repair hot dipped galvanizing
JIMMIE
on a hot dipped piece of steel. I have some zinc and I was wondering
if there was a way I could apply the zinc rod sort of lie soldering to
repair the damaged galvanized coating. In the past we have sprayed the
area with cold- gal and this has not been satifactory.
Jimmie
rmcdemus
http://rittercnc.com/welding/repair-hot-dipped-galvanizing-16079-.htm :
Bob McDemus
Hi Jimmie:
This is a common request that has been cropping up for people doing repair
and construction in the field for things like Wind Mill towers. The Navy
addressed it years ago by going to a Thermal Spray Process, sometimes
called spray welding, for applications on the ships. Basically you take a
heat source, melt zinc or aluminum, atomize it, then spray it. It
basically is hot dip galvanizing that you can do on site. To see the
thermal spray equipment and some video's of the process, go to
www.thermal-spray-depot.com and look at the web site.
A second web site that you can look at is www.reneuxit-thermal-spray.com.
There is a summary available there of a 19 year corrosion test that was
done by the American Welding Society (AWS) on thermal spray coatings.
Hope that helps
Bob McDemus
-------------------------------------
JIMMIE wrote:
> Jimmie
##-----------------------------------------------##
Delivered via http://www.rittercnc.com/
Metalworking Forums
Web and RSS access to your favorite newsgroup -
sci.engr.joining.welding - 11711 messages and counting!
##-----------------------------------------------##
Ernie Leimkuhler
I have always had good luck repairing the zinc with Cold Galvanizing
spray.
The can should be really heavy or it isn't worth spraying.
In article
<8dea91fc-55fe-4706...@a21g2000yqc.googlegroups.com>,
Jim Wilkins
> We use a lot of hot-dip for projects at the Dive School.
>
> I have always had good luck repairing the zinc with Cold Galvanizing
> spray.
> The can should be really heavy or it isn't worth spraying.
>
> > ...In the past we have sprayed the
> > area with cold- gal and this has not been satifactory.
>
> > Jimmie
The Crown 7008 Cold Galvanizing Compound I brushed onto repairs on my
pickup truck didn't hold paint and is about half covered with rust
color.
jsw
Martin H. Eastburn
The larger than normal can was a heavy one.
I zincked my large outdoor vise then painted it bronze over the zinc.
I have always heard that if you have zinc plating on anything - paint it.
It will last many more years if done.
I have zinc plated fence line that is rusting top down.
Zinc flows and it dissolves with acidic rain - e.g. tree leaves drip acidic
rain. An example are oaks. Tanic acid. Redwood more Tanic acid....
Martin
Jim Wilkins
wrote:
...
> Zinc flows and it dissolves with acidic rain - e.g. tree leaves drip acidic
> rain. An example are oaks. Tanic acid. Redwood more Tanic acid....
> Martin
LPS3 protects the galvanized steel roofing on my woodshed from oak
leaf tannic acid pretty well. I thin it at least 50% with kerosine and
spray with their pump spray bottle. A light coating lasts at least a
year. The plating on the Home Depot and lowe's corrugated panels is
thin enough that I've bought some (discounted) that already had
corrosion and rust spots from trapped water.
jsw
fran...123
"Martin H. Eastburn" <lion...@consolidated.net> wrote in message
news:B64Jm.166385$Jp1....@en-nntp-02.dc1.easynews.com...
The way zinc on steel works to protect the steel is the zinc is sacrificial.
As long as there is zinc in the area of the water droplet where the
corrosion is occurring the steel in that area won't corrode until all the
zinc is gone. This is the opposite of chrome where if you get a pit in the
chrome the corrosion occurs faster in the pit. more layers of paint may
well keep the corrosion in general down but as for protecting a defect in
the coating painting over galvanizing would seem not to be sensible. I can
assure the zincs on steel fishing boats under the water line aren't painted
but the hull is. Now whether there is really an electrical connection with
the paint on zinc I can't say.
Fran
TinLizziedl
storkenst...@cox.net says...
Exactly right. Zinc will work to protect the steel, but it won't last
forever.
On boats the hull is painted but the welded-on studs are not. The studs
provide an electrical connection (grounding) between the zinc and the
steel hull. If you do not have that connection, or if the zinc gets
painted, there won't be much if any electrolysis of the zinc, leading to
corrosion of the steel.
Once the zinc in attached securely (typically with Nylock nuts and split
washers) you can paint the studs, but you still must leave the zinc bare
to allow the electrolysis to occur.
--
Tin Lizzie
"Elephant: A mouse built to government specifications."-Lazarus Long
Martin H. Eastburn
I do posts and such. Boats have are riding on an electrolyte and the motor
and boat both cause corrosion with each other. Thus the sacrificial magnesium rods.
Martin