Author Topic: Popular Mechanics Boiler (Read 45819 times)

ieezitin · « **Reply #75 on:** July 31, 2014, 04:22:51 PM »

At work on our low pressure steam we use Key-Tite or never-seez on all threaded joints, my employer,s procedure calls for Teflon tape and Never-seez but I omit the Teflon tape. When we install unions we soap up the threads too so it comes apart easy.

One advantage of Key-Tite is that it never sets.

Ket-Tite is a registered Trade mark name.

Anthony.

awemawson · « **Reply #76 on:** July 31, 2014, 04:46:13 PM »

When I re-plumbed my launderettes years back I did it in stages. Water distribution originally was in 2" screw galvanised. Getting a good seal onto fittings as I gradually replaced it all with copper over a few nights (keeping shop open during the day) was a nightmare. You could wrap as much teflon tape as you like round the male before screwing, and it would still leak - quite repeatable! I reverted to 'Boss White and Hemp' which instantly cured all problems. It wasn't until a bit later I found the reason. The hemp, put in dry, expands if a leak wets it and seals the joint. Sometimes the old ways are the best.

Not sure if 'Bosswhite' got across the great pond to the US but is a whiting and linseed oil composition. Now banned here for potable water.

vtsteam · « **Reply #77 on:** July 31, 2014, 11:21:08 PM »

Thanks Anthony, I looked it up and it only seems available from the manufacturer with a $66 minimum quantity.

I also found this non Teflon stuff which seems pretty good in the specs:

http://www.gsasupplyco.com/gasntnonsofs.html.

Andrew -- is "whiting" white lead in linseed oil? I actually have some of that as an old unopened tub of traditional gesso.

ps. some forms of hemp are also banned here.....

mattinker · « **Reply #78 on:** August 01, 2014, 12:06:57 AM »

Whiting is calcium carbonate, CaCo3 Chalk, the "hemp" is sometimes known as skrim in the UK I know what it is in French "fillasse" , I found oakum as a translation on the web. Wind the threads of hemp round the screw thread (previous in a clockwise direction as on would with teflon. It is very different to Lead oxyde. The jointing compound (or it's modern equivqlent)should be available in plumbing suppliers

Regards, Matthew

PekkaNF · « **Reply #79 on:** August 01, 2014, 03:09:43 AM »

I pretty much hate teflon tape on any sytem that has small orifices, screens or such. I have cleand up fules systems, pumps etc. because someone had a bright idea. Bits of it always ends somewhere where it does most harm. Here probably into safety valve.

Teflon tape works on reasonably good brass fittings, when it is taped over male thread same way than you thread the union over it. DO NOT turn back at all when tightening. If turned back, it needs to be completely removed and replaced. Most good fittings works without it. Cast iron unions/iron pipe (central heating) seems to work best with traditional hemp/white paste. But pressure is not much in central heating system water circulation.

Pekka

awemawson · « **Reply #80 on:** August 01, 2014, 08:55:01 AM »

Quote from: vtsteam on July 31, 2014, 11:21:08 PM

Thanks Anthony, I looked it up and it only seems available from the manufacturer with a $66 minimum quantity.

I also found this non Teflon stuff which seems pretty good in the specs:

http://www.gsasupplyco.com/gasntnonsofs.html.

Andrew -- is "whiting" white lead in linseed oil? I actually have some of that as an old unopened tub of traditional gesso.

ps. some forms of hemp are also banned here.....

Steve, I think others have answered this before I got to it !

The chap I bought my last house from 32 years ago was the heating and ventilating contractor who installed the plumbing in Terminal 3 Heathrow. He swore by just using oil based gloss paint on screwed joints, which seems to work. Mind you looking at the state of the house plumbing when we bought it I shudder to think what the airport terminal pipes are like

He got his come uppence though - BOTH his wives turned up at his funeral, and oh was there a fuss

vtsteam · « **Reply #81 on:** August 01, 2014, 09:48:41 AM »

Thanks guys, I should have looked up whiting. Oakum/hemp I'm familiar with.

My father in law once brought me a full gallon of raw linseed oil he didn't want any more -- looks like it's from the 50's judging by the label. I've used boiled linseed oil before because it air dries easily, but not raw, so I've had no particular use for it either.

But maybe now, to make up a once a year removable traditional putty it might be just the thing. I'm wondering however -- whiting -- I haven't seen it anywhere in the local hardware stores as such, but we do have something which might be the same thing -- plumbers putty -- oil based chalky and smelling of linseed oil, and also very similar, window glazing compound -- white chalky, linseed oil-ish smelling, and supposedly non drying.

Last night I ordered some of the Gasoila non-teflon pipe compound, since I found it for $5 plus change on Amazon in a small quantity. The specs say good for potable systems, NFS approved, and good to 400F. But, still, whatever is in it is unknown and it's reaction to high temps above that also unknown, while whiting and oakum are very well known ingredients, and non toxic no matter what the temp.

You know Andrew I came across the paint as joint compound recommendation elsewhere in old writings re. model engineering. I was tempted by that, too.

so many choices.......

vtsteam · « **Reply #82 on:** August 03, 2014, 06:42:13 PM »

With most of the other problems solved, it's back to the relief valve today. I decided to do an outside barrel ball and spring type, but to use as much ready-made brass plumbing as I could, to keep with the overall theme -- which turned out to be quite easy.

First I turned a bit of brass to the ID of a 1/8" brass pipe nipple:

vtsteam · « **Reply #83 on:** August 03, 2014, 06:43:20 PM »

Checking fit:

vtsteam · « **Reply #84 on:** August 03, 2014, 06:44:35 PM »

Drilled to 1/8" for the steam passage:

vtsteam · « **Reply #85 on:** August 03, 2014, 06:47:45 PM »

I drilled a recess of 3/16" then added a bevel out to the edge of the valve seat plug. These two steps will help guide the 3/16" stainless steel ball to the 1/8" valve seat at the center.

vtsteam · « **Reply #86 on:** August 03, 2014, 06:48:29 PM »

This is a better view of it:

And with the ball in place:

vtsteam · « **Reply #87 on:** August 03, 2014, 06:49:43 PM »

Then I silver brazed the valve seat plug into the pipe nipple:

vtsteam · « **Reply #88 on:** August 03, 2014, 06:52:35 PM »

With the ball in place I formed the valve seat to the ball with a light tap on a drift.

vtsteam · « **Reply #89 on:** August 03, 2014, 06:54:41 PM »

With the valve body and seat done, I started on a plunger to take the spring pressure and push the ball into the seat. I decided to use 1/8" brazing rod as the stem. Here I'm turning the plunger end:

vtsteam · « **Reply #90 on:** August 03, 2014, 06:55:50 PM »

And here's what it looks like with the rod in place. The bevel will help center the ball:

vtsteam · « **Reply #91 on:** August 03, 2014, 06:57:41 PM »

Here's how the plunger, spring and ball go together. The plunger has been brazed to the stem already:

vtsteam · « **Reply #92 on:** August 03, 2014, 06:59:26 PM »

Finally, I drilled a 1/8" standard pipe cap to .136" to give good clearance on the 1/8" stem:

vtsteam · « **Reply #93 on:** August 03, 2014, 07:01:10 PM »

Here's the completed relief valve assembled with a 1/8" to 1/4" pipe bushing:

vtsteam · « **Reply #94 on:** August 03, 2014, 07:03:19 PM »

I'm looking forward to doing pressure tests on the valve tomorrow with the new hand pump. If all goes well after adjustments, we may be steaming!

tom osselton · « **Reply #95 on:** August 03, 2014, 07:26:00 PM »

That looks quite impressive your safety valve looks to be quite natural and you could also adjust the spring tension easily with a spacer.

vtsteam · « **Reply #96 on:** August 03, 2014, 08:00:05 PM »

Thanks Tom, I;m going to re-thread the top end of the barrel from 1/8" pipe taper thread to 3/8" straight thread so I can screw down the cap to adjust pressure somewhat. Probably put a thin locknut there if I do so the adjustment can be locked. Right now the friction of the taper thread works, but there's little adjustment.

The main adjustment on this type of safety valve, though is the spring itself. The current spring is a hardware store type. I have a few others with different rates that I bought today, but all are spring steel. Once I find the right one for the working pressure, I'll either order a stainless version from McMaster Carr, or if I have the right SS wire, try winding one myself.

I was wondering where I would find SS spring wire, and then remembered I have quite a selection of saltwater stainless steel fishing leader stock, which is about as stiff as music wire. I think i would make good springs.

Looking forward to tomorrow!

S. Heslop · « **Reply #97 on:** August 03, 2014, 09:15:02 PM »

It looks real swish in black and gold; the best colour combination.

Have you got an engine to run with it?

vtsteam · « **Reply #98 on:** August 03, 2014, 09:59:29 PM »

Oui!

several....

Although I really want to make a new one

perfect excuse.

Might just try the old Tesla disk turbine first, though I have a feeling it won't do anything with this little (and this wet) steam. But you never know until you try. But it sure won't pose much resistance -- it has a nozzle efficiency of a soda straw. I have 4 piston steam engines of various sizes, another one half built, ......and well my top secret tunaturbine, the antiTesla, which has never been tried on steam, or indeed publicly revealed. I don't know if I dare speak of it even here...

tom osselton · « **Reply #99 on:** August 03, 2014, 10:50:34 PM »

Well it sounds fishy!

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Author Topic: Popular Mechanics Boiler (Read 45819 times)