Jeff Borne's excellent videotape, Superdetailing the Walthers Blast Furnace - Part 1, to accomplish this task.
First, find a workable length (at least 8 inches) of tube that is the exact diameter of the tube you plan to connect with - in this case, 3/4" - then wrap a sheet of 50-grit sandpaper one full rotation ONLY around the tube (see figure bf_kitbash_250.jpg). Holding the 11/4-inch connector pipe's angled end flat on the sandpaper-covered tube (figure bf_kitbash_255.jpg), rub it back and forth until a round concavity has been formed (see figure bf_kitbash_260.jpg); press the rounded angle end onto a piece of 3/4"-OD tubing (figure bf_kitbash_265.jpg), then grind a bit more until you are satisfied with the fit. Repeat for the second connector pipe.
Having confirmed that your downcomer can be sloped downward at a 45° angle, you may now insert the home-made lateral tees into each side of the 1"-OD segment. The two connector pieces should meet in or near the middle, but they do not have to align exactly (see figure bf_kitbash_270.jpg) - the important thing is for the external, visible ends of the connectors to protrude from the downcomer at equal lengths. Once you are satisfied with their appearance, cement the connector pipes together via PlasticWeld.
To ensure correct clearance, place your semi-completed downcomer top assembly between the two legs of the uptake wye as described for the 'C' furnace modeling project (see figure bf_kitbash_181.jpg). It should fit loosely, with a gap of approximately 1/8 of an inch; if it does not, your junction assembly is too wide to fit between the uptake neck pipes you will build in the coming section. Grind away tiny amounts of plastic from the concavities of each connector tube (to maintain equal visible lengths) using the tube-and-sandpaper jig, until the 1/8-inch gap is achieved.
Uptake neck pipe sections can be made by cutting two 13/4-inch lengths of 3/4"-OD tubing; you will also need a matching pair of 9/16"-OD tube segments in 13/4-inch lengths to use as dowels. The two 3/4"-to-9/16" concentric reducers will attach to the top end of each neck.
In the 'B' Furnace chapter, I described how to compensate for the uneven interior diameters of the Walthers tubing and the Plastruct tubing that need to be connected. The 9/16"-OD tube fits perfectly into the top opening of the wye, but is too narrow to grip the inside of the adjoining 3/4"-OD Plastruct tubing section. To correct this deficiency, you need to wrap two rings of Evergreen .020" by .250" strip styrene around the dowel. (For detailed instructions on this procedure, refer to the section titled "Overcoming the Walthers Compatibility Gap.")
With the bottom end of the dowel tube inserted into the apex of the wye, there should be just the right amount of clearance for the male end of the reducer to fit into the top of the 3/4"-OD neck tube. Figure bf_kitbash_185.jpg shows the separate finished components on one side, and a completed neck pipe attached to a wye on the other.
The next task is to attach the uptake neck pipes to their corresponding connector tubes. First, position the downcomer top subassembly between the two neck sections so that the topmost point of the downward-sloping downcomer is at roughly the same level as the top ends of the necks. A medium-sized Quick-Grip clamp can be used to hold the structure in the correct position (see figure bf_kitbash_275.jpg); then liberally apply PlasticWeld to cement the joints, allowing 10 minutes before handling.
Before the glue hardens permanently, you should examine your semi-finished top assembly to make sure the connector pipes have proper vertical alignment with the uptake neck pipes (see figure bf_kitbash_280.jpg).
Two more steps need to be completed prior to final assembly: attaching the concentric reducers and preparing a replacement explosion valve maintenance platform (see figure bf_kitbash_285.jpg). To build the platform, cut out a rectangle of Evergreen .020" sheet styrene, 1 inch wide by 3 inches long. Apply some syrupy, dark-colored paint onto the tops of the dowel ends on the two concentric reducers, carefully set the rectangular sheet upon them, then gently lift it off without any sideways movement; the two circles mark the places for cutting holes wide enough to slip over the reducers.
You should now be ready to connect all of the subassemblies together. Figure bf_kitbash_290.jpg shows an unpainted mock-up of the 'A' Furnace uptake configuration.
For painting, I first applied a coat of Rust-O-Leum black primer. After allowing 10 minutes for it to dry, I "dusted" the structure with a very thin layer of Rust-O-Leum rust brown. Please note: it is very important to have the component pieces connected to each other during the painting operation - this prevents mismatches of color.
Figure A_model.jpg shows the final assembled, painted model. (Finishing work on the downcomer pipe is covered in the section titled "Enlarging the Downcomer: Part 2" near the beginning of this article.)
You have just seen three different examples of how to enhance the appearance of your Walthers HO blast furnace on your home or club layout, with four primary modifications: placing solid sheet styrene over the bell platform handrails; installing a thicker-diameter downcomer; shortening the uptake "legs", lengthening the "neck"; and changing the top junction of the downcomer and uptakes from an inverted "U" to an inverted "M" configuration. What I hope you've learned is that you do not need to sacrifice a large amount of spare time to obtain a better-looking blast furnace; with the necessary tools and materials, you should be able to complete any one of the sample projects in a few evenings. Then you can resume enjoying another primary activity of model railroading: running trains! -KJL
1) The Cyclopedia of Industrial Modeling - First Edition, by Dean Freytag,
2002, MF2Q Publications ( http://www.maine2footquarterly.com/books.htm )
2) Superdetailing A Walthers Blast Furnace - Part 1, VHS video by Jeff Borne,
2002, Prairie Works ( http://www.prairie-works.com )
3) HO Scale Steel Mill Drawings by Michael L. Rabbitt
Over 16 different sets of highly-detailed, HO scale drawings of steel mill structures of various types and eras. Prices range from $7 to $50 per set, depending on complexity. For further information, send SSAE to:
Michael L. Rabbitt
