filling holes in bronze castings

[Gary Clarke 4Participant @garyclarke4]

Hello All!

I am restarting a locomotive build – luckily the previous builder didnt get far!

One of the problems I have is that the hornblocks have been drilled but the frame were likely drilled first and then through into the the castings. The casting holes are not in great locations in the castings and look off. Likely no-one will see them but I am wondering how to fill the holes in and salvage the castings. Any ideas please on how best to proceed? these are not the only castings I need to fix and I am in Canada so replacement castings (if available) are an expensive last resort. Fix if at all possible!!

thanks!!!

[Gary Clarke 4Participant @garyclarke4]

[Brian WoodParticipant @brianwood45127]

Hello Gary,

Brazing if you have the means would be a good option as that will give you equivalent strength in the filled holes if you need to rework them with threads

Regards

Brian

[JAParticipant @ja]

I recently had this problem but of my own making.

Turn a length of bronze rod to 0,2mm below the hole diameter. Cut the rod to length and silver solder in place for each hole. Tidy up afterwards.

The holes I filled were blind and I rather nievely thought I could just fill them with silver solder. The little bit of rod is needed to stop the solder flowing up and out of the hole.

JA

[richard folwellParticipant @richardfolwell36886]

If you don't want to heat up the castings then drill the existing holes to the nearest tapping size and tap. Now use threaded rod or screws and Loctite in place. Leave overnight to cure then file flush. Even if your new holes overlap the screws will still remain in place.

[Gary Clarke 4Participant @garyclarke4]

Thank you all for the informative replies.. I will likely go the bronze rod and silver solder technique as that is what I have on hand. First try will be on the easiest to remanufacture casting!!

[Gary Clarke 4Participant @garyclarke4]

Thank you all for the informative replies.. I will likely go the bronze rod and silver solder technique as that is what I have on hand. First try will be on the easiest to remanufacture casting!!

[Phil H1Participant @philh196021]

Gary,

What about the frames? Do you also need to fill those and re drill them so that frames and horns line up?

[Gary Clarke 4Participant @garyclarke4]

Phil, I am restarting with new frames.. the old ones had holes in them!! (in the wrong places!)

thanks, Gary

[Phil H1Participant @philh196021]

Ah right. Which engine are you building/ rebuilding?

[JAParticipant @ja]

Gary

Pictures/photographs please. Then we can get some idea of the magnitude of the problem.

JA

[Gary Clarke 4Participant @garyclarke4]

ok will get some taken.. its a CLARKSON Princess Royal in 3 1/2 gauge.

[Neil WyattModerator @neilwyatt]

I would make free-fitting brass plugs and braze them in place.

Neil

[Phil H1Participant @philh196021]

Gary,

Another option to consider maybe?

If you are making the frames from scratch, you could simply use two bright mild steel sections per axlebox (one either side) or even a 'U' shaped 1/4" thick steel plate riveted or held with screws to the back of the frames. You simply need to make the slots narrower to fit the axleboxes.

I am in the middle of Rob Roy and if I built another 3 1/2" gauge engine, I would definitely dispense with the cast main horns. They seem to be more trouble than they are worth and obviously very expensive if you buy them.

Silver soldering up your existing main horns is a straightforward enough job but 4 or 5 holes per horn x 6 plus clean up becomes quite a task.

Phil H

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