anyone know how to eliminate rust from coming back

I recently got a buick gs hood, it had a thick layer of surface rust from sitting in a shed, anyways i got it home and removed most of it with sand paper, there are some black spots still of rust in there, nothing too major, metal is still good, i need to know if i can use a chemical to stop it from coming back, also i will also plan on using por 15 rust protector paint/primer, but will this affect the color i paint the car, which will be either saturn yellow or artic/apollo white. anyways, i was also planning on sandblasting, but cant this warp the metal..thanks

 

Eastwood makes a great Rust Encapsulator. I had use it on a couple other old cars I ahve had with good results

 

Will this work good for the top of the hood, i will have to primer it a lighter color (assuming it is black) in order for the paint either artic white or saturn yellow to look its best right.

 

I've heard good things about osfo (sp.?) phosphuric acid .. supposed to work great and you can sand and paint it nicely. I think it turns green when it is working its mojo with the rust in question.

 

Forty years of restoring ol 55-7 chevys I use nothing but OSPHO (phosphoric acid).....light sanding first, Ospho, after it dries, neutralize w/water, rustoleum primer.

 

Just used some of that stuff on my hood, looks like it works good, it makes the rust that was still in there turn black and the bare metal white, is this normal.. also will it keep it from coming back...what primer should this be coated with.. would por 15 rust prevent. paint work..i will plan on painting the car saturn yellow and will this change the color after applied.

 

Move to Arizona.

 

haha, thats a good one, although im actually in California..I dont think the car will ever see any reall time outside storage after it is done.. Im actually going to keep it where it belongs, right in my garage, Next to my bros :blast: chevelle..Any ways, i just wanted to know what type of primer should be used to protect it, also if there is a certain primer that goes under the saturn yellow paint, should i add a lighter primer on top of the darker rust primer.. just wondering how that is done...thanks guys

 

No do not use POR on sheet metal you want a nice finish on. Pay some $$ and seek a body shops advice. POR is meant for frames and hidden type things not a surface where you want good paint.

 

Ok, that is good thanks, I was actually planning on sand blasting the whole hood.. It actually is very clean right now, but im affraid of it coming back, it only had surface rust, which is a good thing, but i know rust can be tricky and darn hard to go away..Do you guys think if it is sand blasted it will remove it all..also as far as the professional work, im having a friend over he works on protype cars, not sure what company but i know he works there, he is the bodyman for that company and he is experienced at that, he has done several overhaulin cars at a previous shop so im kind of excited to start to work on the car along with him..thanks

 

STOP!!!!!!!!!!!!!!

Don't get anywhere near the hood with a sandblaster...much too easy to warp the sheet metal. Maybe use a handheld blaster to clean the underside metal structure---BUT---You should mask off the underside of the actual outer hood skin with tarpaper or cardboard. Also-if blasting on the understructure and you blast inside the various small holes punched in the understructure and HIT the underside of the hood skin---you stand a good chance of warping the hood skin in that spot. So stuff those various holes with something to block the blaster also.

On the Ospho....if you have a WHITE RESIDUE, this should be removed before any type of paint/primer is applied. This is a byproduct of the phosphating and it will inhibit paint adhesion.

If it were me I would continue to try and get the pitting removed via a DA air sander with 80 grit discs. Is the pitting REAL DEEP?...or are there just very small spots left??

EDIT: I just re-read your latest post and it sounds like you don't have any heavy pitting....I would spend some serious time going over it with a DA sander as I suggested above. Get it cleaned down to all shiny metal...with no black spots/rust areas. At that point I would use one of PPG's Metal Prep solutions and move on immediately to a couple good coats of Epoxy Primer (DP90 for example as a PPG product). Check with your paint supplier and see if they have a brand specific metal prep for whatever brand primer you use).

Also---there's no need to go with a heavier grit on the sanding/DA discs...80 grit should be plenty "gritty" enough to get the job done.

GIVEN THE CHOICE ( and assuming you have the time and equipment) I would not want to paint over the Ospho treated surface....I would err on the side of more sanding until the metal is CLEAN on its own.

 

Thanks another good point, I was planning on doing that, but how about the underside, i see some good places where rust is an issue, once again nothing too major, it is just surface rust that has been there a while, and needs to be sanded, this can easily be sanded al the way down to shiny metal, just though sand blasting was better, i guess not, also i dont use a d/a i use a polisher with a 7" disc, and it gets the job done faster than the d/a, now my concern is getting the underside all prepped up, i guess i can use por15 for this right.

 

Is this a variable speed polisher? The reason being is you can also generate a fair amount of heat on the sheet metal using something like that. At a minimum you shouldn't bear down or spend much time at all sanding any one area. Do the work in the shade...anything to keep the heat down. (Heck---I guess you could tape over the vents at the back of the hood and block of the hood scoop holes and turn on a small sprinkler aimed at the underside!!!--OOOPS!--Your polisher is electric so not a good idea:laugh: ).

POR--Again, just my opinion but this is not the place for POR if you have the time to fully prep the hood.

You could get some of the 3M or Norton Clean-N-Strip discs and chuck one on a drill and go at alot of the underside. These are 4"-5" or so in diameter/approx 3/4" thick and some come with an integral mandrel so all you have to do is tear off the packaging material and chuck it up in your drill. You can find these at auto paint supply places and at HDepot, etc. Not the cheapest products but as long as you don't run them where they are rotating into an edge on the sheet metal they will last a decent amount of time. What I am saying is there are a lot of sheet metal edges of the hood underside and you don't want the "Wooly Wheel" (another name for these cleaning discs) rotating on your drill where it can CATCH ON THE SHARP STAMPED EDGE of the underside metal...this tends to tear off pieces of the wooly wheel and they don't last as long.

You could also use these Wooly Wheels on the hood topside...maybe follow up with a light going-over with your polisher/sander.

I would use Eastwood Rust Encapsulator on the underside before I would use POR (and other POR knockoffs)...but frankly you shouldn't need much of this stuff...maybe down in areas where you can't get real good access with your cleaning-disc-of-choice. The rest I would, again, try to get CLEAN and metal prep and paint with a good epoxy. You could leave it at that or follow up with a satin black paint.

A lot of this depends on what you want out of this hood. Is this a resto or are you just looking for function and something you can put on as quick as possible? Even if it's a "just want it done now" deal...taking the time to get a good base of high quality primer on there now will preserve the underlying metal very well for a possibly more extensive resto job later on.

 

Everything Sounds good:TU: thanks, also make allot of sense, i polisher/sander i was using, i actually had it at about 1000 revolutions, that was the lowest, i figured at higher speeds the disc would burn out and cuase heat, so i used the lower speed instead.. i will try to do that for the underside, also i will just remove every spot of rust out, im actually not in a big hurry, i just want the bodyman to have it ready when he gets here, thatway i know forsure it was sanded to bare metal..im actually kind of picky about that:rant: and want to be clear minded that the paint wont pop up after a while.. after everything is all done my only big task is going to be either getting the gsx stencil kit or trying to make the stripes my self which would be a very hard challenge but something i would like to take on.:Comp: ..thanks guys keep it up.

 

Just realize that bare metal IS bare metal....in a perfect world as soon as you hang up the polisher and are satisfied it is CLEAN, you could:

>Blow the hood off with air

>Reach for the Wax and Grease Remover and wipe the whole thing down til the towels come up clean

>Apply a metal prep (whatever brand you are using for primer)according to the manufacturers instructions

>Wax and Grease again and....

>Mix some epoxy and spray it.

If the hood sits in bare metal for any period of time I would want to run over the whole thing again with a DA (or your polisher) and then move on to the prep and paint steps above.

 

Ok, that sounds good..right now im in the process of removing every spot of little black residue from the hood, after that when i get pure metal, i will do the following..thanks for the great info, all i have to do know is clean the underside and the air cleaner to move onto the next step.

 

Wow, what varied opinions on this subject! Age old debate. Here's what I'm goiong with inside and under my '72. RustBullet. I am about to apply this very soon. I will let you know the results. Seems the first 3 mil coat pinholes allowing oxides out, then second 3 mil coat seals the pinholes and locks things down. It is paintable, however being inside, I could care less since interior covers it all. I'm using silver, it is available in black also.
Anyone here used this before? I know POR seems to be the default choice, but...

 

how does it work, does this work good on exterior metal... i was told that por 15 could not be used as a bottom coat...Let me know what happens..i have gotten the metal down to bare and would like to protect it against rust for as long as i can.

 

I'm fairly sure Rust Bullet is another "version" or variation of POR15.

 

Not sure... It seems to have different attributes. Check their website, it's pretty good. Seems straight-up. I guess I'll find out soon. ray: