should i be worried

[tassie targa 76]

my dad and i just repaired and painted my 76 targa

quite a bit of repair work done carrera flares welded in, acrylic primed and spray puttied then 8 coats of gp white in acrylic.

also painted the calipers using acrylic primer and slow dry enamel, then the paint basicaly fell off, (the calipers)spoke to the paint shop they said i should have etch primed the cailpers first.

ok no problem cleaned the caliper back and etched pimed ready for a coat of colour.

what is worring me now is, if i should have used etch primer on the body due to the galvanise, much of the body was either sanded back to metal or left with only a dull looking galvinised coating.

there are no sighs of an issue at this stage, but havent bolted doors or fenders back on yet

[wachuko]

Ouch... someone in the know should be replying to this thread... would be sad to go through all this trouble, put the car back together only for the paint to chip in a few months...

Hope someone with real knowledge on this topic can chime in...

[xsboost90]

i repaired a friend of mines 911 years back- who had a full respray done. They took the car to bare metal and then primered and sprayed the car- looked good. They did not etch primer the car. His car was a track car and basically every rock chip went to bare metal and started to rust. I fixed a damaged fender and resprayed the entire front clip- that was where most of the chips were- and afterwards the car when i chipped just would go to the first layer of primer. Bare metal should go to etch primer, finish bodywork, then a filler primer, sealer and paint. I usually dont seal but its good to do.

[tassie targa 76]

thanks but not what i wanted to hear

Regards Michael

[A horse with no name]

Hi there... You say you 'sprayed' putty' then painted it. Could you be more specific on the 'sprayed' putty?
The main thing with any paint job is cleanliness and prep work- Etching priming is not always a must - On Aluminum it is. But if etching primer is not used on a stripped bare metal then a very high quality euathane primer should be used. it will keep any mositure from ever getting to the metal. You can then do your body work on top of it. and then reprime just the repaired spots .

I have done 4 ground ups...Only one was stripped by "Ready Strip" where they dip /svsubmerged and when out it is done it is a very shiny tin work.- These strips have to be painted with a urethane two pot primer ASAP to prevent surface rust and particulary prevent moisture and give you it gone base. It sticks- It's the best base.

The others I did Was automotive/ aircraft stripper - from there it was power washed well then hand washed-

Then it was machine sanded with 800 to take all 'burn' marks plus any residue to until the the" whole body was 'shiny' - At that stage it was sprayed with an etching primer due to the smooth bare metal. The primer under coat needs it so as to adhere to it- All of the body work had been done and what was left was very light fiinishing with Wurths spot putting which was done after the application of the Primer-undercoat.

Once that was done then came the days/weeks of blocking - spot putty filling- repriming and block sanding - In time I had it ready to paint. As you may know that even before re spraying primer the body has to be grease free and is wiped down with a grease silicon cleaner. - When the body was 'spot on' it was ready for the top coats- I preferred the solid colour of a three coat two pot mix of acrylic Urethane . It was then blocked with 400 and then I sprayed another 2 coats of the same two pot mix of acrylic urethane.

Now it becomes a labour of love- Colour sanding. I always use 1200 + 1400 3M . it was then a matter of putting whatever time was needed to get it blemish free and flat.. It was then machine polished with 3m and if any minor blemishes were noted as I went-Then back to blocking colour sanding with 1600 3m then Machine polishing it out to a super gloss.

I can't highlight enough about everything needing to being cleaned properly throughtout every stage/ process. If not it will - one cause fish eyes in the paint and the real bummer is of the paint not adhearing, It will flake easy and or chip very easy...They are a small body so you just may have to take it down again and redo it- Go speak to any of the major brand paint rep for product and method- PGG is as good as any. This may not what you wanted to hear but if you havdn't proceeded in a similar way you most likely will need to strip it down and start offer. - Big Bummer ay.

Ps- where you paint it should be warm and dry with no dust. Often easier to rent a paint booth over a weekend. Many shops will do this fora couple of hundred max.

cheers

[Fishcop]

What specific primer did you use; basic acrylic or 2 part (two pack) polyurethane? If you sanded the bare metal, there's a fair chance you removed the galvanising layer, so it should be treated as a 'bare metal' restoration regardless.

You don't have to use a chromated "etch" primer, a good quality epoxy primer is arguably superior (an argument not really worth having - some prefer epoxy, some prefer etch). At the very least a good quality 'direct to metal' (DTM) primer/filler should have been used.

Find a sacrificial area and "poke it with a stick" and see if you can get it to lift... if not, don't stress, you're probably fine. If it does lift, it's best you know now and can repair/redo as necessary...

[mreid]

You have a choice - epoxy primer or a metal etching primer over bare metal. If you sprayed a high build sanding primer like feather fill directly over bare metal, you will not have a great bond and the paint could pull away or chip to bare metal easily. Paint layers require either a chemical or mechanical bond to adhere properly. High build primer will not form either very well with bare metal.

[A horse with no name]

Hi...I should have been a little clearer on the products

Etching wash primers have to a large degree been replaced with epoxy primer's such as PPG's DP and then primed with a two-componentd urethane undercoats and followed through topcoats. When dry it is very hard and body fillers can be used on top of them...Best to have all major body work done prior to applying so that you don't end up grinding it off. It's a great product and is an excellent moisture barrier for the remaining undercoats and of course top coats.

Note...You should stick to whatever paint line that you choose to go with as they are manufactured to be used in unison with each step.

The new epoxy primers do not quite have the same adhesive properties as the older ones of say 10- 20yrs. ago due to most countries banning their use because of their chemical structure ...Kind of like spraying agent orange?

Maybe a bad analogy but they were indeed not good for ones health. If using, you need to use the direct fresh air oxygen type intake mask system. Not a good back yarder product to be using without having this equipment.

I know these older style epoxy primers and top coat materials are still available through some manufactures as I purchased some recently through a friend that has a body shop. I used it to repaint my aluminum fishing boat that I had paint stripped. They will no longer sell them to someone off the street.

I have to say that I have a bias for the two- part urethane finishes but many would argue the values of the base code clear systems... They both provide great finishes...To get that 'show quality' look it basically involves lots and lots and lots of hours. There is an expression that I should have never read as it drove me crazy when doing a job:

"Just when You think it is good enough...It isn't" It has to be the best truism that I have ever heard...to drive you crazy that is.

If adhered to it has the ability to have you... Filling- spot filling- block sanding- priming- spot filling- block sanding -over and over until it is 'right', including doing the same when colour sanding and polishing.
A high quality finish can easily take hundreds of hours depending of course your level of skill. Even the 'best' put in - lets say - lots of hours.

Hang in there as the end result will be well worth your time and energy.

Cheers

[tassie targa 76]

Find a sacrificial area and "poke it with a stick" and see if you can get it to lift... if not, don't stress, you're probably fine. If it does lift, it's best you know now and can repair/redo as necessary...[/QUOTE]


we used a quality acrylic to bare metal primer and have as suggested above hit it with a stick.

so far all seems good

regards Michael

[A horse with no name]

Hi again...By the looks of your photo's you are doing one heck of a good job!

With 8 coats of finish you have lots so as to be able to colour sand and polish 'IF' you care to do so that is.

Question: What did you exactly do to prep for the primer on your rear bare metal quarter panels? Your answer will provide some insight into how well the adhesion of the primer will be.

Trivia:
One benefit of any quality primer, such as epoxy, is the moisture barrier that they provide to prevent moisture from leeching through and creating rust from the 'inside' out of any panel.

E.G. Even if a great job has been done of the cutting and welding in a new piece of metal; if the back/inside of the welding area has not been cleaned up and primed - then coated, in most cases the rust will eventually come back. Something as simple as one minute 'pin hole'[/I] in the weld will of course accelerate it.

Cheers

[962porsche]

if you did not use a direct to metal primer ( DTM) then the products will delaminate .
even most DTM primer don't like to stick to any galvanized substraight .
for the most part you will find at 1st it will chip very ez then later on it will start to peal .
you should have used a E-type primer ( Etch or Epoxy ) and one that is chromated . the only time you don't want to use a E-primer is when your using a product like feather fill also known as polyester spray filler or like product . if you use a E-primer under spray fillers the solvents in the E-primer will delam the spray filler about 6 months to a year later .

it is totaly NOT true at all that E-primers of old are better than ones offered today . in fact it's just to opposite !
the products now are of much better grade . the main content of epoxy primer is methoxy and propanol they are far better than even the same of 10 years ago . many people think that because products have to now be VOC compliant that they are less of a product .

the answer to the trivia is only a chromated primer does that .
chromates etch the substraight and only chromates do the etching .
propanol , methoxy and butyl benzyl phthalate is what bites into metals making them adhere . you will find DTM primers along with E-primers have one to all three of them .
because talc is the main content of filler primers it does not hold out any moisture . it does just the oppasite talc soaks up moisture . also talc offers no adhesion at all that is why you need a product like a E-primer under it over bare metals .