So I picked up a wrecked 2013 Altima off a co-worker's daughter. I got it cheap enough for me to dump some money into it to flip at profit or even keep myself and use as a new daily driver which I'm leaning towards at this point.

Anyway, over the past week or two I have been sourcing cheap parts for it on Offer Up. I picked up a brand new still in box (aftermarket Taiwanese) hood for it which has the black "primer" coating on it. After doing some research it appears this is not a primer per se but rather more likely "e-coat".

I have bought OEM parts where necessary (inner frame rail structure replacement pieces) but for the most part this is a very budget rebuild hence the hood/fender/bumper on Offer Up. I have seen mention online about wiping a spot on the black coating with a lacquer thinner rag and seeing if the coating comes off, and if the coating doesn't come off you can paint right over it. Is this true?

1) If I can't or shouldn't paint right over the black coating, what does my plan of action need to be? Scuff it and prime it? If so, what type of primer or sealer exactly? I will be doing a base/clear job on it and the car is black Nissan KH3 paint code.

2) The fender and bumper cover are aftermarket panels that have previously been painted. The paint on the fender is fine but is scratched up and has a couple of dings I need to take care of maybe with a little filler, whereas the bumper has paint on it but I can tell they painted straight onto the black plastic and it's peeling.

Should my plan on the bumper cover to be largely to take it back to the black plastic as best as possible? If not, just sand off the peeling parts and then some sort of sealer over the whole thing before the base coat?

Again, this is a budget rebuild to keep my total cost as low as possible, and will be a backyard spray type of job, but I certainly don't want all this peeling off in a year or two.

Thanks in advance

In the back yard do you have something to paint inside of or are you just out in the open? on the bumper cover if it was painted improperly and peeling take a pressure washer to it and see if can peel it up.
Jay D.

No I don't have anything pre-existing to paint in but I can and likely will rig up a little booth with some plastic sheeting and wood.

james92se wrote:I have seen mention online about wiping a spot on the black coating with a lacquer thinner rag and seeing if the coating comes off, and if the coating doesn't come off you can paint right over it. Is this true?

This is 2019, not 1959 when parts were sprayed with oil to prevent in transit rust. These days even the smaller factories making parts have invested millions of dollars in coating facilities and they're hardly going to compromise that expenditure. Certainly on metal parts, just about all ex-factory coatings are applied using an electrostatic process, thus the terminology "e-coat". This gives the most uniform coating and ensures adhesion. Whether the coating can be removed with thinners or not is largely irrelevant - some parts now come with a water based primer and this can be removed with thinners too, despite being a modern, high technology and high performance product.

Best practice is to use a wet-on-wet sealer/primer/undercoat (the names are, to a large extent, interchangeable) over the factory coating. Some products require no preparation other than washing while for others a scuffing with Scotchbrite is necessary. I prefer to scuff all anyway - it's quick and easy and can only improve adhesion.

Using the right product over the factory coating is important. Epoxy, mixed as a sealer, is fine, or you can use one of the newer, high performance 2K undercoats. Some of these go on in a single coat, others recommend 1.5 coats, but they all give the best possible base for your top coats. Applied as directed they're super smooth and can be overcoated in 20-60 minutes with just air dry. No need for sanding, in fact, for the ones I use, it's recommended not to sand, with denib after base, if necessary.

See the video here.

I would use Cromax NS2607 which is a Value Shade 7 (very dark grey) primer/surfacer. Other paint companies have equivalents.

For your previously painted parts the same primer/surfacer can be used, after preparation and/or repair as necessary. Scuff or sand the guard and remove all flaking paint from that bumper.

Have a look around your local area to see if there are any paint shops who will rent out a booth on a short term basis. Many will, even if not advertised. This is a much better alternative and one which is probably no more expensive than the horribly unsafe use of a plastic sheet "booth" at home. Insufficient air flow, extreme risk of fire/explosion and poor results from inadequate design are just some of the reasons why you should not consider this, especially for a small, one-off project like yours.

I think I will scuff it first. You mention a Scotchbrite pad but I don't believe I have any. I DO have a huge array of painting materials I bought a couple of years back including a wide variety of sandpaper and haven't used much of and surely I could use some of that rather than buying a Scotchbrite, right? What would be an equivalent sandpaper grit to use to scuff the hood? 600? 1000?

Okay, so, if I'm understanding correctly I can use a nice 1:1 epoxy primer. Do I NEED to mix it as a sealer or is there any harm in just going full strength 1:1 on all three parts? I just want to have a totally simplified plan of action going into this even if it "wastes" a bit of extra material for the sake of simplicity.

I did not mean to imply I would rig up some sort of wannabe sealed enclosure. I meant more along the lines of a three sided "booth". I can't imagine this would be unsafe.

Thanks so much for your thorough input and advice.

You could use P600 but remember that sandpaper has a much higher propensity for wearing through, so, be careful.

If you mix the epoxy as a sealer then you do not need to sand it - just wait 20 minutes and go with your basecoat. Mixed "full strength" you will get more texture and are much more likely to need to sand this out. It does not need to be thick to work. Why make work for yourself when the non-sanding mix gives such good results and fits perfectly with your desire for simplicity in your plan?

One of the things that terrifies me when I see all those "Make your own paint booth in your garage for under $50" videos on Youtube is the risk of explosion and fire. Take a nice low humidity day and plastic sheeting will build up huge amounts of static. One spark with all that paint vapour floating around inside such a booth and "boom". Not nice. That's why professional paint booths are (and are required to be, by legislation) made of metal and/or non-combustible materials.

An open-face, or 3 sided painting enclosure may give you some protection from wind blown dust but, without filtering dust will get in the open side and without extraction overspray will build up inside. They're ok for prep work and priming but not for final coats, especially large surfaces like a bonnet.

excilent on the booth. that's the reason I ask where you were doing the painting. if your going to be outside some what covered or not you should be concerned about your coatings dry times and how many. you'll want to keep them as minimal as possible. 2 coats will not collect near as much dust and dirt as 4 coats and dry times will be faster with 2 coats rather than 4. there are all kinds of problems with painting outside or semi covered.
Jay D.

Ah okay well I guess I just better spend a few bucks on the Scotch pad. I'm guessing the grey (~600-800 grit) ones?

And sounds like I should just go ahead and mix it as a sealer. Does this just mean I add 25% reducer type of thing to it? Definitely sounds very appealing to not have to sand and just spray base half an hour later.

So, a slight change of plans here.

I'm now planning to paint on Christmas or Christmas Eve as it'll be in the high 60's here in Dallas. The used bumper that I purchased on Offer Up for this project revealed some slight puncture looking defects all across the front of the bumper and some other imperfections that I simply won't have time to mess with before needing to paint next week as I work 60+ hours a week.

Sooo, I went today on lunch and bought a new "raw" plastic bumper from Auto Fit. The bumper is 100% definitely raw plastic and does NOT have any sort of primer or anything on it.

Here's my plan on the bumper:

1) thoroughly wash bumper with hot water and dish soap using grey Scotch Brite pad
2) wipe it down with rubbing alcohol and paper while not letting the alcohol dry (one wet paper towel, one dry paper towel)
3) spray adhesion promoter - have Bulldog on the way
4) spray sealer (two part epoxy primer reduced 25%)
4) spray base
5) spray clear

Obviously on the painting follow proper flash times, etc. which I won't spell out here but is this plan copacetic?