Copper Rivets as Boiler Stays?

[brozier]

Hiya,

Just been reading the latest installment of Julia's excellent boiler making series in ME and I noticed she's using Rivets for boiler stays. I'm assuming these are copper with the preformed head on the inside of the firebox.

This looks like an excellent idea as threading hundreds of stays looks like hard work.

Has anyone else used this method?

Cheers
Bryan

[ilvaporista]

Yes.

Taken directly from Alec Farmer's great book. Make sure that there is enough 'gap' for the silver solder to flow.

[mutley]

yep, have been for years, as have most of the proffesional boiler makers.

Andy

[ukjimoo]

Yes, i did mine this way. My local boiler builder told me this is the way it is done these days and all his boilers are done with rivets.

I think you have to increase the size though. From memory, my design called for 4BA threaded Phosphor Bronze and he told me to use 3/16" dia copper rivets with the heads on the inside as you say.

[durhambuilder]

If you are an amateur boiler maker I would still put in a few threaded stays amongst the rivets otherwise you will have problems holding the plates the correct distance apart whilst soldering.

[ron]

If you buy a boiler kit it's copper rivets that are supplied for the stays.
Ron

[durhambuilder]

Sorry just had another thought! Rivets should only be used in a fully silver soldered boiler which with some deeper fireboxes are tricky to make with normal propane torches, Threaded and nutted stays must be used if using a high melting point soft solder for caulking.

[mutley]

deep fireboxes are not dficult to make and you can silver solder the stays with a propane torch using a cyclone burner. All you need to do is leave the backhead till after the stays are done. The plates wil hold themselves the correct distance apart if you assemble the boiler in the right order.

[baggo]

I use copper rivets to make threaded stays where these are necessary. I found (much to my surprise) that it was easy to thread the rivets by holding the head in a drill chuck in the lathe headstock and thread them all the way along using a tailstock dieholder. They are then threaded in from the outside until the head is flush against the wrapper and nutted on the inside as usual. I actually silver solder the heads on the outside as this is relatively easy to do and then use Comsol on the nutted end.

I have wondered if it would be satisfactory to have the rivet head inside the firebox (assuming you have room to screw them in from the inside) thus eliminating a separate nut. The outside end would be silver soldered and the head inside the firebox sealed with Comsol. Would the rivet head be as strong as a separate nut?

John

[simonwass]

I used copper rivits on my Invicta, difference here was that I put the heads on the outside so the unlagged boiler would look nice, and it does!

[simonwass]

Jul 2, 2008 20:35:15 GMT John Baguley said:

I have wondered if it would be satisfactory to have the rivet head inside the firebox (assuming you have room to screw them in from the inside) thus eliminating a separate nut. The outside end would be silver soldered and the head inside the firebox sealed with Comsol. Would the rivet head be as strong as a separate nut?
John

I shouldnt see why this will not work, much better to do a full silver solder job though. Problem with comsol is that you cant do any more high temp jobs. On my Clayton I put in 2 extra bushes for an electronic water gauge (afterthought), couldnt have done so if there was any comsol on it (I know theres no stays but you get the idea!)
The Brit that won IMLEC last year has Loctited stays, threaded stays Loctited in with nuts Loctited on top.
My Invicta's name plates are screwed to the boiler with screws Loctited in.
My Clayton's firehole door hinge and catch again use screws Loctited in.