Cast Iron repair

[1776]

So, I've got a old antique candle holder that broke. It is cast iron, from what I can tell. I've been looking around trying to figure out how to repair cast iron. It seems there are two options for me; #1 Castaloy. #2 Welding.

 Of the two, Castaloy seems the easiest. I've never welded, but we do have a welding shop in town. And with my forge (being able to heat the cast iron up to 1500+) , I'm pretty sure I could get it welded.

 Of the two, which one seems to be the strongest, and most reliable method. Also, which method have you done?

 I'm really nerves about this one, It is an antiques, from my family. So a family heirloom. And I don't want to mess it up even more.

 Thanks guys!

 

1776

[ThomasPowers]

Brazing or JB Weld would be my suggestions  Most of the "strongest" methods will have a very visible repair zone on them! Epoxying a mending plate on the back also comes to mind---easy to remove if you decide on another method.

[1776]

25 minutes ago, ThomasPowers said:

Brazing or JB Weld would be my suggestions  Most of the "strongest" methods will have a very visible repair zone on them! Epoxying a mending plate on the back also comes to mind---easy to remove if you decide on another method.

So, what type of brazing? Keep in mind, this is going to be hanging on the wall, and used.

[Jim Coke]

Greetings 1776,

Like Thomas said I am for a thin repair plate with epoxy or JB.   It will last forever..  Most cast like that is very porous and I sure would not heat it to brazing temperatures.  Just this ol boys 2c 

Forge on and make beautiful things 

Jim

[1776]

2 hours ago, Jim Coke said:

Greetings 1776,

Like Thomas said I am for a thin repair plate with epoxy or JB.   It will last forever..  Most cast like that is very porous and I sure would not heat it to brazing temperatures.  Just this ol boys 2c 

Forge on and make beautiful things 

Jim

Hmmmm. I guess it can't hurt. I'll give it a try.

 Thanks

[JHCC]

Based on my experience from the art restoration studio, a big thumbs-up to the epoxy and repair plate idea. There's nothing quite as bad as realizing that the repair that you're attempting is (A) making things worse and (B) irreversible.

Here's what I would do, were I in your situation. Get a piece of sheet brass a bit bigger than the backplate of the candle holder and trace the entire pattern onto it: wreath, eagle, heart, everything. Then using a jeweler's saw and some needle files, cut and file the brass so that each element is a hair smaller than the cast iron element that it backs up. Then clean the back of the cast iron and epoxy the brass in place. Clean off the excess epoxy before it hardens: a sharpened popsicle stick, q-tips, and acetone are good for this.

This will give you the greatest possible surface area for adhering the brass to the cast iron, will add a structural element that strengthens the entire piece, and will be essentially invisible from the front.

[SLAG]

Also the round tooth picks are good for urging the epoxy into tight places.

SLAG.

[ThomasPowers]

You can also blacken the edges of the brass using livers of sulfur to remove any gold gleam...

[1776]

17 hours ago, JHCC said:

Based on my experience from the art restoration studio, a big thumbs-up to the epoxy and repair plate idea. There's nothing quite as bad as realizing that the repair that you're attempting is (A) making things worse and (B) irreversible.

Here's what I would do, were I in your situation. Get a piece of sheet brass a bit bigger than the backplate of the candle holder and trace the entire pattern onto it: wreath, eagle, heart, everything. Then using a jeweler's saw and some needle files, cut and file the brass so that each element is a hair smaller than the cast iron element that it backs up. Then clean the back of the cast iron and epoxy the brass in place. Clean off the excess epoxy before it hardens: a sharpened popsicle stick, q-tips, and acetone are good for this.

This will give you the greatest possible surface area for adhering the brass to the cast iron, will add a structural element that strengthens the entire piece, and will be essentially invisible from the front.

Thanks, I'll be giving this a try.

 

[JHCC]

1 minute ago, 1776 said:

Thanks, I'll be giving this a try.

 

Post pictures to show how it works out!

[1776]

On 3/30/2017 at 1:54 PM, JHCC said:

Post pictures to show how it works out!

Lol. I'm kinda bad at that, but I'll try!

[SoCal Dave]

What about epoxy or JB weld and then tig braze the back?  I would only trust someone who really knows how to tig braze. Good luck.    

[Frank Turley]

Quote

On small items, I have had luck stick-welding with a stainless rod, the rod being suitable for 304 stainless steel. I have only done this on items used around the shop, as for example, a drill press vise frame. It wasn't a family heirloom. I'd be afraid to weld on a valued piece as shown in the photo.

 

[jlpservicesinc]

They make a Cast iron filler rod for Tig welding..   But with any cast iron item it comes down to cost of replacement vs damage done from Brazing, welding or the like..  

 

I have an oil pan from a 32 backhoe that someone butchered when repairing it.. Now it will take 4X longer to fix it..   Personally I wouldn't weld or fix it without having a practice piece to experiment with before the real fix.. 

[BIGGUNDOCTOR]

If you epoxy it, I would use a perforated back plate so the epoxy can really get a bite onto it. Hopefully the back is a rough casting which will give a good bite onto it.

I would also look into using a silver solder like Force 44 from Brownell's. The melting temp is around 440°F. I have seen other solders that the demonstrator melted with a match onto a bent paperclip, and you could not get it broken apart. When you fix it, make sure that it is clamped tight so there is no gap showing in the front. You may have to get creative to hold it, bit take your time, and get it right.

 

[Wroughton]

On 4/2/2017 at 9:35 AM, jlpservicesinc said:

They make a Cast iron filler rod for Tig welding..   But with any cast iron item it comes down to cost of replacement vs damage done from Brazing, welding or the like..  

 

 

Nickel stick welding rod works well for Tig welding cast iron . Just beat off the flux on your anvil and hit the trail. As Frank said, stainless is also a good choice and the approved method for joining different alloys together. Preheating the whole works is advised as well as a slow cool down. Wrapping in fiberglass insulation afterwards works well for me. 

That being said, I think the conservators touch is required for this item. All the reasons for this are well covered above. The brass backer sounds like a great idea. BBD's solder idea sounds interesting as well but still requires heating. 

[Alan Evans]

JHCC's suggestion is the Rolls Royce version, and would look best / closest to the original.

If you do not to want to put in the time for piercing the complete backplate, the strength of support for the actual break would be achieved with less than an inch of brass either side, sufficient to get a good bond.  You could then use further strips top and  bottom to maintain the plane of the backplate against the wall...

Based on the "make a mistake...make it a feature" philosophy....an even simpler solution would be to mount the two pieces of iron on a back plate/shield. A glass mirror, a panel of wood, stainless steel or brass the size of the blanket background in your photograph neatly chamfered, to suit the position and room decor.

Mirrors and mirror polished brass and stainless steel are often used as reflectors to enhance the candle light. 

The TIG rods I use for dissimilar metals are either 29/9s, 312 or 23/12s, 309. I have found the 312 works really well for all sorts...tool steel hammer pallets, mild to stainless, even silicon bronze to stainless. I found them far better for dissimilar than the stainless specific 304 or 316 rods. Indeed great for everything...apart from cast iron, I have never had success welding it. I will only go for silver solder or braze for that now.  But I would not attempt to solder, braze or weld your piece for fear of further damage, you do not know what other areas were strained before the break happened where it did. There may be cracks running parallel to the break on either side...

A backplate reinforcing of some sort using glue is definitely wise. 

Alan

[1776]

On 4/11/2017 at 1:27 AM, Alan Evans said:

JHCC's suggestion is the Rolls Royce version, and would look best / closest to the original.

If you do not to want to put in the time for piercing the complete backplate, the strength of support for the actual break would be achieved with less than an inch of brass either side, sufficient to get a good bond.  You could then use further strips top and  bottom to maintain the plane of the backplate against the wall...

Based on the "make a mistake...make it a feature" philosophy....an even simpler solution would be to mount the two pieces of iron on a back plate/shield. A glass mirror, a panel of wood, stainless steel or brass the size of the blanket background in your photograph neatly chamfered, to suit the position and room decor.

Mirrors and mirror polished brass and stainless steel are often used as reflectors to enhance the candle light. 

The TIG rods I use for dissimilar metals are either 29/9s, 312 or 23/12s, 309. I have found the 312 works really well for all sorts...tool steel hammer pallets, mild to stainless, even silicon bronze to stainless. I found them far better for dissimilar than the stainless specific 304 or 316 rods. Indeed great for everything...apart from cast iron, I have never had success welding it. I will only go for silver solder or braze for that now.  But I would not attempt to solder, braze or weld your piece for fear of further damage, you do not know what other areas were strained before the break happened where it did. There may be cracks running parallel to the break on either side...

A backplate reinforcing of some sort using glue is definitely wise. 

Alan

Thanks!

[arftist]

On 4/1/2017 at 5:01 PM, SoCal Dave said:

What about epoxy or JB weld and then tig braze the back?  I would only trust someone who really knows how to tig braze. Good luck.    

Impossible. The epoxy will vaporize and interfere with the weld. 

TIG brazing is the easiest form of either TIG work or any other kind of brazzing. Use a silicon bronze welding rod. Bare.

On 4/9/2017 at 0:44 PM, Wroughton said:

Nickel stick welding rod works well for Tig welding cast iron . Just beat off the flux on your anvil and hit the trail. As Frank said, stainless is also a good choice and the approved method for joining different alloys together. Preheating the whole works is advised as well as a slow cool down. Wrapping in fiberglass insulation afterwards works well for me. 

That being said, I think the conservators touch is required for this item. All the reasons for this are well covered above. The brass backer sounds like a great idea. BBD's solder idea sounds interesting as well but still requires heating. 

Fiberglass is not quite sufficient. Instead it should be deeply buried in ash.

[Wroughton]

9 hours ago, arftist said:

Fiberglass is not quite sufficient. Instead it should be deeply buried in ash.

Well......ok. I guess I have more insulation sitting around than ash. I have rolled things up well enough that they were still quite warm the next day. Think a couple layers of insulation and duct tape. More insulation equals higher R rating so I'd argue you can keep your ash. For small items I wrap and then brick up in the appropriate sized gas forge for more insulation. Furthermore, I'd need a dumpster of ash to take care of the last vise I fixed.  

To weld the vise I TIG welded with nickel stick rod for cast iron after I took the flux off. Bronze would probably be that much more forgiving and less prone to cracking. I'll try it on the next cast fix.  

[arftist]

14 hours ago, Wroughton said:

Well......ok. I guess I have more insulation sitting around than ash. I have rolled things up well enough that they were still quite warm the next day. Think a couple layers of insulation and duct tape. More insulation equals higher R rating so I'd argue you can keep your ash. For small items I wrap and then brick up in the appropriate sized gas forge for more insulation. Furthermore, I'd need a dumpster of ash to take care of the last vise I fixed.  

To weld the vise I TIG welded with nickel stick rod for cast iron after I took the flux off. Bronze would probably be that much more forgiving and less prone to cracking. I'll try it on the next cast fix.  

Fiberglass stinks when heated that much. 

I have an ash can (galv)

I scoop out a sufficient quantity into a bucket or whatever, toss the part in, cover in ash. The largest item I have done this way was an exhaust manifold. 

Did't mean to attack your method, it works for you. For me, ash is much more convenient. 

 

As to braze welding large parts, I agree, brass is easier. 

I pretty much only nickel things that are exposed to great heat such as wood stoves and exhaust manifolds. 

Silicon bronze bare rods work great with TIG FYI.