UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 61
Default Mechanically polishing brass that's pitted?

I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.

I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.

So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.

Any guidance would be much appreciated.

VT

  #2   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 39,563
Default Mechanically polishing brass that's pitted?

Vet Tech wrote:
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.

I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.

So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.

Any guidance would be much appreciated.

VT

if its a smooth surface - or was, simply emery it down to get level,
then start on fine emery and T-cut or jewellers rouge or valve grind
compound, THEN finish with brasso.,
  #3   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 61
Default Mechanically polishing brass that's pitted?

On 26 May, 20:50, The Natural Philosopher
wrote:
Vet Tech wrote:
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.


I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.


So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.


Any guidance would be much appreciated.


VT


if its a smooth surface - or was, simply emery it down to get level,
then start on fine emery and T-cut or jewellers rouge or valve grind
compound, THEN finish with brasso.,


The letter box is flat/smooth so I guess the emery paper is OK but
what grade would you suggest and could I use this with an orbital
sander?

The knocker however is a big ring with twisted sort of ribbing (sorry
there must be a more appropriate description) so it might need
different treatment. This is a real challenge.

VT
  #4   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 2,379
Default Mechanically polishing brass that's pitted?

On 26 May, 20:35, Vet Tech wrote:
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.

I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.

So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.

Any guidance would be much appreciated.

VT


Solvol Autosol (from Halfords) and a mop attachment for your drill.
  #7   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 103
Default Mechanically polishing brass that's pitted?

On 26 May, 20:35, Vet Tech wrote:
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.

I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.

So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.

Any guidance would be much appreciated.

VT


The Brass stuff will have originally been epoxy laquered, whose
remnants are still as tough as old boots. I usually burn it off with
a gas torch etc, before starting with the abrasives.
  #8   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 5,175
Default Mechanically polishing brass that's pitted?

On 26 May, 20:35, Vet Tech wrote:
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.


Garryflex blocks, in a range of (coloured) grits. Also sold under the
Roebuck name.

Webrax / 3M / Mirka pads (like pan scourers with grit in) in brown
(very fine) and grey (ultra fine) grades

Rouge or tripoli block on a cloth or powered cloth wheel / Dremel felt
bob.

Lacquer with a methacrylate lacquer, nothing else on brass. (Rustins)


Tilgear, Axminster et al sell this stuff.


Don't use Autosol, it's expensive and too hard for brass. Don't use
anything with ammonia (including Brasso) as it'll be shiny today,
dulled tomorrow.

As always, finish one grit before moving finer. Skipping grits too
quickly is a waste of effort.

Use the right lacquer.
  #9   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 435
Default Mechanically polishing brass that's pitted?


"Vet Tech" wrote in message
...
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.

I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.

So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.

Any guidance would be much appreciated.

VT


Put a magnet on it first, and feel the weight... Lots of 'brass' these days
turns out to be plate when you get it (Screwfix for example did solid brass
electric sockets for a while, but continued advertising them as the same
when they were made of plate.). The pits are often holes that go down to
the iron underneath on old stuff, and, on new stuff ally, and you don't want
to rub the plate away getting down to the bottom of the pit.

Assuming it is solid brass then you may first need to go over it with
nitromors as it is often lacquered, and even if it isn't this will get off
the ground in skin and grease too. If you do adopt chemical or heat methods
watch out for the core metal of some of the old knobs: I got a shock when
the grey metal (presumably zinc/magnesium) that took the square turning rod
of one of mine melted and ran out - took a lot of fiddling to make a
replacement - when I was trying to hurry old lacquer off...

Then as TNP says, there really isn't much option but to choose the minimum
grade of emery/wet or dry, that will enable you to rub down past the pits.
Deep ones you may even have to start off with riffler files. Keep the
scratches all going the same way with the first grade, then rub these
scratches away by going at right angles with the next grade down; then at
right angles again, and so down through the grades. When you have got down
to 600 or 1200 - 1400 - depending on how much of a perfectionist you are -
T-cut or similar metal polish in a circular motion will rub out the fine
scratches that are left. If your pieces are easily detachable you may find
it easier to polish with wet and dry under the tap with a dash of wash-up
liquid now and again. In preparing metals for microscopic examination a
polishing sloping surface with water running over several grades of wet or
dry was used, followed by a final burnish on a diamond lapping wheel.

Brasso and Autosolve and similar products don't really polish: they just
fill in the finer scratches: which you can prove for yourself by wiping a so
'polished' surface with paraffin, which wipes the 'shine' back off. It is
better to polish properly - by reducing scratches to the minimum acceptable
size - and then oil your product, rather than go for a brilliant finish that
will mark and pit after the first fingerprint or raindrop.

For a real brilliant finish you will need a proper polishing mop or buffing
wheel, for which you can get several grades of cutting 'soap' and jewellers
rouge. But it would still be best to wipe the surface with an oily rag
regularly afterwards. (Oh and it'll get v hot on a buffer so leather gloves
are in order.)

The irregular shape of your knocker would probably be best tackled with
various grades of brass brush wheel, but you will need (as with the buffing
wheels) to find a way to clamp your drill securely, or get a bench
grinder/buffer - which is always worth having. Once you have cleaned it
with the brush wheel, then you go on to the polishing soaps on the buffing
wheel again. Keep different mops for different grades of buffing soap.
*Don't* whatever you do, be tempted to use an iron brush wheel.

If you don't want to tackle the mops and such, you can achieve a fair bit on
irregular surfaces with, say, strips of towelling or bootlaces. and various
grades of grinding paste. Hold the knocker in soft vice jaws and work the
strips of cloth 'shoe shine boy fashion' through it with one end in each
hand: you may actually find this easier than a pukka buffer in fact.

Sounds hard, but it is actually satisfying producing a good polish: rather
like getting that perfect sharp edge on a chisel or scythe.

S


  #10   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 39,563
Default Mechanically polishing brass that's pitted?

geoff wrote:


As long as you had a tube of solvosol, grease and hermatite, what more
did you need ?


A motorbike, and a patient girlfriend.


  #11   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 3,819
Default Mechanically polishing brass that's pitted?

In message , The Natural Philosopher
writes
geoff wrote:

As long as you had a tube of solvosol, grease and hermatite, what
more did you need ?

A motorbike, and a patient girlfriend.


Still got the bikes (enfield and BSA)

seem to have got through a number of girlfriends since then, though
--
geoff
  #12   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 39,563
Default Mechanically polishing brass that's pitted?

spamlet wrote:
"Vet Tech" wrote in message
...
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.

I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.

So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.

Any guidance would be much appreciated.

VT


Put a magnet on it first, and feel the weight... Lots of 'brass' these days
turns out to be plate when you get it (Screwfix for example did solid brass
electric sockets for a while, but continued advertising them as the same
when they were made of plate.). The pits are often holes that go down to
the iron underneath on old stuff, and, on new stuff ally, and you don't want
to rub the plate away getting down to the bottom of the pit.

Assuming it is solid brass then you may first need to go over it with
nitromors as it is often lacquered, and even if it isn't this will get off
the ground in skin and grease too. If you do adopt chemical or heat methods
watch out for the core metal of some of the old knobs: I got a shock when
the grey metal (presumably zinc/magnesium) that took the square turning rod
of one of mine melted and ran out - took a lot of fiddling to make a
replacement - when I was trying to hurry old lacquer off...

Then as TNP says, there really isn't much option but to choose the minimum
grade of emery/wet or dry, that will enable you to rub down past the pits.
Deep ones you may even have to start off with riffler files. Keep the
scratches all going the same way with the first grade, then rub these
scratches away by going at right angles with the next grade down; then at
right angles again, and so down through the grades. When you have got down
to 600 or 1200 - 1400 - depending on how much of a perfectionist you are -
T-cut or similar metal polish in a circular motion will rub out the fine
scratches that are left. If your pieces are easily detachable you may find
it easier to polish with wet and dry under the tap with a dash of wash-up
liquid now and again. In preparing metals for microscopic examination a
polishing sloping surface with water running over several grades of wet or
dry was used, followed by a final burnish on a diamond lapping wheel.

Brasso and Autosolve and similar products don't really polish: they just
fill in the finer scratches: which you can prove for yourself by wiping a so
'polished' surface with paraffin, which wipes the 'shine' back off. It is
better to polish properly - by reducing scratches to the minimum acceptable
size - and then oil your product, rather than go for a brilliant finish that
will mark and pit after the first fingerprint or raindrop.

For a real brilliant finish you will need a proper polishing mop or buffing
wheel, for which you can get several grades of cutting 'soap' and jewellers
rouge. But it would still be best to wipe the surface with an oily rag
regularly afterwards. (Oh and it'll get v hot on a buffer so leather gloves
are in order.)

The irregular shape of your knocker would probably be best tackled with
various grades of brass brush wheel, but you will need (as with the buffing
wheels) to find a way to clamp your drill securely, or get a bench
grinder/buffer - which is always worth having. Once you have cleaned it
with the brush wheel, then you go on to the polishing soaps on the buffing
wheel again. Keep different mops for different grades of buffing soap.
*Don't* whatever you do, be tempted to use an iron brush wheel.

If you don't want to tackle the mops and such, you can achieve a fair bit on
irregular surfaces with, say, strips of towelling or bootlaces. and various
grades of grinding paste. Hold the knocker in soft vice jaws and work the
strips of cloth 'shoe shine boy fashion' through it with one end in each
hand: you may actually find this easier than a pukka buffer in fact.

Sounds hard, but it is actually satisfying producing a good polish: rather
like getting that perfect sharp edge on a chisel or scythe.

S


Superb article. Should be in the wiki.
  #14   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 435
Default Mechanically polishing brass that's pitted?


wrote in message
...
On 26 May, 20:35, Vet Tech wrote:
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.

I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.

So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.

Any guidance would be much appreciated.

VT


The Brass stuff will have originally been epoxy laquered, whose
remnants are still as tough as old boots. I usually burn it off with
a gas torch etc, before starting with the abrasives.


Yup, but watch out for those melty centres - see below...

S


  #15   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 435
Default Mechanically polishing brass that's pitted?


"Andy Dingley" wrote in message
...
On 26 May, 20:35, Vet Tech wrote:
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.


Garryflex blocks, in a range of (coloured) grits. Also sold under the
Roebuck name.

Webrax / 3M / Mirka pads (like pan scourers with grit in) in brown
(very fine) and grey (ultra fine) grades

Rouge or tripoli block on a cloth or powered cloth wheel / Dremel felt
bob.

Lacquer with a methacrylate lacquer, nothing else on brass. (Rustins)


Tilgear, Axminster et al sell this stuff.


Don't use Autosol, it's expensive and too hard for brass. Don't use
anything with ammonia (including Brasso) as it'll be shiny today,
dulled tomorrow.

As always, finish one grit before moving finer. Skipping grits too
quickly is a waste of effort.

Use the right lacquer.


All seconded, save the lacquer bit: always looks better polished and wiped
over regularly with oily rag. Or you'll be repeating the whole process
again before long.

S




  #16   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 259
Default Mechanically polishing brass that's pitted?

geoff wrote:

Funny you should say that. I just purchased some Solvol Autosol (brought
back memories of the late 60s and motorbikes)


And, by coincidence, I've just found half a tube of it which must be
what, 30+ years old

Those were the days eh?

As long as you had a tube of solvosol, grease and hermatite, what more
did you need ?


If there's one thing that I like
It's a burn up on my bike
A burn up with bird up on my bike
  #17   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 259
Default Mechanically polishing brass that's pitted?

Vet Tech wrote:
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.

I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.

So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.

Any guidance would be much appreciated.

VT


Please excuse my ignorance: what causes pitting in brass?
  #18   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 61
Default Mechanically polishing brass that's pitted?

On 27 May, 03:30, Gib Bogle wrote:

Please excuse my ignorance: what causes pitting in brass?


Don't really know, but these are the original bits that have been on
the front door since 1928 so maybe chemical corrosion from London
pollution?

VT

  #20   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 61
Default Mechanically polishing brass that's pitted?

On 27 May, 00:40, "spamlet" wrote:



Put a magnet on it first, and feel the weight... *



OK, I did the magnet thing and there was no attraction and going by
the weight, it feels like solid brass.



VT


  #22   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 43,017
Default Mechanically polishing brass that's pitted?

In article
,
Vet Tech wrote:
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.


I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.


So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.


Any guidance would be much appreciated.


Soak in artificial (non brewed) vinegar first - that removes the
oxidisation which is pretty hard. Makes subsequent polishing easier.

--
*When the going gets tough, the tough take a coffee break *

Dave Plowman London SW
To e-mail, change noise into sound.
  #23   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 39,563
Default Mechanically polishing brass that's pitted?

Vet Tech wrote:
On 27 May, 03:30, Gib Bogle wrote:
Please excuse my ignorance: what causes pitting in brass?


Don't really know, but these are the original bits that have been on
the front door since 1928 so maybe chemical corrosion from London
pollution?

VT

salt probably
or sweat.
  #24   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 5,175
Default Mechanically polishing brass that's pitted?

On 27 May, 07:44, Vet Tech wrote:

OK, I did the magnet thing and there was no attraction and going by
the weight, it feels like solid brass.


Watch out for brass over diecast zinc too.

For Screwfix I either check in the shop first, or I buy just the one
of something before buying a batch. They mix solid brass and brass
over zinc, yet describe them randomly in the catalogues as "brass",
"brassed" and "polished brass finish".

Not many castings (like doorknockers) are going to be brass on steel,
i.e. magnetic. That's more likely for things that are pressed from
sheet, such as mirror plates and lock escutcheons.
  #25   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 5,175
Default Mechanically polishing brass that's pitted?

On 27 May, 01:00, "spamlet" wrote:

All seconded, save the lacquer bit: always looks better polished and wiped
over regularly with oily rag. *Or you'll be repeating the whole process
again before long.


What's the practical likelihood of that happening on a door knocker?

Perhaps your household is better run than my own, but I'm afraid we
have such terrible trouble in finding parlourmaids these days there's
no likelihood they'll be able to polish the brassware and starch the
antimacassars before tea.


  #26   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 39,563
Default Mechanically polishing brass that's pitted?

Owain wrote:
On 27 May, 11:29, Andy Dingley wrote:
All seconded, save the lacquer bit: always looks better polished and wiped
over regularly with oily rag. Or you'll be repeating the whole process
again before long.

What's the practical likelihood of that happening on a door knocker?


Well, if you leave the oily rag in a tin next to the bin, you get into
the routine of doing the knockers weekly when putting the bin out.

Perhaps your household is better run than my own, but I'm afraid we
have such terrible trouble in finding parlourmaids these days there's
no likelihood they'll be able to polish the brassware and starch the
antimacassars before tea.


That's because the parlourmaid classes are too busy getting their tits
out for Page 3.


No, they are all vying for labours deputy prime minister position.

No better than they should be.
Owain

  #27   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 3,348
Default Mechanically polishing brass that's pitted?

On Thu, 27 May 2010 05:30:15 -0700, Owain wrote:

On 27 May, 11:29, Andy Dingley wrote:
All seconded, save the lacquer bit: always looks better polished and
wiped over regularly with oily rag. Â*Or you'll be repeating the whole
process again before long.

What's the practical likelihood of that happening on a door knocker?


Well, if you leave the oily rag in a tin next to the bin, you get into
the routine of doing the knockers weekly when putting the bin out.

Perhaps your household is better run than my own, but I'm afraid we
have such terrible trouble in finding parlourmaids these days there's
no likelihood they'll be able to polish the brassware and starch the
antimacassars before tea.


That's because the parlourmaid classes are too busy getting their tits
out for Page 3.


But who oils their knockers...?

--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor
  #28   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 435
Default Mechanically polishing brass that's pitted?


"Bob Eager" wrote in message
...
On Thu, 27 May 2010 00:55:29 +0100, spamlet wrote:

"Bob Eager" wrote in message
...
On Wed, 26 May 2010 13:19:52 -0700, wrote:

On 26 May, 20:35, Vet Tech wrote:
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so
they're pitted and looking very tired.

I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.

So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.

Any guidance would be much appreciated.

VT

Solvol Autosol (from Halfords) and a mop attachment for your drill.

Funny you should say that. I just purchased some Solvol Autosol
(brought back memories of the late 60s and motorbikes) and I have a
Dremel with suitable attachment. For exactly this purpose. I just don't
have the circular tuit right now.


Not polish: wipes off with paraffin and if you don't oil it you end up
having to grind off the marks made next time it rains. I ruined the
finish on my Ducatti with the stuff before I realised, and went for
anodising and wax instead.


I used it on alloy casings.

--


So did I, and then it rained and I ended up having to sand off the rain
spots and start again. An oil film is better than a fake shine. Once you
take the oxide film off ally, anything can happen.

S


  #29   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 435
Default Mechanically polishing brass that's pitted?


"Andy Dingley" wrote in message
...
On 27 May, 01:00, "spamlet" wrote:

All seconded, save the lacquer bit: always looks better polished and wiped
over regularly with oily rag. Or you'll be repeating the whole process
again before long.


What's the practical likelihood of that happening on a door knocker?

Perhaps your household is better run than my own, but I'm afraid we
have such terrible trouble in finding parlourmaids these days there's
no likelihood they'll be able to polish the brassware and starch the
antimacassars before tea.


Dealing with dirty, crazed, lacquer, which has caused pitting where the air
and crud has gone down the cracks, is a lot harder than a regular once over
with an oily rag. Your choice.

S


  #30   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 60
Default Mechanically polishing brass that's pitted?

On 27/05/2010 00:40, spamlet wrote:
snip

Put a magnet on it first, and feel the weight... Lots of 'brass' these days
turns out to be plate when you get it (Screwfix for example did solid brass
electric sockets for a while, but continued advertising them as the same
when they were made of plate.). The pits are often holes that go down to
the iron underneath on old stuff, and, on new stuff ally, and you don't want
to rub the plate away getting down to the bottom of the pit.

Assuming it is solid brass then you may first need to go over it with
nitromors as it is often lacquered, and even if it isn't this will get off
the ground in skin and grease too. If you do adopt chemical or heat methods
watch out for the core metal of some of the old knobs: I got a shock when
the grey metal (presumably zinc/magnesium) that took the square turning rod
of one of mine melted and ran out - took a lot of fiddling to make a
replacement - when I was trying to hurry old lacquer off...

Then as TNP says, there really isn't much option but to choose the minimum
grade of emery/wet or dry, that will enable you to rub down past the pits.
Deep ones you may even have to start off with riffler files. Keep the
scratches all going the same way with the first grade, then rub these
scratches away by going at right angles with the next grade down; then at
right angles again, and so down through the grades. When you have got down
to 600 or 1200 - 1400 - depending on how much of a perfectionist you are -
T-cut or similar metal polish in a circular motion will rub out the fine
scratches that are left. If your pieces are easily detachable you may find
it easier to polish with wet and dry under the tap with a dash of wash-up
liquid now and again. In preparing metals for microscopic examination a
polishing sloping surface with water running over several grades of wet or
dry was used, followed by a final burnish on a diamond lapping wheel.

Brasso and Autosolve and similar products don't really polish: they just
fill in the finer scratches: which you can prove for yourself by wiping a so
'polished' surface with paraffin, which wipes the 'shine' back off. It is
better to polish properly - by reducing scratches to the minimum acceptable
size - and then oil your product, rather than go for a brilliant finish that
will mark and pit after the first fingerprint or raindrop.

For a real brilliant finish you will need a proper polishing mop or buffing
wheel, for which you can get several grades of cutting 'soap' and jewellers
rouge. But it would still be best to wipe the surface with an oily rag
regularly afterwards. (Oh and it'll get v hot on a buffer so leather gloves
are in order.)

The irregular shape of your knocker would probably be best tackled with
various grades of brass brush wheel, but you will need (as with the buffing
wheels) to find a way to clamp your drill securely, or get a bench
grinder/buffer - which is always worth having. Once you have cleaned it
with the brush wheel, then you go on to the polishing soaps on the buffing
wheel again. Keep different mops for different grades of buffing soap.
*Don't* whatever you do, be tempted to use an iron brush wheel.

If you don't want to tackle the mops and such, you can achieve a fair bit on
irregular surfaces with, say, strips of towelling or bootlaces. and various
grades of grinding paste. Hold the knocker in soft vice jaws and work the
strips of cloth 'shoe shine boy fashion' through it with one end in each
hand: you may actually find this easier than a pukka buffer in fact.

Sounds hard, but it is actually satisfying producing a good polish: rather
like getting that perfect sharp edge on a chisel or scythe.

S


Excellent, thanks for that. Just did 6 door handles and the letter box
surround. I've tried on a number of occasions over the past 5 or 6 years
with Brasso/similar, and never got anywhere.

Nitromors didn't *seem* to do a great deal except degrease. I used one
of those decorator's sanding sponge things for awkward corners. I'm
going with your oily rag maintain sheen method.

Rob


  #31   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 435
Default Mechanically polishing brass that's pitted?


"Gib Bogle" wrote in message
...
Vet Tech wrote:
I've got items of door furniture (letter box, knocker etc) that are
made of solid brass but they've not been polished for years so they're
pitted and looking very tired.

I've tried Brasso and lots of elbow grease but I'm just not getting
down to a level where it would make a difference.

So I'm looking for the best way to get them all buffed up by using
something that I can attached to my drill.

Any guidance would be much appreciated.

VT


Please excuse my ignorance: what causes pitting in brass?


Never really looked at brass, but with the right etching solution on a
properly polished and clean metal surface you can see the crystal structure.
Most people don't realise that metals are crystalline. (I was jealous of a
metallurgist I knew who could bring up the crystals in mag alloy
beautifully, but I never could get the etchant right.) The point being that
alloys are complex materials made even more complex by impurities, bubbles,
and the like. Each of these, and the surfaces and edges of the crystals
will have different reactivities. Then there is the electrochemical
environment to consider: what other metals are coming into contact, and is
there an electrochemical potential difference between them? Then there is
the acid in sweat; differences between people and the things they put on
their hands. And the air and rain quality and many times so on. The
problem is made worse by attempts to preserve the surface with lacquers or
varnish. Even if they do not crack, they are still too thin to keep the air
out forever, and the metal underneath gradually dulls. Once they craze or
chip the metal in the chip or craze, is preferentially attacked and pitted,
and then the corrosion spreads under the lacquer. And that's before we
think of all the damage we do with our keys, rings etc.

This is why you usually see museum staff handling things with disposable
cotton gloves. And also why a lot of conservation effort goes into undoing
the damage done by earlier attempts at conservation...

S


  #32   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 435
Default Mechanically polishing brass that's pitted?


"Rob" wrote in message
...
On 27/05/2010 00:40, spamlet wrote:
snip

Put a magnet on it first, and feel the weight... Lots of 'brass' these
days
turns out to be plate when you get it (Screwfix for example did solid
brass
electric sockets for a while, but continued advertising them as the same
when they were made of plate.). The pits are often holes that go down to
the iron underneath on old stuff, and, on new stuff ally, and you don't
want
to rub the plate away getting down to the bottom of the pit.

Assuming it is solid brass then you may first need to go over it with
nitromors as it is often lacquered, and even if it isn't this will get
off
the ground in skin and grease too. If you do adopt chemical or heat
methods
watch out for the core metal of some of the old knobs: I got a shock when
the grey metal (presumably zinc/magnesium) that took the square turning
rod
of one of mine melted and ran out - took a lot of fiddling to make a
replacement - when I was trying to hurry old lacquer off...

Then as TNP says, there really isn't much option but to choose the
minimum
grade of emery/wet or dry, that will enable you to rub down past the
pits.
Deep ones you may even have to start off with riffler files. Keep the
scratches all going the same way with the first grade, then rub these
scratches away by going at right angles with the next grade down; then at
right angles again, and so down through the grades. When you have got
down
to 600 or 1200 - 1400 - depending on how much of a perfectionist you
are -
T-cut or similar metal polish in a circular motion will rub out the fine
scratches that are left. If your pieces are easily detachable you may
find
it easier to polish with wet and dry under the tap with a dash of wash-up
liquid now and again. In preparing metals for microscopic examination a
polishing sloping surface with water running over several grades of wet
or
dry was used, followed by a final burnish on a diamond lapping wheel.

Brasso and Autosolve and similar products don't really polish: they just
fill in the finer scratches: which you can prove for yourself by wiping a
so
'polished' surface with paraffin, which wipes the 'shine' back off. It
is
better to polish properly - by reducing scratches to the minimum
acceptable
size - and then oil your product, rather than go for a brilliant finish
that
will mark and pit after the first fingerprint or raindrop.

For a real brilliant finish you will need a proper polishing mop or
buffing
wheel, for which you can get several grades of cutting 'soap' and
jewellers
rouge. But it would still be best to wipe the surface with an oily rag
regularly afterwards. (Oh and it'll get v hot on a buffer so leather
gloves
are in order.)

The irregular shape of your knocker would probably be best tackled with
various grades of brass brush wheel, but you will need (as with the
buffing
wheels) to find a way to clamp your drill securely, or get a bench
grinder/buffer - which is always worth having. Once you have cleaned it
with the brush wheel, then you go on to the polishing soaps on the
buffing
wheel again. Keep different mops for different grades of buffing soap.
*Don't* whatever you do, be tempted to use an iron brush wheel.

If you don't want to tackle the mops and such, you can achieve a fair bit
on
irregular surfaces with, say, strips of towelling or bootlaces. and
various
grades of grinding paste. Hold the knocker in soft vice jaws and work
the
strips of cloth 'shoe shine boy fashion' through it with one end in each
hand: you may actually find this easier than a pukka buffer in fact.

Sounds hard, but it is actually satisfying producing a good polish:
rather
like getting that perfect sharp edge on a chisel or scythe.

S


Excellent, thanks for that. Just did 6 door handles and the letter box
surround. I've tried on a number of occasions over the past 5 or 6 years
with Brasso/similar, and never got anywhere.

Nitromors didn't *seem* to do a great deal except degrease. I used one of
those decorator's sanding sponge things for awkward corners. I'm going
with your oily rag maintain sheen method.

Rob


Glad of the feedback. If you were able to polish it without too much
swearing, the lacquer was probably mostly gone or wasn't there in the first
place, but it is always worth doing as even with Nitromors, some of the
finishes take some time to wrinkle up: and as you say, it degreases and
brightens a bit even if there is no actual lacquer left.

Now you have it properly cleaned and polished you can give it an occasional
Brasso to remove any slight dullness (You can do similar with white spirit
and ammonia on cotton wool), but still go over it with the oily rag after.

I just keep a cotton cloth with 3 In One oil on it, in a plastic bag with
the dusters.

Cheers,

S


  #33   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 3,819
Default Mechanically polishing brass that's pitted?

In message , Gib Bogle
writes
geoff wrote:

Funny you should say that. I just purchased some Solvol Autosol (brought
back memories of the late 60s and motorbikes)

And, by coincidence, I've just found half a tube of it which must be
what, 30+ years old
Those were the days eh?
As long as you had a tube of solvosol, grease and hermatite, what
more did you need ?


If there's one thing that I like
It's a burn up on my bike
A burn up with bird up on my bike



So - solvosol, grease, hermatite and KY then ...


--
geoff
  #34   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 4,092
Default Mechanically polishing brass that's pitted?

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Gib Bogle
saying something like:

Please excuse my ignorance: what causes pitting in brass?


Carbonic acid in the rain, impurities in the brass, forming simple cells
of reaction.
  #35   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 5,175
Default Mechanically polishing brass that's pitted?

On 27 May, 03:30, Gib Bogle wrote:

Please excuse my ignorance: what causes pitting in brass?


Not much. Brass is usually failrly resistant to such attacks. it will
discolour readily, but not pit as such. If it does start to corrode to
the level of pitting, it's usually (depending on alloy) by
dezincification. This is a corrosion of the more reactive zinc part of
the alloy, leaving excess copper behind. It forms large pink areas.

Pitting in "brass" is usually most serious because it's an indication
that the "brass" wasn't brass in the first place, but was a relatively
inert plating of brass over a reactive diecast zinc body. Pitting is
caused when the plating is perforated and the zinc underneath starts
to react (which it will do, with almost anything). The pitt can be
hiding a more serious hole beneath, and polsihign it just strips away
even more of the plating.
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Polishing a pitted flywheel D.M. Procida UK diy 56 January 1st 09 08:27 PM
Flat roofs, glue or mechanically fasten? [email protected] Home Repair 8 April 24th 08 03:59 AM
Small brass parts - Polishing questions [email protected] Metalworking 13 December 21st 07 05:54 PM
Polishing Brass Knockers! Thomarse UK diy 21 December 15th 06 05:07 PM
Fan Mount for Mechanically Challenged Steve Home Repair 2 August 10th 05 02:25 PM


All times are GMT +1. The time now is 09:48 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"