Another Finishing Thread!

[YouAre]

Hey Guys,

I've been searching this forum and other websites about a definitive finishing, but haven't found any general consensus on the subject

I'm trying to get into doing my own finishes, and I've learned 100 ways that don't work but still haven't found one that does, heh.



I generally try to wet sand (basically take wet/dry sand paper, and sand under running water....right?), then throw on some duplicolor self etching primer, then throw on some coats! The main issue with this is that little imperfections show up through the paint. Can anyone gives me tips on how to best prepare the surface of a hammond style box for basic paint?

Also, sometimes I want to print something onto glossy photopaper, and lay it onto the pedal. I tested Krylon glossy clearcoat, and it "yellowed" everything. Is there a clearcoat that doesn't do that? I don't know if Rustoleum/Krylon is acrylic or enamel based, but I know it'll have to match...Any suggestions? Brush or spray is fine by me.

I'll ask about brushed finishes later...let's master a basic flat finish first. Heh...

Thanks guys!

[Earthscum]

The trick is in what you said... it shows any imperfections underneath, so start by smoothing out the underneath.

So, you have the metal smooth... if you notice, after your primer is down, you see a bunch of little bumps and pills that you notice after your paint is on. When that first coat of primer is dry, sand it down until the metal JUST starts to show through. Basically, Primer is made to fill small imperfections, so you always want to think of your first coat of primer as your final coat of body filler. It's also your "revealer", where it shows any dings and dents that will show through later. If you take good care of your fitst coats of primer, everything goes smoother down the line... literally    (btw, this is from professional experience.)

[YouAre]

The trick is in what you said... it shows any imperfections underneath, so start by smoothing out the underneath.

So, you have the metal smooth... if you notice, after your primer is down, you see a bunch of little bumps and pills that you notice after your paint is on. When that first coat of primer is dry, sand it down until the metal JUST starts to show through. Basically, Primer is made to fill small imperfections, so you always want to think of your first coat of primer as your final coat of body filler. It's also your "revealer", where it shows any dings and dents that will show through later. If you take good care of your fitst coats of primer, everything goes smoother down the line... literally    (btw, this is from professional experience.)

OoooooooOOOOOHooohh! So the primer fills in the little cracks and imperfections? Awesome! So primer fills them in, we sand it down so that the only primer that's visible is in the cracks, then we paint? or do we do another coat of primer, THEN paint?

Thanks!

[davent]

Another tip, multiple light (dry) coats will give you much better results then trying to lay it all on at once. Spray let dry,  sand - spay let dry sand (320-400grit paper)... until all the pits and bumps dissappear then onto your colour coats.  (Basically it all comes down to patience.)

dave

[Earthscum]

You always want your primer to entirely coat the surface. Your primer is basically the equivalent of the sticky stuff on tape. Your paint won't stick (or at least not very well) to bare metal. The primer actually etches the surface as it cures, locking itself to the surface metal. Your paint will soak into the primer's topmost layers and adhere.

Basically, you:

Metal Finish
Prime
Re-level (sand smooth, fine grit)
Prime
Re-level again, if needed, otherwise you are ready to paint.

BTW, go spend the $3 or so on a tack cloth. This stuff is sticky, like Gorilla Snot on linen. Use it to wipe the surface clean. Sometimes it will catch something that you didn't see. Basically, you just use it to wipe the dust off right before you shoot your box with primer or paint.

Also, acetone is your friend. Use it to prep your bare metal. ACETONE IS EXTREMELY FLAMMABLE!!! The vapors creep across the floor and can ignite from even static. Ya always want to do the acetone wipe (to pull surface oils out of the VERY porous aluminum) outside, or in your dedicated painting area.

Lacquer thinner will sometimes leave a residue behind that won't evaporate out of the pores of the aluminum right away, and that will botch your paint job. Basically, I've had things flake, look like it went through a sand blaster (little pits), even just paint sliding off the area (avalanche).

And, finally, like they always say... MULTIPLE LIGHT COATS!!!

If you REALLY want the ultimate finish, use some of that ultra-fine sandpaper you have and wet-sand the box and apply a finish coat, or better yet a clear coat. It will re-gloss the base coat.

For more tips and tricks on painting, visit PowerBlock.com! (sorry, I really gotta quit watching that every single weekend!) Actually, I'm halfway serious. Automotive sites have all sorts of awesome stuff... pinstriping, decals, graphic layout... lots of awesome stuff.

[davent]

This is the last pedal i completed. The box's not a Hammond and was, by comparison quite pitted. Sanding took care of a lot of it but not all. Primed it first with AutoAir bare medal primer. Then switched to Zinser BIN primer which is seems to be high in solids so only took a few coats to get a nice smooth unpitted primed surface ready for paint. Clearcoat is StewMac water based guitar sealer and lacquer (this will really test your patience).

Gotta' get me some acetone and chack out PowerBlock,com.
dave

[Earthscum]

Very nice! Clean paint edges... what tape do you use? I've always liked the cheap vinyl  stuff for model painting, but I tried out some of the stuff from 3M and liked it more... just didn't like the price, lol. I'm a big stickler on cutting edges.

[davent]

Thanks! For that one it was just a 1/4" masking tape from the local art supply store but if you spray with clear after masking but before starting the next colour i've found you can get a pretty good edge. Also use FBS Proband Fineline in  different widths and translucent frisket films. I think spraying the clear (or base colour before starting the second colour is really the key. Another tape i used to be able to get up here was called Kleen Edge, came in a couple different tacks and it worked real well.

Frisket and masking tape

FBS tape and masking tape

Take care
dave

[Procreatur]

First - I use aggressive air tools with 3M plastic discs to prep the surface, then sand with 120, 220 and prime with self etching primer. Self etching primer provides the best adhesion to aluminum. I wet sand that smooth with 400 grit, then cover it with either hi-build primer, or regular primer depending on what I have available. Hi-build can be laid on super thick in the areas you wish it to fill, but it won't fill anything larger than superficial marks.

After priming, it's 600 grit wet, color x 3, 1000 grit wet, clear x 3, 1500, then clear again. I haven't striped a box yet, but it's on my to do list. Lay the clear on as thin as possible while still allowing it to appear wet. Clear dries exactly like it goes on in most cases.

Tack cloth is a great idea, as is clearing after taping to blend the lines.

[phector2004]

Dave,

Your finishes are excellent!

Are there any issues with the paint being thicker where there is no tape, or even worse, the adjacent paint chipping when you peel the tape off?
Do you do the curves with masking tape as well??!

[R.G.]

Go to a car parts store. Find and buy the paperbook book which tells you how to fix dents and repaint.

In there you'll find info about primers, filler and -> spotting putty <- for getting glass-smooth auto finishes.

[davent]

Dave,

Your finishes are excellent!

Are there any issues with the paint being thicker where there is no tape, or even worse, the adjacent paint chipping when you peel the tape off?
Do you do the curves with masking tape as well??!

Thanks Phil,

Those two boxes were first painted black then 1/16" FBS (vinyl) tape was used to layout the lines. The colours were then sprayed, which can involve quite a few layers of paint. That does leave a canyon of a black line that has to be filled with clear, with the clear i've been using that means dozens of coats with an airbrush. I tried painting the black lines after the fact on a recent pedal but had a hard time getting a uniform width for the line. Another problem is it's hard to get the tape to stay flat in the curves so you get a fair amont of underspray that you have fix with a steady hand and paint brush.

Haven't had any problems with tape removal. (i'm using acrylic paints, Createx, AutoAir and Golden.)

Taping

 

Canyon and underspray

[deadastronaut]

my 2p worth...

always use a block...primer....and spray a colour dust coat (guide coat) you will see any low/hi spots when sanding.......

any serious small digs use cellulose stopper........is that worth 2p?..

yep i used to spray cars too.......until they started using isocyanates..(cyanide).didnt like wearing apparatus to paint....lol..


@davent...nice job on them..love the goldy one..

[R.G.]

yep i used to spray cars too.......until they started using isocyanates..(cyanide).didnt like wearing apparatus to paint....lol..

Catalyzed urethanes (the isocyanates) are hard, tough, glossy. And toxic.

[KazooMan]

yep i used to spray cars too.......until they started using isocyanates..(cyanide).didnt like wearing apparatus to paint....lol..

Catalyzed urethanes (the isocyanates) are hard, tough, glossy. And toxic.

Yep, R.G. is correct (as usual), isocyanates can be very toxic (but they are not cyanide).  The Bhopal disaster was a mass leak of methyl isocyanate.  Over 20,000 deaths and many, many more individuals with serious debilitating injuries.

Read and head the warnings on the spray can.

[Govmnt_Lacky]

Just caught this thread and thought I would ask. Is there a good CLEAR sticker paper that can be used for full-face labeling of an enclosure? Don't want to use decal paper and prefer sticker paper that is made for a Laser printer. Any suggestions?

[deadastronaut]

yep i used to spray cars too.......until they started using isocyanates..(cyanide).didnt like wearing apparatus to paint....lol..

Catalyzed urethanes (the isocyanates) are hard, tough, glossy. And toxic.

ok... im no chemist..but it was nasty all the same.....

[armstrom]

I'm a bit late to the game here, but my best results have come from powder coating and using bake-on laser decals.



The flash on the camera makes the black toner look more "textured" than it does to the naked eye. That is a full-face decal with no softener applied. I'm using bake-on decals which just happen to bake at a lower temperature than the flow-out temp of the powder coat.

Powder coating is really quite simple once you get the hang of it. The equipment isn't terribly expensive either. A $50 gun from harbor freight and a $20 toaster oven and you're in business. My next step will be to try to print in reverse on the decal and apply it with the toner facing down before I bake it so that the decal seals in the toner. I wasn't able to scratch the toner off of the decal very easily but it can happen if you don't clear coat over it (that picture has no clear coat).

Here's another powder coat finish I did on a tube microphone I built for a friend.


The range of colors available is really great, and it's hard to beat the durability and cure time. Once the part is cool it's ready to go.. no worries of leaving the paint to dry long enough, or not getting good adhesion on the aluminum.

[Govmnt_Lacky]

Armstrom,

That is a FANTASTIC finish on the "Cram It." That is EXACTLY how I want my finishes to look. I am going to be getting a powder coat setup as you stated above.
I would like to know a little bit more about your "Bake on Laser Decals" that you use. Could you share the info on where you buy them and your process for application? Maybe a PM??


Thanks 

[armstrom]

Thanks. These are the decals I use: http://texascraft.com/hps/product.php?productid=16602&cat=0&page=1
They're also available in white if you have a color laser and want full-color decals (keep in mind the decal won't be clear so none of your finish will show through). As for applying  them they go on like regular water slide decals (soak the decal until the backing separates, then slide the decal onto the part and squeegee out all the bubbles (Air and water). Once the decal has fully dried I simply bake it in my powder coating oven at 325 for 15 minutes and the decal melts onto the surface. The decals don't state that you need to use a dedicated oven (not one being used for food) but since the part I'm putting the decals on was powder coated I don't want it out-gassing into my kitchen oven. So I would still recommend getting a dedicated toaster oven for baking decals on to powder coated boxes.

One alternative to setting yourself up for doing powder coating is to simply buy your boxes pre-coated from pedal parts plus. The price he charges is very reasonable considering how much time and cost you will invest trying to perfect your technique with the powder coating system. I just happened to have my powder coating equipment from a previous car project so I didn't have to invest much. I forgot to include the cost of an air compressor in my description (if you don't already have access to one). You also need a way to remove the powder when you inevitably botch a coating job. In the beginning something ALWAYS goes wrong. You don't apply enough powder, you get contamination in the finish that looks bad, whatever. Up until you bake on the powder you can just wipe it off with a cloth or paper towel and spray it again, but after you bake it you will need to grind it off. I use the surface prep pads on an air angle grinder. Makes quick work of stripping off the cured powder. You can also use them to prepare the box for accepting the powder.  One of these: http://www.harborfreight.com/air-tools/grinders/1-4-quarter-inch-front-exhaust-air-angle-die-grinder-52848.html  with this http://www.harborfreight.com/complete-sanding-disc-kit-43029.html