One of those jobs I've looked at and passed by for years is our front
gate. It's not been touched in 41 years and probably not before that for
a while.

The posts are steel square RHS and the gates welded mild steel with
scroll patterns. They appear to have been primed with a zinc rich paint
like galvafroid and then painted black. Now about 50% of the surface is
rusty.

I can wire brusk the rust and paint over with smooth hammerite but
wondered if it was worth applying some phosphoric acid based rust eater
and deterent first. If so what is a cheap source as those little tubs
for rust spots on cars are far too expensive.

On Sun, 12 Apr 2020 13:00:48 +0100, AJH wrote:

One of those jobs I've looked at and passed by for years is our front
gate. It's not been touched in 41 years and probably not before that for
a while.

The posts are steel square RHS and the gates welded mild steel with
scroll patterns. They appear to have been primed with a zinc rich paint
like galvafroid and then painted black. Now about 50% of the surface is
rusty.

I can wire brusk the rust and paint over with smooth hammerite but
wondered if it was worth applying some phosphoric acid based rust eater
and deterent first. If so what is a cheap source as those little tubs
for rust spots on cars are far too expensive.

I bought a gallon equivalent from amazon for around £20 it was called
toilet cleaner.

On Sun, 12 Apr 2020 13:00:48 +0100, AJH wrote:

One of those jobs I've looked at and passed by for years is our front
gate. It's not been touched in 41 years and probably not before that for
a while.

The posts are steel square RHS and the gates welded mild steel with
scroll patterns. They appear to have been primed with a zinc rich paint
like galvafroid and then painted black. Now about 50% of the surface is
rusty.

I can wire brusk the rust and paint over with smooth hammerite but
wondered if it was worth applying some phosphoric acid based rust eater
and deterent first. If so what is a cheap source as those little tubs
for rust spots on cars are far too expensive.



Sorry, it's called toilet descaler....Phosphoric Acid 10%-30% and it is
bright red. £14.69 for 5 litres.

On 12/04/2020 13:22, John wrote:
On Sun, 12 Apr 2020 13:00:48 +0100, AJH wrote:

One of those jobs I've looked at and passed by for years is our front
gate. It's not been touched in 41 years and probably not before that for
a while.

The posts are steel square RHS and the gates welded mild steel with
scroll patterns. They appear to have been primed with a zinc rich paint
like galvafroid and then painted black. Now about 50% of the surface is
rusty.

I can wire brusk the rust and paint over with smooth hammerite but
wondered if it was worth applying some phosphoric acid based rust eater
and deterent first. If so what is a cheap source as those little tubs
for rust spots on cars are far too expensive.

I bought a gallon equivalent from amazon for around £20 it was called
toilet cleaner.


Used in Hydroponics "pH Down" is 81% phosphoric acid.

I have noticed that in the past few weeks certain chemicals that I have
purchased in the past and require again now are either in short supply
with many retailers saying out of stock or have gone up in price (in one
case the price per litre is now the same as I paid for 5 litres in
December.)



--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 12/04/2020 13:00, AJH wrote:
One of those jobs I've looked at and passed by for years is our front
gate. It's not been touched in 41 years and probably not before that for
a while.

The posts are steel square RHS and the gates welded mild steel with
scroll patterns. They appear to have been primed with a zinc rich paint
like galvafroid and then painted black. Now about 50% of the surface is
rusty.

I can wire brusk the rust and paint over with smooth hammerite but
wondered if it was worth applying some phosphoric acid basedÂ* rust eater
and deterent first. If so what is a cheap source as those little tubs
for rust spots on cars are far too expensive.


Sounds like a big area to treat but some phosphoric acid based treatment
would be my choice, followed by either a zinc based primer and/or
hammerite. When we bought the current house (20+ years back), the side
gate was pretty rusty. I took a wire brush to it (on a drill), treated
as above. I think we've painted it once since. I noticed yesterday it
still looks fine. (Checking for jobs that may need doing!)

--

https://www.antislavery.org/slavery-...forced-labour/

On 12/04/2020 14:16, alan_m wrote:
On 12/04/2020 13:22, John wrote:
On Sun, 12 Apr 2020 13:00:48 +0100, AJH wrote:

One of those jobs I've looked at and passed by for years is our front
gate. It's not been touched in 41 years and probably not before that for
a while.

The posts are steel square RHS and the gates welded mild steel with
scroll patterns. They appear to have been primed with a zinc rich paint
like galvafroid and then painted black. Now about 50% of the surface is
rusty.

I can wire brusk the rust and paint over with smooth hammerite but
wondered if it was worth applying some phosphoric acid basedÂ* rust eater
and deterent first. If so what is a cheap source as those little tubs
for rust spots on cars are far too expensive.

I bought a gallon equivalent from amazon for around £20 it was called
toilet cleaner.


Used in Hydroponics "pH Down" is 81% phosphoric acid.

I have noticed that in the past few weeks certain chemicals that I have
purchased in the past and require again now are either in short supply
with many retailers saying out of stock or have gone up in price (in one
case the price per litre is now the same as I paid for 5 litres in
December.)



Thanks, shame I cannot pick any up locally but it still works out
cheaper than the descaler if I dilute it to 30% even with delivery

AJH wrote:
One of those jobs I've looked at and passed by for years is our front
gate. It's not been touched in 41 years and probably not before that for
a while.

The posts are steel square RHS and the gates welded mild steel with
scroll patterns. They appear to have been primed with a zinc rich paint
like galvafroid and then painted black. Now about 50% of the surface is
rusty.

I can wire brusk the rust and paint over with smooth hammerite but
wondered if it was worth applying some phosphoric acid based rust eater
and deterent first. If so what is a cheap source as those little tubs
for rust spots on cars are far too expensive.

https://www.hunker.com/13415944/how-...th-naval-jelly

An experiment I did with this years ago, when you rinse
off the rust, any shiny metal underneath *rusts almost instantly*
after the rinse. It takes a very short time for the surface
rust to come back. This has to do with the naval jelly etching pores
into the metal and increasing the surface area. You cannot
possibly apply a finish fast enough, to stop that from happening.
You would need a finish that can be applied right over un-rinsed
pure naval jelly (which is not going to happen).

Test the process on a separate rusty metal sample you keep
for the purpose, to see what the effect will be in advance.

Don't panic if that happens. Just make sure that the finish
you're applying, after you rinse off the naval jelly thoroughly
and allow time for the surface to dry, that finish should be rated
for "application over rust".

My conclusion was, I wouldn't be using any more of this for
home projects. It's fun to play with, but doesn't change the
nature of the problem you're trying to solve.

When I refinished the steel rear landing on the back of
the house, I just used a wheel and a rust paint over top.
And this did not do well, anywhere that there was standing
water from rainfall. Since I took the wheel to the under-side
of the landing too, the finish under there held up well.
And probably won't need to be re-done. Using the wire wheel
under there, was "pure hell". I looked like a coal miner
when I was done.

Paul

I guess it depends on the state of the posts at their base. I'd hate to have
primed a gate only to find only the rust is holding the post together!

The last time I needed to do my font gate I knew a bloke who worked at a
plating company, and he immersed it in a bath and stripped all the paint of,
another to remove the rust then he had to fix a few dodgy welds, then dipped
it in some zinc primer stuff and I painted it Hammerite hammer finish cream.
However it does not after many years need to be redone, but do wonder if it
could stand it... grin.
Brian

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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"John" wrote in message ...
On Sun, 12 Apr 2020 13:00:48 +0100, AJH wrote:

One of those jobs I've looked at and passed by for years is our front
gate. It's not been touched in 41 years and probably not before that for
a while.

The posts are steel square RHS and the gates welded mild steel with
scroll patterns. They appear to have been primed with a zinc rich paint
like galvafroid and then painted black. Now about 50% of the surface is
rusty.

I can wire brusk the rust and paint over with smooth hammerite but
wondered if it was worth applying some phosphoric acid based rust eater
and deterent first. If so what is a cheap source as those little tubs
for rust spots on cars are far too expensive.

I bought a gallon equivalent from amazon for around £20 it was called
toilet cleaner.

On 12/04/2020 21:50, Paul wrote:

https://www.hunker.com/13415944/how-...th-naval-jelly

An experiment I did with this years ago, when you rinse
off the rust, any shiny metal underneath *rusts almost instantly*
after the rinse. It takes a very short time for the surface
rust to come back. This has to do with the naval jelly etching pores
into the metal and increasing the surface area. You cannot
possibly apply a finish fast enough, to stop that from happening.
You would need a finish that can be applied right over un-rinsed
pure naval jelly (which is not going to happen).

I don't know what 'naval jelly' is, but phosphoric acid is not like
that, and phosphoric acid is what the OP was asking about.
IME phosphoric acid immediately converts any iron oxide to iron
phosphate, which is stable, and impervious to air and water.

And black, not shiny.

Once rinsed and dried its a good base for zinc primer.


--
Outside of a dog, a book is a man's best friend. Inside of a dog it's
too dark to read.

Groucho Marx

AJH Wrote in message:
On 12/04/2020 14:16, alan_m wrote:
On 12/04/2020 13:22, John wrote:
On Sun, 12 Apr 2020 13:00:48 +0100, AJH wrote:

One of those jobs I've looked at and passed by for years is our front
gate. It's not been touched in 41 years and probably not before that for
a while.

The posts are steel square RHS and the gates welded mild steel with
scroll patterns. They appear to have been primed with a zinc rich paint
like galvafroid and then painted black. Now about 50% of the surface is
rusty.

I can wire brusk the rust and paint over with smooth hammerite but
wondered if it was worth applying some phosphoric acid based rust eater
and deterent first. If so what is a cheap source as those little tubs
for rust spots on cars are far too expensive.

I bought a gallon equivalent from amazon for around £20 it was called
toilet cleaner.


Used in Hydroponics "pH Down" is 81% phosphoric acid.

I have noticed that in the past few weeks certain chemicals that I have
purchased in the past and require again now are either in short supply
with many retailers saying out of stock or have gone up in price (in one
case the price per litre is now the same as I paid for 5 litres in
December.)



Thanks, shame I cannot pick any up locally but it still works out
cheaper than the descaler if I dilute it to 30% even with delivery


1 litre 81% £10.99 delivered off eBay...
--
Jimk


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 13/04/2020 08:58, The Natural Philosopher wrote:
On 12/04/2020 21:50, Paul wrote:

https://www.hunker.com/13415944/how-...th-naval-jelly

An experiment I did with this years ago, when you rinse
off the rust, any shiny metal underneath *rusts almost instantly*
after the rinse. It takes a very short time for the surface
rust to come back. This has to do with the naval jelly etching pores
into the metal and increasing the surface area. You cannot
possibly apply a finish fast enough, to stop that from happening.
You would need a finish that can be applied right over un-rinsed
pure naval jelly (which is not going to happen).

I don't know what 'naval jelly' is, but phosphoric acid is not like
that, and phosphoric acid is what the OP was asking about.
IME phosphoric acid immediately converts any iron oxide to iron
phosphate, which is stable, and impervious to air and water.

And black, not shiny.

Once rinsed and dried its a good base for zinc primer.


That's my understanding too, hydrochloric acid gets the rust off faster
(tried it after advice from here a year or so ago) but the iron chloride
it is converted to is soluble and the fresh iron underneath is very
reactive in air, as you say the phosphate is insoluble and stable for a
while before you paint.

On 13/04/2020 08:30, Brian Gaff (Sofa 2) wrote:
I guess it depends on the state of the posts at their base. I'd hate to have
primed a gate only to find only the rust is holding the post together!

I started cleaning up the bottoms of the posts today and the rust has
perforated the metal just above the concrete in a couple of places on
each post, I wire brushed them, applied a first aid thin band of paint
and am wondering whether to squirt some foam in to exclude water and air?

In the mean while I have taped over the holes. I could plate over with a
welder but it's probably not necessary as they are firm.

I have yet to order the pH down.

On Monday, 13 April 2020 08:58:02 UTC+1, The Natural Philosopher wrote:
On 12/04/2020 21:50, Paul wrote:

https://www.hunker.com/13415944/how-...th-naval-jelly

An experiment I did with this years ago, when you rinse
off the rust, any shiny metal underneath *rusts almost instantly*
after the rinse. It takes a very short time for the surface
rust to come back. This has to do with the naval jelly etching pores
into the metal and increasing the surface area. You cannot
possibly apply a finish fast enough, to stop that from happening.
You would need a finish that can be applied right over un-rinsed
pure naval jelly (which is not going to happen).

I don't know what 'naval jelly' is, but phosphoric acid is not like
that, and phosphoric acid is what the OP was asking about.
IME phosphoric acid immediately converts any iron oxide to iron
phosphate, which is stable, and impervious to air and water.

And black, not shiny.

Once rinsed and dried its a good base for zinc primer.

HCl works the way Paul describes. I sometimes use it but yes, if you rinse it then let it dry it'll already be rusty. Cleaned metal must be coated immediately, eg with zinc or paint.

Zinc coating is best if you want it to last well. Can be done with a dead battery electrode & battery charger. For something like a gate, pickle & hot zinc dip sure is easier/quicker, and the zn coating is thicker and gets in where handheld electro-zinc doesn't.


NT

On Monday, 13 April 2020 23:17:51 UTC+1, AJH wrote:
On 13/04/2020 08:30, Brian Gaff (Sofa 2) wrote:

I guess it depends on the state of the posts at their base. I'd hate to have
primed a gate only to find only the rust is holding the post together!

I started cleaning up the bottoms of the posts today and the rust has
perforated the metal just above the concrete in a couple of places on
each post, I wire brushed them, applied a first aid thin band of paint
and am wondering whether to squirt some foam in to exclude water and air?

In the mean while I have taped over the holes. I could plate over with a
welder but it's probably not necessary as they are firm.

I have yet to order the pH down.

Foam saturates in time, keeping the metal permanently wet.


NT

On 13/04/2020 23:17, AJH wrote:
On 13/04/2020 08:30, Brian Gaff (Sofa 2) wrote:
I guess it depends on the state of the posts at their base. I'd hate
to have
primed a gate only to find only the rust is holding the post together!

I started cleaning up the bottoms of the posts today and the rust has
perforatedÂ* the metal just above the concrete in a couple of placesÂ* on
each post, I wire brushed them, applied a first aid thin band of paint
and am wonderingÂ* whether to squirt some foam in to exclude water and air?

In the mean while I have taped over the holes. I could plate over with a
welderÂ* but it's probably not necessary as they are firm.

I have yet to order the pH down.
bare metal + car body filler, then sand down then phosphate the rest
then paint


--
Its easier to fool people than to convince them that they have been fooled.
Mark Twain