# How to straighten a bent cab roof on a steamer



## servoguy (Jul 10, 2010)

There have been any number of approaches to straightening out a bent cab roof on a steam loco. Most or all of them result in a broken roof. I have just successfully straightened a bent roof on a 2025 loco. I bought the loco for $30 without a tender. In order to straighten it out, I needed one piece of data: Zinc has an elastic limit of zero. What does this mean? It means that zinc will cold flow. Put a stress on a piece of zinc, and it will deform to relieve the stress. So I bought a clamp at Harbor Freight and used the clamp to put a stress on the bent part and I left it alone for 24 hours. This got the process started, but with the clamp I was not able to get the roof completely straight. I then clamped the end of the bent part to my work bench and added the motor and steam chest to the shell to increase the torque to straighten the roof. After a couple of days, the roof was nearly straight. Right now, the clamp is back on the roof for the final straightening. I should have a good report in a couple of days. This is not something that can be accomplished in a few minutes or hours. Anything that is die cast should be able to be straightened using this technique.:thumbsup:


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## ASQTec (Apr 24, 2011)

Good tip! I straightened the fatigued cast frame of my '49 Lionel 622 the same way. Tightening the clamp a quarter turn a day over six days gave me a straight frame with no damage.


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## gunrunnerjohn (Nov 10, 2010)

For something like a bent roof on the steamer, I wonder if making a wooden mold in the shape for each side would be useful. Just keep tightening the clamp(s) a bit each day until the roof is in it's final shape.


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## tjcruiser (Jan 10, 2010)

Servoguy,

Interesting approach! Thanks for the info.

Question, though ... I have a prewar 1668 cast shell that has bent cab SIDES ... down low, near the cab entry steps. To correct this, I was thinking (???) of stripping the shell (planned for repaint, anyway), and then HEATING the cab section with a plumber's torch. Then, with the metal hot, slowly work it back into place.

But as I said, I've only been thinking about doing this ...

Any opinions? Anyone???

TJ


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## Wabashbud (Jun 25, 2010)

I am thinking that with both heat and torsional stress the metal should react quicker. But how much heat and how much stress? Interesting thread I am interested to read more.

Bud


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## sjm9911 (Dec 20, 2012)

Servoguy, great idea . I can't wait to try it out.!


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## servoguy (Jul 10, 2010)

I don't think heat is a good idea. Zinc is not like steel. It will melt instantly before you realize what is happening. Since the slow approach works, I am going to stay with it. If the part has zinc disease, I think you are out of luck.


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## sjm9911 (Dec 20, 2012)

Ok what is zinc disease ? And if you have to heat it how about a low heat in the oven. Just a little bit. Like before you paint them? But if servoguys way works what's another day or two?


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## servoguy (Jul 10, 2010)

sjm, don't go dropping your locos just to try out this approach. But you can buy locos cheap if they are bent. Recently I bought a 2065 with a nice whistle tender for $65. The loco was pretty well scratched up, but I touched it up with a fat sharpie. The tender needed lubed and a wire fixed, but it whistles really good. It is in very good condition.


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## sjm9911 (Dec 20, 2012)

Like I said before, everything I buy is cheap. I dont know enough about trains yet to spend a lot of money! Maybe I never will. But I will take your advice , sharpies recently purchased (large size). I looked for paint brush size applicators. They were not avalible ( just kidding, maybe) . I dont drop things on purpose ( i sometimes throw them in frustration now and then) on the ground. So you can see why I need to try this out!


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## sjm9911 (Dec 20, 2012)

By the way , the 2065 is a very nice engine. I like the side ( drive )rails. Very detailed. Thats why I originally liked the 1666 ( im not a fan of its slide pick ups) You will have to school me on wistle tenders, I have a few that are non working at the moment.


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## servoguy (Jul 10, 2010)

First thing to check on a whistle tender is the wires from the pickups to the whistle relay. If they are bad (insulation missing or broken off) the whistle isn't going to work well

Second thing to check is the relay to see if it picks up when you operate the whistle control. These relays are very reliable. I don't think I have ever seen a bad one.

Third thing is to lube the motor. There are two bearings, one on the brush plate which is very easy to see, and one below the armature which is somewhat hidden. You do not need to disassemble anything to lube the motor. I use a pin oiler or toothpick to lube the lower bearing.

Fourth thing is to check for bugs building nests in the whistle and blocking the air flow.

Take one of your tenders apart and we will walk you through the servicing.


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## sjm9911 (Dec 20, 2012)

I'm counting on the help. When I get to servicing them.( soon ) . I will post. As always thanks.


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## servoguy (Jul 10, 2010)

I buy stuff cheap, also. I enjoy fixing things and making them work again. One of my specialties is 022 switches. I soon will have 100 of them. I wrote a long post "022 and 711 switch operating pblms" which you can find using Google. After I get done servicing them, they work better than new and will probably last 100 years.


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## gunrunnerjohn (Nov 10, 2010)

sjm9911 said:


> Ok what is zinc disease ? And if you have to heat it how about a low heat in the oven. Just a little bit. Like before you paint them? But if servoguys way works what's another day or two?


It's more correctly called Zinc Pest. It happens due to impurities in the die-cast material. Stuff produced in the pre-war and earlier post-war period are more likely to develop it. Once it happens, there is no going back.


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## pjdog1 (Jan 3, 2013)

Hello verybody. I'm new to this forum however I have straighten 50 or so bent roof Lionel castings.

I put the engine casting in the oven at 175 degress. Let it sit there for 5 or 10 minutes. Then remove it, using my wifes pot holders to pick up the casting. then, Using a set of smooth jawed pliers very slowly pull up on the bent roof. It may take a few times but it does work. And the casting will not break.

jack


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## sjm9911 (Dec 20, 2012)

Thanks, since I already have train disease. I definitely do not want " zinc disease.


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## tjcruiser (Jan 10, 2010)

OK ... dumb question ...

How do I know if my Lionel prewar 1668 loco shell is zinc-based, or some other alloy, instead???

TJ


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## gunrunnerjohn (Nov 10, 2010)

I think they all were zinc based. Aren't all of those die-cast?


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## carinofranco (Aug 1, 2012)

I have straightened cab roofs by making oak molds that match the curvature.--a concave one for the outside and a convex one for the inside and then slowly clamping them together. the oak is hard enough to take the stress.


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## gunrunnerjohn (Nov 10, 2010)

carinofranco said:


> I have straightened cab roofs by making oak molds that match the curvature.--a concave one for the outside and a convex one for the inside and then slowly clamping them together. the oak is hard enough to take the stress.


I suggested that yesterday, nice to know someone has actually done it and it works.


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## rrbill (Mar 11, 2012)

Some otherwise nice looking locomotives for sale on eBay have bent/misshapen cab roofs. You sometimes have to look carefully at the photos to see the damage, and the sellers often don't mention it. Buyer beware.


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## servoguy (Jul 10, 2010)

My 2025 is almost straight. All done with a clamp from Harbor Freight. Should be straight by tomorrow evening.


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## jwse30 (Jun 30, 2012)

I have also used the oak scraps to straighten a bent roof. But I heated the roof with a propane torch, and then used a hammer on the upper oak piece to straighten the metal. It worked, but sure wasn't as gentle as using a clamp. 

I also had a 2055 that had taken a header off a table earlier in its life causing the cow catcher to be bent downward a bit. It would short out on my switches, so it needed to be bent back up. I used the same propane torch and a pair of channel locks to bend it back up. 

As an aside, the paint they used back then is amazing. After heating it with a torch and hitting it with a block of wood, it was still intact. 

J White


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## rrbill (Mar 11, 2012)

The original Lionel PW paint has had several decades to cure. It should be about like boiler plate by now.


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## santafe158 (Jul 14, 2010)

I have a 2020 turbine which I believe has a bent roof corner, but it is so slight I'm not 100% sure. I only notice it when I'm looking from a certain angle.


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## rrbill (Mar 11, 2012)

You're right, Jake; sometimes the damage is subtle and sometimes it's very obvious. I imagine if you aren't sure there's deformation there, others wouldn't notice it at all. If you attempt a repair, please let us know how it comes out.

I have wondered if anyone has ever tried to paint their steamer's cab roof red oxide in an attempt to make it look more prototypic, or would this be considered "gilding the lily?"
Bill


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## sjm9911 (Dec 20, 2012)

Servoguy, is it straight yet? Update, update!


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## Big Ed (Jun 16, 2009)

tjcruiser said:


> OK ... dumb question ...
> 
> How do I know if my Lionel prewar 1668 loco shell is zinc-based, or some other alloy, instead???
> 
> TJ


 
There is also TIN PEST. 


http://en.wikipedia.org/wiki/Tin_pest


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## santafe158 (Jul 14, 2010)

rrbill said:


> You're right, Jake; sometimes the damage is subtle and sometimes it's very obvious. I imagine if you aren't sure there's deformation there, others wouldn't notice it at all. If you attempt a repair, please let us know how it comes out.


I don't really plan on repairing it. I don't notice it when it's running and to me, it's part of its history. :laugh:


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## rdmtgm (Nov 25, 2011)

I agree with you SantaFe. When I repaint an engine I don't feel the need to fix every imperfection. Same reason I Shower and put on clean clothes, but leave my beard White, I am getting old and don't need to hide it


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## servoguy (Jul 10, 2010)

I think all the die cast parts that Lionel & others made are zinc. I read a book a few years ago published in 1948 about zinc die casting. It was written by the owner of a zinc die casting company in New York City. In the book, he talked about the problem of lead contamination. He had all the lead anchors removed that were used to hold down his machines. Apparently even trace amounts of lead can lead to zinc disease. Lionel must have taken steps to remove the lead contamination before WWII as most of the later die cast parts do not have a problem with zinc disease. I do have a post war box car that has die cast ends, and is suffering from zinc disease.

The military in this country does not allow use of RoHS compliant solder due to failure problems. Go figure.


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## servoguy (Jul 10, 2010)

My 2055 is now straight enough I do not perceive any distortion. I am waiting for a smoke element and then it is going back together.:thumbsup:


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## sjm9911 (Dec 20, 2012)

Good to hear. (Can you tell I was waiting for the results by update , update ) I will be trying this in the future!


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## tjcruiser (Jan 10, 2010)

Very helpful info / dialog above, guys.

Thanks! It'll help me out with my 1668 shell.

TJ


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## cole226 (Feb 8, 2013)

rrbill said:


> You're right, Jake; sometimes the damage is subtle and sometimes it's very obvious. I imagine if you aren't sure there's deformation there, others wouldn't notice it at all. If you attempt a repair, please let us know how it comes out.
> 
> I have wondered if anyone has ever tried to paint their steamer's cab roof red oxide in an attempt to make it look more prototypic, or would this be considered "gilding the lily?"
> Bill


in reply to bill on painting a cab roof, i say they're yours, what ever makes u happy.

i try to keep my layout fairly time generic. i run steamers in various stages of weathering, and keep diesels fairly clean. that way i can model turn of the century thru about 1960. just keep things that time stamp u off the layout (or replaceable). for instance, gas stations and pumps can really date things. trucks and autos can be swapped out


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## sjm9911 (Dec 20, 2012)

Servoguy, I did use your idea on one of my engines, its under my" my first layout thread" . I used a screw and bolt spreader to slowly bend my cab back into shape. ( I did not take before pics ) . Thanks for the idea!


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## servoguy (Jul 10, 2010)

Recently I bought several very use 022 switches. Some of them had the lantern holder bent, and I straightened them all out using a clamp. They bend quickly. Each took about an hour.


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## sjm9911 (Dec 20, 2012)

You are " king of the o22 switches" . I did use your old posts on the web to fix some of mine! ( that was before I joined this fourm and was first staring my layout. I have a lot to learn in this hobby.


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