Unlucky or what !

I'm slowly progressing with the build of a Stuart Compound - today I was working on the last of the eccentric straps. The main kit is quite old as it is an original Stuart but these eccentrics came from Bridport as I wanted to build it with reversing.

All was going well - i'd bored and grooved for the eccentric when I noticed a small casting flaw - some grey material in the bronze !

As can be seen its in just a bad place !

Weighing up options :-

1. Start again - ruled out !

2. Leave it - it will be OK ?

3 Cut a groove / clean up fit a brass strip slither and soft solder (or comsol)

4 Ditto but silver solder.

Problem is likely to be solder in the groove that will br difficult to remachine out if silver solder as its very narrow and tool will likely dig in and break (0.8mm) - any ways of blocking groove with any pastes etc ?

Any advice greatfull received.

Richard.

I would try Option 4, and use a chain-saw file to clean-up the offending blemish. Once it looked OK, I would silver-solder in a bit of round bar to match - size and colour. Then machine to remove the excess.

The major advantages of using a chain-saw file are that the diameter of the file can be selected from a wide range (from about 1/8 inch to 1/4 or more) to suit the size of the blemish, and to match an off-cut of rod. And being the same diameter throughout, the fit of the newly filed groove should be plenty good enough.

I hope this helps

Cheers, Tim

you could try masking with Snopake (red) and then the silver solder will build up not run all over the place.

It's on the inside edge so will hardly be visible when assembled so you could just leave it as is.

If it bothers you then use a small milling cutter to cut a regular slot, mill up a bit of matching material and loctite into the slot, file flush on the 3 faces.

That is unlucky.

For me, I would choose option 2, leave it as is. The flaw in the bore will not affect the operation of the part. On the side it might be visible. This might niggle at you after a while.

If I were to try a reclamation, I would clean up the surfaces, mask off with one of the proprietary products, then silver solder as Bernard Towers has said.

You will have to see how much it annoys you and take it from there.

Neil

I would choose option 5, return to supplier and demand a replacement casting. It won’t take long to re machine a new casting, possibly about twice as long as you will spend fiddling about trying to salvage the original one.

Edited By Baz on 17/08/2023 19:51:06

Hide it (It is only a model and not highly stressed. If it breaks there will very little other damage and it can easily be replaced) or get in contact with Stuarts. They are a good firm and if they are not prepared to replace it a new casting will only set you back by about £20.

Don't mess about trying to fill the flaw with solder. You will learn a lot about silver solder but it won't be to your advantage (I have been there).

Have you tried machining the cast iron double eccentrics? I broke two casting before using mild steel.

JA

I'm only looking at pictures of course but did you really not notice that until after you'd machined the part?

I'm with Baz ! Return as flawed. There a good firm. Noel.

Thanks for all the replies, as the consensus seemed to be 'leave it don't worry it will work OK', I though I;ll give it a bit of reinforcement and went for file it out a bit and fit a brass flat and soft solder - worked fine and difficult now to see.

The proof will be when it runs eventually !

Peter - no - the mark on the top side was not visible and when I reduced the thickness on that side it became visible (I had probably opened it up a bit when I took the pic.

JA - yes I have machine the double eccentrics but not 100 % happy with my setting out so about to remake in steel in 2 parts as per my Double Ten.

Richard.

There is a product i have used in the past called Belzona bronze its an epoxy putty used for repairing bronze pump casings, its bronze colored and is available in different package sizes. It would fill that void and be able to be filed easily to form. There may be another maker that makes a similar product in modelling sized packs.

There is enough strength in the part for what it does and that will sort out the cosmetic side of things.

I don't know what the cost is these days mind you so it may be more cost effective to go the replacement route with Stuart as others have suggested if the cosmetic look is going to keep you up at nights.

BR Roland