I need to repair a safety shield from a large "bench" grinder. The
shield is cast iron and has a crack. I want to know what is the
easiest way to repair this, with the choices being: silicon bronze,
fluxed silver brazing sticks, or TIG with 99% nickel.

i

I need to repair a safety shield from a large "bench" grinder. The
shield is cast iron and has a crack. I want to know what is the
easiest way to repair this, with the choices being: silicon bronze,
fluxed silver brazing sticks, or TIG with 99% nickel.

I need to repair a safety shield from a large "bench" grinder. The
shield is cast iron and has a crack. I want to know what is the
easiest way to repair this, with the choices being: silicon bronze,
fluxed silver brazing sticks, or TIG with 99% nickel.

I need to repair a safety shield from a large "bench" grinder. The
shield is cast iron and has a crack. I want to know what is the
easiest way to repair this, with the choices being: silicon bronze,
fluxed silver brazing sticks, or TIG with 99% nickel.

On 2009-07-15, whit3rd <whit3rd@gmail.com> wrote:
On Jul 14, 10:10?pm, Ignoramus13927 <ignoramus13...@NOSPAM.
13927.invalid> wrote:
I need to repair a safety shield from a large "bench" grinder. The
shield is cast iron and has a crack. I want to know what is the
easiest way to repair this, with the choices being: silicon bronze,
fluxed silver brazing sticks, or TIG with 99% nickel.

Nickel, is the usual recommendation. I've always been
told the whole castiron part has to be heated to prevent
cracking, so it'd take a small bed of charcoal in addition
to the TIG welder.

Based on all I have heard so far:

1) I need to clean the cracks, regardless of joining method. This is
a crack on a grinder's shield, so I think that I will try to wedge the
crack a little wider and sandblast.

2) Brazing
- Preheat in barbeque
- Heat to read hot in forge
- Apply silver braze

OR

2) Welding
- Preheat in barbeque
- Weld with TIG and 99 nickel rod

On 2009-07-15, whit3rd <whit3rd@gmail.com> wrote:
On Jul 14, 10:10?pm, Ignoramus13927 <ignoramus13...@NOSPAM.
13927.invalid> wrote:
I need to repair a safety shield from a large "bench" grinder. The
shield is cast iron and has a crack. I want to know what is the
easiest way to repair this, with the choices being: silicon bronze,
fluxed silver brazing sticks, or TIG with 99% nickel.

Nickel, is the usual recommendation. I've always been
told the whole castiron part has to be heated to prevent
cracking, so it'd take a small bed of charcoal in addition
to the TIG welder.

Based on all I have heard so far:

1) I need to clean the cracks, regardless of joining method. This is
a crack on a grinder's shield, so I think that I will try to wedge the
crack a little wider and sandblast.

2) Brazing
- Preheat in barbeque
- Heat to read hot in forge
- Apply silver braze

OR

2) Welding
- Preheat in barbeque
- Weld with TIG and 99 nickel rod

On Jul 14, 10:10?pm, Ignoramus13927 <ignoramus13...@NOSPAM.
13927.invalid> wrote:
I need to repair a safety shield from a large "bench" grinder. The
shield is cast iron and has a crack. I want to know what is the
easiest way to repair this, with the choices being: silicon bronze,
fluxed silver brazing sticks, or TIG with 99% nickel.

Nickel, is the usual recommendation. I've always been
told the whole castiron part has to be heated to prevent
cracking, so it'd take a small bed of charcoal in addition
to the TIG welder.

Had a look at the Nickel 55 weld on this cast iron guard. The good
news is that for the most part, there was good fusion, except for the
last 1 inch where the bead appears a little cold. After slow cooling
inside a hot grill, no cracks appeared. I think that this guard now is
as good as new, for its intended purposes of guarding the wheel. This
was, fortunately, a cheap repair.

i

I have welded successfully many cast iron machine parts with OA and
brazing rod with a ground out V.
Many years ago I saw a book produced by one of the large welding
supply companies (Linde) in which the author claimed that using a
conventional grinding wheel to V a broken casting would produce an
unsatisfactory job because the grinding process would smear the
surface to be brazed with graphite from the cast iron.
He advocated heating the metal to melting temperature and blowing the
metal away by turning up the oxygen.

Have any of you heard of these seemingly crazy ideas?

Engineman

I have welded successfully many cast iron machine parts with OA and
brazing rod with a ground out V.
Many years ago I saw a book produced by one of the large welding
supply companies (Linde) in which the author claimed that using a
conventional grinding wheel to V a broken casting would produce an
unsatisfactory job because the grinding process would smear the
surface to be brazed with graphite from the cast iron.
He advocated heating the metal to melting temperature and blowing the
metal away by turning up the oxygen.
He also described a process that he called "Lindewelding" which he
claimed was a fast way to weld mild steel with OA.
It involved using a carburizing flame which he claimed sped up the
process by converting mild steel to high carbon steel which he said
has a lower melting point.
Have any of you heard of these seemingly crazy ideas?

Engineman

On Jul 15, 7:13???pm, Ignoramus32217 <ignoramus32...@NOSPAM.
32217.invalid> wrote:
Had a look at the Nickel 55 weld on this cast iron guard. The good
news is that for the most part, there was good fusion, except for the
last 1 inch where the bead appears a little cold. After slow cooling
inside a hot grill, no cracks appeared. I think that this guard now is
as good as new, for its intended purposes of guarding the wheel. This
was, fortunately, a cheap repair.

i