filling holes in bronze castings

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filling holes in bronze castings

This topic has 13 replies, 6 voices, and was last updated 6 May 2021 at 10:08 by Phil H1.

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2 May 2021 at 16:56 #542766
Gary Clarke 4
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@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!!!
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2 May 2021 at 16:56 #2031
Gary Clarke 4
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@garyclarke4
2 May 2021 at 18:19 #542780
Brian Wood
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@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
2 May 2021 at 18:19 #542781
JA
Participant
@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
2 May 2021 at 18:44 #542785
richard folwell
Participant
@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.
3 May 2021 at 16:46 #542926
Gary Clarke 4
Participant
@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!!
3 May 2021 at 16:46 #542927
Gary Clarke 4
Participant
@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!!
4 May 2021 at 10:37 #543061
Phil H1
Participant
@philh196021
Gary,

What about the frames? Do you also need to fill those and re drill them so that frames and horns line up?
5 May 2021 at 17:15 #543342
Gary Clarke 4
Participant
@garyclarke4
Phil, I am restarting with new frames.. the old ones had holes in them!! (in the wrong places!)

thanks, Gary
5 May 2021 at 17:53 #543356
Phil H1
Participant
@philh196021
Ah right. Which engine are you building/ rebuilding?
5 May 2021 at 18:12 #543363
JA
Participant
@ja
Gary

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

JA
5 May 2021 at 18:54 #543381
Gary Clarke 4
Participant
@garyclarke4
ok will get some taken.. its a CLARKSON Princess Royal in 3 1/2 gauge.
5 May 2021 at 19:31 #543389
Neil Wyatt
Moderator
@neilwyatt
I would make free-fitting brass plugs and braze them in place.

Neil
6 May 2021 at 10:08 #543487
Phil H1
Participant
@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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