Order of Filler Use

[Charlie]

I did a lot of body work a long time ago, when everything was lacquer based. My son now wants me to 'help' him do some body restoration work. I've read all the 'training' articles on the site and archived posts, but I'm still a bit unclear about the order of using the new materials.

First question: If I understand it correctly, the order of application is:

1. 'Bondo' Filler
2. Polyester Glazing/Spot Putty
3. Guide Coat
4. Epoxy Primer or Polyester Primer
5. Guide Coat
6. Repeat 4-5 until happy (unless you've really screwed up #1)
7. 2K Primer
8. Top/Color Coat

Have I gotten it right?

Back when I used lacquer, a primer coat as always applied before the spot putty, but probably because the spot putty was really just a very thick lacquer primer.

2nd question: Iis there a difference between Epoxy Primer and Polyester Primer, or are they same thing... Does the Epoxy/Polyester Primer or the 2K primer require a special gun, or can it be shot with a standard HVLP gun?

3rd question: At what point is the body work relatively water resistant? The paint shop said they will apply the 2K primer just before the top coat, so I'd rather not shoot it myself if the work will be relatively water resistant after the Epoxy/Polyester Primer, as it's gonna take us some time to work our way around the whole car.

I wanna get some info from the folks on this site before I go down to the Body Supply store and talk to a kid with no experience and only knows what the boss or the mfg TDS 'suggests'.

Thanks,
Charlie

[88GT]

I always put 2K over my filler, but any of those primers will make the area water resistant

[Len]

First question: If I understand it correctly, the order of application is:

1. 'Bondo' Filler
2. Polyester Glazing/Spot Putty
3. Guide Coat then block or board sand
4. Epoxy Primer or Polyester Primer epoxy primer on the surface and 2K (filler primer) on top.
5. Guide Coat then block sand
6. Repeat 4-5 until happy (unless you've really screwed up #1)
7. 2K Primer is block sanded to tweak the surface.
8. Top/Color Coat

Back when I used lacquer, a primer coat as always applied before the spot putty, but probably because the spot putty was really just a very thick lacquer primer. If you have any of that old lacquer-type putty around throw it away.

2nd question: Iis there a difference between Epoxy Primer and Polyester Primer, or are they same thing... Does the Epoxy/Polyester Primer or the 2K primer require a special gun, or can it be shot with a standard HVLP gun?

Epoxy primer is usually used to make everything else stick to the surface. In other words it's a "direct to metal" primer. The 2K (polyester primer) is like spraying a light coat of filler that is guide coated then block sanded to complete the leveling process. In most cases a separate primer gun is used and it usually has a 1.6 tip or larger depending on the primer being sprayed.

3rd question: At what point is the body work relatively water resistant? The paint shop said they will apply the 2K primer just before the top coat, so I'd rather not shoot it myself if the work will be relatively water resistant after the Epoxy/Polyester Primer, as it's gonna take us some time to work our way around the whole car.

Epoxy primer is usually fairly moisture resistant while polyester primer is usually more porous. We usually strip the paint off the metal do the body work then apply epoxy primer HOWEVER, if the body work is going to take some time we will change the plan of attack. For longer projects we strip the car then apply epoxy primer then remove the primer in areas where are doing metal work then reprime those spots when the straightening is finished.

[Charlie]

Got it. Thanks.
(All my lacquer-based supplies are long gone)

Charlie

[Charlie]

oops, forgot to ask, can I apply Phosporic Acid/Picklex/Zero-Rust to the rust pits and areas I can't get at by sanding, before I apply any spot putty or epoxy primer ?

Charlie

[Len]

We use Picklex by spraying or brushing it on, working it in with a scuff pad then wiping off the excess and allowing the surface to dry well before we apply filler or epoxy primer.

[Charlie]

Not to beat this thread to death, but...
I went to the supply shop yesterday to get Epoxy primer, Polyester putty and 2K Urethane filler (all Nason). But the counter clerk said I needed to use a 1.4 tip for the Epoxy and a 1.8 tip for the 2K, which seemed contrary to what I've been reading for the past few weeks. Neither tech data sheet had any 'recommended' gun settings (and he 'guessed; those would be about right).

Once I think I understand (or at least have a better grip on things), I'd rather buy guns from Len, who puts so much effort into this forum. It's not that I don't trust the clerk, but he has an immediate profit incentive with a novice like me

[Harry Phinney]

I've not used Nason, but the jobber's recommendations are probably good. Epoxy primers vary a fair amount in their viscosity. Some spray quite well with a 1.4 mm tip, while others do better with a larger tip. 2k primers invariably work best with a large tip - at least 1.7 mm in my experience.

Harry Phinney

[Len]

Filler primers also come in a variety of viscosities, I have some I shoot with a 1.4 but most need a 1.7 or larger.