Migging Cast Rayburn

[Barking Mat]

Here's my problem, it's a rayburn, had it for about three or four years now, very secondhand, when we bought it it was missing the 'chimney control box' ie the baffle and air moderator(?) and just below this corner was a piece of cast iron (broken) about half the size of a postcard from inside the 'flue'? system.
The long and short of this is that when you lit it, it would smoke until the chimney was hot enough and drawing properly. And for clarity it would smoke from around the top enamel cast horizontal whole top thing.
This morning it was duly dismantled, and either the chimney corner, rear right hand side has had an impact to it or rains come down the chimney and caused expanding rust to break a couple of castings. This being where the smoke from the firebox comes up across the top of the oven and then up the chimney.

So I need to weld it back together, it doesn't matter how stong it is really, it just to keep the smoke in, I can't just bodge it back together with gun gum or fire mastic due to how its broken, once tacked together it can be smothered in fire mastic to make it air tight, but how....

I've just re-read the tutorial on cast, I can give it lots of preheat, I've only got standard steel mig wire 0.8, or I've got an arc with loads of 6013's, and i've got oxy-acetaline so perhaps I could braze it with rods??? I have recuperated all the bits and as soon as I find my camera I'll post some photos, just the technique I'm wondering about?

Thanks people, Mat

 

[shenion]

Brazing will work. Any mild steel will filler will crack and fail.

With arc, you can get nickel/iron rods for cast that don't need preheat.

With MIG, you can use stainless wire.

 

[Barking Mat]

Thanks Shenion, I try brazing it, results shortly hopefully.

 

[pedrobedro]

Can't you drill and bolt plates to it if anything else fails?

 

[Barking Mat]

Not alot of success with brazing, not sure if im using the wrong rods or not heating the cast up enough. I finished of on my bigggest nozzle marked '400' and I was getting the cast orange hot and some of the rod has well attached itself but not to the two pieces, in other places its just blobbed and sat on the crack, and in other places it's just run through. Possibly my lack of skill at even heating?
Yes Pedrobedro, I've just stopped and cleared up and was wondering about drilling holes, maybe garden wire to stitch it together and good old fire mastic?

 

[Tigman]

Are you using flux with your rods or have they got flux in the rod ?

 

[the artfull-codger]

Not alot of success with brazing, not sure if im using the wrong rods or not heating the cast up enough. I finished of on my bigggest nozzle marked '400' and I was getting the cast orange hot and some of the rod has well attached itself but not to the two pieces, in other places its just blobbed and sat on the crack, and in other places it's just run through. Possibly my lack of skill at even heating?
Yes Pedrobedro, I've just stopped and cleared up and was wondering about drilling holes, maybe garden wire to stitch it together and good old fire mastic?

if it's the flue chamber ie the square box at the back rh side it bolts off from the main hob plate & you can braze it o-k but don't forget to seal it back on when you bolt it back to the hob plate,the flue dilution door has no seal, if it's the main hob then it's a large piece of cast iron & more heat needed plus you'll damage the enamel which is why plating it would be a better obtion if you can, if it's just blobbing then it's either A not hot enough or B the metal is dirty/oxidised you should mix some brazing flux to cream consistency & after cleaning the joints smear them with wet flux, even if using fluxed rods then warm up gently till the flux dries then heat in ernest dipping the rod in dry flux & applying, the rod should flow nicely with the heat from the metal plus heat from the blowpipe. hope this helps.

slan go fol

 

[TechnicAl]

buy a few Nickel Cast Iron rods and stick weld it (AWS ENi-CI). Its the easiest cheapest way.

 

[Tigman]

Nickel Rods aint cheap !

 

[TechnicAl]

He may only need one or two....thats a lot cheaper than a roll of mig wire or throwing money away on other things that dont work.

 

[Tigman]

If you can buy in one or two thats true , I had to buy 2 KG packet £63 if I remember right !

 

[brightspark]

using oxy acet a bit of flux and a brazing rod costs pence just pre heat up with a propane torch to a dull red 1st

 

[s410man]

Brazing will work. Any mild steel will filler will crack and fail.

With arc, you can get nickel/iron rods for cast that don't need preheat.

With MIG, you can use stainless wire.

any particular stainless wire or gas

preheat?

thanks

 

[Barking Mat]

Evening, I've been using rods heating them up at the end and dipping them in a pot of flux and then applying a couple of centimeters of the rod to the pool or blob in this case before repeating.

Its not the flue chamber or box, I've never had one, been meaning to build one, I've got a baffle in a length of chimney pipe next to the stove and it sucks in air from the hole, at the base of the chimney where rain must have come down over a period of years and rotted out the steel bolts which then expanded cracking the fine cast sections at the corner. Difficult to explain will post pics tommorow. The bit above the oven at the back had a hole in it.

And failing giving it a really good clean up and even more heat if that doesnt work I'll look at some arc welding special rods as suggested.

Shouldn't need to light it for a little while yet....... Thanks

 

[shenion]

I used 308 stainless on a cast saw frame. Worked well. Supposedly 312 is best.

You would want a gas with low CO2 content. I used 5%,

 

[Barking Mat]

Here's some photos.
Not sure if they really help alot.