Metal Conditioning And Epoxy Priming 101

[fhernand]

This is the second stage of my previous thread “Paint Stripping 101”. I will discuss how to prep the metal for application of epoxy primer. I realize there are many ways to prep metal and remove rust, however, this is what works for me. The rust you see on the hood is mild pitted and surface rust. Any rust that I would consider to be seriously pitted I would recommend another hood. I do not recommend sand blasting the hood for this will cause warping. On a future thread I will discuss primer and bondo application. Safety tips for this job:

1. Use the metal conditioners in a well ventilated area (these cleaners contain acid).
2. Use a proper chemical rated respirator when applying metal conditioners (I recommend 3M cartridges).
3. Use your goggles when grinding the metal even though you will not see any sparks.
4. Use proper chemical rated gloves.

The tools needed are what you see on the table. Red Scratch Pad, Goggles, Air or Electric grinder, Dust Mask, Respirator (not shown in picture) Grinding Wheel (I recommend these wheels because they work great, heat is minimal, and gets in the pitted areas) Ear Muffs, Measuring Quart, PPG DX 579 Metal Cleaner, PPG DX 520 Metal Conditioner. DX 579 is a multi-purpose phosphoric acid. It is used to deep clean a metal surface prior to paint/primer. DX 520 is also an acid that will produce a zinc phosphate coating on steel and galvanized surfaces. DX 520 is also a rust inhibitor. Follow recommended dilution very carefully.



Concentrate on the rust spots first. Using the top edge of the grinding wheel, grind a small area first then move on. You may wish to use a cross pattern making sure that the wheel gets into the pits. Do not stay on one spot too long you do not want to create heat.


I now like to run the grinding wheel over the entire panel using a flat back-and-forth motion living the panel clean and shiny. Cleaning up the metal this way allows for more penetration when applying the metal conditioners.


You are now ready for the application of DX 579 Metal Cleaner. Follow the diluting and application instructions closely. Mix with water and apply over the entire panel. I like to use a red scratch pad from 3M. The acid should set for about 2-3 minutes. Rinse thoroughly letting the water sheet over the entire panel.



After letting the panel/hood air out for 10 minutes, I now apply DX 520 Metal Conditioner. You do not have to dilute. Apply the acid right out of the bottle and let it work for 2-3 minutes. Rinse well and dry right after. Again I like to use a red abrasive scratch pad. Once this dries, you will notice a fine sheet of zinc coating on the metal. Stuff work wonders!
[img]
http://forums.pelicanparts.com/uploads6/DX520+Metal+Conditioner1137813561.jpg[/img]


I use PPG Deltron DP 40 two-part catalyst epoxy primer. Follow the mixing instructions closely. I put on two wet coats allowing 10-15 minutes between the coats. Make sure that the panel is free of any debris or oils. DX 520 actually has detergent so this should be good enough. Allow epoxy to dry over night. We are now ready for the bondo work and urethane primer.



My next thread will be on Bondo And Priming 101. Thanks

[86 911]

The hood looks brand new. You have a lot of talent to work do this type of work. It's surprising to see a rusted hood go to a primered and ready-to-paint hood in only 2 days. Es muy bien Freddie!

[sp441]

Man you do nice work. I am waiting to do my bodywork until you are done with yours. Bookmarking everyone of these 101 threads!

[Tim Hancock]

I agree 100% with fhernand! I have used the exact PPG chemicals and primer on steel parts and there are also two similar chemicals for prepping alum then DP40 epoxy priming.

I switched to Dupont as my my local PPG store closed. Dupont has the same type products available in case you do not have a local PPG supplier. The products are as follows: Metal conditioner #5717S, Steel refinishing Conversion Coating #224S, Epoxy primer "Corlar" #824S and Activator #826S. Both brands basically work the same.

In both PPG and Dupont, the epoxy primer is offered in different colors (part number changes slightly). IMO, this is the "best" way to treat/prime bare steel. As fhernand stated there are other ways to do the job such as skipping the acid prep and using self etching primer, while this works good, the etch/epoxy prime method is still the "best". When properly applied, epoxy is the best coating to prevent moisture penetration long term. In fact many use thinned epoxy as a sealer later in the paint process also because of it's sealing properties.

This process is used by many who build/restore aircraft where long term corrosion just cannot be tolerated for fear of weakening of the thin structural components.

[JackMan]

Great post, thanks. I'll save this one in my files.

wj

[fhernand]

Thanks, great to hear that these threads are helping others.

JackMan- Great comments on Dupont products. Will keep this information handy.

[Nitrometano]

I would apply that concepts to my RX7 project.
Pa' ver si queda mejor de lo que está!!!

[ianc]

Thanks for taking the time to document your work!

ianc

[Zeke]

Originally posted by ianc
Thanks for taking the time to document your work!

ianc

What he said. And, this missing pic:

[JohnJL]

Great post, thanks.

I did the same on my FJ40, and can second the quality of the PPG epoxy...I used the same part numbers.

I did not epoxy the bumbers, axels,suspension or underbody/inside of the panels. Those all got 3 coats of black/silver/black POR15 because of the extreme abuse the truck sees on the underside. The POR was fantastic.

[fhernand]

Thanks Zeke, that is the picture of me applying DX 520 Metal Conditioner using a red scratch pad.

[fhernand]

JohnJL, I'm interested in seeing a picture of your project. Thanks

[GaryR]

Originally posted by 86 911
The hood looks brand new. You have a lot of talent to work do this type of work. It's surprising to see a rusted hood go to a primered and ready-to-paint hood in only 2 days. Es muy bien Freddie!

Matt -

The epoxy primer is not the last step before paint. He will, depending on the depth of the original pitting, fill the low spots with either bondo, laquer putty, or coats of a nice high build, sandable primer. There is a lot of finish work to go before that panel sees paint, stay tuned for the upcoming threads!

I think this all should be stickied under a DIY bodywork heading!

[fhernand]

Thank Gary for the imput. I already have the next threat "Bondo And Primer Surfacer Application 101". It's finding the time now to post it...but I will. Regards, Freddie

[rw7810]

I agree, just like the Engine Rebuilding Forum, I think one that covers autobody, painitng, welding ,etc. would be great. Anybody want to contact Wayne or one of the moderators??

[fhernand]

Bob, this would be a great resource to have indeed.

[fhernand]

I have now posted the third thread on "Bondo And Primer Application 101". Enjoy.

[911rudy]

Have any of you checked out the junk yard prices for a good used hood? It doesn't seem that all of this beautiful work is necessary if the used hood costs the same or even less.

[Nitrometano]

I think that Wayne at Pelican Parts can make a sub-forum or another section on the BBS about Porsche body repair. There Freddie Hernandez (fhernand) and another pelican's guys can post his repairs, painting, surface preparation, welding body parts, rust repair, panel replacement, fiberglass repair or making parts, sheet metal fabrication, bondo application, etc, in that specific forum section.

I think that would help a lot to all of us, because we can find a specific information about body work in one specific forum.

Wayne, what is your opinion????

[rw7810]

I mentioned this to Wayne some time ago and he generally agreed, but has made the additon yet......