Additional Comments Regarding CA and Other Adhesives

MORE CA COMMENTS
Although I normally do not recommend Wikipedia articles, but it does have a nice article on adhesives. https://en.wikipedia.org/wiki/Adhesive  The sections starting with "Mechanisms of Adhesion" and following are very interesting and explain not only how adhesives work but how they fail. This is very important for the modeler to understand why the "glue" didn't work.

I'm more of an inorganic chemist and not into the chemistry of adhesives. I can say CA does not form a chemical bond with many substances modelers use. This leaves the 3 other potential bonding methods.

From experience CA seams to be less effective the smoother or non-porous one or both of the items to be "glued together" are.

Another comment regarding the use of CA adhesives. For that matter any adhesives. Read my post dated January 1, 2015, "Some Modeling Tips and News for the New Year Before Going Further" for other safety comments when working with CA.

Be cautious about what surface you are working on when using CA adhesives. CA will adhere to almost anything. If you have read through the posts in this blog you know I work on a 1/4" thick plate glass. The plate glass provides a smooth flat plane on which to build a model.

A couple of years ago when building something, the work which had been newly glued together with CA was left on the plate glass. In the past I've always been able to lift things glued with CA off the plate glass with a razor blade without any problems.

This time a large section of the model was stuck to the plate glass. In lifting the section, small pieces of the plate glass came along with the model!

There were pot holes in the plate glass!

After replacing the plate glass, whenever working with CA, I now place a large "ZipLock" bag or similar material over the plate glass. CA will not adhere to this material. To use the large bag, the end of the bag where the closure lock is, is cut off. Then the bag is cut with scissors along 2 edges and opened up to provide a larger area of protection for the top of the plate glass..

I tried to use material like "Saran Wrap" but could never get it smooth or to keep it from adhering to itself in a big wad.

Be careful also not to get your fingers stuck together. I have used CA for many years getting CA on my fingers. After setting, CA can be hard to remove from skin. Sometimes it has had to wear off.

Sometimes 2 or 3 fingers were stuck together momentarily. I was able to pull them apart before any damage was done. If it can happen to me, it can happen to you! Safety first!

There have been stories where individuals have glued 2 or more fingers together using CA. The fingers have had to be surgically cut apart. Be careful!

Finally, when is the CA left in the bottle no longer good to use? I use the 1/2 oz. bottle of Super Jet for almost all of the gluing required for model building.

Today I noticed there is about 1/4 of the bottle remaining. Moving the bottle from side to side the remaining CA seems to flow slower than it did when the bottle was new. This indicates to me it's time to toss the bottle out and start a new bottle of Super Jet.

Why not buy 1/4 oz. bottles of Super Jet? There are 2 reasons I don't buy the smaller bottle and finish it off. Number 1: Many times the bottle is finished-off (empty) before the CA inside starts to become thick. Number 2: Pricing - most of the cost of the bottles is the packaging cost. It's less expensive to buy the 1/2 oz. size bottle.

Each modeler has to decide for themselves which size bottle of the CA he is using, is the best for his modeling needs.

OTHER ADHESIVES
Loctite® Epoxy Plastic Bonder is an acrylic formula designed and made to bond repairs in plastic surfaces. It comes in a double syringe dispenser for equal amounts of both components to come out when required for mixing.

When mixed the 2 components react in 20-25 minutes to make "a tough, rigid, high strength bond". The acrylic material "does not shrink and is resistant to water, most common solvents and shop fluids. It has high impact resistance and can be sanded and drilled."

It is recommended for nylon and other plastics. You should check the Loctite web site for more information. All the material in quotes was taken from the Loctite web site.

I trust Loctite to have an excellent product. I am not too keen on having to mix-up an adhesive when it comes to all of the joints which have to be placed together for the Baldie kit.

If you have read over my 2 postings regarding assembling the kit, perhaps 1 batch of the Loctite acrylic adhesive could be used to glue the 2 styrene backings to each of the 2 center doors. Then another batch mixed up for the 4 backings for the 4 end doors. What I'm trying to get at is, having to mix-up batches of acrylic adhesive would add another layer of work to each of the assembly tasks.

While I like what Loctite has to offer in the way of a nylon adhesive, I'm not too sure of the actual application.

Loctite is not the only company offering a nylon adhesive. There are others. One offers a CA adhesive designed for nylon. But, we have other CA products on the market already.

Finally, at least one company has an UV activated epoxy adhesive. The material is applied to the areas to be bonded, then a small UV emitting light source is brought near material. The product is called "Bondic". You can find out more at this web site http://notaglue.com/  .  I wonder how well this adhesive works?

The world of adhesives is getting more and more interesting!

Back to work of the Baldie in the next post.

Cheers,
Ed

 

 


Cheers,
Ed

Finishing a CTM 4000 Baldie Kit Part 2: Drilling Holes, Gluing the Parts Together, and the Brass Skeleton

The prior post should have started with, after contacting Terry Gaskin and getting the instructions, be sure to print them out. I had mentioned to Terry he needed to include the page numbers on the sheets. Having loose sheets of un-numbered pages of paper can be deadly.

If you can print the instructions back-to-back, using both sides of the sheets will help to save on paper.

After seeing the number of pages of instructions you might be scared off getting involved with the kit. But, after you read them over you'll realize half of the instructions involve ordering the parts and then getting them ready to start assembly.

The balance of the pages are filled with assembly instructions and drawings. Most of the pages are drawings. Terry did a great job in illustrating the verbal part of the instructions. While the kit may not be a shake-the-box type of kit, it is moderately easy to assemble.

Back to the assembly - There are dimples where holes for grab irons and handholds are to be attached. The dimples are 0.020" in size. I drilled mine out with a 0.0225" drill. I recommended to Terry the dimples be enlarged to 0.025".

Q-Car used 0.025" brass wire for his CRT 4000 Plushie. I like to use 0.025" brass wire. This size wire is still small enough (scale 1.25") and will hold up to the handling a model will receive during its lifetime.

Eventually the holes will be re-drilled larger than 0.025". Why? When gluing the hand rails etc. in place some of the glue has to be between the brass and the material into which it is inserted.

It's best to drill the holes now by hand since they may be obstructed during the assembly process. Also, you'll find it easier to drill the holes now rather than when the body is assembled.  The 0.020" dimples are small plus it's easy to have the drill slip. Do not use a power drill. The nylon is soft enough for a reasonably sharp drill to go through it when drilled by hand.

There are additional holes to drill for the windshield wipers, whistle air pipe, plus any headlight or route or marker lamps. The holes for route or marker lamps will be drill when needed.

The only holes in question are the sets for the handrails in the ends of the car where the end door is located. It looks like initially these handrails were installed lower then they appear in later photographs. Perhaps the conductors and gatemen complained they were too low to be useful and were subsequently mounted higher.

One last comment about drilling the holes. Some of the holes as you drill them seem to continued to go through the material and not come out the other side. These holes if drilled at a slight angle will come out of the material. It's OK to drill these at a slight angle. When the brass wire is installed, if it is at an incorrect angle, it will be easy to bend it to the correct angle.

Next the 5 parts which make up the sides need to be glued together. To support each glue joint a piece of styrene needs to be glued to the back of the doors to back-up the joint. Butt joints are very weak. Backing-up the joint helps.

If I followed the instructions to the "T", I found the amount of space in which to glue glazing for the window in the door would be too small. For this reason, after each of the styrene backing pieces were cut, a piece of either 0.015" or 0.20" x 0.040" styrene was glued to the backing piece. This pushed the backing piece away from the window leaving more space for gluing in glazing.

The photo shows the center door piece with the 2 pieces of 0.040" styrene backing pieces during the gluing process. Note the 2 cloths pins used as clamps. The red circles are around the additional pieces of styrene attached to the backing piece. Attach these 2 small pieces 1st, then glue the backing pieces to the door pieces.

For the center door attach the backing piece on one side of the door and then on the other side. Remember styrene solvent glue is not "compatible" with CA. Allow the styrene solvent glue to completely cure 1st before using the CA.

Clothes pins, the clamping type, were used to hold all pieces during gluing and afterward. Always allow the CA to cure before going further, A great deal of stress is being placed on the joints even if you do not personally stress a joint.

Once the center door has the backing pieces in place, glue the backing pieces to the back of the end doors. Allow all the pieces to cure overnight before going further.

Be careful of which section with windows is glued to the center door piece. Examine the vertical wows of rivets next to the window in the door.

On the bottom of page 195 of the CERA Bulletin 113, "Chicago Rapid Transit Volume I: Rolling Stock 1892-1947"; is a side photo of a Baldie. Carefully notice the vertical row of rivets to the left of the center door at the window level of the car. There are no vertical rivets to the right of the center door at the same level.

Once the 5 pieces making up the side are glued together, your side will have a slight bow. Do not worry about this. Pieces of brass will be glued to the back which will straighten out and reinforce each side.

This is one side. The center door had been attached 1st. The end doors were attached last.

 

This is the side after all the CA had cured. Note the bow in the side.

A 3/32" square brass tubing is about the smallest size square brass tubing which will resist moderate bending. Yes, this size can be bent and for this reason when shopping for this and the other pieces of brass; inspect them for bends. It is almost impossible to straighten these small sizes of brass into their original unbent shape!

The 3/32" square brass tubing will be glued at the top of the wall while a 3/32" x 3/16" rectangular brass tubing will be glued directly under the interior bottom of the doors. To tell the truth, a 3/32" square brass tubing could probably be used under the doors.

This is one of my sides after both pieces of brass had been glued in place. All the filler pieces have been added to make the interior of the side one flat plane. Notice the green body filler added and sanded.

To hold the brass against the nylon during the curing of the CA adhesive, place as many clamps along the top or bottom as needed. I used so many there was less than an inch between them!

As to the length of the tubing, I cut mine a little short of the length of the side. If I were to make another Baldie, I would cut each piece of brass tubing the length of the side. The top piece would have each end tapered at a 45 degree angle to clear the glazing of the end windows.

To assemble the body into a square piece, some years ago I discovered if a car side and end were glued together square and the other side and end were glued together square; then when the 2 side/end assemblies were glued together, the body was square. Make sense?

Only one corner of a side and end can be assembled square with the model. On the ends the dash below the motorman's window is not square with the side. The other side, I'll call the passenger side, is square with the side.

The assembly will be done up-side-down on the glass plate I use. To prevent the CA from adhering to the plate glass, a large "ZipLoc" type of bag will be opened up and laid over the glass.

Using as many machinists' squares as possible the side and end are glued together and held squarely in place. The same is done with the other side and end. Allow the CA to cure over night.

These are views from both sides of the side/end gluing process.

While the curing is taking place, cut out the floor and/or make the floor if it has not been done already. A drawing of the floor is included in the instructions. I had a piece of 3/23" thick basswood on hand. It turned out to be exactly the correct thickness required.

To glue the 2 side/end pieces together squarely, again up-side-down, on the piece of plastic bag glue the 2 assemblies together and insert the floor in place. Check the entire assembly for squareness and allow to cure overnight.

The next day a piece of styrene, wood, or brass can be glued inside of the end doors to serve as a tab to which the floor will be screwed. Be careful! the sides and ends assembly is extremely fragile. The floor was taken out. then the pieces were glued to the interior of the doors and after a couple of minutes the floor was placed back in place.

A  green arrow points to the styrene tab.

 

The roof is glued onto the body next. Place the body with the floor in place right-side-up on the opened plastic bag. Place the roof on the body. My body did not have any tabs to locate the roof. I had to locate the roof on the body as best I could.

 

If there are no problems, apply CA to the top of the walls of the body. Place the roof back on the body. Apply pressure on the roof if required. As mentioned before my roof had a slight bow. It was high in the center. Machinist weights were added to the roof. Allow the CA to cure over night.

 

If you find gaps after the CA has cured, like I did, apply more CA through the windows and use the large wide rubber bands the USPS uses for the mail to secure the roof to the body. Be sure to have the floor in the body during this process. Again allow the CA to cure over night.

 

I found it best to lay the body on its side during the curing process. This allows the CA to flow into the top of the body side and roof contact areas. This should take care of the attaching the roof to the body.

 

If everything is square, add pieces of styrene into the 4 corners of contact between the sides and the ends. I used 0.188" x 0.125" styrene. My pieces were just short of the windows down to the top of the brass piece at the bottom of the sides. Allow the CA holding the pieces in place to completely cure.

 

For the side of the end where the motorman is located. This end is bumped out for additional room for the motorman. You need to add some stripes of styrene to fill in and support the added pieces.

 

This process is to support the joint between the ends and the sides of the body. These 4 joints may be the weakest of all the joints making up the body.

 

These pieces can be seem through the end windows. I used a Dremel Tool with a small round end mill to shave off the corner of the pieces of styrene not attached to any nylon of the body. This is the one corner which can be seen inside the body. Since I did not want to weaken the joint being supported, my cuts were tapered. The top of the added styrene piece was cut off the most with the bottom cut off the least.

 

Unfortunately I did not take photos of this and my drawings were too poor to be used! I apologize for not taking any photos.

 

To get this post into the blog and out on the web, let's cut the material off here. We'll pick it up from here with the next post.

 

Cheers,

Ed

 

 

 

Finishing a CTM 4000 Baldie Kit Part 1: Inspection and Cleaning

Photo Viewing Note

To obtain the best view of the included photos, click on the 1st photo to see all of the photos in a larger size.

The kit to make a CRT/CTA 4000 Baldie will make either a trailer or a powered car. This is definitely one of those build to the photo type of kit. The Baldie 4000 were altered so much, you may need to have the photo to back up what your model looks like. Finding alterations has turned out to be a joking matter between Bruce Moffat, Terry Gaskin, and myself.

In some ways writing this is difficult because the kit I assembled was the original kit as Terry Gaskin had prepared the 3-D drawings for the 3-D printing of the parts. My recommendations for what could be done to improve the kit may have been incorporated into the 3-D drawings.

At the same time I do not wish to repeat the instructions you will received for ordering and assembling of the kit. Instead my comments are to reinforce the printed instructions you have. Included in my comments are some items of which you need to be aware to enhance your kit building or problem solving.

When you get the kit from Shapeways save all of the packaging until the kit is complete. Should you have a problem with a part where the part was not printed correctly Shapeways will reprint the part. The process of getting Shapeways to reprint the part may include your sending photos of the shipping label and other labels of the packages. Save everything!

If there are any problems contact Terry 1st before contacting Shapeways!

When you receive the parts examine all of them for problems. One of the printing problems is what I'll call "fading away". The printing of the part will look OK at one end but will start to fade as you look down the side. For example, at the right edge the rivets will be of correct size but as you look from right to left, the rivets will become smaller and smaller. At the left side there are no rivets visible.

This is an example of "fade out". The top panel has the problem while the bottom panel was correctly printed. I did not discover the problem until after the parts were "cleaned" in "Bestine". The panel with the problem has a slight curve. We do not know if the curving is related to the printing problem.

What I found odd is when I mentioned the problem of "fading away" my friend who was involved in a 3-D printing project 25 or more years ago knew about the problem. He was able to describe it to me without any difficulty. What struck me is the problem has been around for more than 25 years while at the same time 3-D printing has been known to the general public for about 5 years. In the intervening time one would have thought this problem would have been resolved. Or, perhaps the problem has been resolved and this is the best we can get today.

Another problem is the part can have a curl or bow. While some curl may be natural to the material, a curl of more than a few degrees is wrong. The test to see if the curl is too much, ask yourself if you can correct the curl. Heat of any type will not correct the curl. The correction must be mechanical - in other words, you have to "glue" something to the curled piece to straighten out it out. This includes structural brass or another piece of the kit.

My roof had a slight bow. It was corrected by attaching the roof to the body of the car. CA was used to glue the roof to the body.

The cleaning solution "Bestine" recommended for the removal of the wax from the body parts can be obtained form the web. "Bestine" is flammable and evaporates quickly. It is best used in a paint hood or in a well ventilated area.

Do not handle the solution with bare hands; wear chemical gloves! I used a large size plastic tub with a snap on lid to soak the parts. A used margarine tub will work out well. Mine was from a lemon-strawberry sherbet.

Please excuse the color of the photo. It's due to the use of fluorescent bulbs. Inside the container can be seen the "Bestine", parts of the sides, and the tweezers used. This is inside of my paint hood.

To place the parts into the "Bestine", a long tweezers were used. When parts are taken out of the solution place them on a clean paper towel. Any long tweezers can be used.

This is a side part. Note the ribbing which occurs as part of the printing. The ribbing has to be sanded flat and smooth.

I left the parts in the "Bestine" for up to 30 minutes without any problems. A new toothbrush was used to get the wax off the parts. Inspect the parts again! It was not until the wax was removed did I find a problem with the 3-D printing mentioned up in this post.

Here are some of my parts. Initially a small bottle brush was used. It worked OK but a new toothbrush with stiff bristles worked better.

When you are done with the "Bestine", it can be returned to the metal can in which it came. It's best to use a small funnel to prevent spilling during pouring the solution back into the can. 

These are the parts for my sides and ends. They are on a shop towel. I like to use the shop towels as they are soft. A couple of rolls were purchased a few years ago. Since they do not get wet and used in the normal manner, they can be reused over and over again.

The next activity is to sand all the parts. For the roof use new 320 grit garnet paper. Unfortunately I had reused some garnet paper and the process took a long time. most of the grit was already worn off.

For the sides, sanding sticks, or some of the other sanding tools covered in post dated January 1, 2015, " Some Modeling Tips etc." can be used. Sanding the various side and end pieces does not take as long as you may think.

Here are a number of parts for the sides and ends after sanding. Be sure to clean all the parts of any sanding dust.

In the next post we'll start to glue the parts together and build an endoskeleton of brass.

Cheers,
Ed

Introducting a New CRT "Baldie Model with More Comments on 3-D Printing

For me, 3-D printing started 25 plus years ago when a good friend of mine was trying to tell me about the last project to which he was assigned by his employer.

He had been involved in setting up  a computerized process by which an item could be built in 3 dimensions by printing the material. The overall goal of the project was to vastly reduce the number of machine and other parts his employer had to keep in stock and thereby reduce the storage and carrying cost of all these parts.The process was called stereolithography.

His description of the process seemed impossible to fathom. How could a computer printer, as I knew of a printer back then, print out an object in 3 dimensions like a gear for example.

On a different note, the more I learned about 3-D printing by talking to individuals involved in the process, the more the bits and pieces I heard in each conversation started to fit together. Without actually designing an item by drawing it out in 3 dimensions and then having to deal with an organization like Shapeways to get my design printed in 3-D, I gained a working understanding of the pros and cons of 3-D printing.

When Terry Gaskin approached me about test building his new CRT 4000 Baldie kit, I discovered I had to pass on to Terry how to improve his kit from the kit builder's stand point. Terry had designed and engineered an interesting kit. My observations regarding building the kit will be shared with you in the next post.

Three dimensional printing is so unique and "mind bending", being told what the process is like builds an almost impossible picture in the mind. You have to be told of so many new, involved processes at one time. Without seeing what is going on, each part of what you hear becomes what sounds like a "pie-in-the-sky" idea.

Three dimensional printing is not what you printer does at home or in the workplace where you may work. The 3-D printer does not print in the strict definition of the word "print". From what I can tell the 3-D printer and print head may be specific to the material being used to make the object.

The print head does not transfer ink to paper like your printer at home. Instead it may have more than one laser, aimed at a specific point, to heat the material being used into a molten mass which becomes the object being made. Or, the print head may activate a "glue" to hold the material together.

You may have seen a process similar to 3-D printing in TV programs where a forensic scientist has a computer make a skull or head out of slices of paper individually cut and "glued" together. The skull is "read" into the computer. The computer in turn decides the size of each sheet of paper to be cut. Or, if a head is to be made, the computer utilizing a program adds on the muscle mass to the skull, and then decides the size of each sheet of paper to cut.

The individual sheets are somehow stuck together with adhesive in the order in which they are printed. Watching the process is amazing.

The computer generated head can be painted for the individual whose skull is used. Furthermore a wig, or different wigs, can be placed on the head. The head with painted facial features and hair have been used to identify missing individuals.

Bill Becwar a good friend of mine who is a computer programmer wrote an email to me in which he explains 3-D printing. In the email he wrote,  

"Yes, 3D printing is a tough concept to explain to someone who hasn't seen it, partly because it is so new, and partly because there are a number of different types, each with different techniques and materials.  On greatly simplified explanation is to think about it as machining in reverse, where material is added on to make a part, rather than removing material.  Our Canadian friends had a pretty good segment on "How It's Made" a while back, explaining the process pretty clearly.  It's on YouTube:  https://www.youtube.com/watch?v=i6Px6RSL9Ac  .  Although it sure isn't cheap, the idea of making cast parts in metal without expensive tooling or lost wax wok is pretty amazing.  It does for objects what word processing did for text."

The YouTube video he recommends watching was part of a Science Channel program "How It's Made". If you have not seen this video, please watch it.

Micro Mark and other vendors have a 3-D printer available. The price is not cheap. At the same time what can be printed using this printer is limited in size and materials used.
 
Shapeways has told Terry Gaskin they plan on purchasing larger printers which will be able to print the side of the Baldie in one piece utilizing a builder friendly material. Builder friendly meaning a nylon requiring less sanding and at the same time free of some of the current printing problems. I'll mention 1 or 2 problems in the post on building the kit.

A larger printer, if it is 50% larger, does not cost 50% more. Instead it costs far more, perhaps 10 times more than the printers Shapeways currently has.

While I can say more about 3-D printing, it's time to go on to other topics.

The new Baldie kit has been added to the post dated February 11, 2012 "Available CRT/CTA Rapid Transit Models in Kit or Other Forms". The new model should actually be called a CRT/CTA Baldie.

You may ask when will a list of O scale CSL/CTA streetcars kits, bodies, etc. be made and posted. The list was started. I lost interest in it. If someone is interested in making a list, it will be posted, and the writer acknowledged. 

Finally on the blog page is a section titled "Total Passengers" and a number. This number is the number of times the blog has been viewed. In a few days, if it has not already, the number of times this blog has been viewed will pass 50,000.

For those of you who read my blog, Thank You! I appreciate you viewing the blog and returning for more material. I run the blog in a way so as to not repeat material unless it is very important. For this reason, it's best to read the entire blog from the beginning to pick-up on information.

As long as I am thanking everyone, take a look at the blog Randy Hicks (Hicks Car Works) from the Illinois Railway Museum has been writing. A link appears in the right hand side of this post under the section titled "My Blog List". Randy has been doing a wonderful job restoring the Museum's CA&E cars. He deserves many thanks for his work!

The next post will be the start of the CRT/CTA Baldie kit. It's been in the works for a couple of months so it's time to sift through my notes and photos.

Cheers,
Ed

Introducing a New CRT "Baldie" Model and Modeling Techniques

To paraphrase a well known TV sci-fi show, "To boldly go where no man has gone before . . ."; Chicagoan Terry Gaskin under the name "Chicago Traction Models" has produce a new kit for a Chicago Rapid Transit (CRT) "Baldie" 4000 to accompany the Q-Car 4000 "Plushie".

Ever since Q-Car produced the Plushie 4000 in the early 1970's, I have wanted a model of a Baldie. The Baldies operated alone or with other Baldies or Plushies. The new kit answers my desire.

What makes things more interesting Terry is making the kit out of 3-D printed parts. For the modeler this kit is a whole new realm of model making. We need to go through some of the behind the scenes of this new realm to understand what makes Terry's work more suited to the modeler.

Someone mentioned at a recent Trolley Evening, "3-D printing may very well be the new form of scratch building!" However, when one considers the number of hours required to make the 3-D drawings for a printer to be able to do the 3-D printing, printing only 1 model is a shame.

First, you do not get the kit from Terry. He spent many hours designing the 3-D drawings which are used to make the parts. The printing of the parts is done by a separate organization - Shapeways. You need to contact Terry at 1958mga@comcast.net to be given the instructions on how to order the parts and construct the kit.

The instructions are long due to the need for you to be told how to pretreat (clean) some of the parts prior to construction. The actual construction is straight forward and Terry includes plenty of drawings and tips for constructing a great model.

I taught high school chemistry and have been interested in material science for some time. The material used in 3-D printing is not an epoxy therefore I'm calling the material plastic. 

From reading the Material Science Data Sheet (MSDS) obtained from Shapeways, the material used for the Baldie kit is a nylon. There are many different plastics and within the term plastics are different nylon plastics.

From recycling you may be aware not all plastics are the same. The different types of plastics have different physical and chemical properties. The solvent for one plastic will not dissolve another. This the reason styrene glue will not work with other plastics.

For now, if you are not aware of how 3-D printing works, the object (part) is made by building up multiple rows of material upon itself. Think if it as building a wall of bricks. Instead of individual bricks side by side for each layer, each layer in 3-D printing is one long brick. The wall is one long brick layered upon one long brick until the wall is made. No form of grout or cement is used between layers. the layers are fused together.

A difference in the position of the print head as it goes back and forth printing each layer causes a ribbed surface between the layers. It's this ribbing that needs to be sanded smooth by the modeler. The next post will explain more about 3-D printing.

To give the modeler the best model possible Terry chose to have the roof printed using one plastic while the sides and ends are printed from a different plastic. The material chosen for the roof is hard, durable, flexible, sandable, does not hold detail as well and is less expensive. The roof being a curved surface and due to the print process requires more sanding than other printable plastics to produce a smooth surface.

Other individuals have available through Shapeways 1/4" scale streetcar, commuter and interurban bodies available using the same material Terry chose for the roof. Although these bodies are one piece, modelers are finding them hard to finish. It's hard to sand them to a smooth surface for final priming and painting. Friends of mine know modelers who have these bodies and are unable to finish them.

From what I've been told Shapeways is unable to print entire O scale models using a more modeler friendly plastic material due to the size of the print job.

For the sides and ends of the Baldie kit Terry chose a different plastic to print these parts. This plastic is far easier to work with than the plastic used for the roof. The modeler has to do minor sanding to achieve a smooth surface and at the same time not loose the detail. To achieve the best possible printed parts, the balance of the body, excluding roof, was broken into parts.

The process to obtain a smooth surface by sanding is explained in Terry's instructions. The ends are 1 piece. The sides are composed of 5 pieces - the 2 end doors, 1 middle door, and 2 panels of windows between the doors. One benefit of the 5 part side is the individual parts are easier to sand and protect the detail. If you have looked at photos of the CRT/CTA 4000's you will realize part of the gestalt of the 4000's are the multiple rows of rivets. It's these rivets the modeler wants to maintain.

At the same time the multiple piece side and separate ends, allows for all the variations found in the Baldies. The CRT/CTA 4000 may have been the series of cars these 2 companies, CRT and CTA, built and rebuilt the most of all their cars.

A month ago, Bruce Moffat tallied up about 2 dozen varieties of changes to the Baldie bodies before the entire series was retired. By now, his tally may be up to 3 or 4 dozen changes.

It seems like the CRT did just enough modifications to keep the cars current with operating conditions. Under CTA ownership the 4000 underwent the most number of "rebuildings" to make the cars ever more interesting.

The CTA's "L" cars can be broken down into 4 broad groups - the woods, the steel 4000's, the "spam-cans" (6000's), and everything afterward!

Terry initially decided to build the Baldie from the 1940's to match the Q-Car 4000. He now has additional parts to make the original cars plus the cars with as many of the window and end variations as possible. With the 5 part side it will be easy to make a model with square windows in the side, doors with the oval, rubber gasket windows, and ends with Christmas tree route/marker lights - or - you name it! There are so many variations it's impossible to list them all here.

To assist the builder of his kits, Terry will have both exterior and interior parts available.

In the next post more info on the 3-D printing process will be given. The post after the next will be the start of building my Baldie from Terry's kit. The building process will take the Baldie up to the same point of finishing as my Q-Car Plushie from prior post. From there the 2 models will be finished together.

When finished, my 2 models will be operated as a 2-car 1940's CRT "Evanston Express via Subway" which originated from either Kenwood or Jackson Park. I have to check! Interesting? Yes? No?

Cheers,
Ed