I have an old Chicago vertical trilight signal. There is a rain gutter over the top of the door on the main casting of the signal. There is about a 3-4 inch long curved segment that was broken off at sometime. I am currently working on restoring this signal and would like to repair this lip. I don't have the old piece of course. I was considering using a Bondo type product to reproduce the lip with and then sand it to shape. Then I would run a needle scaler over it to make it look like cast iron. The lip sticks out about an inch and is about 1/2 inch thick give or take. Any suggestions of a better way to repair this and/or a good product to use to recreate the lip?

I have also been looking for a manual online for this signal and have found a Chicago catalog that contains an earlier model of my light but nothing matching mine. Does anyone have a lead on where a catalog or manual might be hiding?

Thanks!

I have had good results with JB-Weld (tm) on cast iron repairs (non-structural appearance repairs). I have also had good luck with torch brazing for structural repairs to cast iron.

My concern would be if this area is likely to be broken off again then a brazed repair would be more secure long term. Brazing filler metal is as strong or stronger than most cast iron.

You can also drill some holes on the broken surface and thread them and insert some short machine screws (with some thread locker). The machine screws will add some structural strength to the repair. Make the screws come out below the final surface. You can do this for JB-weld or brazing.

Brazing would probably be done best if you remove all the electrical parts from the unit first to prevent heat damage.

Either method needs a extremely clean surface, wire wheel the heck out of the broken surface and wipe it down with acetone to remove any oil.

Good luck, Kevin.

thanks for the suggestion of the JB Weld. I will look into that. Fortunately it is not a structural part that I am needing to repair.

Make sure you use the classic JB Weld and not the quick setting version. The properties are different and the older version is stronger. At warmer temperatures it tends to run a bit and you will need to build some kind of dam to hold it in place while it sets. Once had to use it for an emergency repair on the road on a cast clutch housing; last I knew it was unexpectedly still holding. It gets hard enough when set to file/sand/machine to match existing surfaces.

It can be purchased in larger quantities than the small tubes common in most hardware stores.

Bondo doesn't work that way. It is basically sheetrock compound for metal surfaces. It has very little flexural strength and will fall apart over time. Or instantly, if you try to use a needle scaler on it!

I like the others' idea of using JB Weld. Roll a little strip of sheet metal to the same radius and tack that on to act as a dam until the filler material is partially set up. If you can drill some screws in edgewise as dowels that will make it very strong and unlike to break off again.

Further JB Weld notes (have used it a lot in stone and other repairs):

Any metal you use in creating dams may be very difficult to remove later. I prefer masking tape/cardboard which can be easily torn off and the remainder removed by sanding.

When sanding it is relatively easy to match a 400 grit surface; have gotten good matches with 800.

It will normally take several hours to fully set. This can be speeded up by putting the area welded under a heat lamp (halogen trouble light works well, too). Theoretically this should result in a weaker set but I have not noticed much difference with JB Weld. Note that if you do this you will need a very good dam as it gets even runnier with the heat.

Depending on how you do the weld you can get air bubbles which show up afterward. These can be filled with a second application. This tends to be less with the heat application.

I have not been able to get a firm answer from the manufacturer as to just how much heat the set weld can endure. My observations have JB Weld able to withstand heat better than the other commonly available epoxies I have used. You can probably count on 250 to 300 degrees F; your mileage may vary.

Timothy

I should have been a little more specific, for cosmetic repairs on castings I have used the "Steel Stick" version of JB Weld (tm). Comes in a clear tube and has an inner and outer layer (like filled candy). You chop off how much you need and knead the layers together.

https://www.lowes.com/pd/J-B-WELD-Steel ... Oz/3389024

Comes out like stiff clay.

Then you apply and shape to fit. Let it set and file sand etc.

If you can get some 6-32 or 8-32 machine screws perpendicular to the existing broken surface and cut the heads off below the final outer surface you will get a good strong "lip/rim" sticking out that will likely stay there for a good long time.

I used it on vertical surfaces with no runs or drips, did not need any dams. Not sure it will stand up to a needle scaler.

But you could probably press some other broken chunk of casting (or 40 grit sandpaper) against it between the initial setup and the final cure (10 - 30 minutes) and get a "casting look".

Start with a small batch to get the feeling for it. Worst case you can grind it back down and add new layers.

Lots of YouTuber's posting their projects, one guy said; "It's like the steel version of Playdough"

Good luck, Kevin.

(Note, I have mixed it with bare skin with no long term effects (except for a little twitch every once in a while that could just be from an old highschool football injury) but if you have sensitive skin you can use gloves, your mileage may vary.)

I appreciate all of these responses. I will "stake" the JB Weld as suggested. I didn't know about the putty version of JB Weld either but see my local Lowes has 22 of them in stock.

I do appreciate all of you with skills that I have yet to acquire being wiling to share them with me.

You try lining a sheet metal form with something nonstick like wax paper or a release agent like wax or silicone coating. Experiment before hand.

I have used corn oil as a 'cheap' release agent for JB Weld and for 'marine epoxy' putty. That also works reasonably well, in my experience, with real silicone caulk.