"notsomethingstructural" (notsomethingstructural)
07/12/2017 at 00:14 • Filed to: None
0
27|
"notsomethingstructural" (notsomethingstructural)
07/12/2017 at 00:14 • Filed to: None | 0
| 27 |
As is my most terrible habit, I’ve done endless reading on this and am no closer to a solution (no matter how well informed I am - for better or worse). Can anyone suggest a solution for my particular application here?
I’m working on taking care of some rust that’s formed under the mounting points for my spoiler. The preference is to confine all of the touch-up to under the spoiler since the car is getting a respray in a year or so. It doesn’t have to be perfect. Sanding it all off down to bare metal was easy enough. There is some light pitting, and possibly some tightly adhered rust scale embedded in the pitting (not visible to the naked eye - the discoloration in the photo is residue from an iron digester I had laying around). So this is a direct-to-metal application with little rust, and I would strongly prefer to brush it on instead of spray. I do not want to use 2K products since it’s touch-up.
I had previously purchased some high-solids rust inhibitor (rust bullet automotive) but they recommend a minimum of a 6 mil build and I know from experience sanding this shit is fucking impossible. I put a light-to-moderate coat on but it was flashing rust underneath within 2 days. So that’s gotta get sanded again.
I don’t want to do this three times, so what’s the best way to do it? I would think it’s etch/prime, fill/prime, seal(?), topcoat. Here’s what I’m looking at and considering.
Eastwood !!!error: Indecipherable SUB-paragraph formatting!!! - is this a good first step? Does the surface be treated with something to eliminate residual scale beforehand or will the etch take care of it? If so - rust converter? !!!error: Indecipherable SUB-paragraph formatting!!! ?
Step 2 - Rustoleum !!!error: Indecipherable SUB-paragraph formatting!!! primer, or !!!error: Indecipherable SUB-paragraph formatting!!! primer, or primer !!!error: Indecipherable SUB-paragraph formatting!!! ? What’s the difference between these? I believe the filler/sandable are lacquer base and the surfacer is acrylic, and the filler is hi-build and the sandable is multicoat? I’m iffy about Rustoleum since their guidance is spotty- is there a better filler/sandable one-component out there?
Assuming I went with the Rustoleum sandable primer - does it need to be sealed if it is to be exposed to weather? And I assume primer/sealers are non-sanded sprays only?
Alternately - what have you used in touch-up, direct-to-metal work?
Frank Grimes
> notsomethingstructural
07/12/2017 at 01:46 |
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I do not want to use 2K products since it’s touch-up.
huh?
Birddog
> notsomethingstructural
07/12/2017 at 02:14 |
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The Eastwood self etching primer is ok stuff. I avoid Rustoleum products. Just a personal preference. The finish is going to depend a lot on prep and quality product.
SEM makes a good hi build primer and the PPG Omni line is pretty decent and affordable as well.
I’m a little curious on the 2K thing too.
Do you have a local paint shop? Are you doing this all with rattle cans?
Rustholes-Are-Weight-Reduction
> notsomethingstructural
07/12/2017 at 03:24 |
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Not a fan of wings on an RX-8 anyway.
as for the touch up, I would go either with rust converter then conventional primer, or use rust protection primer. If you’re going to respray it eventually anyway, I wouldn’t bother too much, just mask it off, get a color matched spray can, and spray over it
BiTurbo228 - Dr Frankenstein of Spitfires
> notsomethingstructural
07/12/2017 at 04:49 |
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Yeah if it’s going to get sprayed soon I wouldn’t worry overly. You’ve already done a decent job of de-rusting, so pick up some zinc primer, a halfway decent colour-matched paint can, and a lacquer coat and get some paint on it.
So long as it doesn’t rust (which it shouldn’t, provided you get paint on all the bare metal areas), all it has to do is protect it until you get the proper job done. Anything more is wasted effort, although you could view it as a learning experience in case you need to do it again.
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BiTurbo228 - Dr Frankenstein of Spitfires
> notsomethingstructural
07/12/2017 at 04:49 |
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Yeah if it’s going to get sprayed soon I wouldn’t worry overly. You’ve already done a decent job of de-rusting, so pick up some zinc primer, a halfway decent colour-matched paint can, and a lacquer coat and get some paint on it.
So long as it doesn’t rust (which it shouldn’t, provided you get paint on all the bare metal areas), all it has to do is protect it until you get the proper job done. Anything more is wasted effort, although you could view it as a learning experience in case you need to do it again.
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notsomethingstructural
> Frank Grimes
07/12/2017 at 07:52 |
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no two component / catalyzed paints
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notsomethingstructural
> Birddog
07/12/2017 at 08:24 |
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I don’t want to use a 2-component because I’ll never batch it right and it’s a huge pain in the ass for this super limited application that no one will see. It’s also more expense.
The PPG looks like it would fit the bill pretty well actually, aside from the headache of having to get to the supplier. I’m going to look into this more.
(Edit: ah, crap, the PPG etch primer is a 2-component - think it’s OK to use the Eastwood or SEM as a base?)
SEM has a self-etch so that’s good, but I’m not sure which of their various surfacing primers would be right. Where do you buy their stuff?
And I’m planning to brush it on lightly in coats... sand the primer coat and then use touch-up and sand that. Again, no one can see this. From what I’ve gathered, people say it’s fine, just be ready to sand more.
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notsomethingstructural
> BiTurbo228 - Dr Frankenstein of Spitfires
07/12/2017 at 08:28 |
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I’m trying to do the learning thing, the finish won’t be perfect and ideally I wouldn’t brush-apply anything that isn’t concealed, but that said I’ve definitely had a couple shitty cars where I wouldn’t want to strip grind prime and shoot the whole panel especially since I have nowhere to do it. If this goes well, I have a Focus with some rust (damn rock chips) I’d think about doing the same thing with.
I know jack shit about autobody and my plan is try tiny projects where I can’t fuck up too bad and maybe I’ll do bigger ones. This is a good start.
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notsomethingstructural
> Rustholes-Are-Weight-Reduction
07/12/2017 at 08:30 |
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Well, the converter won’t react since I stripped all the rust off, and the protecting primer I used is rusting underneath. Mind you, it’s a little on the thin side, but that said I don’t want to build it over flush with the neighboring paint either.
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BiTurbo228 - Dr Frankenstein of Spitfires
> notsomethingstructural
07/12/2017 at 08:40 |
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Yeah that’s a great thing to do :) we all start knowing jack shit about stuff, and only through experimentation (or, interestingly, more from copying other people*) do we learn how to do stuff. If that’s the case, I’d just get a rough background of what might work or not, pick something and see if it works. It’s all an experiment, so just pick something and try it :) it’s basically impossible to ruin it seeing as it’s getting resprayed shortly.
*Read an article in New Scientist a while ago about an experiment into problem-solving between humans and chimps. People expected the humans to exceed the chimps handily in problem solving, but if anything the chimps proved to be slightly better at it. However, when they showed an example of another chimp/human completing the problem, the human picked up how to do it about twice as fast as the chimp. We’re not brainier than chimps because we’re smarter, we’re brainier because we’re really damn good at copying what other people do, allowing us to skip vast swathes of the learning experience.
tl;dr watch some youtube videos ;)
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notsomethingstructural
> notsomethingstructural
07/12/2017 at 19:08 |
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Are there any evening oppos who could help me out with this paint/primer quandary?
benjrblant
> notsomethingstructural
07/12/2017 at 19:14 |
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I think you’ve read and posted more than my knowledge of automotive finishing. If it’s going under the spoiler plus the car is getting a re-spray in a year, do what you feel is best?
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notsomethingstructural
> benjrblant
07/12/2017 at 19:28 |
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¯\_()_/¯
Steve in Manhattan
> notsomethingstructural
07/12/2017 at 20:40 |
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Glad I read to the end - thought those were bullet holes, for a second.
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notsomethingstructural
> Steve in Manhattan
07/12/2017 at 20:44 |
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hey guys, does PPG have a wash for getting red organic-based stains out of corroded metal? asking for a friend
crowmolly
> notsomethingstructural
07/12/2017 at 21:08 |
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To be honest, you’re a bit all over the map.
But my $0.02:
Using a rust converter/acid (Phosphoric, Naval Jelly, Ospho, DX579, etc) will take care of the rust in the pits but you have to make sure you wash it off and follow the instructions to the letter . You may also get flash rusting so you have to prime fast. Otherwise you will have adhesion issues.
Then just hit it with whatever rustoleum primer you want and duplicolor over that since you are repainting.
If you want a more “formal” answer (keep in mind this is a rough script) :
Use real auto paint and follow what’s listed on the tech sheets
Wash area well
Strip to bare metal, leave the substrate in proper grit as per tech sheet (180, etc)
Wipe with wax and grease remover
Acid treat any remaining rust if necessary. FOLLOW INSTRUCTIONS TO THE LETTER for your paint system. If they say no acid (SPI for example) then don’t do it.
Wipe with wax and grease remover
Epoxy primer (etch has kind of fallen out of favor)
Body filler app/sand
Primer surfacer app/sand
Base, clear
Cut and buff
Rust and Dust and Frank Grimes will probably jump in too.
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crowmolly
> notsomethingstructural
07/12/2017 at 21:23 |
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I don’t want to use a 2-component because I’ll never batch it right and it’s a huge pain in the ass for this super limited application that no one will see.
It is a pain for something no one will see, but I’m positive you will mix it correctly. It’s tough to fuck that up if you know basic math and are careful. And you are asking questions- so I presume you are careful and have attention to detail.
If you can, stick with the same paint line on stuff as it’s known to work together. As an example, using PPG surface prep stuff (DX579/DX520) with an SPI epoxy may not work out as intended.
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Frank Grimes
> notsomethingstructural
07/12/2017 at 22:31 |
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why wouldnt you want to use those 2k products? lookup what paint you want to use and find the data sheet and it will tell you what products are acceptable to use. some of them allow you to prime small spots with aerosol primer I dont think you can paint with 2k paint over self etch.
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notsomethingstructural
> crowmolly
07/12/2017 at 23:41 |
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I’m completely all over the map. I have no idea what I’m doing! And in endeavoring in trying to do this “good-er” than the shitty job that’s already fucked up, I realize now I had no idea how absurdly complicated autobody is until you grasp the ropes. So it’s a learning experience, and at this point I’d rather learn the steps to do it right for when I eventually get a space where I can shoot things myself. To that end, I’m using the future respray more as a crutch if it goes south than an excuse not to learn. Anyways. I’ll try not to ask every question I can think of.
First one is do you have a suggestion for a good, readily accessible, affordable system? PPG Omni seems like it might fit the bill, though it’s a moderate headache for me to get to my supplier and I don’t have prices yet. Other high-quality brands that maybe ship through Summit or something? Quarts available? My preference is still 1K if it’s possible, and most DTM from PPG is 2K (more on that in your other question).
Some of the reason I’m reluctant to use epoxy primer is I don’t want the first coat to build too much - I want to build with the surfacer and do a final level out with the topcoat (which will still be brush-applied and sanded to the current level of the paint). Will the epoxy build too much, and if so, is it sandable?
Will epoxy primer flash rust underneath with, say, a week or two of exposure, or does it need to be sealed?
Let’s start with those. Any help you give me... thanks so much.
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notsomethingstructural
> crowmolly
07/12/2017 at 23:53 |
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The other reason I don’t really want 2K is I don’t REALLY want to buy a set of syringes to put the tiny bit I need in paper cups then throw them out. Just seems like a waste - if this goes well I would do other spots later on, or on other cars. That’s a lot of syringes and paper cups to get through a quart.
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notsomethingstructural
> Frank Grimes
07/12/2017 at 23:54 |
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I’m using Mazda touch-up paint because the match is damn near flawless and I don’t have the ability to shoot the whole trunk lid. So I’m really out on my own here.
Any suggestions for a product line to look into?
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Birddog
> notsomethingstructural
07/13/2017 at 03:17 |
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Ah! I didn’t realize you were brushing. The Eastwood or SEM should work fine. You want an etching primer for sure no matter what.
How do you plan to top coat? There has to be some blending before the spoiler goes back on. Or is the footprint of the spoiler larger than what’s in the pics?
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crowmolly
> notsomethingstructural
07/13/2017 at 13:21 |
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Anyways. I’ll try not to ask every question I can think of.
Ask away- sorry if I came off like a dick. And preface- my experience is with restoration work, not collision work. Collision shops do things a bit differently since time = money.
First one is do you have a suggestion for a good, readily accessible, affordable system? PPG Omni seems like it might fit the bill, though it’s a moderate headache for me to get to my supplier and I don’t have prices yet. Other high-quality brands that maybe ship through Summit or something? Quarts available? My preference is still 1K if it’s possible, and most DTM from PPG is 2K (more on that in your other question).
PPG Omni is good and is also *somewhat* affordable. PPG in general seems to be more expensive than others. It sucks that you have to get it from a specialty supplier. I’ve heard good things about Eastwood and Summit’s house brands if you need something a bit cheaper. I laid down some of Eastwood’s epoxy last year and it did well, even though DP40-90LF lays down easier. I mentioned SPI a few times, their stuff is good and can be ordered directly. They may not have the color(s) you want though.
Really anything *good* will be catalyzed. I know that’s not what you want but I can’t think of any auto paint that’s sold without a catalyst other than touch up paint.
Some of the reason I’m reluctant to use epoxy primer is I don’t want the first coat to build too much - I want to build with the surfacer and do a final level out with the topcoat (which will still be brush-applied and sanded to the current level of the paint). Will the epoxy build too much, and if so, is it sandable?
Will epoxy primer flash rust underneath with, say, a week or two of exposure, or does it need to be sealed?
Epoxy is meant to be sprayed direct to metal to form a solid bond for the next stage of primer- surfacer/filler. Resto and hobbyists use it because it’s good at creating a sealed coat above the metal. A good epoxy application can protect the surface for years with no other topcoat.
It doesn’t build up too much- that’s what the primer surfacer is for. And you don’t really sand it. You can, but it’s tough and sanding is kind of unnecessary.
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notsomethingstructural
> Birddog
07/13/2017 at 22:36 |
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I’m guessing the touch-up will stick out by 1/4" to 1/2" in the worst spots, or “you kind of have to look for it.” Closer to the cabin will possibly be visible but the rust was not too bad there. The back you’ll really have to know because it’ll be underneath. The flaking rust was only visible if you looked with eye level at the deck of the lid.
Is there a reason to go with etch over epoxy? Etch was my initial preference but I’m slowly being talked out of it. I figured with etch I could save a step and skip an acid or converter wash... BUT with the epoxy it sounds like I won’t have to topcoat right away (compared to an etch and sandable laquer or urethane primer). I like the flexibility of having time to topcoat, since I’m really confined to working weekends and I don’t have a garage. I don’t want flash rusting under the paint.
Basically the sanding is already feathered so I’m gonna lap the primer on to the feathered edge, sand it and expose slightly more of the old primer (on the edges, just like 2mm), then topcoat all of it with a touch-up pen (don’t judge me) and wet sand it flat. I’d think that’s fine.
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notsomethingstructural
> crowmolly
07/13/2017 at 23:41 |
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Oh I didn’t think you were a dick. No worries. I’m just clueless, and unfortunately verbose. I can get carried away.
Yeah, I know PPG isn’t cheap, but there’s a reason for that. I probably don’t need PPG on this but that said I wouldn’t mind a basic familiarity with their products. If I was to stay in any one family I don’t love that Eastwood and Summit is all 2K aside from the primer/etcher, which you’re discouraging me from. PPG does have at least has a 1K surfacer in the Omni line and I can’t imagine it’s junk. SPI only sells the surfacers in gallons so they’re right out. Any other suggestions?
Where I’m at - Eastwood has the 1K self-etch , and PPG (and Rustoleum, for that matter) have the 1K surfacers - BUT if that has to be sealed then going that route I would still need a 2K sealer. If I switch my preference to epoxy, I’ll skip the sealer but it’ll have the extra rust converting/cleaning steps and still need a surfacer. Right?
Some people have brought up the SEM line, and nosing around in that, it looks like they have a high-build DTM sandable epoxy primer I can get through Summit. Wonder if that would work. Summit also has the SEM 1K self-etch... and SEM does sell ready-to-go surfacers but for plastic only. Their stuff for metal needs a 1:1 reduction and of course Summit doesn’t sell it anyways. So close though.
At the end of the day low-build or somewhat sandable is a plus, since it’s being brushed and will certainly have a couple high spots before I get to the surfacer. I’m leaning toward the DTM sandable epoxy from SEM, since I’d be fine with doing a 2K system if it’s something I can put right down, sand it, and ignore it until I’m ready to topcoat.
Otherwise, it pains my wallet but PPG is probably the right fit. 2K epoxy then 1K surfacer beats Eastwood’s 2K + 2K. So the two follow-ups - do etch/surfacer layups need a sealer before getting wet? And any other thoughts / how’m I doing?
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crowmolly
> notsomethingstructural
07/14/2017 at 09:38 |
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I just saw the press release from Oct 2016- PPG SUA1045 is a new 20oz sprayable primer/surfacer:
This looks like good stuff to use.
I think you are correct in your assumption that using a 2k epoxy will kill the need for a sealer. You DON’T need to do metal prep/acid unless you have pitted metal that you can’t clean any further. Like I think I mentioned, a lot of shops don’t even touch acid most of the time.
Eastwood also has this:
http://www.eastwood.com/ew-2k-aerosol-epoxy-primer-gray-26898.html
So you might be able to:
Surface prep w/80, 180
W&G remover
Eastwood epoxy (and body filler if necessary)
PPG surfacer
Block sand, etc
Color
Clear
Also, have a look at this:
There’s a ton of good info in there and it details some of the processes.
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notsomethingstructural
> crowmolly
07/14/2017 at 12:14 |
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I’m an engineer by trade so wow that PPG guide - I think I just finished
They don’t even detail an etch primer build-up - very telling. I think that makes up my mind on the possibility of etch.
So - yes, wire wheel, 80, 180 grit. W&G wipe (SXA330 or Omni MX190). I will probably use a cleaner (SX579) or converter (I have some at home) but not both. W&G wipe.
At that point it would be a conventional 2K epoxy (DPLV or more likely Omni MP172) and surfacer (DPS305x or the 1K Omni MP281). Sand as/when needed.
ALTERNATELY it looks like PPG and SEM have high-build sandable epoxy. If that route is viable, I’d prefer to do that. Here’s the SEM . And the PPG . Any experience with either of those? I would probably reduce to more like a sealer so I could brush on more thin coats.
I think we’re almost done here haha. Thanks again for all the help. This has been an awesome thing to learn about.