surface rust
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surface rust
started sanding and grinding truck and I am having trouble getting down to metal where there is a lot of surface rust. I am geting down to a black hard substance. where the paint is still there it is nice shiny metal any advice? Also I will be putting rustolum on while I finish this job (slowly). good idea or not?
thanx.
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Elder User
Joined: Feb 2004
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From: San Luis Obispo, CA
There are several different forms of iron oxide aka: rust. The red form most people associate with the word rust is the chemical compound Fe2O3. Another common form of rust is Fe3O4. It is harder and darker. That is theory . . .
In practice, it will take a lot of energy to get rid of all the rust. You can use chemical (acid) to reduce the iron oxide back to iron. (Reduction is the opposite of oxidation.) Unfortunately, while you do get the iron back, it is a fine powder that will not stay a part of your steel body, so the surface will still be uneven and need filling with layers of a "high-build" surfacer/primer. Naval jelly is a convenient jellied phosphoric acid that is designed just for the purpose of reducing rust chemically. My experience is that the "black rust" will take too many applications of naval jelly to be worth using in a case like yours with large areas to deal with.
Another way to deal with your situation is to mechanically abrade the rust with a serious sand-blasting. If you can spend $$$, a pro can do the work. Get someone who has experience because you do not want half of your good steel to be blasted of in the process (unless you are building a racer and want thin fenders).
An option I am considering is to remove whatever rust will reasonably come off with sanding, then do some chemical work to remove any of the red rust. Finally I am considering sealing up the surface with an epoxy primer that will not let any moisture through, before proceeding with the rest of the paint job. I would be interested in other's experiences with this approach. A more expensive solution is the paint-over-rust (POR) paint, but the cost and difficulty seems to be a little much for a whole vehicle.
In practice, it will take a lot of energy to get rid of all the rust. You can use chemical (acid) to reduce the iron oxide back to iron. (Reduction is the opposite of oxidation.) Unfortunately, while you do get the iron back, it is a fine powder that will not stay a part of your steel body, so the surface will still be uneven and need filling with layers of a "high-build" surfacer/primer. Naval jelly is a convenient jellied phosphoric acid that is designed just for the purpose of reducing rust chemically. My experience is that the "black rust" will take too many applications of naval jelly to be worth using in a case like yours with large areas to deal with.
Another way to deal with your situation is to mechanically abrade the rust with a serious sand-blasting. If you can spend $$$, a pro can do the work. Get someone who has experience because you do not want half of your good steel to be blasted of in the process (unless you are building a racer and want thin fenders).
An option I am considering is to remove whatever rust will reasonably come off with sanding, then do some chemical work to remove any of the red rust. Finally I am considering sealing up the surface with an epoxy primer that will not let any moisture through, before proceeding with the rest of the paint job. I would be interested in other's experiences with this approach. A more expensive solution is the paint-over-rust (POR) paint, but the cost and difficulty seems to be a little much for a whole vehicle.
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Joined: Jan 2007
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The first question to ask is what are you looking for in the final result. Me personally, I'd leave the rust and drive it just the way it is,, but that's just me. I happen to like rusty old cars,, they have more character.
POR-15 is a good choice, but as said above, it'll be a bit expensinve to do the whole truck. If you're doing a complete restoration on it, sandblasting would be the way to go, or a company like redi-strip who could dip the whole truck and go from there. I've played with just about every supposed rust inhibitor on the market and none of them work with the exception of POR-15 and Rust Bullet, so the choice is really up to you.
POR-15 is a good choice, but as said above, it'll be a bit expensinve to do the whole truck. If you're doing a complete restoration on it, sandblasting would be the way to go, or a company like redi-strip who could dip the whole truck and go from there. I've played with just about every supposed rust inhibitor on the market and none of them work with the exception of POR-15 and Rust Bullet, so the choice is really up to you.
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