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Old FFForums Archive => Model Help* (Check Stickies and Search First) => Assembly/Scratchbuilding => Topic started by: GlauG on December 14, 2008, 02:47:24 PM

Title: Cutting and sanding metal parts
Post by: GlauG on December 14, 2008, 02:47:24 PM
A search for "sanding aluminium" didn't bring up much of use, so I ask this of the forum;  How does one sand aluminium parts after sawing?  What do you use, metal files, sandpaper, sanding stones etc?  I've just cut some aluminium pipe for something, but while I had a bit of a go at it with a metal sander, the finish is still kind of rough.  Any suggestions?
Title: Re: Cutting and sanding metal parts
Post by: fulcy on December 14, 2008, 02:57:08 PM
You'll want to do a progressive sanding - first use a file to remove the burrs, then move onto the sand paper to smooth out the course marks left by the files.

Do not use any type of sanding stone with aluminum - the stones are more intended for use with ferrous metals, and aluminum tends to just melt and get stuck in the stone.
Title: Re: Cutting and sanding metal parts
Post by: FichtenFoo on December 14, 2008, 05:11:15 PM
Also, what kind of aluminum parts? Tube? Sheet? Machined? For tubes I put them in my drill and use a file for the edge, a triangular router bit for the inside edge, then fine steel wool all over.

Sheets, dremmel, metal files, sandpaper, etc...
Title: Re: Cutting and sanding metal parts
Post by: GlauG on December 15, 2008, 03:49:26 AM
Like I said in the OP, specifically it's an aluminium pipe. :)  A small one, I've cut it at a diagonal angle for use as barrels for some weapons. 
(http://img514.imageshack.us/img514/264/1021573er4.th.jpg) (http://img514.imageshack.us/my.php?image=1021573er4.jpg)

I rubbed all the burrs off with a wooden cocktail stick, then had a go with a metal nail file I've got, and it's okay but not perfect.  Unfortunately my drill's in storage right now, but I'll try and progressive sand some of the sharp outside edges with some wet-and-dry.  Thanks for the advice. :)
Title: Re: Cutting and sanding metal parts
Post by: chaos_theory on December 15, 2008, 06:04:57 AM
I would have thought an old Warhammer 40K guy might have a set of mini files for the metal figures.  :P I got a set of 8 files for $16 US in all kinds of shapes: round, oval, triangular, square, flat, etc. If there are any stores that cater to wargames in Japan check there.

Try wrapping some of that sandpaper around the cocktail stick you used for sanding the interior
Title: Re: Cutting and sanding metal parts
Post by: GlauG on December 15, 2008, 06:41:45 AM
I've got metal files, but they tended to leave my old lead and white metal minis looking a bit rough. ;)  I'm looking for a smoother surface here.  I'm also back in the UK, which is a mixed blessing for hobby stuff...  I'll have a go at it later tonight/tomorrow and post progress pics. :D
Title: Re: Cutting and sanding metal parts
Post by: igor57 on December 19, 2008, 12:00:32 AM
Find a Jewellers suppliers and check out their smooth cut files.    The jewellery ones are much finer then your average ones.   Pick a flat wide tapered one with a square file edge on one side and a rounded file edge on the other. Actual file (ignoring the tang) of about 150mm.  More versatile.   

A small trick with Aluminium is to use a droplet of oil (automotive is fine) or kerosene on the file.   Yeah I know that it's a pain subsequently for pre-paint clean-up but for aluminium is aids the cut hugely.   Then wet and dry paper probably starting at 240 grit and then 320, finishing with 400.     

The alternative is a scotchbrite wheel on a bench grinder/polisher, this works a real treat.   

As Fulcy says the stones and aluminium can be a pain but diamond burrs make a lovely job on aluminium particularly if you want a textured surface.     

Quick point, if you ever want to use aluminium round for pins, mounts, locators etc check out you local welding suppliers.  Huge amount cheaper then buying through a model shop.  Feeder rods for Tig welding is what to ask for.   Comes in 1.2, 2.4. 3.2, and 4mm ........

Have fun!