Future rust prevention, I need some help. What about POR15?
 

I’m in the process of completely refurbing my '73. The car is disassembled to a tub state. The rotted front pan has been drilled and cut out, and the battery boxes have been cut off and replaced with flat sheet metal.

The battery box panels have been have been fit and welded in place. Surface prep was done with a grinder and denatured alcohol. I used 20ga galvanized sheet metal for the patch panels, and welded them with a Lincoln 100 HD converted to MIG with C02/argon mix for shielding gas. After the welding was done I sprayed the seam with a cold galvanizing compound, ground it flat, and used an aerosol primer on it. I am starting to notice an orange (rust) color around the welds already and I’m a little confused and frustrated. Have I done something wrong on the battery boxes, or is this normal? I want to make sure I’ve got this process down to a routine exercise before I strike an arc anywhere near the front pan.

Another area of concern is the surface rust that I have removed from one of the one of the rear kidney bowls and the front platform above the gas tank under the master cylinder reservoir. The kidney bowl is obvious contamination from the surrounding backseat area (leaky window seal that I caught before the longitudinal wheelhouse was eaten up), but I’m not sure what happened up front. It looks like brake fluid has overflowed, eaten away paint, and surface rust has resulted over time. I used my angle grinder with a wire wheel to clean it up real good and followed with a coat of the aerosol primer. Rust is showing through the primer after a week. :mad:

I want to make sure that rust never eats up the front of this car again. I live in a very humid climate and I have limited time (1 solid day a week) to tool on this car. I’m worried about controlling the rust as I expose unprotected metal while my work progresses.

I need to change something about the way I’m trying to control the rust situation in my car as I’m working on it. It seems like its trying to rust out from under me. I really need about 80hrs straight to work on the car, but that’s not going to happen as long as I’m among the employed. What can I do to more efficiently control the re-appearing rust as I’m working on this car on the weekends?

If I shoot the front clip with some POR15 can I stop worrying about this and work on the car as I have time? Is this stuff that good? I was planning on shooting at least one coat of POR after all of the metal work was done up front anyway, will a base coat help me avoid the problems I’m having? Will the POR stop the surface rust from coming back in the areas like under the master cylinder reservoir?

Yup,
raw primer is porous and doesn't stop rust from forming. You should use POR15 or Wurth Rust Guard liberally over the welds and bare sheet metal as base coats. These products are a reducing protective formulation which seals out water and air (without which rust cannot form).

Anytime I have bare metal exposed the first thing I coat with is a self-etching primer. I like to use a CR (chromate) wash two-part self-etching primer made by Sikkens...it will protect bare metal from rusting. I'm sure other paint manufacturers also have a self-etching primer. I then top the primer with Wurth Rust Guard.

In some climates there'll be flash rust in a couple of hours. I kept having it pop up after using store bought metal prep(as per instructions) but didn't have any with POR15s "Metalready".

The single chemical cans are useless. Use the 2-stages polymer types and a primer made for raw metal so it has the self etching to get rid of incidental rust and that will actually stick to the metal. The zinc coating should be protecting the raw metal as a sacrificial layer, so rust coming back is odd.

BTW, I hope POR15 works because I've done the interior, trunk and entire underside(especially wheel wells) with it and so far am impressed with the tough shell. It dosn't fix rust itself, and doesn't stick well to loose or greasy paint or smooth surfaces.

I use Por-15 products.
Two thin coats are better than one thick coat. It has to be primed with their liquid. Sometimes I'll prime with white vinegar.......Ron

POR-15 products are great, use them and be happy!

"The" body and paint website is Autobodystore.com. They have message board similar to this one where the pros really compare notes. The owner, like Wayne here, also runs a supply store and is very helpful on the phone and on the board. For whatever reason, the board is generally dismissive of POR 15 and leans towards a product called Picklex 20. I used on my Mach 1 restoration, which I conpletely Da'd to bare metal and spritzed with this stuff... it then sat for 7 months (!) in my garage like that waiting for the bodyman to get to it. No surface rust, and the bodyman now swears by it too. The other product I would pitch is 3M weld-thru coating. SPray both pieces right where you are going to weld. Welds are super-prone to rust as it's really pure steel.

I came across a paint called "Hammerite" and used it on the rusted lower sections of my 82 bronco to buy me spme time untill I can fix it. Well the paint held up for 4 years without any new signs of rust. Since then I've used it brackets and swim platform on my boat and again no rust. I now using it on the floor pans of my project. Not saying it's the only solution, but worth a look.
http://www.hammerite-automotive.com/
Carl

I am in the same boat as you are Shuie. My tub is down to the bare metal and I am in the process of cleaning off all the little bits of paint body shultz and primer that was left after the inital paint stripping. I also have some flash surface rust to deal with. I will be using the Por-15 but first I will wash the entire tub with a marine clean dry it and the metal etch Metal ready. Metal ready and marine clean are Por-15 products. The metal ready is a Phosporus(spelling?) acid That converts rust and lays a protective coating. I will shoot two coats of Por-15. 45 minutes after the second coat I can spray a light layer of the primer I am going to use. The tech's at Por -15 said this will allow the primer and Por-15 to chemically bond together. Then I can prime as much as I want before painting. They do not recommend using Por-15 over anthing except bare metal treated with metal ready etching solution. You can certainly do sections of the car if you want to. I thought about it but decided to wait until the whole tub is ready.

Thanks guys!

I just ordered some Marine Clean, Metal Ready, and some POR15 from the POR store.

Im doing everything in sections, because everytime I think about this car as a whole I want to sell it and move on. Its less overwhelming in sections :)

Hey Guys,

I have a 72T that does not have huge rust issues. There are some holes in the battery boxes and some surface rust in areas around the battery boxes and seam running crossway in front of the gas tank hole. I have not gotten the front down to bare metal. However, I have scraped away at places that had signs of rust. I plan on using por-15 on those areas.
Can you use Por 15 over the top of the coating over metal (like the underbody coating) that came from the factory. What other places are there that are absolute rust worries that could use a coat of POR-15 I might miss.

I applied it over the undercoat after washing it well and giving it a sanding with 80 grit and it seemed to stick. Also chiseled off all loose undercoat that was peeling. The scary thing was the floorpan looked good except a fine crack revealed advanced surface rust.

From what I have read putting Por-15 over anything other than the bare etched metal is a waist of money. They state to remove the possibility of rust reoccurring the Por -15 must bond directly to the metal.

Not in my case. I had some left-over Por-15 clear rust preventive that I wanted to use because of the limited time before the rest of the can cures.

So I cleaned up the outer fender wells of the front wheels with tolune, then acetone, then scratched it with sandpaper. Then applied the clear in 40degF temps. It stood a week before the roads..
That was 40k miles ago. It remains un-chipped and a simple water hose cleans it 90% worth. The A-frame with Por-15 black has some chips.
So I guess the stock fender well flex-undercoating aided the non-chipped Por clear......Ron

Be sure to remove and/or neutralize all the rust -- I use a chemical convertor product. It's recently been discovered that bacteria are involved in rust formation -- your car really is being eaten up.

"very humid climate" Baton Rude is worse than that! I grew up there and couldn't wait to leave. I feel for sorry for anyone that lives there. Also, hope you are not anywhere near N. BTR as the air pollution will eat your apint near the chemical plants (if they don't explode and kill you first).

I'd advise moving to New Orleans or Lafayette -- better food & culture to ofset the mosquitos, bugs, corrpution, and .....

I was out of town last week for some training. Upon returning to my office this morning, I couldn’t help but be remember how bad this place sucks.

Randy, you sound homesick. Here’s what you've been missing:

All of the refineries have been running full production 24/7 and laying off the Chem E's ever since the price of fuel really started to go up. In an effort of efficiency they have cancelled all of their maintenance contracts. Everyone knows that things like catcracking units don’t require a whole lot of maintenance, right?

That whole West Nile Virus scare last year was such an over reaction on the medias part.

As far as the political circus is concerned, I’m really disappointed in things here. I honestly can’t believe that someone from Louisiana didn’t think of recalling a gubernatorial election before this California thing happened.

Thankfully, DEQ has just announced that we will only be allowed to buy reformulated gas starting next year, so the air pollution problem should be cleared up soon :rolleyes:

Hah - I agree, La. is being upstaged by Florida and Cal. (all southern tier states, tho...). I've been back for 2 weeks every year since I left at age 18 (I'm 51 now) -- still enjoy New Orleans(!!). Sounds like you're a ChemE. Financially, it could be worse, eh. (you could have just gotten your EE degree in 2000). Good luck! And enjoy the food -- even if you have to drive 90 miles south or west...

I actually graduated EE/C in 2000 from LSU. I guess it could still be worse though. My fiance graduated ChemE in '01, has two other technical degrees, and is currently out of work :confused: . The bottom has completely fallen out of the ChemE field here.

The food is damn good though.

You can, but you'll get no benefit out of it, like others have said, its got to be directly on the metal. When I bought my car the better part of two days was spent by myself and two helpers removing all the underbody coating on my car down to absolutely bare metal, etched with Metal Ready and POR15'd.

POR-15 really needs to go to bare metal for best results. I have been using it since it first came out and have never had any rust return where it was applied properly. It really is designed to be top-coated with a good UV-resistant color coat if it is on surfaces that see direct sunlight.

We have used the chassis black for years with very good results. They have changed the formulation over time so that it is supposedly more UV-tolerant so that may not be an issue anymore.

For really tough topcoats I have been using PM Industries paint for a couple of years now. It seems to be less prone to chipping than POR-15 but will chalk out it not clear-coated.

WORD OF WARNING - POR-15 is a polyisocyanate so very good respirators with NIOSH-approved particulate filters are a necessity when shooting it. It is actually worse than Imron was for killing your lungs (know of at least one excellent painter that is now taking a dirt nap from his exposure over years with no respirator).

Paint has come a long way in being able to handle existing rust and staying adhered to less-than-perfect subsurfaces. POR-15 or PM Industries (I am sure there are others, too) will really help keep the rust gremlin at bay.

POR-15 markets products to a special clientele, in particular those that are emotionally attached to their cars and those that are willing to buy anything that sounds too good.

For one, why would you "encapsulate" rust with paint. It is true that rust is an oxidative process which requires air (oxygen) but once it has developed why would you want to enclose it with a urethane paint like POR 15? The best and only way to preserve metal is to remove the rust by mechanical means such as sanding, sand or media blasting, cutting and welding, or if it is surface rust you can try "dissolving" the rust with HCl (hydrochloric acid or muriatic acid). The latter will "eat" any iron-oxide so be careful because small surface rust may end up being pitholes in metal if this acid goes to work.

It will really clean rust off of metal, but the metal will start to re-rust instantly before your eyes. You have to wash this acid off (it is very "AGGRESSIVE" stuff, read warning labels!) to neutralize it, otherwise it may bleed through paint later. Lacquer thinner can be used to wipe over areas treated with muriatic acid to rid the metal of this stuff. At this stage you may consider neutralizing rust formation with Metal-Ready by Por 15. Wear some chemical gloves throughout all these procedures.

Metal Prep by POR-15 is an overprized phosphoric acid mixture that is marketed to an "upscale" automotive restoration market. I bought a gallon of this stuff after reading about it only to find out that it is the same stuff I have been using for decades on my marine applications and car restorations.

You can purchase the same stuff under different brand names at Home Depot and Advanced Auto Parts. Look for it under the names "Right Stuff", "Ospho" (the original product), and just plain "Phophoric Acid Rust Treatment".

The hardware and automotive parts stores get about 1/3 the price of POR-15. Buy it from POR-15 and you will pay for Mr. POR's retirement.

After the above two step I like to use steel wool or a scotch guard scuffing disk on a drill to loosen the dried on sediment of the chelated rust that form with the "Metal-Ready" stuff. Then mucho thinner to clean the metal, and also Prep-Sol or equivalent (auto paint supply store) to remove whatever silicone or grease on the surface. Next step is to shoot etching primer or a nice epoxy primer (uses catalyst). Lacquer primers are lousy for bare metal. They are porous and don't adhere like urethane primers.

To paint over bare acod treated metal in areas that will not be finished, like floors and underside of car, I like to use a marine product by Pettit Paints (?sp.). It has a high content of ZINC which is the best rust "deterent". This paint covers very nice, it can be sprayed or brushed, but do not let it dry on your skin. It will not come off until you shed your hide. 1 or 2 coats of this stuff and your metal will be better coated that any POR 15 paint. This paint is on metal on boats below the water line and on galvanized boat trailer to prevent rusting. When dry it looks like a cold galvanized product. Tested in a marine environment to withstand many hours of salt spray. You can then finish the underside of the car with body schutz or undercoating of choice. You can paint over this product if silver is not your color of choice.

Sold I believe as Zinc Chromate paint by Pettit Marine Paints (West Marine) in qts. for about $25.00. Unlike POR-15 this product has a long shelf life).

Happy restoring! I have some pictures of my 911 in different stages including all of the ones discussed in my "dissertation" above. I will be happy to send any one the correct names for these products.

Disclaimer: I have no commercial interest in any of these companies nor products, nor do I have any grudges against POR-15. I just want people to know that there are excellent (sometimes equivalent) , sometimes better, product available at LESSER cost.

Mike Nahar

71 911T/ RS Replica (in progress...)

Mike Nahar:

I got to admit I am emotionally attached to my car. I have also read the opinions on this board about the use of POR-15 and the quality result it provides. I won't be just slappin the POR-15 over rust. I myself have spent a lot of time removing all the rust and old undercoating from my tub.

Now how about showing us some pictures of the restoration you have done. The people on this board including myself LOVE to see pictures of 911"s being well taken care of and pampered..

Mike or other experienced members,

What is the best way to remove the undercoating from the metal surface in order to get to the metal inside the trunk. My chisel method seems very slow and the angles make the electric sander impractical. (Is there a magical liquid I can pour on to make it all go away?)

Thanks

Ron

Ron: I used a heat gun and a lot of elbow grease.

I'd love to post pictures but I have yet to figure out how to do that. Can someone walk me through it.

As for removing the schutz, use a heat gun and a metal putty knife or wide chisel. I would only remove in the area you are repairing and any loose stuff. In the trunk area it sticks pretty well. I have found some rust formation under the schutz coating in the rear fender wells, but I reckon the rust started from the inside out. Water or condensation probably got under through the seam where the panels meet. This is a critical area to inspect. I left my inside of the quaters untouched, but I cleaned all the seam areas and used my OSPHO (Metal-Ready) then I brushed on my Zinc Chromate paint. Next I will reschutz those areas. To replicate the factory schutz you can use Wurth's SKS and spray it on or dab it on with a sponge. I like 3M's high build undercoat in spray cans. Very similar to Wurths's and cheaper. Use only SKS is originality is important.

Mike

You can use a plumber's torch if you have a face mask, fire extinguisher and good ventilation. Make sure there is no gasoline around or a battery. This stuff will burn and smell really noxiuos but it will come off easy that way.

Ive been using an angle grinder and a heavy wire wheel to remove the under body coating with good success. It makes a mess, but I dont think there is a clean way to get this stuff off.

Hey 6771...

Forgive my ignorance, but what exactly do you mean by "Heat Gun"?

Thanks

Ron

I have used all of the above methods to remove the Wurth body shultz undercoating. The heatgun and Paint scraper with replaceable razor blades worked well for the flat areas. An air die grinder with an assortment of wire wheels worked well on curved areas. A dremel with the flexable cable attachment and an assortment of diamond tip grinding bits worked great on the creavices, seams and corners. I used aircraft stripper to remove the paint and any remaining light bits of undercoating and primer.

Mike Nahar:

When you select to post a reply the window that you enter your text in has a hypertext link under it that says attach multiple. Select the attach multiple link a window will open to allow you to upload a picture or multiple picturs from your harddrive. Make sure the names are unique and the file size is less than 100K for each picture. Don't name the pictures like 911, door, fender, since most of those names have been used and it will not upload that file. Use something like (door7865.jpg) this will make the file unique and won't match anyfiles allready uploaded.

heat gun = super blow dryer -- blows air past resistance heating coils to generate stream of hot air.

You can use a propane torch to do the same thing faster- wave a 3" flame over the surface , wait a second or so for it to soften the surface,and scrape the shultz off. Too much heat will start it burning or start the carpet on fire on the othere side.

6771911esses: Thanks for the info, it's great to have better alternatives to something that works pretty well. The Zinc-chromeate paint applications should work pretty well. Where is a good source for it?
The "encapsulation" of rust(anything at all) seems better atempt of preservation than seeing the rusted frames abandoned in the middle of a field. Thanks for the inspiration in preservation!!

I've heard used motor oil is better than nothing, but I'm looking into using a goo rust neutralizer/converter followed by "Wax-Oyl"-a combination of kerosine and parrafin-which the Brit restorers seem to love.

I will try to link some pictures later. Wax-Oyl is bloody messy. I had it on my Morgan and went thru hell to remove it. It is sticky and tary. I like this stuff that JC Whitney sell for about $40.00. You get a gun with different wands and about 3 qts of product. You will need an air compressor to spray this stuff. It is great for inner structural cavities that can not be reached with paint or anything else. It seems like the same stuff Ziebart et al. use. Simple to use. I would only inject it in the concealed cavities. Anywhere that you can reach with paint or undercoating, I would use a product that dries and doesn't stay tacky.

Cheers.

Mike

John70t: I don't get that "attach multiple" hyperlink. I found some instructions to include an URL but I would have to have these pictures posted then on a website. Correct?

re: used motor oil

It is a toxic waste -- don't put it on your car. Recycle it -- an wear gloves if you do it very often.

New motor oil is not toxic.

Mike, posting pics is easy- as per targa80's advice:
1. just put a copy of the pic on your desktop(or someplace where you can find easily) and give it a unique name(add a couple of numbers after).
2. On the "post reply" screen: click on the "attach multiple" at the bottom, and a pop-up will ask you where to find your pic and press send.
It takes a second even if nothing seems to happen, then the hypertext shows that your pic (now stored on the pelican server) has been added to your post.

john70t,

I found the links, now I just need to decrease the picture files and I can post some pictures. Thanks all.

Mike

Look for Irfanview on the net-it's free and a great viewer. To change file sizes I think go under batch conversion and try different settings.

I have resized some pictures to post. The silver gray finish on the rear shelf panel is the urethane zinc chromate paint. This went over metal that was derusted with a heavy duty wire brush on a grinder and then treated with Ospho (= Metal-Ready).

On the other picture you can see the front of my car that is devoid of any paint. It had been treated with Ospho as well. I a dry, non-humid garage it will not rust for many weeks. I would suggest to prime asap if possible.

Mikehttp://forums.pelicanparts.com/uploa...1067912875.jpg

http://forums.pelicanparts.com/uploa...1067912891.jpg

Note the new welded section on the shelf panel. The corners were cut out and removed. I welded replacement sections in on the seam as to duplicate the appearance of the factory panel. A bit of seam sealer on zinc chromate primer, next a light coat of body schutz or 3M high build undercoat, then the final color.

Mike