Prep work - Sanding aluminium before polishing

[ayvi8or]

Hi there,

I have a couple of questions regarding sanding aluminium before polishing it.

I have a number of engine covers that are quite tricky to sand back because of their contour lines and placement of holes ect.

I have started out with around a 180 grit wet and dry paper, using different fluids (metho, kero and water) to see what gives the best result (metho seems to work best for me). It seems to take quite some time and I am curious to know if I am able to use a dry sander for the first couple of passes over the aluminium before hitting it with the wet and dry paper. Would this be okay to do?

Also, I am looking at some sanding drums but I noticed that there is no wet and dry paper to suit these drums. Does anyone make this stuff at all? I haven't been able to find a great deal of products in terms of wet and dry mouse sander pads either. Could anyone point me in the right direction for this too?

Any help would be greatly appreciated.

Thanks

[baz]

Hi there,

I have a couple of questions regarding sanding aluminium before polishing it.

I have a number of engine covers that are quite tricky to sand back because of their contour lines and placement of holes ect.

I have started out with around a 180 grit wet and dry paper, using different fluids (metho, kero and water) to see what gives the best result (metho seems to work best for me). It seems to take quite some time and I am curious to know if I am able to use a dry sander for the first couple of passes over the aluminium before hitting it with the wet and dry paper. Would this be okay to do?

Also, I am looking at some sanding drums but I noticed that there is no wet and dry paper to suit these drums. Does anyone make this stuff at all? I haven't been able to find a great deal of products in terms of wet and dry mouse sander pads either. Could anyone point me in the right direction for this too?

Any help would be greatly appreciated.

Thanks

i never wet sand !

[vortechyank]

Nor do i, usually, but i've been told it's an almost mandatory thing for aluminium? I've been shown some proof of identical sections dry sanded and wet sanded, and the wet almost appears to look that bit more uniform and colored. I dunno.

[ayvi8or]

Hey guys, thanks for the replies.

Like I mentioned, I have read a few mixed methods of sanding, some say wet and dry others just say dry. Some say sand up to 400 grit, others say 1200 grit...

I noticed that there are some little sanding band attachments for the dremel tool, about a 180 grit which I think would be great to start with to get rid of a few scratches and get to the hard to reach spot. I guess after the hard first part is done I can then hit it with the wet and dry stuff.

[baz]

i m not saying that wet sanding won t work,i just think its useless , sanding down to 1200 is also useless in my opinion since a good buffing compound will easily remove 800 grit sanding marks and with the right tecnique and tools it will even remove 320 grit lines and since i do this for a living i don t have time to waste on useless steps .

[baz]

Nor do i, usually, but i've been told it's an almost mandatory thing for aluminium? I've been shown some proof of identical sections dry sanded and wet sanded, and the wet almost appears to look that bit more uniform and colored. I dunno.

sorry but the words ( almost appears to look)do not really sound like a proof to me
but if in fact they really were more uniform and colored then i would think that your buffing compound or your buffing tecnique is not up to par

[ayvi8or]

Interesting. I will try sanding one cover with wet and dry and the other just dry - considering that I will be using the same wheels and compounds it will be interesting to see what difference, if any, there will be.

I ended up buying a Dremel, I will buy a few small sanding bands off ebay (100 of them for $5!) just to use as the first pass on the covers.

I am now looking at buying a Baldor bench grinder $$$

[vortechyank]

sorry but the words ( almost appears to look)do not really sound like a proof to me
but if in fact they really were more uniform and colored then i would think that your buffing compound or your buffing tecnique is not up to par

oh well i mean, i'm on your side, i don't wet sand myself, and have always dry sanded, but i mean, it was this person trying to sell me on the wet sand technique with their own examples.
Also with the grits, i think it depends. I can dry sand soft steels from 180-1500 to a mirror lustre without any buffing at all and just finishing with metal polish. Of course, it takes longer. Stainless too with the assist of a drill. However, with aluminium, i've found it's near impossible to go past the 600 or so, and there's no need. It's so easily scratched, i find hand finishing impossible, you just need power tools and compounds. Unless there's any big gouges or casting, you don't really need any sanding period and can start up with a rough sisal and black.

The dremels are great ayv, just be careful with the bands, they can be destroyed very easily, 100 of them sounds like a great deal, and mandatory!

[ayvi8or]

Thanks for the reply.

There are just a couple of small markings that have been pressed into the Al. I am sanding it out to try get a nice flat finish or as flat as I can.

I am struggling to find a 3600rpm bench grinder here in Aus too! Do you guys wear gloves when you sand? My hands are blacker than a coal mine worker.

[vortechyank]

Yeah mate i wear cotton gloves and am usually perfectly clean, aluminium oxide is very filthy stuff. To be honest, i have never used a bench grinder, it's either the dremel or just a regular electric drill for me, works a treat. Too hard to work most things around a benchy anyway in my experience, there are just too few things of what i do ( car engine parts ) that are so simple as to use a bench grinder successfully