Hi Guys

I am profiling a bracket shape out of 12 thk aluminium.

Got as far as the rough profile with a jig saw and a bit of chain
drilling and will dress it to shape with a file next.
The question is, how do I get a decent finish on this?
The edges will need tidying as will some scratches that were
already present in the metal surface.

Is this a job for ever increasing grit sand paper?
How do I achieve a polished finish if that isn't asking the obvious?

Thanks

Phil
--


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 16/10/2020 19:16, thescullster wrote:
Hi Guys

I am profiling a bracket shape out of 12 thk aluminium.

Got as far as the rough profile with a jig saw and a bit of chain
drilling and will dress it to shape with a file next.
The question is, how do I get a decent finish on this?
The edges will need tidying as will some scratches that were
already present in the metal surface.

Is this a job for ever increasing grit sand paper?
How do I achieve a polished finish if that isn't asking the obvious?

Thanks

Phil


https://www.toolstation.com/abracs-n...RoCKLAQAvD_BwE

then acetone, then primer, then spray.

Bill

On 16/10/2020 19:16, thescullster wrote:
Hi Guys

I am profiling a bracket shape out of 12 thk aluminium.

Got as far as the rough profile with a jig saw and a bit of chain
drilling and will dress it to shape with a file next.
The question is, how do I get a decent finish on this?
The edges will need tidying as will some scratches that were
already present in the metal surface.

Is this a job for ever increasing grit sand paper?

yes

How do I achieve a polished finish if that isn't asking the obvious?
Wver increasing grit sand* paper?
Followed by a buffing wheel and cutting/polishing compound

*wet and dry, used wet.

It won't stay shiny long though. Not aluminium. Always ends up looking
dull and slightly oxidated.


Thanks

Phil



--
Renewable energy: Expensive solutions that don't work to a problem that
doesn't exist instituted by self legalising protection rackets that
don't protect, masquerading as public servants who don't serve the public.

On 16/10/2020 22:45, The Natural Philosopher wrote:
On 16/10/2020 19:16, thescullster wrote:
Hi Guys

I am profiling a bracket shape out of 12 thk aluminium.

Got as far as the rough profile with a jig saw and a bit of chain
Â* drilling and will dress it to shape with a file next.
The question is, how do I get a decent finish on this?
The edges will need tidying as will some scratches that were
Â* already present in the metal surface.

Is this a job for ever increasing grit sand paper?

yes

How do I achieve a polished finish if that isn't asking the obvious?
Wver increasing grit sand* paper?
Followed by a buffing wheel and cutting/polishing compound

*wet and dry, used wet.

It won't stay shiny long though. Not aluminium. Always ends up looking
dull and slightly oxidated.

It will be fine if you lacquer it or it is in a nice dry environment.
Humidity and alkalis are the enemy of aluminium metal.

Its weak point will be the screws/bolts since dissimilar metals in
contact also leads to corrosion problems.

Anodising will work but not for a mirror finish. Not really DIY either.

--
Regards,
Martin Brown

On Fri, 16 Oct 2020 19:16:15 +0100 (GMT+01:00), thescullster
wrote:

The edges will need tidying as will some scratches that were
already present in the metal surface.

Is this a job for ever increasing grit sand paper?

Yes.

I like something around 120 grit to finish, maybe 220. Sandpaper on table, push
over it along a guide to get the final scratches parallel and straight to
finish.

How do I achieve a polished finish if that isn't asking the obvious?

Finer paper, and/or Scotchbrite, and then polishing wheels: felt and sewn, with
the buffing compounds. I have cheap Wolfcraft "Hobby Polishing Set", felt and
sewn wheels, blocks of compound, an arbor, goes in a drill. Works fine, will
take ally to mirror finish with patience. (Leaves a black waxy mess imbedded in
your finger skin:-)


Thomas Prufer

Normally you would not aim for shiny, more a brush look,with a mildly
abrasive rotating brush of some kind. Then of course, if you are really
keen, you may need to get it anodized professionally, or maybe dipped in
alochrome to seal it. The latter gives a kind of almost satin finish with
tinges of gold sometimes in certain lights. Not as hard as anodising though.
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"thescullster" wrote in message
...
Hi Guys

I am profiling a bracket shape out of 12 thk aluminium.

Got as far as the rough profile with a jig saw and a bit of chain
drilling and will dress it to shape with a file next.
The question is, how do I get a decent finish on this?
The edges will need tidying as will some scratches that were
already present in the metal surface.

Is this a job for ever increasing grit sand paper?
How do I achieve a polished finish if that isn't asking the obvious?

Thanks

Phil
--


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 16/10/2020 19:16, thescullster wrote:
Hi Guys

I am profiling a bracket shape out of 12 thk aluminium.

Got as far as the rough profile with a jig saw and a bit of chain
drilling and will dress it to shape with a file next.
The question is, how do I get a decent finish on this?
The edges will need tidying as will some scratches that were
already present in the metal surface.

Is this a job for ever increasing grit sand paper?
How do I achieve a polished finish if that isn't asking the obvious?

Thanks

Phil

Finish the edges by draw filing (file used at 90 degrees to normal use)
with a fine file

On 17/10/2020 12:16, thescullster wrote:

Had forgotten the term draw filing as I have been away from the tools
for decades. Will have to look at the most appropriate fasteners as I
will be tapping screws into the aluminium body.

self taps for thin sheet, but tap holes for machine screws in thicker
Or use some kind of nut insert - Al is not strong in shear...


--
Outside of a dog, a book is a man's best friend. Inside of a dog it's
too dark to read.

Groucho Marx

Wrote in message:
On 16/10/2020 19:16, thescullster wrote: Hi Guys I am profiling a bracket shape out of 12 thk aluminium. Got as far as the rough profile with a jig saw and a bit of chain drilling and will dress it to shape with a file next. The question is, how do I get a decent finish on this? The edges will need tidying as will some scratches that were already present in the metal surface. Is this a job for ever increasing grit sand paper? How do I achieve a polished finish if that isn't asking the obvious? Thanks Phil Finish the edges by draw filing (file used at 90 degrees to normal use) with a fine file

Thanks for all the advice guys.

Had forgotten the term draw filing as I have been away from the
tools for decades.
Will have to look at the most appropriate fasteners as I will be
tapping screws into the aluminium body.

Phil
--


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

In article ,
thescullster wrote:
Wrote in message:
On 16/10/2020 19:16, thescullster wrote: Hi Guys I am profiling a
bracket shape out of 12 thk aluminium. Got as far as the rough
profile with a jig saw and a bit of chain drilling and will dress
it to shape with a file next. The question is, how do I get a decent
finish on this? The edges will need tidying as will some scratches
that were already present in the metal surface. Is this a job
for ever increasing grit sand paper? How do I achieve a polished
finish if that isn't asking the obvious? Thanks Phil Finish the
edges by draw filing (file used at 90 degrees to normal use) with a
fine file

Thanks for all the advice guys.

Had forgotten the term draw filing as I have been away from the
tools for decades.
Will have to look at the most appropriate fasteners as I will be
tapping screws into the aluminium body.

At school, we were taught not to use the best files on ally, as it clogs
the teeth. But that was before the days of readily available abrasive
sheets of all types.

--
*A plateau is a high form of flattery*

Dave Plowman London SW
To e-mail, change noise into sound.

On 17/10/2020 13:06, Dave Plowman (News) wrote:
In article ,
thescullster wrote:
Wrote in message:
On 16/10/2020 19:16, thescullster wrote: Hi Guys I am profiling a
bracket shape out of 12 thk aluminium. Got as far as the rough
profile with a jig saw and a bit of chain drilling and will dress
it to shape with a file next. The question is, how do I get a decent
finish on this? The edges will need tidying as will some scratches
that were already present in the metal surface. Is this a job
for ever increasing grit sand paper? How do I achieve a polished
finish if that isn't asking the obvious? Thanks Phil Finish the
edges by draw filing (file used at 90 degrees to normal use) with a
fine file

Thanks for all the advice guys.

Had forgotten the term draw filing as I have been away from the
tools for decades.
Will have to look at the most appropriate fasteners as I will be
tapping screws into the aluminium body.

At school, we were taught not to use the best files on ally, as it clogs
the teeth. But that was before the days of readily available abrasive
sheets of all types.

Chalk or paraffin can help with clogging, and my remaining memory pixies
seem to think that caustic soda solution can be used to clean files that
are clogged with aluminium