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Doug C Samba Member
Joined: January 07, 2013 Posts: 255
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Posted: Wed Apr 06, 2016 5:49 am Post subject: Wash before shooting primer ? |
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I will be stripping my car of all paint today (and probably tomorrow too) WITH polycarb PADS on A GRINDER (no chemicals). The car sits outside under a car port. I planned to wash the entire surface with either deluted "Prep & Etch" (Phosporic acid) or Water/Vinegar (@ 4:1). Which do you guys recommend ? Or should I just clean with a wax & grease cleaner and shoot the primer?
If using one of the acid washs mentioned.. how will I final rinse with clean clear water while the windshields and all glass is removed but wiring harness and electricals are still there? (all interior has been removed though).
Doug C |
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wcfvw69 Samba Purist
Joined: June 10, 2004 Posts: 13389 Location: Arizona
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Posted: Wed Apr 06, 2016 7:30 am Post subject: Re: Wash before shooting primer ? |
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On raw metal, I always wipe it down with an oil and grease remover. I then make sure my first coat of primer is an "etching" primer that will "bite" into the metal for a good bond.
If I'm going to leave it in primer, I'll follow up the etching primer coat with an epoxy coat of primer that seals off any moisture getting to the metal. _________________ Contact me at [email protected]
Follow me on instagram @sparxwerksllc
Decades of VW and VW parts restoration experience.
The Samba member since 2004.
**Now rebuilding throttle bodies for VW's and Porsche's**
**Restored German Bosch distributors for sale or I can restore yours**
**Restored German Pierburg fuel pumps for sale or I can restore yours**
**Restored Porsche fuel pumps or I can restore yours**
**Restored Porsche distributors or I can restore yours** |
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Doug C Samba Member
Joined: January 07, 2013 Posts: 255
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Posted: Wed Apr 06, 2016 9:30 am Post subject: Re: Wash before shooting primer ? |
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thank Bill. Unfortunately I won't be able to get any etching primer. I do have Epoxy Primer though. I would think the polycarbide grinding pad would leave plenty of tooth for the epoxy primer though. If not, I could go over the bare metal with a red scotchbrite - which I was going to do anyway if I got any flash rust before spraying the epoxy primer. And/Or I could use the red scotchbrite in conjunction with whatever acid wash I ended up using.
The car will stat outside but the car port will become a temporary enclosed both before spraying the primer and the car will be painted with in a few days after that.
I'm leaning towards water/vinegar and a red scotchbrite. Either way - I'm afraid of getting it on electricals during the wash and rinse.
Doug C |
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jspbtown Samba Member
Joined: January 27, 2004 Posts: 5156
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Posted: Wed Apr 06, 2016 9:37 am Post subject: Re: Wash before shooting primer ? |
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I have always just used a degreaser/wax remover.
One thing I did start doing was to go over everything with alcohol after the degreaser and before the paint.
I don't know why but it reduced my contamination issues significantly. |
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wcfvw69 Samba Purist
Joined: June 10, 2004 Posts: 13389 Location: Arizona
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Posted: Wed Apr 06, 2016 10:44 am Post subject: Re: Wash before shooting primer ? |
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They make an acid prep wipe for bare metal as well. It provides an etching for the epoxy to stick to as well. That's all the etching primer is. It just has a light acid in it. _________________ Contact me at [email protected]
Follow me on instagram @sparxwerksllc
Decades of VW and VW parts restoration experience.
The Samba member since 2004.
**Now rebuilding throttle bodies for VW's and Porsche's**
**Restored German Bosch distributors for sale or I can restore yours**
**Restored German Pierburg fuel pumps for sale or I can restore yours**
**Restored Porsche fuel pumps or I can restore yours**
**Restored Porsche distributors or I can restore yours** |
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eshan2 Samba Member
Joined: July 10, 2002 Posts: 271 Location: Denver North Carolina
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Posted: Wed Apr 06, 2016 4:39 pm Post subject: Re: Wash before shooting primer ? |
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You have to be careful with etch primers. Some epoxy primers have bad reactions with them. It is best to follow the paint systems instructions. Some epoxy needs a specific grit sanding scratch left behind. _________________ I love the smell of nitro in the morning.
1963 Beetle currently under reconstruction.
Ernest. |
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esde Samba Member
Joined: October 20, 2007 Posts: 5969 Location: central rust belt
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Posted: Thu Apr 07, 2016 4:06 am Post subject: Re: Wash before shooting primer ? |
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If you do not get some 2k primer sprayed on the epoxy within a few days you will have a ton of work ahead. There's only a few day window where the two will bond, after that the epox will need to be mechanically scuffed, and it eats through sanding discs. Ask how I know |
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panicman Samba Member
Joined: December 18, 2011 Posts: 2290 Location: Canby, OR
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Posted: Fri Apr 08, 2016 8:12 am Post subject: Re: Wash before shooting primer ? |
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I bought and used the wipes from the paint store.
The product degreases and removes any contaminants, and it dries immediately. I don't remember the active ingredients in it, but it is intense; it ate through my nitrile gloves pretty quickly. _________________ Plate of shrimp |
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Mike Fisher Samba Member
Joined: January 30, 2006 Posts: 17970 Location: Eugene, OR
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Posted: Fri Apr 08, 2016 8:39 am Post subject: Re: Wash before shooting primer ? |
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I would use the phosphoric acid on all bare metal, since you can not strip a whole car & primer it in 1 day. Buy the 2k primer & spray it over the epoxy primer the same day. _________________ https://imgur.com/user/FisherSquareback/posts
69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold
Society is like stew. If you don't keep it stirred up you end up with a lot of scum on the top! - Russ_Wolfe/Edward Abbey |
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brainwash Samba Member
Joined: June 22, 2014 Posts: 64
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Posted: Sat Apr 09, 2016 6:17 pm Post subject: Re: Wash before shooting primer ? |
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Mike Fisher wrote: |
I would use the phosphoric acid on all bare metal, since you can not strip a whole car & primer it in 1 day. |
I'm stripping in batches and hitting the bare metal with Metal Blast to etch it. Then priming with SEM High Build Primer Surfacer. Trying to minimize flash rust. _________________ '78 Westfalia |
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jason Samba Member
Joined: August 07, 2002 Posts: 3444 Location: Garage
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Posted: Sun Apr 10, 2016 2:14 pm Post subject: Re: Wash before shooting primer ? |
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It depends on the product your going to use on what to wipe with. I use SPI epoxy. It says it has the etching chemicals in it for bare metal. I talked to them and they say to clean with their cleaner and shoot the primer. You have a week to topcoat or to add filler on it. If longer scuff. They also say you don't have to topcoat. Not expensive either.
Epoxy usually doesn't like etching chemicals, you need to surgically clean. When the metal heats up the chemicals leach out and attack the primer. |
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Doug C Samba Member
Joined: January 07, 2013 Posts: 255
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Posted: Fri Apr 15, 2016 7:30 pm Post subject: Re: Wash before shooting primer ? |
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Mike wrote:
Mike Fisher wrote: |
...Buy the 2k primer & spray it over the epoxy primer the same day. |
What advantage is there to spraying primer over primer? I never heard that before. My plan has been - after epoxy primer, skim coat the entire car in a thin layer of filler for blocking (done in sections with in 5 days), then shooting a sealer coat, let it flash, shoot 3 coats of color.
Doug C |
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Doug C Samba Member
Joined: January 07, 2013 Posts: 255
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Posted: Fri Apr 15, 2016 7:47 pm Post subject: Re: Wash before shooting primer ? |
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Mike Fisher wrote: |
I would use the phosphoric acid on all bare metal, since you can not strip a whole car & primer it in 1 day. |
My car is in my temporary paint booth/car port and I have it (the car port) covered in heavy mill plastic (but the ends are still open). I finished stripping the main body of the car a few days ago inside this booth. I knew it would be a few days before I shot my epoxy primer and I basically accepted the fact that I'd get flash rust before then and have to deal with it. Almost as soon as I got the body completely stripped it started raining! To my surprise there was NO flash rusting the next day. This morning I woke to heavy fog outside - but there was still NO flash rusting from it!! The rain didn't touch the bare metal but I would have thought the fog would have gotten me for sure.
I can not strip the whole car in a day but since there's no visible rust I thought I would go back over the entire surface with 80grit on a DA just to help eliminate any microscopic rust in the sanding scratches (of my bare metal body). Or is that a thing? I mean if you don't see rust is it a fair assumption that you're good for epoxy primer? Everything is still shiny and fresh looking at this point.
Doug C |
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Mike Fisher Samba Member
Joined: January 30, 2006 Posts: 17970 Location: Eugene, OR
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Posted: Sat Apr 16, 2016 1:44 pm Post subject: Re: Wash before shooting primer ? |
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The epoxy dries rock hard, so it's wise to spray some high build primer the same day & not wait 5 days for skim coat of filler. What if your 5 day skim coat filler doesn't stick to the Epoxy! Show us your Volvo & spray booth now! _________________ https://imgur.com/user/FisherSquareback/posts
69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold
Society is like stew. If you don't keep it stirred up you end up with a lot of scum on the top! - Russ_Wolfe/Edward Abbey |
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Doug C Samba Member
Joined: January 07, 2013 Posts: 255
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Posted: Sat Apr 16, 2016 5:55 pm Post subject: Re: Wash before shooting primer ? |
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Here it is from a couple days ago, and before I covered the sides of the temporary booth with plastic sheet (just before it started raining too btw). The metal is even cleaner today after I re-abraided the surface w/150grit followed by a red scotchbrite pad (appx 350 grit). I wanted to avoid having to worry about removing any phosphoric acid - but I've decided to go ahead and wipe the car down with some.. because I noticed tiny stain spots on the surface that I could not remove with the 150 grit today. I'm afraid of them being rust.
Doug C |
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Joseph DR Samba Member
Joined: December 20, 2004 Posts: 180 Location: Texas
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Posted: Tue Apr 19, 2016 9:48 am Post subject: Re: Wash before shooting primer ? |
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Doug C wrote: |
Mike wrote:
Mike Fisher wrote: |
...Buy the 2k primer & spray it over the epoxy primer the same day. |
What advantage is there to spraying primer over primer? I never heard that before. My plan has been - after epoxy primer, skim coat the entire car in a thin layer of filler for blocking (done in sections with in 5 days), then shooting a sealer coat, let it flash, shoot 3 coats of color.
Doug C |
Doug, that's a cool lookin' car and fun project!
The epoxy primer seals off the metal and prevents moisture from getting to it. But it is not friendly to sand, as Esde noted. Also, you will still see sanding scratches on the metal. It does not hide them.
After epoxy then you can do SOME filler work (I did not do the whole car like on Overhaulin'. I don't have the man power or the time to do that.)
Next is high build primer. It goes on fast/easy and then you can block sand it. Do a guide coat with cheapo black spray. If you don't do high build primer, but instead do a skim coat of filler on the WHOLE body. Man, that is A LOT of work! I bet it'll take you much longer than 5 days to do it.
Plus, wherever you don't put filler you will need to scuff and reshoot it with epoxy after the first epoxy window expires.
Finally base and clear.
I would recommend the high build primer over skimming the whole car with filler. _________________ 1964 Beetle |
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kman Samba Member
Joined: November 04, 2005 Posts: 739 Location: Michigan
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Posted: Tue Apr 19, 2016 3:16 pm Post subject: Re: Wash before shooting primer ? |
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Nice Volvo. Even if it isn't a VW. |
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Doug C Samba Member
Joined: January 07, 2013 Posts: 255
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Posted: Wed Apr 20, 2016 5:10 pm Post subject: Re: Wash before shooting primer ? |
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[/quote]Doug, that's a cool lookin' car and fun project!
...
I would recommend the high build primer over skimming the whole car with filler.[/quote]
Thanks! I love this car but there are always a few old vw's I'm always keeping an eye out for. And the help on this forum for paint and body is amazing!! Thanks guys.
Yea, when Mike eluded to 'priming over the epoxy immediately' I totally spaced on the high build primer.. of course I am aware of doing that. I just (for whatever reason) do not immediately think of it as primer - I guess because it's often referred to as 'shaper/surfacer' I guess.
I actually do have a new 1 quart can of the Polyester high build Surfacer that I bought to spray over the worst areas (passenger rear quarter). But I am now seeing that I should have invested in an entire gallon to do the whole car as it now seems a better choice than the lite weight filler that I did buy.
Doug C |
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kman Samba Member
Joined: November 04, 2005 Posts: 739 Location: Michigan
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Posted: Thu Apr 21, 2016 4:06 am Post subject: Re: Wash before shooting primer ? |
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For the yellow brown flash rust stains that show up, I use a red scuff pad sprayed (not soaked) with some metal ready. Wait a about 1/2 hour or so then clean as usual. |
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Doug C Samba Member
Joined: January 07, 2013 Posts: 255
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Posted: Thu Apr 21, 2016 4:55 pm Post subject: Re: Wash before shooting primer ? |
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ok, well.. what I ended up doing is : diluting my phosphoric acid 30% to water @ 70%. The product (a general hardware store phos acid) suggested a 50/50 mix with water to promote adhesion before painting bare metal and I'd read here of someone doing a 30/70 mix with good results. I was not after better adhesion but rather to dissolve microscopic rust before shooting my primer. I applied it like Eastwood's video of there "After Blast" phosphoric acid product for bare metal - that is, I sprayed it on and almost immediately wiped it off. The surface looked good when finished.
The bad: after reading on this forum of the need to rinse phosphoric acid after applying it, in order to neutralize it - I rinsed the hood and two front wings with clean water, dawn dish soap and a red scotchbrite. These areas started turning yellow/gold as I was doing this rinse !!! Crap! It's a mild rust flash all over these areas. So, I stop as soon as I realize this and start drying the front of the car. Lots of yellow/gold on my towel. Once I had it dry I scrubbed this whole front area with a dry red scotchbrite which removed it. Then I went over the entire car with grease & wax remover. The whole car looks good to go again for primer, as far as I know.
What do you guys reckon though? Is grease and wax removed enough to neutralize the 30/70 mix? My rags are pretty clean now btw. I guess I effectively removed all of the mix from the front of the car with the damn wash, but whatever.. there is not rust and no rain in the forcast for a couple of day. I'd like to shoot primer asap.
Doug C |
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