| brushed aluminum finish, how to? - Click HERE for Original Thread |
| power |
| We'll see if this post works. I have timesaved aluminum parts before but the results do vary with some parts having flaws such as slight rolling of the edges, etc. What other methods are there to "grain" the parts with the same if not better results. There must be a way:) |
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| Sch3mat1c |
I think it's done with a belt sander.
Tim |
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| Pbassred |
| I once did a "machined" finish (circles) using a 1" wire brush atachment with an electric drill. You need to watch it on brass because it tarnishes so quickly. You could get the brushed finish with the edge of a wire brush disk. |
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| Coulomb |
You could use a belt sander but if you wander at all it ruins the effect. I found if you make a jig with some 1x1 screwed to a panel of 3/4" board that traps your sanding block from wandering left or right, you can then pass the sand paper back an forth over your face plate to get the nice finish.
Anthony |
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| Peter Daniel |
I'm using 6" belt sander with 100 or 120 grid belts. Depending on the tension on a belt you will get more or less of the rolling of the edges. To wet the surface I'm using Varsol (or paint thinner) with very good results.
If you really want to avoid rolling of edges, the best approach would be making part longer and after sanding, trimming it off.
It's hard to get perfectly uniform finish on a belt, so after that I'm using Sotch Brite pads to further smooth the surface. Depending how long you do that, the finish can become really nice and pro looking.
Recently I started using Alodine at home and I'm getting fast and satisfying results, without having to wait 2 weeks for anodizing house to finish my panels.
I recently acquired Mark Levinson top cover door from their top of the line CD transport, and to my surprise their sanding job (done on a belt) was inferior to mine;) |
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| power |
the problem i see by doing the sanding manually with a belt sander is that if your workpiece is wider than the belt it would be difficult no to leave steps. Scotch brite may take it out but if you are doing several parts consistancy comes into play.
I have seen another process where acid is used to create the brushed finish. Very professional but also very expensive.
Beautiful looking work Peter! |
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| BrianGT |
I recently found that using a random orbit palm sander, with 80, 100, then 220 grit paper works great for taking out scratches in aluminum panels, then using a kitchen type brillo pad works great to give it that brushed look. I like using the kind with the sponge attached, as it allows for a more uniform pressure on the metal. The brillo pad easily takes up the scratches left from the 220 grit paper on the sander. I got the advice on the brillo pads from the machine shop guy here at school. That is what they use before anodizing aluminum panels. Before I used synthetic steel wool, but had problems with a non-uniform finish.
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Brian |
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| purplepeople |
Try dragging a coarse hand-file sideways in the direction of the brushing. Takes more time than power tools, but you have much more control. I like to use a palm sander to get most of the surface, then drag my file to finish the "brushed" effect. A sanding block can work, but the softness of the block can really make for uneven corner radii.
:)ensen. |
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| Peter Daniel |
You can make a block out of soft wood, like cedar.
I use belt sander as it is faster and deep scratches are easily removed. But I've herd from some memvers that using coarse scotch brite type pads works very well too.
Professional finishers use this type of wheel and as far as I know it's done manually. This leaves short lines (different than from belt sander).
We had Amp-1 finished this way, but I still wasn't much satisfied with the quality of a job. After first inspection 30% had to be redone. |
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| jewilson |
| You can check you one of your local machine shops. The have large belt and drumb sanders, up to 36" wide. Just tell them you want a brushed finish using either 120 or 150 grit. Besure to tell them which way you want the grain runing. |
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| cowanrg |
for home use, ive been using a bench sander, then a hand sander (wooden block with paper attached), then finishing it off with scotch pads.
its slow going, but has predictable results. its pretty fool proof. the face plates on my avatar are taking around 1.5 hours per fin. because of the perfection of the machining work, we have to get the finish perfect too. you could easily get this done in an hour or less if you werent trying to get it perfect. |
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| Peter Daniel |
| Actually the grain direction is dictated by the material. You could go across the natural grain of aluminum, but the results are always better if you go along. I tried few times doing it across. |
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| sam9 |
I've used the hand method - a sanding block wider than the workpiece starting with moderately coarse wet&dry (use wet) paper until the scratches and dings are gone, then progressively finer paper until it looks right. Tricks: find a way to hold the workpiece adsolutly immobile B: stand, sit ot squat in a postion that helps you make complete strokes from one end to the other and as straight as possible C: count the strokes after fixed number reverse the workpiece and make the same number from the opposite direction (otherwise one end will tend to look different from the other) D: lots of soapy water E: wear old clothes and don't be afraid of making a mess.
I have not bothered with alodine yet - I'll try that on the next project |
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| jewilson |
| Aluminium Oxide sand paper is the best for metal it will not wear out as fast. You can use granet or other woodworking sand paper they just don't last as long. If you have a Drum sander Aluminium Oxide is a must. |
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| Jason_N |
Changing the subject slightly...
So what can you do with the aluminum after you are finished brushing? I would like something that is clear (or close to it) and that I can do myself. What are the options?
Thanks,
Jason |
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| Peter Daniel |
| Alodine. If you want to have it close to clear, use very light solution and brush any excess after. The pic I posted previously shows the alodined piece. You can also use some protective spray, but this will always look artificial. |
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| jewilson |
| You can spray it with a polyurethane or Lacquer it has to be clean of all oils. Don't get you finger on it. If you spray it, the aluminum will lose some of it ability to conduct heat, so don't spray the heat sinks. Anodizing is cheap and doing Alodining is cheaper, call around and anodizing can be done in many colors . |
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| sam9 |
Anyone know a good source for the solution?
Can anyone suggest a URL with instructions for applying it?
I did a Google search and got a huge listing that I haven't had time to sort out so if anyone can point to some sources they can recomend from their own experierce . . . . |
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| Peter Daniel |
http://www.airtechcoatings.com/cgi-...M&search=action
Buy the smallest amount in powder form. When making solution Use quater or less of what they recommend (when mixing) as the original receipe makes the liquid too strong.
Don't buy aluminum prep (or any cleaner) as it doesn't work well and you don't need it.
When doing actual alodining, clean the parts directly before dipping (with scotch brite). Don't dip it for more than few seconds, as the color becomes too strong and you might not like it. Extent time for required appearance. If finish is too strong or uneven, additional scotch brite brushing (after alodine) fix the problem.
Check also this older thread for more suppliers http://www.diyaudio.com/forums/show...3982&highlight= |
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| sam9 |
| Thanks much. I'll bookmark those for my next project. |
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| Magura |
| quote: | Originally posted by Peter Daniel
I'm using 6" belt sander with 100 or 120 grid belts. Depending on the tension on a belt you will get more or less of the rolling of the edges. To wet the surface I'm using Varsol (or paint thinner) with very good results.
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Ohh Peter...please dont do that...i guess we all like you here...and if you keep on using paint thinner while using your belt sander...we suddenly wont have you around for a while. An electrical motor makes sparks, and a belt gets static....more sparks.
I have seen it blow up in the face of a guy using a powerdrill...not a nice sight.
How were your experiences with anodising at home?? easy?? cheap?? deadly poisonous??
Magura
:hot: :hot: :hot: :hot: :hot: :hot: :hot: :hot: :hot: |
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| Peter Daniel |
| I started using Varsol after the recommendation from a commercial place that do metal finishing. |
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| Magura |
I dont know what VARSOL is, but i sure hope its not flameable like paint thinner.
I usually use petroleum(kerosene) it works well, is easy to clean of and is almost impossible to ignite.......and it isnt paticulary poisonous (unlike paint thinner, wich is not for home use, since the fumes are very toxic).
Magura |
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| Magura |
Point taken :)
I just got vorried that youd blow up:eek:
Magura |
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| tiroth |
| Have you looked at the MSDS for Varsol? Not very nice stuff to come in contact with. Any solution to this? I would think even latex-type gloves would be even more dangerous than the varsol. |
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| Magura |
Accept the fact that your hands will eventually fall off if using kerosene or varsol....but you got a nice looking amp :D
Magura |
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| rcrump |
| Peter, just take it to a shop that does grain sanding and alodine coating....There is an art to grain sanding and worth the minimums involved in graining and coating......My shop has a $25 minimum......Don't care for alodine coating as either bright silver or gold as I recall.....Like it either black or clear anodize..... |
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| Peter Daniel |
| quote: | Originally posted by rcrump
Peter, just take it to a shop that does grain sanding and alodine coating....There is an art to grain sanding and worth the minimums involved in graining and coating......My shop has a $25 minimum......Don't care for alodine coating as either bright silver or gold as I recall.....Like it either black or clear anodize..... |
I tried most shops in my area (including the one that does Sonic Frontiers ). Unfortunately, I wasn't always happy with the quality of their job.
The plates had to be redone, anodising had to be stripped, brushed again and anodised again. It all took additional time, so now, when doing prototypes and small runs, I prefer to do finishing myself.;) The good part is that I can have it all done in one sfternoon, without waiting a week or two for metal finishers. You know how it is, when only chassis keeps you from listening to your next creation.
BTW, I think I mastered the art of grain sanding pretty well;)
The minimum they charge here is $75 -100 CAD. Of course if it's 20 pcs or more, I'm not trying to do it myself. |
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| rcrump |
| I have had some trouble as well with finishing, but finally found a good shop to do the grain sanding and anodize work. I still have to run all over the place with knobs as have to be bead blasted, have lines engraved in them, then anodized and then paint filled......Three different shops involved......The grain sanding/anodize shop have $25 minimums, the bead blasting is $15 and engraver wants $50 minimum.....Runs about $300 to have our two chassis 60 pound preamp chassis finished and engraved.....Found a guy with a pantograph machine who does nice engraving and normally have it engraved through the anodize with the black anodized units. No set-up involved so each unit can be touch different as respects the lettering....` |
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| Magura |
whats the difference between anodizing and alodine???
Magura:smash: |
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| Jocko Homo |
Anodizing is an electrochemical process that changes the chemistry of the aluminum, in such as way as to make a very hard surface. It creates an oxide layer that is pretty tough.
IOW......scratch resistant, etc.
Alodine is a simpler operation that just puts a nice finish on aluminum, but can easily be scratched.
Alodine is basically a dip. Anodising requires electrolysis.
Typical application:
Front panel: anodise. It has to be able to withstand handling and abuse.
Metal parts inside unit: alodine. Shiny enough, but will not withstand scratches. Mostly to prevent oxidation of the surface.
Jocko |
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| Peter Daniel |
The difference between anodizing and alodine could be compared to treating wood with hard lacquer or using sealer.
Alodine has effect of the sealer. It penetrates surface of aluminum, but does not create any protective surface like anodizing. That's why it is not a protection against scratches at all.
What I find appealing though is the simplicity of applying. Just dipping for few seconds is enough, and to me, it sometimes creates nicer finish than anodizing.
I usually brush it off a bit with scotch brite pads, after applying, and this removes any goldish shine. The aluminum looks more like stainless steel and is completely resistant to stains when handling. As long as you take enough care not to scratch it, it is a cheaper alternative to anodizing.
This panel was treated with alodine: |
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| gmphadte |
| take a bigger plate (bigger than required) do the finishing/brushing first and then cut it to size. this will get rid of the problems at the edges. Needless to say; cutting job should be perfect. |
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