Mrs. Robinson, Revisited.......

[Stilldrillin]

After almost a couple of years delay. I've made a tentative start, on completing my Robinson engine rebuild.

Shop time is still very limited. But, I'll post whenever there's some progress.

Here's the original saga. Just getting the engine to the condition I hoped it would be in, when it arrived...... http://madmodder.net/index.php/topic,3555.0.html

The flywheel casting halves are eccentric to each other, and the bosses have been machined true to the opposing sides! 

Turned away as much of the balance weight as I could.......




The engine has been dropped, and one foot is broken.

Milled away the ragged edge......




And made a cast iron block to fit in the recess........




I've had little practice at silver soldering. But, never (yet) had a failed joint.

What's the best sequence to use, for a sound joint in this situation? Should I flatten the wire, and lay between the parts?

Any tips would be much appreciated.

David D

[vtsteam]

Stilldrillin, the main thing to try to do is not crack the casting. Too much localized heat and too rapid cooling can cause cracks. I would have a bucket of wood ashes nearby to plunge the part into and let cool for half a day. But I have a wood stove, don't know whether you do.

Parts must be absolutely clean in joint -- no fingerprints. flux parts. Clamp parts or wire them so they can't move. If a joint is close, but not absolutely closed. I'd feed from the outside -- the braze will wick in usually.

When heating the part. play the flame over a large area, to heat gradually instead of too localized, Gradually focus down onto your braze area.

Both parts need to be equally hot, so spend more time on the more massive piece.

When flux boils from the metal heat (not the flame) usually it's time to apply silver braze. Braze should melt from contact with the hot metal rather than just the torch. If the metal is too cool, the braze will ball up in the torch flame instead of flow onto the metal. Hold the flame on the metal just long enough to get good flow but no so long that it flows off the piece or overheats it.

You can back the joint with aluminum sheet if you think solder will flow through and drip out.

That's about all the tips I can think of.

[Divided he ad]

Good luck David! 

Talk about a steep learning curve!


All sound advise above from all the things I've heard in the past....

Still makes it no easy task in reality... If you have any spare stuff I'd suggest a practice run. 


The wiring together works for me too.... Worked well recently on my rocket.



I might thin that new part down a bit too... Much less to remove once the shape is all big and awkward to hold/machine.






Ralph.

[Stilldrillin]

VT.
No wood ashes here....... Central heating, powered by natural gas condensing boiler.

Thanks for the run through.
Just the usual common sense set up, and procedure.  Allied with careful heating.

I just wondered if c/i needed any special treatment. Thanks for the alloy sheet tip!


Ralph.
Thanks for your sympathy! No spare stuff...... Especially castings!

Yes! the block can be reduced a little at one end, as the joint face is tapered.


Thanks, both, for the support. Just needed a slight confidence boost, having only done 3 or 4 conventional joints previously........   

Win, or loose...... Pics will be shown!

David D

[Stilldrillin]

Well.....

When I'd dropped the insert on the floor, for the third time, while trying to wire it into place. I realised, it was April 1st.... 

Finally got it fixed, with flux more or less where I wanted it, and positioned on a fire brick.

After some time of heating, I realised my blowlamp was ok for copper plumbing. But, well underpowered for this job! 

The flux was bubbling, but no sign of any red heat! 

Only thing to do was dab and hope.........

The solder slowly melted, and puddled. So, I dabbed some more. Hoping it might flow through. 

Then I went for me lunch, leaving it to cool........




Turned it over, a couple of hours later. Not too bad........




Milled off excess. Expecting it to come unstuck.

Why do we always go that one thou too deep? 




Still attached. Looking ok.........




Rolled it over. Angle grindered and drilled 5mm........




A couple of dabs of filler and some paint, should look ok! 

Thanks for the support Chaps. Much appreciated! 

David D

[vtsteam]

Looks Good!! 

[Brass_Machine]

Very nice fix. Once again, without a doubt, you have sown you are a master at rebuilding/reconditioning/re-engineering hopeless cases!

Well done.

Eric

[Stilldrillin]

VT.
Thank you! 


Eric.
Thanks! I don't know about being any sort of, Master Bodger. 

But, I must say, I feel much more confident with the varied techniques needed. Compared to 4 years ago, when I joined Modder. 

David D

[sbwhart]

Good fix Dave

It's good to see you back on the case 

Stew

[Stilldrillin]

Thanks Stew!
It's a good feeling.

Not out of the woods, yet. But gentle progression, at last....... 

David D.

[tom osselton]

Here you may find this interesting about silver soldering

 

[Divided he ad]

Job well done David 

Knew it'd be fine     




Now just a little bit of tweak and  assembly 






Ralph.

[krv3000]

well dun

[Stilldrillin]

Thanks for the vid. Tom!

Love how he allows the solder to take it's own time, to flow around the joint.


Ralph, Bob. Thanks!

Tweaking is ongoing, slowly, as weather and other commitments allow. 

David D

[Meldonmech]

I have never tried silver soldering cast iron, mainly because I've never needed to, so I  have found this post very interesting. The foot has turned out well.
                                               Neat job            Cheers  David

[Rob.Wilson]

Good to see your getting some shop time David 


Very nice repair job on the casting  good as new 


Rob

[Stilldrillin]

David, Rob......

Thank You! 

David D

[Stilldrillin]

All stripped again......




Looks better than the first stripdown! 

Starting to clean parts, and adjust them to fit each other properly. Never seen a drawing, so I'm building blind. 

I used Bluecol top up mixture for coolant.
There is rust in the nooks and crannies, despite piping air through the engine for 3 days, after running. Would machine coolant mix be kinder?

What do others use?

David D

[Stilldrillin]

Made a little headway.

Spent a lot of time filing and fitting together. Cleaning out threaded holes, and shortening new screws to fit.

Painted some parts........




Not happy with the deck surfaces. So, will scrape off, and re paint. 

Didn't like the pifflin' 3/16"dia. m/s crankshaft, holding a 4.5" dia. cast iron flywheel. 

So, I replaced with 6mm silver steel, and new bushes......




In real life, these engines were usually located in the scullery, to supply water from the well, to an in house storage tank.

Does anyone know what kind of pump would be used?

David D

[fcheslop]

Well you did ask,A WATER PUMP
OK I will go quietly

[Stilldrillin]

Sigh....... 

Thanks Frazer!   

David D

[vtsteam]

Took a photo of a page -- hope it's clear enough.

[Stilldrillin]

WOW!! 

Thank you for the research VT. 

I thought the originals must have been supplied as a pump unit. But I have only ever come across solo engines. Never coupled to anything. 

David D

[Stilldrillin]

Slow, but steady progress.   

I've sleeved the flywheel bosses back to a sensible diameter. Also, the bore to 6mm.
The colour's not as orange, as it seems here........




Lit a small burner, to cook the paint a little.....




Warmed gently, for 5 mins or so........




Didn't want any paint blisters....... But it's a trier......




Finally coming together! 

David D

[vtsteam]

Looking wonderful!!