#1  
Old 04-19-2021, 08:09 AM
dataway's Avatar
dataway dataway is offline
Ultimate Warrior
 
Join Date: Jan 2012
Location: Saratoga NY
Posts: 8,921
Default Various questions on epoxy priming

Within a week or so I will be rolling the body outside for sand blasting areas such as the firewall, door jambs, window channels etc.

I have treated some of the areas, underside of roof, front body mount cavities etc with Ospho .... after reading all the dire warnings on the SPI forum I didn't find any info on neutralizing these areas. How is that done?

Also, after reading some of the seemingly extreme prep needed for epoxy primer it kind of makes me lean toward a basic direct to metal enamel like the factory used.

The steps for the SPI epoxy seem to be degrease, mechanically clean or blast, water born cleaner, solvent cleaner, possibly scuff with marron pad, blow it off, tack rag it, then shoot the epoxy?

What are you opinions on a DTM enamel versus the epoxy? I have seen plenty of firewalls that were blasted, wiped with typical solvent cleaner, blow off the lint and painted with DTM that still looked fine 20 years later. The stuff is not picky and still stick to just about anything. Worth the extra steps to use epoxy? Bear in mind I'll be dead in 20 years.

How about door jams and trimming? Should use the epoxy in those locations if I plan on a BC/CC paint? Obviously I can't use a DTM enamel there and have to use some kind of primer. Using the epoxy in all locations would simplify the spraying of course.

The SPI forum has me somewhat paranoid about the adhesion of the epoxy.

  #2  
Old 04-19-2021, 08:35 AM
nytrainer's Avatar
nytrainer nytrainer is offline
Ultimate Warrior
 
Join Date: Aug 2011
Location: Long Island, NY
Posts: 1,096
Default

If you “pickled” the bare metal with Ospho then what you need to do to neutralize it is to reactivate it by scrubbing with Ospho solution then rinse well.
Then it’s important to hit the bare metal panel(s) with 80 grit sandpaper (or equivalent media blasting) before spraying epoxy primer. You can do this process a panel at a time if need be. Choice is yours but any body filler needed can be applied either under or over SPI epoxy. Follow the 7 day window requirements on any subsequent coats whether they be filler, primer surfacer or base.
I wouldn’t trust using expensive top coats over anything but proven substrates.

__________________
1968 LeMans conv. 350 HO - 4 speed triple white (hear it idle here) https://www.youtube.com/watch?v=eVmq...ature=youtu.be
1968 LeMans conv. 350 - 4 speed Solar red/pearl
The Following 2 Users Say Thank You to nytrainer For This Useful Post:
  #3  
Old 04-19-2021, 08:53 AM
Big Bear's Avatar
Big Bear Big Bear is offline
Senior Member
 
Join Date: Feb 2014
Location: Ont Canada
Posts: 132
Default

https://youtu.be/-yA8q4K-_Bo Check out link. Tested products various ways. Cant go wrong with blasting,epoxy and top coat with two part urethane.

The Following User Says Thank You to Big Bear For This Useful Post:
  #4  
Old 04-19-2021, 09:48 AM
Greg Reid's Avatar
Greg Reid Greg Reid is offline
Ultimate Warrior
 
Join Date: May 2003
Location: Palmetto, GA. USA
Posts: 16,163
Default

I've never gone through any excessive prep to spray epoxy. All I recall is that if you are going to put anything over it, including more primer, it needs to be sprayed within the manufacturer's window...usually about a week. Otherwise, it needs to be scuffed first.
Maybe my ignorance but other than that it was basically, sand, degrease and spray. Never had any to peel. It really sticks.. I have used filler both over roughed up epoxy and on bare metal under the epoxy.
I have a couple of nickel sized spots on my car (one on the bottom corner of a door and one right behind the endura bumper) that have some blisters so I didn't do a perfect job by any means but I've been told by knowledgeable folks that it looks like some outgassing from the filler I used on some repaired areas. Considering where the spots are, possible that re-sprayed epoxy before the filler fully cured on a couple of metal repairs..

__________________
Greg Reid
Palmetto, Georgia

The Following 2 Users Say Thank You to Greg Reid For This Useful Post:
  #5  
Old 04-19-2021, 11:58 AM
grandam1979 grandam1979 is offline
Ultimate Warrior
 
Join Date: Feb 2005
Location: Ohio, Findlay
Posts: 1,428
Default

I stripped a hood last fall cleaned it very good with thinner and sprayed it it still looks fine 6 months later. I’m thinking of putting a carbon fiber wrap on it but still up in the air.

The Following User Says Thank You to grandam1979 For This Useful Post:
  #6  
Old 04-19-2021, 12:01 PM
tjs72lemans tjs72lemans is offline
Ultimate Warrior
 
Join Date: Oct 2017
Location: Winona, MN
Posts: 1,157
Default

I mostly agree with Greg. I have used SPI as well as other epoxy primers and use the same approach as Greg with no issues.

The Following User Says Thank You to tjs72lemans For This Useful Post:
  #7  
Old 04-19-2021, 12:54 PM
dataway's Avatar
dataway dataway is offline
Ultimate Warrior
 
Join Date: Jan 2012
Location: Saratoga NY
Posts: 8,921
Default

The underside of the roof is my main concern when it comes to the Ospho ... that's going to be a doozy to reactivate, scrub and rinse. I assume you can NOT blast over the Ospho because it will imbed in the metal? Would there be a better choice for under the roof? That's going to involve a lot of water inside the body which could take weeks to fully dry out.

So ... unless I plan to scuff I need to do any top coats of anything within 7 days?

Will scuffing give me adhesion as well as if I was inside the 7 days? I ask this because I work slow, I'll only be doing one area of the body at a time.

Can I prime and trim the jambs and such with BC/CC in the final color and then spray the rest at a later date? I'll probably get the trim out done this summer, but it could be a year or more (we plan on moving) before the rest of the body gets painted. The car will probably be mostly assembled during the final painting so I have lots of areas to trim out, jambs, inside top of fenders, trunk, cowl etc.

My plans for the car have changed from a very detailed restoration, to more of a very nice driver. Long story, but I'm no longer that concerned with squeaking out the last bit of resale value at some future date because I probably won't be selling it.

A couple of years ago I repainted the big snow thrower for my tractor, used a PPG epoxy primer ... I just blasted, solvent wiped and shot it epoxy, then in enamel. Have now noticed in abused area it will take the top coat off but the primer is still there ... and by abuse I mean running into things with it, so no fault of the top coat.

As always, thanks much for the advice.

PS. Is pure alcohol ever used as a waterborne cleaner? I know it's very often used as a pre cleaner for many types of adhesives.


Last edited by dataway; 04-19-2021 at 12:59 PM.
  #8  
Old 04-19-2021, 01:33 PM
Greg Reid's Avatar
Greg Reid Greg Reid is offline
Ultimate Warrior
 
Join Date: May 2003
Location: Palmetto, GA. USA
Posts: 16,163
Default

Quote:
Originally Posted by dataway View Post

So ... unless I plan to scuff I need to do any top coats of anything within 7 days?
Most of my car was in epoxy for years before I topcoated. I would do spot repairs, sand and respray more epoxy as needed at various times and locations over those years.

Quote:
Will scuffing give me adhesion as well as if I was inside the 7 days? I ask this because I work slow, I'll only be doing one area of the body at a time.
According to the data sheets that I recall and my experience, yes, it will adhere fine with a scuff coat. I did it many times with scotchbrite pads and/or sandpaper.

Quote:
Can I prime and trim the jambs and such with BC/CC in the final color and then spray the rest at a later date? I'll probably get the trim out done this summer, but it could be a year or more (we plan on moving) before the rest of the body gets painted. The car will probably be mostly assembled during the final painting so I have lots of areas to trim out, jambs, inside top of fenders, trunk, cowl etc.
I jambed mine but my painter said that he'd have preferred I hadn't. Can't remember why but it wasn't a huge deal. I do recall the guy at the paint store also telling me aftewards to sand all of my jamb work away if it was on the outer surfaces anywhere, which I did, but it was ok in the jambs. All of this just convinced me that I probably should have just waited for the painter's advice.
One thing you don't want is a tape line between the jambs and the outers. That's why I had overspray fogged on the outside. I'd didn't think it'd be an issue but, like Sgt. Schultz..... I know nut-zing... really when it comes to body work and painting. Just asked questions and tried to follow the advice.
I have found the epoxy primer to be very, very durable when testing adhesion. It really sticks and is tough and even just a little flexible when dried.

__________________
Greg Reid
Palmetto, Georgia

The Following User Says Thank You to Greg Reid For This Useful Post:
  #9  
Old 04-19-2021, 03:23 PM
dataway's Avatar
dataway dataway is offline
Ultimate Warrior
 
Join Date: Jan 2012
Location: Saratoga NY
Posts: 8,921
Default

Excellent info ... yes I was planning to just taper off the paint to the outside body so it could be sanded down later .... and I think one of the painters here said when it came time to paint the outside you could tape off inside the doors but don't press the tape down ... so the outside coat fogs into the panel gaps ... then inside the jambs that fog can be wet sanded down later. .... or something like that

But then again ... when it comes to the outside paint ... the only places probably a real pain to do the trim would be hinge area, fenders where they show under the hood etc. There would be no sill plates, not trunk weather strip (or doors) no glass installed, stuff like that ... but would have fenders and hood bolted on ... I could remove valance and bumper for painting.

Good to know that it can stay in primer for a while, that was my worry.

I feel a plan forming in my head

  #10  
Old 04-20-2021, 12:18 AM
SS-TA SS-TA is offline
Senior Member
 
Join Date: Oct 2006
Posts: 217
Default

I have used both SPI and PPG Epoxies. Two other important notes 1) Induction period - the hardener needs to be mixed with the epoxy, stirred and allowed to sit a minimum of 30 minutes before re-stirring and spraying. 2) Epoxies should not be mixed or sprayed if the temperature is below 65 F as the hardening chemistry will not take place.

The Following User Says Thank You to SS-TA For This Useful Post:
  #11  
Old 04-20-2021, 07:05 AM
dataway's Avatar
dataway dataway is offline
Ultimate Warrior
 
Join Date: Jan 2012
Location: Saratoga NY
Posts: 8,921
Default

I always tend to get a bit dodgy on both those things

  #12  
Old 04-20-2021, 08:01 AM
n20ta2's Avatar
n20ta2 n20ta2 is offline
Ultimate Warrior
 
Join Date: Dec 2007
Location: Cape Cod MA
Posts: 1,000
Default

I used Ospho in a few areas on my roof where thrvpaint had peeled at one point and had some pitted rust. I neutralized the area using a solution of backing soda and water with a green scotchbrite then I rinsed it very well. I then wiped with lacquer thinner, wax and grease remover then I epoxy primed it. It held up great while I did all my bodywork

__________________
1969 GTO street strip project 11.1 forged 461, highport heads
1995 Trans-am 420 ci sb 14:1 compression 9"ford
9.89@132 1.34 60ft SOLD!
  #13  
Old 04-20-2021, 11:27 AM
grandam1979 grandam1979 is offline
Ultimate Warrior
 
Join Date: Feb 2005
Location: Ohio, Findlay
Posts: 1,428
Default

I have always used exstend for rust seems to work good been using it for years now.

  #14  
Old 04-20-2021, 03:43 PM
dataway's Avatar
dataway dataway is offline
Ultimate Warrior
 
Join Date: Jan 2012
Location: Saratoga NY
Posts: 8,921
Default

Quote:
Originally Posted by nytrainer View Post
If you “pickled” the bare metal with Ospho then what you need to do to neutralize it is to reactivate it by scrubbing with Ospho solution then rinse well.
Then it’s important to hit the bare metal panel(s) with 80 grit sandpaper (or equivalent media blasting) before spraying epoxy primer. You can do this process a panel at a time if need be. Choice is yours but any body filler needed can be applied either under or over SPI epoxy. Follow the 7 day window requirements on any subsequent coats whether they be filler, primer surfacer or base.
I wouldn’t trust using expensive top coats over anything but proven substrates.
Dave, what do you think about re-spraying it with Ospho (that's how I originally applied it) scrub it with a big bristle brush and then high pressure wash it? Figure a high pressure washer will get less water in the car compared to using a hose.

Since it's just the underside of the roof that was bare metal from the factory I'm tempted to just shoot it with some red oxide primer.

  #15  
Old 04-20-2021, 08:00 PM
tjs72lemans tjs72lemans is offline
Ultimate Warrior
 
Join Date: Oct 2017
Location: Winona, MN
Posts: 1,157
Default

When I restored my 55 Chevy, I brushed on Rust Bullet to tackle the surface rust.
This stuff sticks well and neutralizes/inhibits rust. You could then even shoot your red primer over that. Otherwise, I don't think the primer would do much over surface rust for protection.

The Following User Says Thank You to tjs72lemans For This Useful Post:
  #16  
Old 04-20-2021, 09:10 PM
Formulabruce's Avatar
Formulabruce Formulabruce is offline
Ultimate Warrior
 
Join Date: Nov 2004
Location: North East of AMES PERFORMANCE, in the "SHIRE"
Posts: 9,363
Default

You can neutralize with Dawn Dish soap and warm water. Rinse well, dry throughly. You are trying to release
Phosphates ( usually of zinc or Iron).
Never use DTM acid primer on anything but a old frame on a yard truck..
As stated, induction time is mandatory as well as temp of metal and paint.
Buy yourself a giant thermometer and a cheap egg timer. Both will help keep you on track.

The Following User Says Thank You to Formulabruce For This Useful Post:
  #17  
Old 04-21-2021, 03:15 AM
dataway's Avatar
dataway dataway is offline
Ultimate Warrior
 
Join Date: Jan 2012
Location: Saratoga NY
Posts: 8,921
Default

While I'm at it, if I'm going to get this body wet ... what do you think about a high pressure washer to remove old caulking etc?

  #18  
Old 04-21-2021, 08:41 AM
TAKerry TAKerry is offline
Ultimate Warrior
 
Join Date: Feb 2018
Location: North Eastern MD
Posts: 1,146
Default

I doubt a pressure washer would hurt anything, I have never had a car in a spot where I can use that technique. You were concerned about water in crevices, one thing I do when I wash my cars is to take the yard blower to it and dry if off. Once your done washing give that a try.

  #19  
Old 04-21-2021, 04:18 PM
dataway's Avatar
dataway dataway is offline
Ultimate Warrior
 
Join Date: Jan 2012
Location: Saratoga NY
Posts: 8,921
Default

I have a big backpack Stihl blower and a big compressor ... most of the cavities have drain holes correct?

  #20  
Old 04-21-2021, 07:16 PM
Formulabruce's Avatar
Formulabruce Formulabruce is offline
Ultimate Warrior
 
Join Date: Nov 2004
Location: North East of AMES PERFORMANCE, in the "SHIRE"
Posts: 9,363
Default

When your car is moving at 55 mph, it has about 20 psi at the vents inside the car, and the rockers for the factory flush and dry system to work.
When I do that type of wash, I always leave a air hose in the rockers from the front by the kick panels, into the rockers, for an hour each side.
the lower seams on the pinch weld dry slowly.
A good bake in the sun on a warm day helps a lot.

The Following User Says Thank You to Formulabruce For This Useful Post:
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:58 AM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017