My 94 Barth Breakaway has some rust spots on the stairs. Any idea how I can get some touchup paint?

I can't help with the finish color, but I'd recommend acid-treating with a phosphoric acid primer which will neutralize the rust that can't be removed mechanically. Sand, then give the area two or three coats of cold galvanizing primer.

OSPHO... can you still get this stuff?

quote:

Originally posted by timnlana:
OSPHO... can you still get this stuff?

H3PO4 is available from chemical supply houses, aircraft suppliers sell it as "Skin Brightener", hardware stores sell it as "Naval Jelly". It is also a component in many industrial detergents, such as Acidet and Britex.

I use muriatic acid first, as it is cheaper, to kill rust, then apply H3PO4 to provide a phosphate coating to retard immediate and future rusting.



[This message has been edited by bill h (edited January 09, 2006).]

Ospho's one brand, Phosgo is another. I don't like Naval Jelly, as it has to be rinsed with water. I'd avoid muriatic acid, as it can decrystallize some iron alloys if used to excess (and it's nasty stuff).

Oxalic acid is fine, but hard to find anymore....takes longer, but it's nearly benign.

quote:

Originally posted by Rusty:
I'd avoid muriatic acid, as it can decrystallize some iron alloys if used to excess (and it's nasty stuff).

It used to be used a lot in factories for pickling steel, and in plating shops. I believe it is not so common now, at least in California, due to the nastiness you mention. The fumes are vicious.

So, how much is excess with a muriatic wash? My understanding of hydrogen embrittlement is that only really high strength or hardened steel alloys are affected. I am not sure it would affect the low and even medium carbon steels we might find on our RVs. I know of a lot of 4130 steel tube fuselages still flying around decades after HCL pickling. Some plating shops say that baking after pickling eliminates hydrogen embrittlement.

This oughta get the thread drift police swat team rolling.

I've had good success with "Extend" rust treatment in boats, cars, & RVs. Latex based, it comes in spray cans, or plain for brushing, and takes less surface preparaton than the other products. Knock off the scale, hit it with wire brush, wash off the rust powder, let dry, shoot it with "Extend," let dry per directions, & topcoat with paint.

From the way it reacts with rust, I'd say the active ingredient is phosphoric acid. It makes a good primer, but doesn't go on smoothly enough to use on exterior body panels.

Liquid galvanize is good. I've also used Ospho and Naval Jelly, but IMHO you get a better return for less effort with "Extend," than any of these other products, especially for things that are hard to sand like bumper brackets, frame members, etc.,, & other rusty places that don't require a smooth and glossy finish as body panels do.

I've had good luck with "Hammerite" brand paints, too, but only the ones that dry with a pearly, or planished appearance.



[This message has been edited by olroy (edited January 10, 2006).]

quote:

Originally posted by bill h:

It used to be used a lot in factories for pickling steel, and in plating shops. I believe it is not so common now, at least in California, due to the nastiness you mention. The fumes are vicious.

So, how much is excess with a muriatic wash? My understanding of hydrogen embrittlement is that only really high strength or hardened steel alloys are affected. I am not sure it would affect the low and even medium carbon steels we might find on our RVs. I know of a lot of 4130 steel tube fuselages still flying around decades after HCL pickling. Some plating shops say that baking after pickling eliminates hydrogen embrittlement.

This oughta get the thread drift police swat team rolling.

I wasn't talking about a "wash". Several of us got into a discussion about the best way to remove rust from marine engines (this was before the phosphoric acid treatment became common). My next door neighbor collected beer cans, and used oxalic acid to de-rust 'em. Another boat owner swore by muriatic acid.

So I had two cast-iron manifolds I'd replaced on my boat, and soaked one in oxalic acid and the other in muriatic acid for about three days. Both solutions removed the rust. But the one soaked in muratic acid could be marked with one's thumb, and metal flaked off with a fingernail, it was so soft.

That's not to say a more deliberate use of muriatic acid would cause problems, but it prompted me to stop using it for rust removal (except on concrete).

quote:

Originally posted by Rusty:

So I had two cast-iron manifolds I'd replaced on my boat, and soaked one in oxalic acid and the other in muriatic acid for about three days. Both solutions removed the rust. But the one soaked in muratic acid could be marked with one's thumb, and metal flaked off with a fingernail, it was so soft.

Wow, that's scary! I had no idea cast iron could be broken down like that.

It is the frame and the Barth mild steel parts under the coach that need work.

Anything I can just paint on to "Pickle" the surface would be best, I need to do inside two rails that go all the way aft. I am not too sure I can evenly paint inside the rails and am hoping to find a lighter liquid I can splop inside the rails to kill the rust.

Thanks:

Timothy

Then the phosphoric primer is the way to go.

The front beam on my SOB had substantial rust inside and out due to the water pump's leaking before I got it. I wirebrushed as much as I could reach, wiped out as much loose stuff as I could, then used a kitchen glass swab to slather on the phoshoric acid primer.

When dry, I wiped with mineral spirits to remove the excess, followed by two spray coats of cold galvanizing spray then two coats of epoxy.

Tim, if 'twere me, for that job I'd go with the aerosol can "Extend." It's a Loctite product. Check their website for more info. Much easier to spray, than to paint, or swab it on. Try one can & see how it works, then decide. Your local hardware, or auto supply store should have it.

Rick,

Trade the Barth, Damon makes a good product and they don't have steps.

Or.....try cleaning the rust as well as you can and give "Rust Bullet" a try. It doesn't require the use of acids and is generally a two coat application. It's not necessary to top coat unless you can see the area and want to match the paint. Steps take a beating and will require maintenance from time to time.

Rust Bullet is a tough product and has worked well for me.

Bill G

[This message has been edited by goodwinw (edited January 13, 2006).]

I wanted to get some touch up paint for my storage doors which I had to remove some rust. I found the numbers for the paint in my 3 ring binder and also in the engine department on a sticker. After spending $100 on a can of paint and one special aerosol spray none of it was even close. Believe it or not I found a can of rustoleum which matched perfectly.

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Sikkens has apparently changed the paint from the day Barth was using it to paint their coaches (environmental issues). Our numbers don't match the current paint they are using. There is also the fade factor which will make the paint look different even if you can match by the numbers.

The best match will be to use computer color matching from an auto body shop. This is a project I need to get on as I have a few corrosion spots to deal with.

There is no shortage of projects for me for this coming season. I hope I can get to all of them.

Bill G