Yet another primer question?

[DamonOverboe]

Hi all, from reading the forums, I've settled on I'm going to use Sherwin Williams P60G2 for anti-corrosion on the interior. (I have seen some of the debates about not applying anti-corrosion, but I'm going for it). And fortunately the local commercial SW store keeps this in stock. It was $180 my price with tax for a gallon of the wash and a gallon of the primer.

I don't think this has been asked; but if it has, I couldn't find it. So feel free to point me to the right link if you happen to know. Otherwise, here we go. My main question is, I've seen people recommend:

1. Deburr
2. Prep (Bon Ami + Gray Scotchbrite; then water flush, then dry with air hose)
3. Prime
4. Dimple

And it seems the main reason is the dimples shred the scotchbrite pads if you prep after dimpling.

I'm considering going with this approach instead:

1. Deburr
2. Prep
3. Dimple
4. Re-prep with acetone or lacquer thinner (to remove my greasy paw prints)
5. Prime

Would that end terribly bad? If not, then a follow-up question. The Prep with Bon Ami & Gray Scotchbright just removes oils and scuffs the surface, but doesn't remove the alclad protection. So, could I do steps 1-3, then set the thing aside until I have a batch of them, and do 4&5 say a week or a month later?

 

[Mel]

Hi all, from reading the forums, I've settled on I'm going to use Sherwin Williams P60G2 for anti-corrosion on the interior. (I have seen some of the debates about not applying anti-corrosion, but I'm going for it). And fortunately the local commercial SW store keeps this in stock. It was $180 my price with tax for a gallon of the wash and a gallon of the primer.

I don't think this has been asked; but if it has, I couldn't find it. So feel free to point me to the right link if you happen to know. Otherwise, here we go. My main question is, I've seen people recommend:

1. Deburr
2. Prep (Bon Ami + Gray Scotchbrite; then water flush, then dry with air hose)
3. Prime
4. Dimple

And it seems the main reason is the dimples shred the scotchbrite pads if you prep after dimpling.

I'm considering going with this approach instead:

1. Deburr
2. Prep
3. Dimple
4. Re-prep with acetone or lacquer thinner (to remove my greasy paw prints)
5. Prime

Would that end terribly bad? If not, then a follow-up question. The Prep with Bon Ami & Gray Scotchbright just removes oils and scuffs the surface, but doesn't remove the alclad protection. So, could I do steps 1-3, then set the thing aside until I have a batch of them, and do 4&5 say a week or a month later?

That'll work just fine!

 

[DamonOverboe]

That'll work just fine!

Thank you Mel!

 

[inktomi]

One thing, just consider that you can't use sharpie or isopropyl alcohol on things primed with the P60G2 primer. It takes it right off.

The shop that I started my build at used it, and all they did was clean with acetone and spray - no scuffing. Maybe that's one reason it comes off so easily for me.. but thought I'd mention it. I switched to Akzo epoxy and have been super happy with it.

 

[wirejock]

Consider it this way.
1. Debur
2. Scuff
3. Dimple
4. Prep
5. Prime

Reason is alumimum oxide forms quickly. Ideally you want primer applied as soon as possible after prep.
However, as Mel mentioned your method will work just fine.

 

[Cessnadog]

Ok, Open an account with Sherwin Williams, It saves me a bunch of money vs the walk in price.

My process, stolen from someone:
1) scuff with a maroon scotch brite pad and a spray bottle of water with some dawn dish soap in it.
2) rinse with clean water/Wipe with wet paper towel
3) air dry
4) wipe with lint free cloth and naptha (Coleman fuel)
5) spray p60G2
6) dimple

I figure this gets me two shots are getting the oil off the parts.

 

[lr172]

Ok, Open an account with Sherwin Williams, It saves me a bunch of money vs the walk in price.

My process, stolen from someone:
1) scuff with a maroon scotch brite pad and a spray bottle of water with some dawn dish soap in it.
2) rinse with clean water/Wipe with wet paper towel
3) air dry
4) wipe with lint free cloth and naptha (Coleman fuel)
5) spray p60G2
6) dimple

I figure this gets me two shots are getting the oil off the parts.

Steal more wisely. Never use naptha before paint. It leaves a residue and will create adhesion issues. Use a wax and grease remover.

 

[bertschb]

When I have enough parts prepped for assembly (including dimpling), I just very lightly scrub them with PreKote and a Scotchbrite pad then rinse with water. Dry with a towel, hang 'em up and spray 'em. The primer is VERY difficult to remove once dry. But, I'm using Akzo, not P60G2. I have no idea if this technique would work with P60G2.

 

[RayJay]

I can't say anything about the SW primer, but I've been using a direct to metal primer from my local auto paint supply with a very similar process, except I don't use any aluminum prep. My process is:

Red scotchbrite pad
Wax and degreaser wipe
Dimple
Final acetone or degreaser wipe
Prime

The DTM primer sticks really well doing it like this. Very scratch resistant. Rattle can primers do less well. They scratch and chip pretty easily.
I use a fuji hvlp gun and a homemade 6-stage turbine sprayer that I spent about $500 making.

 

[Mel]

I can't say anything about the SW primer, but I've been using a direct to metal primer from my local auto paint supply with a very similar process, except I don't use any aluminum prep. My process is:

Red scotchbrite pad
Wax and degreaser wipe
Dimple
Final acetone or degreaser wipe
Prime

The DTM primer sticks really well doing it like this. Very scratch resistant. Rattle can primers do less well. They scratch and chip pretty easily.
I use a fuji hvlp gun and a homemade 6-stage turbine sprayer that I spent about $500 making.

I would suggest that you "degrease" before using the scotchbrite. Often the scotchbrite will grind the grease into the aluminum.

 

[Cessnadog]

Steal more wisely. Never use naptha before paint. It leaves a residue and will create adhesion issues. Use a wax and grease remover.

If you look at the MSDS for many (most?) of the wax and grease removers made for painting, they are mostly naphtha…

 

[lr172]

If you look at the MSDS for many (most?) of the wax and grease removers made for painting, they are mostly naphtha…

That may be true, but not sure you are getting pure naptha at the hardware store. Only thing I have found is VM&P naptha (I like it over mineral spirits for cleaning) and don't believe it is pure naptha, as its evaporation rate is much slower than the W&G removers I have used (i.e. less aromatic).

 

[DamonOverboe]

Consider it this way.
1. Debur
2. Scuff
3. Dimple
4. Prep
5. Prime

Reason is alumimum oxide forms quickly. Ideally you want primer applied as soon as possible after prep.
However, as Mel mentioned your method will work just fine.

Thanks for the clarification. When I said prep, I was thinking scuff, your step two (but was planning to use Bon Ami with the scotchbrite when I do that)
Then, your step 4 prep would be where I would do the acetone wash.

I saw a post pop up and then maybe edited saying not to wait too long after prep before priming, and you mention the oxidization. I think that is more in response to step #4, not #2?

When I have enough parts prepped for assembly (including dimpling), I just very lightly scrub them with PreKote and a Scotchbrite pad then rinse with water. Dry with a towel, hang 'em up and spray 'em. The primer is VERY difficult to remove once dry. But, I'm using Akzo, not P60G2. I have no idea if this technique would work with P60G2.

You dimple before scuffing... I guess the very lightly scrubbing them doesn't shred your scotchbrites as bad and/or you don't care, better to leave the protectant on the aluminum until the last minute? I like this approach because I think this will let me batch up a lot of parts to do at once. The air cartridges on the mask say they're only good for 30 days or 40 hours, whichever comes first, so I'd like to be able to do a lot at once. I know I'm optimizing around a $25 consumable, but that's me :-D


I'm very new to this. I do have some Akzo but the P60G2 sounded to be more promising. I hadn't seen the note that sharpie will lift it though.
I do have an account with SW, but it's tied to property management. I may need to ask them about a different account if that price seems high I guess.


Also several of you mention red scotch brite. I saw recommendations somewhere to go with the gray scotchbrite instead; gray ~ 800 grit, red ~ 600 grit. What has been everyone's experience with that?

 

[skelrad]

At the beginning of my build, I tested just about every priming process there is because I was afraid of not doing it "correctly." It's hard not to fret over what to do when it's all new to you! In the end, my testing left me with this: For priming of interior surfaces that will see some wear, the best adhesion was to follow the general approaches above - wipe down (I use acetone), scuff (red scotchbrite), clean off again until the rag comes up clean, then shoot primer. In nearly all cases, I dimpled AFTER priming. I found that most of the quality primers stand up just fine to dimpling as long as they've had time to cure. One thing that I could never truly quantify in my testing was any practical difference between priming immediately and priming after a scuffed surface had sat around for a few days. Maybe there's a difference because of amount of oxidation, but my unscientific scratch tests couldn't detect any. For when it really matters, I'd still shoot primer as soon as possible though.

In terms of interior surfaces that will never see the light of day again, my conclusion was that a quality primer would stick just fine on a clean surface, even if it wasn't scuffed. Yes, it was easier to scratch primer off of a non-scuffed surface, and it tended to flake off a little more than just scratch off like on a scuffed surface. That being said, at least with the primers I tested, it still took physical scratching or chipping to get the primer to come loose. For an area that will never be touched after the build goes together, I doubt you'd see any damage to primer just sprayed on a clean surface. After that realization, while I still tended to quickly scuff everything (scotchbrite pad on hand sander works wonders), I became much less worried about it all.

I do use rattle can primer for hitting small parts that won't see physical abuse, just because it's easier than getting my spray equipment set up. For those, I always clean, scuff, clean. The rattle can primers I've tried definitely don't hold up as well as the other primers when the surface isn't scuffed.

For what it's worth, I ended up using Stewart EkoPrime for the vast majority of my build. It's not as tough as the 2 part epoxy primers, but I love the stuff, and it's plenty tough for anything in the interior. It's super easy to shoot and there's no waste since what you don't use in a session can just be saved for later. I would not use it as part of exterior painting though.

All of this is for interior priming. In other words, don't lose too much sleep over it all! When it comes to painting the exterior, then I'd get pickier about process (I'm about a year away from painting, so no help there yet!).

If you're really uncertain about it all, I'd recommend just taking an afternoon and doing your own tests to prove to yourself what does and doesn't work to your standard (make sure you let the primers cure before you do any adhesion tests though). Then you don't have to wring your hands over doing it "correctly" because you'll know where the line is. I bet you find that you have a lot more leeway than you might think.

 

[DamonOverboe]

At the beginning of my build, I tested just about every priming process there is because I was afraid of not doing it "correctly." It's hard not to fret over what to do when it's all new to you! In the end, my testing left me with this: For priming of interior surfaces that will see some wear, the best adhesion was to follow the general approaches above - wipe down (I use acetone), scuff (red scotchbrite), clean off again until the rag comes up clean, then shoot primer. In nearly all cases, I dimpled AFTER priming. I found that most of the quality primers stand up just fine to dimpling as long as they've had time to cure. One thing that I could never truly quantify ...

Great, thank you for the explanation and experience share, I will definitely test each approach out.

I feel like I have some good momentum going, so I was hoping to keep it going without getting sidetracked too much here. I wanted to do the steps I should now but put the painting off a little bit. But from your explanation, plus others mentioning they scuff before or after deburring, and I've seen several mention the prime then dimple, I figured I had some flexibility but just wasn't sure.

I'm hoping to dimple and then prime, not for fear of the primer coming off because I see a lot of people do that. But, because I'm wanting to keep going with the skeleton and then get several things together to prime at once. I'm rethinking that though just because of the oxidization, I know I've made small scratches here and there so probably better to go get this all done.

And yes, this is all just interior. At the moment I'm leaning towards I'll have a shop do the final painting, but, if I have fun with this and it goes well, who knows, I may talk myself out of that.

 

[wirejock]

It's easy to get stuck in a analysis paralysis. There are as many opinions as there are members of VAF and we all will argue the merits of our method.
Bottom line is the airplane will survive a very long time bare so almost anything and any process is going to help keep corrosion away.
If you really want to test, make some sample coupons and try various methods and products. When fully cured, apply a section of Gorilla tape to each. Leave them in the same environment as your airplane for a week or so. Rip the tape off. You will see first hand what works for you.
Bottom line, paint is weight. Whatever you choose, keep it as thin as possible.
P60G2 weighs almost nothing. Typically it's sprayed two passes 90 degrees from each other till just a hint of color is visible. It gets darker when it cures but stays translucent. Personally, I think the color is beautiful. However, it does come off with alcohol or solvents. Alumiprep strips it like paint remover. Best of luck.

 

[DamonOverboe]

It's easy to get stuck in a analysis paralysis. There are as many opinions as there are members of VAF and we all will argue the merits of our method.
Bottom line is the airplane will survive a very long time bare so almost anything and any process is going to help keep corrosion away.
If you really want to test, make some sample coupons and try various methods and products. When fully cured, apply a section of Gorilla tape to each. Leave them in the same environment as your airplane for a week or so. Rip the tape off. You will see first hand what works for you.
Bottom line, paint is weight. Whatever you choose, keep it as thin as possible.
P60G2 weighs almost nothing. Typically it's sprayed two passes 90 degrees from each other till just a hint of color is visible. It gets darker when it cures but stays translucent. Personally, I think the color is beautiful. However, it does come off with alcohol or solvents. Alumiprep strips it like paint remover. Best of luck.

Yeah I saw a lot of positives about P60G2, saying it's lighter weight and easier to deal with compared to the Akro, so I figured I'd try it out. I do have some Akro too, so I'll test out both and will try a couple different preps on each card as well.

And I totally agree on the analysis paralysis. I didn't suffer from that in the beginning, I knew I had a ton to learn and a lot of skills to develop, but I had no issue saying I'm going to do this. But then TBH I was a little overwhelmed when I saw everything on hand. I started having all the doubts run through my mind, I'm not up to speed on my skills yet, I don't know what I'm going to do with X Y or Z. I probably delayed a little longer than I needed to, getting my shop set up (new home and new to me tools), getting the parts organized. But once I started, it flowed pretty quickly. I read a quote years ago that went something like "it is not necessary to have all of the ingredients on hand before you begin." That's not natural to me but I remind myself of it often. And I justified obsessing over the garage by saying to myself "yeah, but a kitchen sure does help!"