best way to sand enclosures down? (sanding)

[darron]

hey. i use the MXR enclosures, and they are really course and gouged away on the sides. they fit all the components perfectly though while being as small as sensible.

in large batches the sanding kills me! i'm starting with 80p wet and dry, moving up to 180 then moving up to 800. all this done with a cork sanding block. time to step up in the world i think! what tools do you guys use?

thanks in advance for future input on this thread (:

[greenacarina]

For coarse-to-medium stuff (small stuff) I use a 90-degree die grinder with a 2 inch roloc disc  http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93157

You can get different grades of sandpaper and scotch-brite type discs (nothing terribly fine, though).

Chris

[John Lyons]

A 5" Random Orbital sander works well. About $50 in the USA.
You can file down any uneven spot and sand from there.
Make a little jig out of wood to hold the box in place and then you just have to hold on to the sander.

John

[darron]

i've tried an orbital before, it didn't quite get where i wanted. the air grinder sounds like a good thing to try next (:

excellent idea on the wooden jig Basicaudio... I'll have to get around to that one to save the stress on my hands!

i suppose something like belt sander or similar might be a bit too much? i'd be worried about slipping etc.

thanks guys

[The Tone God]

When ever you are not wet sanding use a dust mask or respirator.

Andrew

[aloupos]

I've tried an orbital sander as well, and I don't get the results I'm looking for.  I think the best approach is to use a small belt sander.  You can really pull off that top layer of oxidation.  The grain goes one way, as if you're sanding using a block from side to side.  I'd build a jig to hold the sander in place upside down, and hold the box on the sander so you can do corners etc.  Works very well, very Fast! 

I'm really sorry I bought the orbital now, basically a waste of money for metal boxes.  [maybe I'm not using it correctly, anyone get smooth mirror finish using orbital?]

Anthony

[petemoore]

  For colored finished boxes, I don't read much about using sandable primer..what the auto body guys use to get 'mirror' finish isn't it?

[John Lyons]

I guess we need to define the use and results wanted.
Belt sanders are good for removing a lot of material but changing the belts for different grits is going to be a pain unless you are making a lot of boxes. Sanding with a linear patern as with a belt sander can be a good thing for getting the box flat. Finding fine grit best may be a problem though. For doing a lot of boxes and getting the rough stuff done fast will be better with a belt sander. Then you'll have to do the finer grits by hand.

The Randon orbit sander pad is a bit soft compared to a belt sander which is a hard plate. The good thing with an orbital sander is that you can get many sanding grits and the changeover is fast.

John

[darron]

i'd say you'd be right on that one basicaudio. if you deal with the mxr boxes they are horrible on their sides though and it would be worth it to get that smoothed out. i don't think belt sander belts go anywhere near as fine as maybe 600, probably because they might last 30 seconds, se the final work would have to be done by hand.

[bluesdevil]

How about this:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=43749
I'm also looking for a fast way to get the rough gouges smoothed out of the cheap MXR type boxes!!

[darron]

How about this:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=43749
I'm also looking for a fast way to get the rough gouges smoothed out of the cheap MXR type boxes!!

i was about to buy something VERY much like that the other day at the hardware store, except that as well as the disk it also had a belt on top. i'd use that disk more often i think though.

just about to buy it, when i realized that the store (bunnings) didn't stocks the replacement pads of different grits.

[luap77]

Hi Darron,

I polish aluminium to a mirror finish all the time. The gear we use is simply a 8" rotating flat plate (similar to the vertical rotating disc on the belt/disc snader you referred to), with the plate rotating in the horizontal plane instead of being mounted 90 degrees to your benchtop.

Start with 320 grit wet 'n dry and work your way up to 2400 grit, wet sanding all the way (we have splash shields etc). You should easily see your reflection, though it'll be slightly hazy. For a true mirror, we then move on to diamond paste ($$) and finish with alumina powder at 0.05 micron. This is probably overkill for you I'm guessing. I would simply stop at 2400 and then move straight to Brasso or a good metal polish paste like Autosol (autoshop), which should give you quite a good mirror.

BTW, for sanding discs and belts, contact Norton Abrasives (Saint Gobain) and ask them for a list of distributors in your local area (I'm also in Australia). These guys will be much cheaper than Bunnings and can get you anything in abrasives.

I do use the belt a fair bit actually...

Paul E

[darron]

awesome fill in paul! thanks. i think we've all learnt a bit from that. 2400 grit.. oucccch lol. i think i will try exactly what you recommend though, stopping at the diamond paste of course (:

do you find that the finish tarnishes where your fingers handle the enclosure though? i'm assuming it's either the acid on your fingers or maybe just the water.

[blanik]

you guys are so motivated... i just buy the Pedals Parts Plus "already painted boxes"

http://pedalpartsplus.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=PPP&Category_Code=ENC12

so easier!!! 

lazy R.

[darron]

you guys are so motivated... i just buy the Pedals Parts Plus "already painted boxes"

http://pedalpartsplus.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=PPP&Category_Code=ENC12

so easier!!! 

lazy R.

we've moved onto mirror finishes now
useful for box boxes without paint. etching etc.

[Barcode80]

i'm confused, i thought if you sanded the mxr style boxes then the paint wouldn't stick to the aluminum. are you guys using self-etching primer?

[luap77]

Darron,

They do tarnish! The trick is to use plenty of methylated spirits to clean the panel after the final polish. This will actually remove the microscopic particulates that are adhering in imperfections on the surface with the help of the residual poilish. The polish (you won't see it, but it's there!) retains the particles, and this thin film aids tarnishing. Once clean, put on your latex gloes ( ) and handle the box with these for the decal process and until you get the protective coat (clear-coat etc) on. I try and do all this within a week of polishing. You'll have no problems with tarnish. In the extreme case that you plan to leave a polished box unprotected for some time, store it in an airtight biscuit container. Aluminium does tend to oxidize to a dull finish with time if left unprotected (no clear).

Paul E

P.S. Latex gloves are 6-7 cents/pair when you buy box of 100. Any plastic gloves (food handling etc) will do. Please let us know how you go...

[pyrop]

awesome fill in paul! thanks. i think we've all learnt a bit from that. 2400 grit.. oucccch lol. i think i will try exactly what you recommend though, stopping at the diamond paste of course (:

do you find that the finish tarnishes where your fingers handle the enclosure though? i'm assuming it's either the acid on your fingers or maybe just the water.

Hey darron, to stop the tarnishing get some Estapol clear copper lacquer (used to be called Incralac). It comes in an aerosol & is available in places like bunnings or you can go direct to a Wattyl store, but be warned it's not cheap $17-$20 but it's the best clear in a spraycan for non-ferrous metals on the market in oz by far.. just make sure it is CLEAN.

pyrop

[darron]

i'm confused, i thought if you sanded the mxr style boxes then the paint wouldn't stick to the aluminum. are you guys using self-etching primer?

we're not talking about painting we're talking about sanding...

i etch my enclosures, so there's no need to paint them, sort of. otherwise you can use a self-etching primer for sure, but you don't need to do this mirror polish stuff that this thread has advanced to. maybe 400 and upwards to 600-800 would be good for that purpose.

i'll try out some mirrored ones when i get some new hardware. thanks for the advice pyrop! i'll try not to kill myself too, sounds like those fumes might be nasty.

[pyrop]

i'll try not to kill myself too, sounds like those fumes might be nasty.

I take it you read the datasheet lol.
Just use it in a well ventilated area.

pyrop