Fighting Rust...Help

[240kconvertible]

True, the Metal Prep, as we call it, needs to be neutralised with clean water once it has done its' job.

I find that if you wipe the surface well and dry with paper towels and spray liberally with metholated spirits [de-natured alcohol] you can evict the moisture quicksmart.

I use a pump pack to squirt and spray the metho into all the nooks and crannies to displace any moisture.

Follow that with compressed air [through a water trap] to force dry the metho.

Warm to hot weather is great since the metho will evaporate very quickly on its own.

Then a thorough wipe over with Prepsol [silicon Off, De-greaser etc.] and the yellow/tan colour comes right off and the metal is squeaky clean for etch primer.

All this is well and good, but the environment at the time must be warm and dry.

Cool or humid and you are going to have a battle to get it right:angry:

So that's how it's done, I was filling in my door handles today and when I see that little bit of yellow under the por (visible due to sanding) I get worried about it lasting even though the coat has stuck so well it's takes a power sander to get through it, sanding by hand just takes to long to get through por. I wish I had of known this method to do as I would have liked to not have the yellow tan all over my panels.

Cheers for the tip.

I love a good thread hijack ilikemyz and zcarmannn seems to have forgotten he even started this thread. Let us know what you end up doing with your bonnet.

[240kconvertible]

True, the Metal Prep, as we call it, needs to be neutralised with clean water once it has done its' job.

I find that if you wipe the surface well and dry with paper towels and spray liberally with metholated spirits [de-natured alcohol] you can evict the moisture quicksmart.

I use a pump pack to squirt and spray the metho into all the nooks and crannies to displace any moisture.

Follow that with compressed air [through a water trap] to force dry the metho.

Warm to hot weather is great since the metho will evaporate very quickly on its own.

Then a thorough wipe over with Prepsol [silicon Off, De-greaser etc.] and the yellow/tan colour comes right off and the metal is squeaky clean for etch primer.

All this is well and good, but the environment at the time must be warm and dry.

Cool or humid and you are going to have a battle to get it right:angry:

So that's how it's done, I was filling in my door handles today and when I see that little bit of yellow under the por (visible due to sanding) I get worried about it lasting even though the coat has stuck so well it's takes a power sander to get through it, sanding by hand just takes to long to get through por. I wish I had of known this method to do as I would have liked to not have the yellow tan all over my panels.

Cheers for the tip.

I love a good thread hijack ilikemyz and zcarmannn seems to have forgotten he even started this thread. Let us know what you end up doing with your bonnet.

[Nissanman]

You MUST use Prepsol, Silicon Off, or a similar product prior to painting.

It will remove silicon, grease, oil, all the nasty contaminants that you may have left on the surface.

[The major contributor of crud is the human hand:finger:]

You wipe it on with a saturated rag and wipe it off with clean rag in one fluid motion, one rag in each hand.

I use paper towels but you have to then make sure the fluff is removed.

You need to use a tack cloth anyway so that is when the towel residue is collected:paranoid:

Then a quick squirt of compressed air, through a water trap, and you're good to go:)

[240kconvertible]

Are you talking about general painting or Por specific painting?

I didn't have to use prepsol due to my car being sand blasted which por states is then ready for coating and all my panels were dipped to remove paint and any residue. The only spot that wasn't treated this way was the rear quater panels which were prepsol'd before the metal ready, was applied. In saying this I still didn't like the use of water at the end even if I know it's for the best.

[Nissanman]

I can't comment on the preparation for POR, since I have never used it.

If that is what POR say in their destruction sheet, fair enough:)

However for conventional painting, the metal prep is done to neutralise any remaining rust and prepare the surface for etching.

It needs to be washed of and itself neutralised with clean water.

The last steps prior to applying the etch primer, is a good wash down with Prepsol/Silicon Off wiped off with another clean rag, then a wipe over with a Tack cloth.

There is no point in using Prepsol prior to Metal ready:rolleyes:

The painting is the easy part:cheeky:

[240kconvertible]

There is no point in using Prepsol prior to Metal ready:rolleyes:

QUOTE]

There is if you used paint stripper to get the paint off and you've run out of marine clean

I've never heard of anyone using metal ready without using por, did you use the same metal ready from the por kit?

[Nissanman]

There is the problem.

I'm using Metal Prep as a generic term, not as what POR may specify/supply.

It is essentially phosphoric acid which you dilute in clean water.

It etches the surface of the metal and converts any remaining iron oxide to black iron phosphate.

Probably not at all suitable to the POR process:finger:

Stick to the POR list of treatments, by all means.

Apologies if I confused the issue:nervous:

[EScanlon]

Prepsol instead of Marine Clean is a poor substitute.

Most paint strippers have some form of MEK as the main "stripping" agent to dissolve and destroy the bond of previous paint applications. Prepsol would be fine as an oil, wax, or grease cutter, but probably next to useless against MEK, Acetone and the other chemicals in stripper. IIRC some of the paint strippers can also be neutralized with plain old water (just watch out for the runoff).

You'd be better off using plain old dishwashing detergent solution instead of Prepsol as a substitute for Marine Clean. Marine Clean is just a strong cleaner. Simple Green is yet another good substitute as well.

I'd be more concerned about the Metal Ready, Phosphoric Acid wash, or Metal Prep solution (old Ditzler term) reacting with the Prepsol (or plain old Wax and Grease Remover). Many Wax and Grease Removers use Mineral Spirits as part of their base.

POR is an excellent coating for areas that you won't be applying a visible finish to, such as undercarriages, inside fender wells, frame rails, etc. I wouldn't recommend it be used as a primer base because of the difficulty in sanding and getting a smooth finish. Yes, it does do a great job of self-leveling but it can and does set such that it may end up with a non-smooth finish.

There is a Tie-Coat Primer that can be applied over the POR and sanded smooth. However, the extra expense of the preparation and the POR and Tie-Coat primer instead of Epoxy Primer and a Fill Primer wouldn't justify it's use.

FWIW

E

[240kconvertible]

I actually used a dishwashing liquid concentrate before the prepwash (not prepsol I thought they were the same) then washed with water then used the metal ready. I didn't mention the dishwashing liquid as I thought someone may have a laugh at using that. Guess I was wrong.

It's not as bad as you think using por as an undercoat but it is as you state very expensive. You just have to make sure there are no runs in it as they cause big problems. If you use a high build primer you can cover the por quite easily but the runs will get you.

With the tie coat your not supposed to sand it just keep it clean and apply the next coat of primer. I don't know why but the instructions say the next coat on top of por tiecoat will adhere better if you don't sand it. So all you have to do is spray por then spray tie coat then spray 2k primer and you have a very durable and rust proof barrier on the car. You won't need to pick up the sand paper until the 2k primer is on.

If you live near the sea or are taking your car to England like me it is worth the money putting the por and tiecoat on. That way you'll be able to sleep at night knowing the rust monster won't get to your pride and joy again.

[EScanlon]

Actually the Tie-Coat Primer is their sandable primer. That is one of the key characteristics touted in their catalog.

They have another product that is just a Self-Etching Primer for application over cured POR which is not a high build primer and it also specifically says so.

As to why it would say to NOT sand the Tie Coat, I can only speculate, but I'll admit that I have NOT sanded it the last couple of times I've used it.

As far as spraying POR...be very careful. In fact, without plenty of ventilation AND a good breathing mask I would advise against it.

Unfortunately, the only way I've gotten POR to spray is to use a venturi type air blower to spray un-thinned POR. I have tried spraying using both a HVLP and a regular venturi type spray gun and you just can't thin it down enough to get it to spray properly. That's how I came up with the air blower nozzle set up. With that and 30-40 psi you can spray the inside of nooks and crannies in seconds and get a good film thickness. I've had very good luck with this method and there is very little "mist" spray to worry about. In fact, I was able to spray both insides of the rear fenders of a Z from the tail to the doors and up into the roof channels AND the complete inner tub of the cowl in less than an hour. I can't imagine how long it would have taken to hand brush the same area, but I CAN imagine the mess.

Don't feel bad about using the dishwashing concentrate, you'd be surprised at how many of us look for solutions that are "out of the box". One advantage to that instead of the Marine Clean is that it wouldn't etch your polished aluminum which the Marine Clean seems to do. (It's probably removing every last bit of polish, but it sure feels as if it etched it. Don't ask how I know, but DO trust me that it DOES.)

FWIW

Enrique

[240kconvertible]

I haven't been able to get my high build primer or por products to spray out of any of my guns, in the end I used a engine degreaser gun to spray them on. It worked really well but would put a bit too much on or if you turned the nozzel down it would mist too much.

I'll try using your method for the underside when I get round to it. Could you post a photo of what your set up looks like?

I tried to search on the net but didn't come up with the goods.

Cheers Andrew

[EScanlon]

Well the part number from Harbor Freight (37346 Syphon Spray Blow Gun) is coming up as either not available online or discontinued. This is a shame, as all it needed for cleanup was to replace the PVC tubing and a quick clean up of the tip.

It was a simple Air Blow Gun with a venturi nozzle at the end of the tip. Looks almost identical to this one:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=3962

except it had a tube screwed in to the end of the tip and an open nozzle in place of the rubber tip.

I suppose you could do something similar with this blow gun:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=42939

by either brazing, or somehow making a venturi right at the tip. That way when the air gets released it sucks the POR up through the delivery hose and the air blows it into the cavity you wish to paint.

Just recently while working on a Roadster, I had to drill some access holes to spray the inside of my rocker panels. The Roadster does not have the holes in the rocker panel that the Z has. Then in order to spray all the sides, I used this item:

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=3953

While cleanup with that item was a bit more involved, the syphon tube is inside the air delivery tube and it flows THROUGH the body of the gun, which means you have to completely disassemble it if you want to clean it.

Hope the links work, and although Harbor Freight may be a U.S. only store, surely the pictures will help you find something at your local discount tool place.

HTH

Enrique