Car touch up paint process suggestions

[skeer]

Morning! Ok so I'll try to not make this into a long-winded story.. my wifes 2018 Equinox has 4 small paint bubbles on the front lip of the hood. Being someone who wants to try everything I want to fix it myself. However knowing I'll eff up at least once I went and borrowed an identical hood off a wrecked car at the salvage yard. I do computer work for them so we're friendly. I'm not at home so here's a representative image.

So here's the deal, lower hood lip is roughly an inch tall and runs the full width of the car. Bubbles and loose paint after popping don't extend past the lips bend. First basic idea was to primer just the target area, color target + 3-4 inches, then clear target + 6 inches

First Attempt:
Popped bubbles and turns out.. oxidation, not rust.. white powder.
Wet sanded entire lip w/400 grit, but only bubble spots, down to metal.
Wet sanded entire lip again w/1000 grit
4 coats; white color primer (oem primer color is unknown).
More wet sanding with 1000 grit
(Based on numerous YT videos) I taped off half of the top of the hood assuming color over spray wouldn't make it that far up.
3 coats of color
3 coats of clear coat
Removed the tape only to find a line.. F me. So wet sanded line with 1500 grit, then some 2000 grit. Now that line has moved but it's more of a jagged kinda.. fractal-esque line if you will. I think I'm sanding off the clear over spray but why isn't it fading away and blending?
Panic a bit, I think 'Ok Ill just keep sanding that line and maybe work it down to the edge of the lip'. Sand, sand, sand some more.. the lines moving but can't help but feel I screwed it up.
Last step.. re wet sand the entire sprayed area with 400, then 1000, then 1500, then 2000. Remove all the clear and color I applied except the lip itself, then re-clear coat the whole shebang.

This is all from rattle-can.. had the color custom mixed off paint code. Please don't tell me to take it somewhere and that's it. I know I can't do as good of a job as a real body man, but considering it's just the lip (on the real car) surely it's doable at home yeah?

 

[rlitman]

...Popped bubbles and turns out.. oxidation, not rust.. white powder...

Sounds to me like your hood is aluminum and not steel. That's important to know, because the bare metal priming is very different.

 

[Bill Bowman]

You need to prep for aluminum. It's not rust.

 

[skeer]

Sounds to me like your hood is aluminum and not steel. That's important to know, because the bare metal priming is very different.

Well no sh1t.. damn I never thought GM would have used aluminum in 2018.

 

[skeer]

Ok so a self-etching primer.. easy enough. Just going to have to remove the primer that's on the lip currently.

 

[carlaisle]

Seamlessly blending new paint into old in the middle of a panel is not a first timer DIY project. You would already be finished if you had just done the entire hood.

 

[skeer]

Seamlessly blending new paint into old in the middle of a panel is not a first timer DIY project. You would already be finished if you had just done the entire hood.

Oh I'm sure.. I mean at this point I'm going to have to clear the whole test hood. Or well I mean I don't have to but it'd probably be a great learning experience. On the real guy my questions remain, limiting primer and paint to just the lip and then somehow limiting but not in a way that creates a hard line, on the clear coat.

 

[niget2002]

Personally, I'd limit primer and paint, but I'd just reclear the whole hood.

 

[skeer]

Personally, I'd limit primer and paint, but I'd just reclear the whole hood.

This is the new plan, but how exactly? How to limit primer and paint without having it in your face?

 

[jsigrist]

First, I am not a paint and body man. I have painted six or eight cars after repairing the rust and dents. Most came out good. I have limited work with BC/CC but did just have a similar experience with a Buick rendezvous hood. For your info GM was using aluminum on hoods at least back to 2004. I had to spray the entire hood because the bubbling was in too many areas.

The idea of clear coating the entire hood will probably be successful. If it was mine and I knew the rest of the hood was good I would not go past the lip. When you tape it off to prevent overspray understand that it will go every where so cover the entire hood and surrounding areas with paper and then anything out of range of being disturbed by your paint spray cover with a clean drop cloth.

As for taping the lip I would back tape it. Put your tape on the paper edge and then facing the hood you lay the tape on top with the paper facing the front of the car. the fold the paper back over the top of the hood. This will provide a softer edge which should not leave a noticeable line. I have done this several times with single stage paints and see no reason it won't work with BC/CC. Just don't over sand the paint after spraying or you will likely make your line more visible.

If my explanation on back taping is unclear, as I am sure it is I can go and mock something up and attach a picture.

Also for the prep stage, I would normally wet sand with 320 before primer and then 400 after the primer if it was a sandable primer.

Again, I am not a paint and body man.
Jeff

 

[skeer]

Too bad I can only like this once.

I think I got you on the edge.. essentially the sticky side is up yeah? That might not be a good description but I’m pretty certain I understand.

I am planning on removing the hood entirely from the vehicle but yeah I’ve learned the hard way about overspray on a few occasions lol.
So I removed all the first layer paint and most of the primer.. the couple bubble spots are clean to metal. I acetoned then cleaned all of that will rubbing alcohol. Now it’s got two coats of the self etching primer across the lip.
I’m assuming to lightly sand the primer with a wet 400. Then try your upside down taping with a light color coat or two and let those dry and reevaluate.

 

[jsigrist]

Here are a couple of pics showing roughly how I would back tape. Be sure the tape is well sealed to the paint. I would use regular 3M masking tape instead of painters tape as shown.

 

[jsigrist]

Here are a couple of pics showing roughly how I would back tape. Be sure the tape is well sealed to the paint. I would use regular 3M masking tape instead of painters tape as shown.

Well the pics did not show. Trying again this how I would tape to paint this fender and avoiding the top surface.

 

[jsigrist]

Too bad I can only like this once.

I think I got you on the edge.. essentially the sticky side is up yeah? That might not be a good description but I’m pretty certain I understand.

I am planning on removing the hood entirely from the vehicle but yeah I’ve learned the hard way about overspray on a few occasions lol.
So I removed all the first layer paint and most of the primer.. the couple bubble spots are clean to metal. I acetoned then cleaned all of that will rubbing alcohol. Now it’s got two coats of the self etching primer across the lip.
I’m assuming to lightly sand the primer with a wet 400. Then try your upside down taping with a light color coat or two and let those dry and reevaluate.

That is what I would do. Don't make your color coats too light, at least after the first one. You want the paint to be able to flow. Do the color and then decide on the clear. I suspect you can get away with just clearing the lip, which is what I would strive for. There is less chance of the factory clear peeling than your touch up. Also since you are taking the hood off, you might be able to position it so the lip is horizontal, if you think this might limit runs.

Jeff

 

[alwaysFlOoReD]

I've seen a trick where using 2" masking tape, put half the tape over the edge you want to stop the paint at, then fold the tape up and back. Masking paper is on the half that gets folded back. It is NOT a tight fold, but a "relaxed" fold back. This creates a dead air space where the paint naturally spreads leaving no, or very little line, as opposed to the normal way of masking.
Edit; just as jsigrist in post 13 shows...

 

[jhelrey]

1000 grit is way too fine for primer to adhere to.

 

[skeer]

Very nice, thanks for all of this! And yeah I had plans on repositioning the hood so that the spray angle was as good as I can get it for the lip and then again for the rest when I reclear it all.
I thought the primer would be fine because I removed it all from the bare metal spots and replaced with self-etching.

 

[skeer]

I've seen a trick where using 2" masking tape, put half the tape over the edge you want to stop the paint at, then fold the tape up and back. Masking paper is on the half that gets folded back. It is NOT a tight fold, but a "relaxed" fold back. This creates a dead air space where the paint naturally spreads leaving no, or very little line, as opposed to the normal way of masking.
Edit; just as jsigrist in post 13 shows...

When taping off in this way.. what sort of spray angle do you shoot for?

 

[alwaysFlOoReD]

I didn't do the spray, but iirc he just sprayed normally. Not trying to get under the tape at all. Just let the overspray get under the tape.

 

[skeer]

So did the tape back thing, adhered to just the lip with a smidge under the fold.. above the lip. (wow that sounds dirty outta context)
A day later pulled it all off and I've got the line again, albeit a fuzzy one. It's been pretty damn humid the past two days so Ima let it cure for another day at least. Last friggin thing I want is to lightly sand and rub some paint right off.

 

[kabinenroller]

Well no sh1t.. damn I never thought GM would have used aluminum in 2018.

My 1977 Lincoln had an aluminum hood. My 2004 Lincoln Aviator I owned had composite hood and front fenders and the 2017 Lincoln Navigator I now have has a composite hood.

 

[skeer]

My 1977 Lincoln had an aluminum hood. My 2004 Lincoln Aviator I owned had composite hood and front fenders and the 2017 Lincoln Navigator I now have has a composite hood.

Dare I say, a Lincoln anything != a Chevy Equinox.

Sorry I really didn't mean to come off sounding like a jerk. But that is super neat that even in the mid-70s they thought about weight on the MarkIV's and V's. But I don't think you can equally compare a cheaply priced and cheaply built Chevy compact-SUV against really anything under the Lincoln brand.

 

[skeer]

That is what I would do. Don't make your color coats too light, at least after the first one. You want the paint to be able to flow. Do the color and then decide on the clear. I suspect you can get away with just clearing the lip, which is what I would strive for. There is less chance of the factory clear peeling than your touch up. Also since you are taking the hood off, you might be able to position it so the lip is horizontal, if you think this might limit runs.

Jeff

Humidity is down, temp in the mid/upper 80's today. It's been two days since I re-colored the lip so I guess today is the day for clear. Plan is to spray at least 3 coats alternating directing between each one and giving them ~10 minutes between coats. I'm expecting to end up with orange peel which is wet sanded with 200, 2500, then buffing compound followed by polishing compound.

Was hoping to ask; Does alternating the spray direction/pattern matter? And does it matter for longivities sake, allowing 8-10 minutes between versus a day to cure?

 

[Drkuhar]

Are you grey scotch briting out where your blending your clear. The clear edge can roll back from not biting into the paint underneath during wet sanding or buffing . We used to grey scotch bright way out from blend spots. But we were using blender over the clear edge

 

[skeer]

Are you grey scotch briting out where your blending your clear. The clear edge can roll back from not biting into the paint underneath during wet sanding or buffing . We used to grey scotch bright way out from blend spots. But we were using blender over the clear edge

Nope, I haven't come across using scotchbrite for that. I did see people talking about using a blender.. I thought with that you wouldn't need to ruff it up.
IDK that I've ever seen a grey scotchbrite, lol.

 

[pancholasvegas]

Humidity is down, temp in the mid/upper 80's today. It's been two days since I re-colored the lip so I guess today is the day for clear. Plan is to spray at least 3 coats alternating directing between each one and giving them ~10 minutes between coats. I'm expecting to end up with orange peel which is wet sanded with 200, 2500, then buffing compound followed by polishing compound.

Was hoping to ask; Does alternating the spray direction/pattern matter? And does it matter for longivities sake, allowing 8-10 minutes between versus a day to cure?

Why are you alternating direction when spraying the clear? Coats gone on the same orientation for each-coat. I've only ever alternated directions with specialty coatings like wrinkle paint.

I would follow the flash times as listed on the data-sheet for the paint, that is the most ideal information to follow.
You shouldn't "Expect" Orange Peel - You should have yourself dialed in to minimize that as much as possible before you start spraying.

Of course, this assumes you're using AutoPaint & a spray gun. If these are rattle cans, that changes things.

 

[Metal-Marc]

sand the entire sprayed area with 400, then 1000, then 1500, then 2000.

sanded with 200, 2500

You're sanding wrong. Here's what's available: 200, 320, 400, 600, 800, 1000, 1200, 1500, 2000, 2500, 3000.

You only use 1000 and above to cut clear coat for orange peel. Use 600 max before paint.

Anyway, have fun learning on a different hood. That's experience. Try painting stripes and/or flames fun more fun.

 

[Metal-Marc]

As some mentioned above, I'd paint the whole hood. In fact, I did just that a few years ago. Previous owner tried unsuccessfully to fix a rust spot on the hood lip. Rust came back, and 1/3 of the hood was rattled canned.

I had to sand down all the **** rattle can primer and paint that was added back to the original paint by the previous owner. Then I media blasted the rust out. Phosphoric acid on the bare metal where the rust spot was. Two parts epoxy primer on the bare metal. 2k primer on the whole hood. Block sand the whole hood. Base coat and clear coat the whole hood. I used Nason Dupont and a proper paint gun.

Rust to bare metal.







Two parts epoxy primer, 2k primer.



Base coat.


Clear coat.

 

[Drkuhar]

Nope, I haven't come across using scotchbrite for that. I did see people talking about using a blender.. I thought with that you wouldn't need to ruff it up.
IDK that I've ever seen a grey scotchbrite, lol.

I worked in a warranty shop for international semi and dump trucks. We would spot repair chips or scratches as small as possible. Use 3m red scotchbrite out a couple of inches from the repair. Then grey scotchbrite out quite a ways. Grey scotch Brite is fine scratches that buff out with hand rubbing but allow the clear and blender to bite in and not roll back. We would do a lot of back taping to prevent hard lines anywhere. Imagine a with the repair is the center. Paint goes solid over the repair out to the next area and dust it out. That helps any color difference not stand out. Then clear over the whole panel or clear solid over the repair and dusted area and then dust the clear out from there. If you had blender then you would go over the dusted area to melt in and then buff or hand rub the panel when dry.

Spray can procedure is the same on the color but you would be better off clearing the whole panel but it needs some fine scratches to bite into. You could wet sand the whole hood before clearing. That will stop the rolling back issue you are having.

 

[gahrajmahal]

Dare I recommend a you tube channel covering most of this? I like https://www.youtube.com/@PaintSociety

 

[skeer]

You're sanding wrong. Here's what's available: 200, 320, 400, 600, 800, 1000, 1200, 1500, 2000, 2500, 3000.

You only use 1000 and above to cut clear coat for orange peel. Use 600 max before paint.

Anyway, have fun learning on a different hood. That's experience. Try painting stripes and/or flames fun more fun.

Yeah sorry that was a typo. I'd hope anyone would know better than to try using 200 then immediately 2500. And my jump from 400 to 1000 is only because that's all I had on-hand. the nearest parts store is half an hour, nearest hardware store 15 minutes and the hardware store didn't have what I needed.

 

[Metal-Marc]

And my jump from 400 to 1000 is only because that's all I had on-hand. the nearest parts store is half an hour, nearest hardware store 15 minutes and the hardware store didn't have what I needed.

I'm out in the sticks too. Amazon is your friend.

https://www.amazon.com/s?k=sandpaper+kit&tag=atomicindus08-20

 

[Hank11]

Your mystery line may be because you are putting new primer and new paint over old clear coat. Remove the clear further out from the repair so the new paint is going over old paint and not old clear.

 

[skeer]

This weekend I moved to the actual hood. I did end up roughing up the entire surface in order to re-clear.. I'm pretty sure that I did not wet sand enough for the orange peel, I was super afraid of going through the clear coat. So I spent all yesterday biffing and polishing. I don't own a 'real' buffer so I use a rubber/velcro head on a corded drill. Started with some heavy duty Turtle buffing compound, then a Meguiars Stage 1, followed by Meguiars Polish. It started getting later yesterday so I threw a coat of Turtle Wax on and took it to the car wash for a bath. The pictures below show what I'm pretty sure are indicators of more buffing that is needed.
Second and third pics are showing the paint line, and in the last one if you can see it.. white-ish kinda fuzzy-iness that popped out. You can see some in the first pic too.

 

[Hank11]

There is a prep problem to begin with. You need multiple grits of paper and some rubber or cork sanding blocks. You don’t need a buffer. Go over all the buggered areas and make them smooth and flat. Smooth around all the corners and contours.

Make it look perfect as if it was painted at the factory, but it will be dull. 600 grit is plenty. Then you are ready to paint. Put down a mist coat, let it cook for just a bit then lay down a coat, wait a while, spray next coat. The paint instructions will give guidance on timing of coats.

 

[skeer]

There is a prep problem to begin with. You need multiple grits of paper and some rubber or cork sanding blocks. You don’t need a buffer. Go over all the buggered areas and make them smooth and flat. Smooth around all the corners and contours.

Make it look perfect as if it was painted at the factory, but it will be dull. 600 grit is plenty. Then you are ready to paint. Put down a mist coat, let it cook for just a bit then lay down a coat, wait a while, spray next coat. The paint instructions will give guidance on timing of coats.

I'm not doubting that the prep phase could have been much better.. but I'm confused because the artifacts Im seeing.. those kinda of fuzzy lighter colored areas are not what was painted. There isn't an issue with smoothness.. Im quite shocked at how smooth it actually is.

 

[jhelrey]

I am NOT a pro... but it looks like your base coat didn't fully flash off when you cleared or you had high humidity. You can see ghosting in the clear coat.

 

[K13]

It this a metallic paint? Looks like you have sanded through the clear into the base coat which is a no no with metallic paint because it cuts the metallic and gives you shiny bits "white fuzz".

 

[NFT5]

Agree. Buffed too much and thinned the clear to the point where the base now looks different.

Nothing to do but sand the whole thing smooth to take out all that peel and then respray base and clear. If you're careful and don't go through the clear then you can use that as a sealing layer and not need to use any primer.

I'd suggest a bit of practice first to improve your technique a bit. Start by upping the pressure and holding the gun a little closer. I try to get a finish that is good enough to go out the door, off the gun. You probably don't have the experience to do that, but reducing the amount of rectification work is always a good thing.

 

[skeer]

SOB this is annoying. What ***** is that I did not paint the areas with the fuzz showing through. I sanded to metal the lip and just about an inch higher right on the nose.

When I re-cleared the entire hood, then sanded with 2000 then 2500 before any buffing.. the fuzz wasn't there. If I had somehow sanded through the clear on those areas then I should have seen the line right? Between clear and not clear, yeah?