Aligning boiler bushes

Hi all, I am about to solder on the bushes to my GLR boiler and wondered if anyone has any clever tricks to align them so that the fittings finish up in the right orientation when tightened up.

The only thing I could think of is to dry assemble the fittings to the bushes, position and mark them. The drawback I see with this is the final steam tight assembly will probably be different.

Regards

Bill D.

Since it is good practice to only part thread bushes prior to silver soldering and finish afterwards (in case of local overheating) I think you are searching for gold.

Hi Bill. I've never made a boiler, but I would think that aligning the bushes as such would be the least of my worries . And as Kwil says (I would like to make my next loco boiler, so have/am reading up) - threads should be finished as a final step.

I got some copper washers from Blackgates. You get them with the bore to suit your fittings and the pack contains different thicknesses.

All the thicknesses are very similar - with such fine threads it was amazing to see how many degrees difference was obtained by using thicker/thinner washers. That and a decent thread seal will get you the results you want.

Cheers,

Mike.

The simple answer is Loctite 542 Hydraulic sealant. Put it on the fitting, screw into place as far as it will go (whilst being in the correct orientation) and allow to cure. End of problem.

Buy a selection of copper shim washers, a 40tpi thread will move 25 thou in a complete turn so approx 6 thou for every quarter turn, easy enough to work out for 32 tpi as well.

Hi bill sent you a pm 

dunc

Edited By Dismaldunc on 19/01/2013 14:13:00

Another vote for the copper washers they will allow you to tighten as required to get the fittings in teh right place.

I think that Bill migt have been asking, how do you keep the fittings square to the face of the boiler etc. This is especially true for the water gauge fittings.

Thanks for replies guys.

My question was alignment of the fitting in the sense of it being vertical (or horizontal as the case may be) in other words purely for appearance sake.

From answers it looks as if the options are:-

Tap thread after soldering, far enough in until fitting is correctly aligned, this then relying on sealing of thread only.

Align by means of copper washers of appropriate thickness, this presumably allowing sealing on thread and face.

One other question that is bothering me on this silver soldering lark, the experts general advice is to heat the job, not directly on the part being soldered to avoid overheating of flux.

This works fine on small pieces but on a boiler, even a relatively small one such as the GLR, there is a huge amount of copper to heat compared to the size of the part such as a bush.

The problem I seem to grapple with is that by insulating as much of the boiler as possible the area left around the part being soldered is not enough to keep the flame from directly impinging on the part.

I had this problem when I was soldering the tubes ends from inside the firebox, its impossible to keep the flame away from the flux/solder rings in such a confined space. All appeared to turn out ok in the end though.

I guess there is a happy medium somewhere, all down to practice & experience.

I am still at the stage when after what seems like an eternity of heating, I start to think that the solder is never going to flow then suddenly it goes.

Thanks again.

Bill D.

Do not worry so much about putting insulation so tight around everything, By all means have insulation behind and around what you are doing, but you will have to get heat into the boiler shell to enable a well flowed joint on the bushes. Heat comes from the shell to the bush, not the other way around. If you cannot see what you are doing, it will not be OK.

Ive swapped to using loctite bearing lock and copper compression washers - the washer/fitting face doesnt need to be very tight as its the loctite which forms the seal, just crush it down a few turns till it looks right/is square and leave to cure. East to remove and works every time!

Hi. Where are these crushable washers from Fizzy? And what size fittings?

I bought some crushable washers to use on my boiler fittings but was amazed at how they seemed to resist being crushed, well I gave up before any deformation occured due to being worried about something breaking off.....hence I switched to the shim washers.

I agree that the seal takes place at the threads, that Loctite is magic!

Cheers,

Mike.

Did you heat the Copper Washers uptp 'Red' heat and allow to cool first (or quench)?

Dave

Hi Dave.....ahem, no, I thought they'd be ready to use (blush). I'll give one a go.

Thanks,

Mike.

I get my washers from joe at maccmodels - to fit 5/16 or 1/4 fittings. Not thought about annealing them as mine are still soft but makes good sense. Turn fittings by hand till you cant move them then with spanner or grips for last turn or two. Ive never damaged one,

Dunc,

"Hi Bill sent you a pm"

Sorry, must have my Worzel Gummidge thick head on today but I don't understand what you mean.

Bill D

Nigel where do you get your Loctite 542 from, done a few websearches, nearest found so far is ARC sell a Truloc equivalent.

Thanks Bill D

Hi bill, I sent you a "personal message" if you look at the "my account" box at the top left you will see the "my messages" link

dunc

I use loctite 641 - stiff to undo but not difficult - works like magic on sight glasses

eh???????