Rust converter?

[rotrax]

When I was restoring Vintage and Veteran motorcycles and their various components getting down to bare metal -if after agressive cleaning there was in fact any left- using a mildish phosphoric acid dip worked well. IIRC Naval Jelly and Jelonite are just that in jelly form so they stick. When the surface turns black the ferrous oxide has converted through chemical action into a phosphated layer that MAY inhibit rust-at least for a while!

 

[BlueChip]

I used to regularly "convert" rust by painting with phosphoric acid. It reacts with rust to form an inert phosphate layer and this protects against further rust formation. It is quite good if you can leave excess acid in place (e.g. Inside a hollow structure) where the acid won't be a problem. e.g. Inside tubular spaceframe found on old TVRs.

However, the coating is easily damaged and only reforms if excess acid is still present. It is white, powdery and fairly easy to remove. So not much use on its own as a rust proof coating, but OK for treating surface rust. I had gallons at zero cost so used it quite a lot.

However, I wouldn't pay inflated prices for products using phosphoric acid as the active ingredient. I know that there are lots of other products using various other ingredients but it sounds as if there aren't any really good ones (based on Vyv's comments).

+1 I had access to Phosphoric Acid when I worked in a Lab, and treated a badly rusted Bukh 20 with it after wire brushing. Wash off, scrubbed again and retreated several times in a warm garage. Dried very well and painted with Massey Fergusson tractor primer and then red tractor paint.
Worked very well and no further signs of rust even after several years.

 

[ccscott49]

I used to regularly "convert" rust by painting with phosphoric acid. It reacts with rust to form an inert phosphate layer and this protects against further rust formation. It is quite good if you can leave excess acid in place (e.g. Inside a hollow structure) where the acid won't be a problem. e.g. Inside tubular spaceframe found on old TVRs.

However, the coating is easily damaged and only reforms if excess acid is still present. It is white, powdery and fairly easy to remove. So not much use on its own as a rust proof coating, but OK for treating surface rust. I had gallons at zero cost so used it quite a lot.

However, I wouldn't pay inflated prices for products using phosphoric acid as the active ingredient. I know that there are lots of other products using various other ingredients but it sounds as if there aren't any really good ones (based on Vyv's comments).

I've used ospho, which is basically phosphoric acid, we used it extensively on drilling rigs, seemed to work very well, on the boiat I still use it! A small amount escaped from the rig!

 

[mikewilkes]

A small amount escaped from the rig!

No wonder the oil industry has gone to s**t !!!!!

We use the same, Colin, on our cat. Touch up, or convert, the odd rust spot with phosphoric acid. Bought from the local Brico Depot in France. Had to BUY cos run out of the freebie stuff!!

.

 

[1bobt]

Why should you need to worry about a bit of surface rust on a six ton keel?

 

[Graham_Wright]

No wonder the oil industry has gone to s**t !!!!!

We use the same, Colin, on our cat. Touch up, or convert, the odd rust spot with phosphoric acid. Bought from the local Brico Depot in France. Had to BUY cos run out of the freebie stuff!!

.

I've informed the RSPCA.

 

[Pleiades]

Excellent rust converter products.

In my experience the rust converter products are wonderfully excellent at converting money in one's wallet into empty space.
Of course if ones buys bespoke "marine grade" rust converter products from chandleries the conversion process is so much faster and comprehensive -no trace of money will be left in a very short space of time.

Robin
Pleiades of Birdham
MXWQ5

 

[fisherman]

I have a sneaking suspicion, but no more, that Fertan (from the Bosun's Locker, Falmouth) is effective in some cases, it looks the same as Kurust. Rust Bullet and Galvafroid seem about the same. It is widely thought, apparently, that Hammerite is not the same since being taken over by ICI, and the formula has changed.

 

[davei]

I have used Vactan as a rust treatment for years - works for me. Just make sure there is NO salt on the metal
I just used it for my keel bolts.
Noting to do with the product just a satisfied user

 

[Mistroma]

I've used ospho, which is basically phosphoric acid, we used it extensively on drilling rigs, seemed to work very well, on the boiat I still use it! A small amount escaped from the rig!

Yup, I used orthophosphoric acid (phosphoric acid) and I'd guess that ospho is just a contraction of that name. Some people have mentioned a black coating forming. My memory is that it darkens but dries to a white powdery finish (ferrous phosphate layer).

 

[VicS]

Why should you need to worry about a bit of surface rust on a six ton keel?

The original question was about treating rust on a trailer.