Thread: Painting sequence???

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Alright I've been reading a lot from you guys and I think I have the sequence right but I'd like to make sure.

-Strip old paint
-clean with wax and grease remover
-DPLF epoxy primer
-Scuff sand primer
-Skim with bondo
-flatten bondo using guide coat
-more epoxy primer once flat
-another guide coat sanding
-color coat
-clear coat

Also I will be doing the painting in a homeade paint booth in the back of the factory I work in. I'm thinking of bulding it out of 2x4's and heavy plastic. Then duct tape the seams of the plastic and install an exaust fan in one end and furnace filters in the other end. the room can then be positioned so the exaust fan is pointed out the door. Will this work? Is there a better filter that will filter finer dust than a furnace filter?

The sequence will depend on who you ask. On this list you will get a wide range of methods, so I guess I would tell you to pick one source for your info. That way you won't be trying to combine steps or materials that don't work together.

Two things scare me on your list:

Before I prime, I always treat with metal prep to stop any microscopic rusting that may have already started. The only acceptable alternative for me would be "self-etching" primer. This way you absolutely know that a year from now you won't see any rusting causing bubbled paint.

Also, I would never use bondo over anything but bare metal, unless the manufacturer advises that it's okay. The only thing I will personally use on top of paint is a two-part glaze that is designed for that purpose. You also use it after you've sanded the primer, to correct imperfections, but you'll have to seal those areas before paint.

I would add one more stage to the end of you list:

After your paint has dried, plan on sanding with very fine paper, then buffing. Unless it's a "rat bike", you probably won't get the kind of finish you really want, without doing this.

When you encounter problems...and you will.....just decide how to correct it, keep going, and learn from your mistakes. Each job will get a little better. I've been painting for 40 years, and I still have occasional problems, and still learn new things.

Originally posted by HOTRODPAINT
Before I prime, I always treat with metal prep to stop any microscopic rusting that may have already started.

Also, I would never use bondo over anything but bare metal,

Is phosphoric acid a suitable metal prep?
POR 15 - better?
What other products would you suggest?

I've read both methods with bondo - bare metal - and over primer only.

But then - you opened with "You will hear many opinions"

40 years certainly carries some credible experience!!!!!

Bert

Is there anyone who uses bondo over epoxy primer. I thought that the expoxy primer had more adhesion to the metal than bondo, and also sealed the metal to prevent corrosion. Then skimming with bondo gave a perfectly flat surface. You guys think I should bondo my weld areas and then prime over the top of that???

What about spraytech what does he recommend bondo on top of epoxy primer or on top of bare metal?

SBC, As far as I know, all metal preps include phosphoric acid, as that is what converts rust from iron oxide, to iron phosphate. They also have a residual coating, which will protect the metal temporarily, until you can get some primer on it.

I can't tell you much about epoxy primers. I don't use them because I've used urethane primer for the last 15 years. It's never failed on hundreds of jobs, so I'm not about to change.





Deferr, In the "olden days" bondo had a bad rep. Some of this resulted from people using it over paint, and having it fail. I use it over heavily ground metal only, go right to primer, and touch up with two-part glaze. The result is zero failures.

Today there may be resins used in fillers that bond suitably to sanded paint, but you would have to consult the manufacturers before I would recommend taking a chance on it.

deferr,

PPG recommends using their body filler over their DPLF epoxy primer. Then using a 2K primer over the worked areas with either their K-36 , or NCP 271 Primer fillers .
Other products have a different ways of going about it with their products .
What ever system you use find the the recommendations for their use .
Get the product information sheets on the products you area using , it has alot info on those sheets . Like mix ratios, pot life , temp ranges , clean up , and safety ....ect.


And if you go this route you need to use the full PPG line of products , as mixing and matching products is a NO NO , even though alot are successful with using this method .

SprayTech

I just decided to go with blitz black. Which primers and body filler should I use for this?

sorry I cant be of any help on this , as I only use PPG products strictly .

Maybe someone else will have some answers .

Spray

Ok so upon further research I think that bc/cc black with flattener in the clear coat is the way to go. Spraytech I'm now planning on using PPG's products but I'm not sure if they're in my buget. anyone know how much the materials would be to paint a sedan in bc/cc ppg products. I was hoping less than 500??? somebody let me know

Blitz Black looks good but everyone's argument was just that it was cheaper. If I spend hours and hours sanding and welding on my car I'm not taking a chance to save a few bucks.

I have had alot of success with two products that are very affordable. Both have very good UV resistance and look great for a very long time. Omni has a single stage urethane and so does Martin Senior from NAPA. A lot of different opinions out there but, I have many years experience in using a wide variety of products.
The flattened clear coat process I read about hear seams to be a waste of good materials. Flattener directly effects the UV resistance of all paints, so why waste good clear coat when a single stage paint will give you the same protection with less materials and less steps in the refinishing process.

that's very good to know.

Would either paint give me the half-gloss look I'm going for? Maybe still add flattener??

Also I'd really like to use epoxy primer on bare metal then scuff sand, skim with bondo (doing lots of good body work just need to clean up welds), then start with the products you recommend?

Please tell me more! I'd love to use a single stage if it would give adequate protection.

You want a Satin finish not flat black. This can be ajusted by adding a little more catalyst, and doing a test panel to see if the gloss is right. Not too much extra catalyst. What ever primer surfacer or sealer you use will depend on the amount of bodywork you do. After mud work I like to use a good quality 2K surfacer and followed with Epoxy primer. Wet sand with 400 grit for great adhesion (only with satin colors) followed with sealer and paint. I did my neighbors ford wagon 3 years ago and it still looks good ,he never puts it in the garage,and drives it nearly every day. I used Martin Senior on it. All I can say is it worked for me it can work for you.

Just to toss a little more info in here............
It might help to understand that when people talk about primers they're not always talking about the same thing. As HRP said, you'll get different answers from different folks because they bring different experiences to the table.

As an example from DW's (spraytech) list, there are two primer catagories; the DP which is an epoxy primer/sealer, and the acrylic urethanes K or NCP which are primer/surfacer (but can also be used as a wet on wet sealer with proper procedure). In simplified terms the epoxy primers adhere chemically, the acrylics mechanically (the roughened surface HRP noted). Many believe, and have sucessfully shown, that the chemical bond of the epoxy is "better" than the mechanical bond of the body filler on bare metal. Years of experience doing it the other way successfully would be an adequate argument against that. What the epoxy primer does do effectively though is act as another barrier against moisture migration as body filler is very porous, like a sponge. If you seal it off with primer quickly, that's not much of an issue, but if you let it sit, and there's no barrier between the bare metal and the body filler, then rust will occur under the filler. Atmospheric conditions will dictate how much, how quickly. If you've ever taken off old body work done over bare metal you've likely found surface rust.

As DW said, ppg will allow the use of body filler over the DP products.

As for your top coat, if you're going with ppg you could use DCC black with some flattener. You control the amount of flattener you add, thus the amount of sheen you get. Given the cost of clears a single stage like DCC would be more cost effective.

ok so here's how I see it from you guy's info.

-strip metal
-epoxy primer
-skim bondo
-epoxy primer
-single stage DCC w/flattener

also how much is ...
epoxy primer?
DCC?
flattener?

I know clear can go for 200-300 a gallon. I just did not feel comfortable as this will be my first paint job, and I want the satin finish with lots of chrome look. I'm doing a custom 68 mercedes sedan. chopped top + american V8 + satin black + lots of chrome = SWEET!