nycgps

iTrader: (4)

yea I searched and I read 5 different threads including Aaron's site.

Anyway, I just start taking my 91 FC apart like 2 days ago, I noticed some rust around the area holding the radiator, some on the front member, rear sub frame, etc etc.

For those who used POR 15 , how you guys prep some of the areas say, the front brace right in front of the A/C Condenser ?

Please people, share your POR 15 experience



Thanks

PvillKnight7

iTrader: (16)

Remove all rust.
Remove dirt and oil with acetone.
Spray a 2 part urethane primer sealer.
Spray a color coat.
Spray a clear coat.

If you don't remove all the rust you will see it again soon.

The rusted areas you mentioned are hard to get into with power tools. The rust you can see is only 10% of the rust problem.

daviddeep

iTrader: (4)

I had some rust on the front subframe in the engine bay just below my brake master cylinder where it obviously leaked for the previous owner years ago. Kind of in the spot near where the fuel filter hangs. I bought the POR-15 starter kit or whatever they call it as an experiment. It comes with the two prep chemicals they recommend. I think you're supposed to brush off the loose rust, then etch the area with Metal Ready then wash it with Marine Clean (not sure if I have those names exactly right). Anyway, I followed all their directions and it turned out great. Also did a small area in my my sunroof track area that had some rust bubbles. The worst part is waiting between steps for everything to dry.

Apparently POR-15 won't hold up to UV light exposure so if it's anywhere that will see sunshine, you're supposed to topcoat it with paint. Also, I understand that once it's on, it's on. So you don't want to use it on something you were hoping to strip and repaint later.

rx7racerca

iTrader: (1)

Search for user aaroncake and his project Tina threads - he used Por15 for the underbody, and like all his writeups documented the work with photos and described it in detail.

PvillKnight7

iTrader: (16)

Why don't you buy some zMax and Seafoam while you're wasting money? Por-15 is an over hyped over priced paint that can't compare to 2 part urethane and clear coat.

nycgps

iTrader: (4)

even with POR15 I will still try to sand as much as possible.

I never said I will use power tools to do it.

I took almost all panels off already and I only see rust at a few spot so I guess Im lucky ?

I will use it only in areas that will never see light (somewhere covered by trim/panels.

I don't have a dust free area (nor have the space to make one right now) So its going to be hard to do 2 part urethane & clear coat.

I can try. but not going to look good.

Seafoam works, zMax no.

Aaron Cake

iTrader: (1)

Having a huge amount of experience with POR-15 and much of their product line, the hairs on the back of my neck stick up when someone says that it is "over hyped" and "can't compare to a 2 part urethane". Especially when that person didn't at all refer to an epoxy primer, but instead a primer/sealer which would be applied after the epoxy but before the colour coat. But for now, I'll just ignore that...

Regarding POR-15, the prep procedure is exactly what they lay out in their documentation:
http://www.por15.com/Data%20Sheets/n...directions.pdf

Here are the detailed instructions:
http://www.por15.com/Data%20Sheets/P...cationInfo.pdf

Like any paint product, prep is 99% of the work. Rust in the area to be painted needs to be brought down to one level, otherwise the paint will adhere to just a layer of rust over another layer and will fail soon. My preferred method these days is to just sand blast it all, but obviously, few people have a blaster. So a good wire wheel on a drill will do the job. Don't fool yourself; POR-15 is not a miracle paint. If you are trying to fix a rusty seam, it won't work because there is active rust trapped between the two layers. The seam would have to be cut apart, de-rusted, then welded back together to make a proper repair.

Once the rust is removed down to either a single layer or bare metal, it must be CLEANED to the point of perfection. I generally don't use their Marine Clean product because I just buy big jugs of Super Clean at the local auto parts store. Mix it with water, scrub all the areas, rinse thoroughly and then LET IT DRY.

For sand blasted metal, you can generally paint right over with POR-15 as long as the metal is grease free and dry. I just give it a few hits with brake cleaner and blow off with air.

For areas with rust, or fresh metal/welds, then you must etch with MetalReady. It's basically phosphoric acid with dissolved zinc. It stops much of the existing rust and leaves a zinc finish that POR-15 just loves. It also etches the surface because POR-15 hates a smooth surface. Leave the MetalReady on there for about 20 minutes then rinse clean with water. Don't be alarmed at the white powder that forms (blow it off) or the surface rust.

Then the area must be completely dry. And by completely, I mean BONE FREAKING DRY. This is very important with any paint product but especially true for POR-15 because it cures via moisture. So if there is still dampness, you can end up with trapped moisture under the paint (very bad) and it will get into your POR-15 pot, and start curing it immediately. If it is a humid day, wait until a dry day.

Apply at least two coats. I generally do three. The instructions say between 3 and 4 hours per coat, or when there is slight finger drag. But I have found that it is still off gassing (just CO2) at that point which may create bubbles in the next coat (ruining it totally). So I usually paint right in the morning, then come back to it around 5-6 hours later. The first coat can be sort of light just to cover, then the next coats can be heavier.

Unless you have a full fresh air breathing system, DO NOT SPRAY. Brushing works quite well. Buy cheap brushes because you'll just throw them out. When you buy your POR-15, but the solvent as well because you'll need it to clean up and if you get any on your skin. FOR THE LOVE OF ALL THAT IS HOLY, DO NOT LET IT DRY ON YOUR SKIN. It will not come off. Only time will take it off, and in many areas of our body that means wearing it for 3-6 weeks. Ask me how I know. The solvent will burn your skin so if you use it, wash quickly afterwards. MetalReady is an acid so keep it away from your face (ask me how I know) and wear gloves. Cured POR-15 can only be removed via grinding, scraping or other mechanical means (note: sand blasting generally will not remove it easily) so keep that in mind.

I've been very happy with their products when used correctly. I've had friends who just slapped the stuff on rust and then complain in a few months when it starts to bubble. Directions must be followed for use like any paint system.

As for topcoating and UV resistance....POR-15 is only discoloured by UV exposure, not broken down in any way. And subframes/engine bays do not see enough UV exposure. If you want to top coat it, it should be allowed to dry for a day or so and then primed. The company makes a primer product specifically for this (their "Tie-Coat Primer"). I've had good luck with just letting the POR-15 dry for a day then spraying hardware store rust paint over it. If it has dried for several days it will need to be sanded.

Maybe I should post those pictures of my body which demonstrate exactly why it should not be allowed to dry on skin?

nycgps

iTrader: (4)

Thx Aaron, I read everything on your site and I love your build(rebuild?)

I have a question about prepping --- there is one area I can't just "rinse" it off, that's the spare tire area.

Previous owner of the car never give a **** about the 2 drain holes for the rear lift gate, when I got the car I noticed that one of them was clogged up, when it rains hard enough, crap will flood and water goes into the spare tire area, it created a "puddle" of water.

crap was so nasty it took me a while to clean it up.

then I noticed a bit of rust at the bottom. consider how long it has seen water surprisingly that's the only rusted area. (I checked everywhere else)

since there is no way for me to "rinse" that area with water, I assume I can just clean it with MarineClean/Super Clean first, then use tons of shop towels with clean water to wipe the area ?

*Im going to snap a photo of it right now brb in about 5-10 minutes*

PvillKnight7

iTrader: (16)

2k primer sealer can be used on metal...especially on a place no one will see. Another reason not to worry about dust.

nycgps

iTrader: (4)

What you guys think of "this" ?

I asked a friend he said if its like that I should just give up.


as far as I know its NOT rusted thru (I checked the bottom)

and I think I can grind all the rust away with a wheel ?

PvillKnight7

iTrader: (16)

Did you fix the water leak? Bad hatch seal? It's not bad ..Do the best you can use some paint to make it look pretty and forget about it. A little rust won't make the car fall apart.

nycgps

iTrader: (4)

I fixed it the 2nd day I notice this "issue", previous owner never told me about this "puddle" of water.

took a hanger, bent it to a semi striaght line, warp a piece of old t-shirt and poke the drain thru. then use lots of dish wash thru the hole, gave it some more "rub", good as new.

Need to get a new hatch seal too, old one has crack marks all around. but its not leaking now so I will wait a bit before I get that.

I guess I will try to get a wheel and grind the bad stuff away, clean it and put some touch up over it and forget it ?

Cratecruncher

I use an engine oil gallery brush to clear my hatch drains. Most auto stores have them. They look like a little bottle brush with a 4 ft length of wire for a handle.

Aaron Cake

iTrader: (1)

I'm betting that rust goes all the way through. The factory undercoating is great at hiding pinholes. A few pinholes in that area mean the metal is very thin. The proper way to fix it would be to cut it out and weld in a new section. But if it is just a few pinholes, the POR-15 company makes "POR Paste" which is like thick POR-15 in a tube. It can be used as a patch and works well (not that I would advocate it's use over a proper repair, though).

Rust is like cancer. It needs to be dealt with properly otherwise it will be back.

As for cleaning the area, I'd clean it up, MetalReady it, then just use a few wet rags to wipe off the excess MetalReady. Then let it totally dry and do the POR-15'ing.

Alternately, if it really is just light surface rust, take it off with a wire wheel, clean it up with brake cleaner, then spray hardware store rust paint on it.

But I'm of the attitude that rust is a force of evil and should be dealt with swiftly and with overkill.

nycgps

iTrader: (4)

Got it. I will try to do as much "overkill" as I can.

Lets just see how this goes.

Thx

FC_fan

iTrader: (2)

This is what I'm working with. I can mig weld enough to get by but am no pro. using metal ready and then self etching primer and hardware store rust paint just because the inside doesn't see the elements. lots of work, not worth it. its a sentimental value thing. only major rust on the car other then the other rocker panel (not nearly as bad) and minor surface rust on underside but doing a resto on the whole car alittle at a time.

If I can do this, you can take care of yours.lol. it's called encouragement. to many of these cars are in being thrown away because of things like this.

nycgps

iTrader: (4)

I guess with 211K on the odo my FC is actually in very decent shape.

I don't have any of those rust ... but I will probably add some more under coating here and there to prevent them happening in the future.

Ryan123

iTrader: (3)

You clearly have not used any POR-15 product or you have but cannot read directions..... but Aaron Cake has already taken care of that.



+1

I’m currently stripping all the undercoat from my car and although it looked like it was in good health there were spots hiding underneath that were indictable.

Try pressing on the spots with your finger then LIGHTLY tap on it with a screwdriver to get the feel of how badly its rusted.

I have a Question for you Aaron Cake, what is your opinion of a por-15 coat of the entire car as a primer then using normal paint then following up with the moister drying clear coats?

nycgps

iTrader: (4)

Hmm so what you are saying is the rust somehow can go thru the undercoating and damage the inside?

Strip all undercoating gonna be a mess .... Hmm but if it can help save the car then .... I might do it

Ryan123

iTrader: (3)

By rusting, I mean like dime to quarter size spots. It’s nothing that’s detrimental to the health of the car like rocker panel rot; some people may not even bother with it, but I cannot live with the idea of knowing it is there.

Personally, I’m treating it all with Por-15 ( Marine Clean, Metal Ready and silver Por-150 )then coating it with truck bed liner. I live by the saying “ Go big or Go home” .

daviddeep

iTrader: (4)

I think what happens is that moisture gets under the undercoating and causes rust. The undercoating doesn't necessarily fall off, so it looks intact but is hiding rusty metal. Or in the alternative, sometimes the rust starts on the other side of the metal and eats its way through.

On my previous S5, the floors were rusting from the interior side of the car out. From underneath, the car looked great. A gentle push from the exterior side and suddenly I had some rather huge holes.

nycgps

iTrader: (4)

go big or go home. agreed !

damn I wonder how long does it take to remove all undercoating ... looking at Aaron Cake's site, hmm, seems like its gonna be weeks if not months !

what do you use to remove those "plastic/mud" like undercoating anyway?

on Aaron's site he said he used kerosene, just rub them on till it comes off ?

Next week Im going to remove the dash to remove the carpet. just to be sure that everything is "good"

daviddeep

iTrader: (4)

If you don't need to remove the dash for some other reason, no real need to do that just to check the condition of the floors. With the seats out and all the door sill trim off, you can lift the carpet and see just about everything.

nycgps

iTrader: (4)

do I need to remove the dash to remove the whole engine/emission harness ? I honestly don't know.

I 100% need to rebuild that, because one of the previous owner installed some garbage Viper alarm which ***** up almost everything + the harness is like 20 years old so I guess it might be a good time to rewire them.

Ryan123

iTrader: (3)

It takes forever. Im using a wire wheel and it works well but gets messy.

Ive been told to use dry ice; place it on the inside of the car and then strike the undercoating with a hammer lightly and it will crack off. Just another idea, I may try that