rivets in boiler

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sky
Posts: 37
Joined: Thu Mar 22, 2018 2:17 pm

rivets in boiler

Post by sky »

hello all you wonderful, wise, helpful mentors...
I'm working on my boiler shell, Kozo's A3 in 3/4 size. He has you rivet the shell and other parts. Questions:
1. do you flux the rivets?
2. do you file the heads off the peened over side on the outside of the boiler? I can't imagine you would if solder didn't flow into the rivet hole. And I thought rivets would seal the seam.
3. My guess is I am looking for the solder to be continuous around my riveted strip, thus sealing the joint, correct?
sky
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steamin10
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Joined: Sun Jun 08, 2003 11:52 pm
Location: NW Indiana. Close to Lake Michigan S. tip

Re: rivets in boiler

Post by steamin10 »

Basic rules of silver solder apply: clean, clean ,clean, flux, heat and solder any seam until it is bright under flame. Use a scratch pick if needed, and get a good heat, no cold joints. Under the influence of flame and flux the silver will migrate to where it is clean chemically and wick in. It is a good idea to practice on some copper fittings for plumbing to get the feel of how it works before you risk the final project. It is heat control and cleanliness. If you cook the metal to oxide before it heats, you are done. I encourage you to try, as once learned it will become second nature. I promise. Take heart, you can always make another if need be.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.
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Builder01
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Location: Erie, PA

Re: rivets in boiler

Post by Builder01 »

Yes, rivets should be fluxed and soldered, as well as the strap and the boiler barrel and everywhere you want the solder to flow. When copper is heated to silver solder temperature, it oxidizes, oxidized copper cannot be silver soldered. The flux protects the area to be silver soldered from oxidizing.

Looking at page 236, Kozo does not show the peened end of the rivets filed off. His technique is to peen the rivet into a counter sink. When peened properly, the peened rivet fills the counter sink. But, as he says, the end of the rivet is not really peened, it is just staked, lightly. This is so the rivet is not too tight in the hole and will allow the silver solder to flow completely around the rivet.

Yes, you want the silver solder to flow continuously between the strap and the boiler shell.

If you check out my web site, I have a strap joint on the fire box water leg extension of my boiler.

https://supersimplex.yolasite.com/Plates-and-Tubes.php

This is just like the strap on the bottom of Kozo's boiler barrel. This strap is held in place with only 6 screws, instead of rivets because I can better control how tight the screws are versus a rivet. The screws are really only there to jig the parts together while silver soldering. The screws are bronze, not brass. Part of the prep for silver soldering, is to acid dip every part including the screws. I used acetic acid for cleaning. When clean, everything is fluxed for silver soldering. I used high temp black flux. The screws are purposefully not screwed tight at the time of silver soldering. In fact, each screw was installed after painting each screw, and the joint, with flux. I have a few photos of before and after the silver soldering of this joint, it's about half way down the page. You can see the silver solder has flowed around each screw and the strap. These heads are pretty big and could be filed flush, but, there was no need to. The strength of a silver solder joint, is not in the fasteners, it is the silver solder that has flowed properly between everything.
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DSCN1124 - reduced 3.jpg
sky
Posts: 37
Joined: Thu Mar 22, 2018 2:17 pm

Re: rivets in boiler

Post by sky »

Awesome...thank you for sharing. I can only hope mine turns out as well.
Thanks for the link to your build. Marvelous resource. If you care to pass along any other tips, I am all ears!
sky
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Builder01
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Joined: Mon May 18, 2015 5:26 am
Location: Erie, PA

Re: rivets in boiler

Post by Builder01 »

Hi Sky,

Thanks for the kind words about my website. I was hoping the information might be useful to someone, especially a first time builder. I took a ton of photos during my build, and I thought the site night be a good way to share them, along with the few things i learned. I wish I knew how to organize the site better, but, it kind of works even the way it is. There are various tips on the site, but, you have to dig a bit to find them.

I can say though, Kozo's A3 book is an excellent resource. The sections toward the back of the book about silver soldering, and setting up a work shop and the tooling needed is especially significant. I have just recently re-read some of those sections.

David
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gwrdriver
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Location: Nashville Tennessee

Re: rivets in boiler

Post by gwrdriver »

Builder01 wrote: Wed May 02, 2018 5:35 pmKozo does not show the peened end of the rivets filed off. His technique is to peen the rivet into a counter sink
This is the way to do it. I usually leave my rivets straight, but snipped off if they're over-long in places, and I lightly countersink the exterior rivet holes to give solder (and flux) a channel of sorts to run into and pool. I hold the rivets in place during soldering by peening the rivet shanks, and the holes sometimes, to hold the rivets in place. I've never had a problem with rivets dropping out while soldering but if it makes you more comfortable to peen the end a bit then by all means do so. The important thing, aside from the usual cleaning and fluxing mentioned, is to have enough heat, and give the solder a place it wants to run and stay.

The other thing I differ with Kozo on is his use of solder "snippets" everywhere. Snippets are fine, until things begin to heat up and the flux begins to bubble and flow and next thing you know the snippet you put exactly where it needed to be, ain't where it needs to be! The good boiler builders I know of all use rod or wire so that when a joint demands solder you can give it what it needs instantly, exactly where it's needed, and not have to wonder where that snippet floated off to!
GWRdriver
Nashville TN
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