sanding painted knurling/ribbing? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: August 08, 2020, 09:06:46 pm
content: I have an aluminum extrusion that I am painting, and I wondered if there is a good way to scuff/sand the primer that goes into the 'knurled' part (its like a grip). (this is just a stand made out of scrap extrusion beam)A stainless steel brush is good for the primer coat, but if I want to sand the primer and the paint afterwards before a clear coat, what is a good way to do this? Its parallel lines, not diamond knurl, so so long something has the right shape, it can slide along in there.You might be able to go in manually with a fine tool, but there is alot of it. Most sand paper I think is too thick to wrap around something, it won't get into the grooves.Is there some kind of sanding putty ? A painters/sponge sand block is not deformable enough. Think like a hard drive caddy. I am not doing this with a tooth pick. In fact its not really necessary to do at all, I just want to know if this exists.

author: rdl
author_rank: Super Contributor
timestamp: August 09, 2020, 07:54:25 pm
content: At a couple of places I worked we used dry sand or sand/water slurry to clean and polish odd shaped parts. Maybe something like that would work for you.

author: Cerebus
author_rank: Super Contributor
timestamp: August 09, 2020, 09:14:08 pm
content: Obvious mentions go here togrit (or other media) blastingandtumbling. The former probably too aggressive for your needs, the latter probably not aggressive enough; but useful techniques to be aware of.Steel wool is quite good at conforming to ridges, slots etc. Lots of grades to choose from, from grades close to rough sandpaper in action to 0000 grade which makes a good finishing grade.You can get soft rubber blocks with embedded abrasives that will 'wear' to a regular shape and conform to knurling and the like. "Bright boy" is one trade name for these.

author: coppercone2
author_rank: Super Contributor
timestamp: August 09, 2020, 09:15:40 pm
content: Quote from: rdl on August 09, 2020, 07:54:25 pmso you just buy sand in the correct grit (i assume for paint you don't need hard core abrasives) and mix it with water and use what with it? Gloved hands? some kind of sponge?Do you mix it with something to make it slimey etc?

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 09, 2020, 09:26:49 pm
content: Quote from: coppercone2 on August 08, 2020, 09:06:46 pmSand, bead or other media blasting will do the trick. Most other solutions will be finicky or ineffective.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 09, 2020, 09:30:26 pm
content: Quote from: Cerebus on August 09, 2020, 09:14:08 pmThere's a whole zoo of media types which can be more or less abrasive. You can be quite gentle or abrade holes in the metal depending on your choices.

author: coppercone2
author_rank: Super Contributor
timestamp: August 09, 2020, 09:30:38 pm
content: Quote from: Cerebus on August 09, 2020, 09:14:08 pmyea that will destroy spray paint. I was just wondering how people follow 'automotive' coating rules with small geometry crap.

author: coppercone2
author_rank: Super Contributor
timestamp: August 09, 2020, 09:31:25 pm
content: Quote from: Mr. Scram on August 09, 2020, 09:30:26 pmthis is like a 4 foot long extruded aluminum with a guide rail on it used for a pole. An odd one that is in the shape of triangle (looks like weyland yutakani stuff lol, like how they would join the buildings together on the colonies)I just want a beefy stand I can make different attachments on it, so I can do things like put the torch on it, make a insulated section to clip the welder ground on, etc. Made from scrap, this aluminum had too much oxidation on it, so it could not be polished to look nice without stripping the anodizing, because in some spots it turned like black.. so I just brushed it all, cleaned it, painted it. I put it on a pretty heavy base for safety.I am working on multiprocess welding, like using electricity to preheat, so hook up is getting a bit complicated and i need things neat and safe.

author: KL27x
author_rank: Super Contributor
timestamp: August 10, 2020, 01:01:39 am
content: ^Sounds like a worthy project, Copper.Cerebus, steel wool is god's gift to the garage DIY-er. It won't cut through hard oxide layers, though. This is either a good thing or a bad thing, depending on what you're doing. I recently stripped the sketchy paint-job off the stamped steel doors/covers on a benchtop bandsaw using acetone and steel wool, and to my amusement, it left the original pre-painting prep/etch oxide layer completely intact. I am not even going to repaint it, because it looks great and is just as rust proof as before. Plus it doubles as a dry-erase board.

author: Cerebus
author_rank: Super Contributor
timestamp: August 10, 2020, 01:34:49 am
content: Quote from: KL27x on August 10, 2020, 01:01:39 amAgreed, steel wool is actually quite subtle, that's why I like it. It's also good for producing deliberately distressed finishes (think props or matching existing weathered or faded finishes).For everything else there is Scotch-brite and the angle grinder with a flap disk.If those fail, there is diamond.But seriously I have just about every kind of abrasive from 40 grit garnet paper to fine diamond stones and most things in between (somewhere, I can never find quite the right thing when I'm looking for. When I'm not looking for it ...). Each has its place.

author: coppercone2
author_rank: Super Contributor
timestamp: August 10, 2020, 01:56:41 am
content: but, are you crazy enough to have all the different kinds of sand paper? For instance, I need diamond paper to work granite with.I actually have a steel wool kit, moisture sealed 'husky' box with samples of all the different kinds of wool. Did you know some people clean car windows with 0000?Now just to get it in brass, copper and stainless steel.I actually never tried steel wool on paint. I actually am kind of dissapointed with how little uses I found for it. Luckily the stuff is dirt cheap. On the other hand, its kind of unpleasant to work with. I think the problem is that its meant for working pretty good stock, I work with wretched materials.