galvano.htm
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Some notes on galvanizing steel, from a thread on the OffRoad MailingList
To: Offroad@off-road.com
From: Willem-Jan Markerink
Date sent: Wed, 26 Mar 1997 13:35:56 +0000
Subject: Re: POR-15 vs galvanizing
Send reply to: Offroad@off-road.com
On 25 Mar 97 at 22:41, Susan and/or David Dannenberg wrote:
> I am interested to know if there is any disadvantage to galvanizing.
As for hot dipping vs gun spraying (called Schooperen in Holland,
after the inventor Schoop) vs electro galvanising:
- hot dipping applies the thickest layer, reaches ever spot,
even on the inside, but gives the roughest surface, often with crud
nests of metal and 'drip tears'. Those can be sharp as a needle, so
watch out when you get it back from the dipper, and grind off that
crap.
- gun spraying is less rough, but has an relatively open surface, so it
*must* see an additional layer of coating. Most paint shops don't
like painting galvanized/zinced steel, so powdercoating is the best
option. Inside zinc application doesn't work.
- electro plating is the smoothest, but also thinnest. Best solution
for window frames, as mounting must be a pain with the rough
surfaces. This method also gives you access to gold plating....more
efficient than gold dipping....;-))
General disadvantage:
- welding galvanized steel seems to be quite bad for you health
- if you want to use method 1 or 2 for tubes or otherwise closed
steel, you *MUST* drill holes. Not just to give the zinc access to
the inner surfaces, but mainly to prevent it blowing apart in the
heat....8-))
There must be a number of holes, as they might get clogged with this
melt crud. When submerging into the hot tub, zinc has to have access
from below, and air has to be allowed to escape on top, and this is
reversed on the way out.
And if *you* don't drill those holes, then the guys at the hot tub
*will*, without mercy and with a torch. For them, everything is better
than a tube explode inside the hot tub....8-))
--
Bye,
_/ _/ _/_/_/_/_/ _/_/_/_/_/
_/ _/ _/ _/ _/ _/ _/
_/ _/ illem _/ _/ an _/ _/ _/ arkerink
_/_/_/
The desire to understand
is sometimes far less intelligent than
the inability to understand
[note: 'a-one' & 'en-el'!]
To: Offroad@off-road.com
From: Willem-Jan Markerink
Date sent: Wed, 26 Mar 1997 18:36:11 +0000
Subject: Re: POR-15 vs galvanizing
Send reply to: Offroad@off-road.com
On 26 Mar 97 at 8:11, mike@credit.headwaters.com wrote:
> > A lot of discussion of POR15 for frame off restoraion. Seems like a lot of
> > work and expense to me. Around here hot dip galvanizing is cheap. One place I
> > called charges a minimum of $250 for up to 800 pounds of material!
>
> I haven't looked into hot-dipping, but I've thought about it. I
> made the assumption (uh-oh!) that it would require bare-metal for
> application, which is way more work than just brushing off the loose
> rust.
Yep, I believe you need an acid bath to get it all off, sand blasting
only works on the outside.
But boy do you knock out the Lord of Rust....8-))
--
Bye,
_/ _/ _/_/_/_/_/ _/_/_/_/_/
_/ _/ _/ _/ _/ _/ _/
_/ _/ illem _/ _/ an _/ _/ _/ arkerink
_/_/_/
The desire to understand
is sometimes far less intelligent than
the inability to understand
[note: 'a-one' & 'en-el'!]
To: Offroad@off-road.com
Date sent: Wed, 26 Mar 1997 13:45:28 -0800
From: Rob Mullen
Subject: POR-15 vs galvanizing
Send reply to: Offroad@off-road.com
suedave@pond.com (Susan and/or David Dannenberg) wrote (on the offroad list):
>A lot of discussion of POR15 for frame off restoraion. Seems like a lot of
>work and expense to me. Around here hot dip galvanizing is cheap. One place
>I called charges a minimum of $250 for up to 800 pounds of material!
>I intend to have my little military trailer (bed and frame) done, and I
>believe that Rob Mullen is having his BJ frame done.
DOH! The secret is out :)
Dropped my BJ42 frame off yesterday. It's costing me CA$0.50 (US$0.37) per
pound of steel. I figure my frame weighs around 300lbs (probably less--two
people can lift it) so it'll wind up costing CA$150 (US$111) or so. The
more expensive part is the prep. I had my frame caustic-soda dipped &
pickled to take every nook and cranny down to pure bare steel. That cost me
CA$350 (US$259)
According to the galvanizing sales guy I spoke to, the frame should be good
for ~25 years with no rust. If I add a layer of paint for further
mechanical protection they figure it'll be good for ~35 years rust free.
I'm doing all this on the assumption that the current morons at Toyota
Canada will remain in power and therefore there will be no new diesels
entering the country. I fully intend not to outlast this truck.
>I am interested to know if there is any disadvantage to galvanizing.
There are three disadvantages I know of. In decreasing order of seriousness
they are:
- NO WELDING! My frame's design is cast in stone (zinc?) which I have to
admit is a LITTLE nerve-wracking considering how much prototype-stuff I've
got on it.
- Zinc isn't flexible. For instance, if main frame rail and the boxing
shift relative to each other, a crack in the zinc could potentially form and
let moisture in. That's the main reason I'm going to put a coat of Tremclad
over the galvanizing.
- Any non-galvanized steel item in direct contact with the galvanized
surface (ie, good enough to conduct electricity) will corrode faster. Not a
big deal for me as I intend to have all steel body panels caustic soda
dipped, pickled, and zinc-phosphate coated, which puts a crystaline layer of
electrically non-conductive material on the surface of the steel (also ~25
years no rust if covered by paint)
____________________________________________________________________
Rob Mullen RAMullen@wimsey.com Vancouver, B.C. Canada |
Editor of the TLC FAQ TLCA #3036, Coastal Cruisers |
'80 Toyota BJ40 Diesel Land Cruiser Why walk?...When you can CRAWL!|
'83 Toyota BJ60 Land Cruiser Wagon TLC Offroad (604)299-5600 |
To: Offroad@off-road.com
From: Willem-Jan Markerink
Date sent: Thu, 27 Mar 1997 12:16:36 +0000
Subject: Re: POR-15 vs galvanizing
Send reply to: Offroad@off-road.com
On 26 Mar 97 at 13:45, Rob Mullen wrote:
> - NO WELDING! My frame's design is cast in stone (zinc?) which I have to
> admit is a LITTLE nerve-wracking considering how much prototype-stuff I've
> got on it.
I disagree. On our 60 we have a piece of galvanized pipe added to the front of our
non-galvanized powdercoated brushguard. It seems to result in very toxic fumes, but
it has been welded for sure. And even if, you could always grind that part down to
bare metal....
> - Zinc isn't flexible. For instance, if main frame rail and the boxing
> shift relative to each other, a crack in the zinc could potentially form and
> let moisture in. That's the main reason I'm going to put a coat of Tremclad
> over the galvanizing.
>
> - Any non-galvanized steel item in direct contact with the galvanized
> surface (ie, good enough to conduct electricity) will corrode faster. Not a
> big deal for me as I intend to have all steel body panels caustic soda
> dipped, pickled, and zinc-phosphate coated, which puts a crystaline layer of
> electrically non-conductive material on the surface of the steel (also ~25
> years no rust if covered by paint)
Noticed the same phenomena when, in a naive thought of battering the
Lord of Rust, I mounted SS bolts with normal nuts and washers. Crap.
Might be influenced by the fact that the bumper, in which these bolts
were mounted, was zinc-dipped.
Anyone know a supplier of golden nuts, in sufficient
strength?....8-))
Btw, I would include the paint problem in the above listing. Most
painters hate zinced steel, only powder coating does a good job.
--
Bye,
_/ _/ _/_/_/_/_/ _/_/_/_/_/
_/ _/ _/ _/ _/ _/ _/
_/ _/ illem _/ _/ an _/ _/ _/ arkerink
_/_/_/
The desire to understand
is sometimes far less intelligent than
the inability to understand
[note: 'a-one' & 'en-el'!]
To: Offroad@off-road.com
Date sent: Thu, 27 Mar 1997 13:17:41 -0800 (PST)
From: Gordon Pritchard
Subject: Re: POR-15 vs galvanizing
Send reply to: Offroad@off-road.com
>>>>> On Thu, 27 Mar 1997 12:16:36 +0000, Willem-Jan Markerink
>>>>> said:
On 26 Mar 97 at 13:45, Rob Mullen wrote:
>> - NO WELDING! My frame's design is cast in stone (zinc?)
>> which I have to admit is a LITTLE nerve-wracking
>> considering how much prototype-stuff I've got on it.
W-J> I disagree. On our 60 we have a piece of galvanized pipe
W-J> added to the front of our non-galvanized powdercoated
W-J> brushguard. It seems to result in very toxic fumes, but
W-J> it has been welded for sure.
I've done a bit of welding on my 'Cruiser, with
galvanized parts; specifically I used galvanized pipe for my
through-the-frame Saginaw box mounts. I didn't listen to Park's
suggestion of black pipe...
Last summer I made some high-rise sprinklers for my
wife's vegetable garden which involved welding dipped galvanized
components.
Yes, the fumes are _really_ ugly - use extremely
excellent ventilation and make sure you're upwind of everything.
W-J's suggestion to grind down to bare metal is an
excellent one - the galvanizing forms a powder which takes a lot
of "cooking" to get it out of the welded joint.
Also, the galvanizing burns brightly while you're
welding, and can somewhat obscure your view of the progress of
the bead.
Lastly, it seems that the galvanizing can burn lazily
once you stop welding. At least the flame is easy to blow out,
but have fire extinguishing stuff handy.
If you weld galvanized stuff, I would hazard a guess that
you'll remove the protection for maybe a 3/4" swath either side
of a 1/4" bead... And on the back-side, too. You can buy "Cold
Galvanizing Spray", which is a high-zinc-content industrial paint
that fence-guys use on their welded joints.
-Gord
--
Gordon Pritchard, VE7AGW
gpritcha@bc.sympatico.ca
To: Offroad@off-road.com
From: mike@credit.headwaters.com
Date sent: Fri, 28 Mar 1997 09:36:19 +0000
Subject: Re: POR-15 vs galvanizing
Send reply to: Offroad@off-road.com
> This has been an excellent thread. Is there a particular reason why
> an Acid dip then Powder coating the frame isn't being considered?
If you don't galvanize before the powder coat, then the frame will
rust really fast (startlingly fast) as soon as the powder coat chips
(which it will...).
/---------------------------------------------------/
Mike Graham, TLCA #5047
,
1981 BJ42 24V Diesel Land Cruiser "The Chew Toy"
Find the ORDFAQ at
Diesel Technical LandCruiser list -
To: Offroad@off-road.com
From: Willem-Jan Markerink
Date sent: Fri, 28 Mar 1997 17:42:16 +0000
Subject: Re: POR-15 vs galvanizing
Send reply to: Offroad@off-road.com
On 27 Mar 97 at 16:29, Jim O'Brien wrote:
> This has been an excellent thread. Is there a particular reason why
> an Acid dip then Powder coating the frame isn't being considered?
Because all the powder coating I have seen sofar is crap in the long
term. Once the Lord of Rust makes its entrance, nothing will stop him
from creeping under the coating and eating its way through.
Pipe ends (side bars), mounting points where the bolts stress the
surface, punctures....that's all the Lord needs to start its meal....8-))
Galvanizing is more than coating; it provides a surface that
sacrifices itself to the Lord first, at a much slower pace, and the metal
below is not affected until all galvano is gone in that particular
area. Most trailer frames in Europe are galvanized, with no top
coating. The Lord has no answer on this....:-))
FWIW: when we ordered a steel TJM front and rear bumper for our
HDJ-80, we didn't want the factory (powdercoat-only) black color on
our white Cruiser. Witnessing the steady degradation of the
powdercoated brushguard on our HJ-60, we decided that we wouldn't
loose this battle against the Lord of Rust again. So we had both
bumpers sandblasted, zinc dipped and powdercoated white. The first
chips of powdercoating have already come off, but the shiny zinc
layer is smiling happily to the elements....no sweat!
I will *NEVER* put any major piece of steel hardware on our trucks in
future without this zinc dipping/spraying (also refurbished the
almost eaten battery trays this way). Too much moisture & salt
around, no matter the factory protection. A single chip is all it
needs to rust badly.
Willem (sorry for the biblic content in this) Jan
--
Bye,
_/ _/ _/_/_/_/_/ _/_/_/_/_/
_/ _/ _/ _/ _/ _/ _/
_/ _/ illem _/ _/ an _/ _/ _/ arkerink
_/_/_/
The desire to understand
is sometimes far less intelligent than
the inability to understand
[note: 'a-one' & 'en-el'!]
To: Offroad@off-road.com
From: Willem-Jan Markerink
Date sent: Fri, 28 Mar 1997 17:42:17 +0000
Subject: Re: POR-15 vs galvanizing
Send reply to: Offroad@off-road.com
On 28 Mar 97 at 0:27, Nekromncer@aol.com wrote:
> Hey, maybe I missed it but what about the "zinc" based paint/primer that
> comes in a standard spray can and is easly found in many stores? Any good, or just
> marketing?
The material is the same (highly concentrated zinc), but the bonding
must be less, as will be the mechanical resistance.
Not bad inside the engine bay, but no good on the frame on its own
(without additional protection, which is inherently difficult as zinc
& ordinary paint don't like eachother much).
The spray gun kind of zinc application could be a solution in some
cases, but as it involves a torch, it is better to do an entire
component, and not just a piece (bodywork for example), as the
surrounding surface will be burned without the immediate zinc
protection.
I have seen entire classic car bodies being zinc sprayed this
way....not sure how they tackled the paint problem later on though.
--
Bye,
_/ _/ _/_/_/_/_/ _/_/_/_/_/
_/ _/ _/ _/ _/ _/ _/
_/ _/ illem _/ _/ an _/ _/ _/ arkerink
_/_/_/
The desire to understand
is sometimes far less intelligent than
the inability to understand
[note: 'a-one' & 'en-el'!]
To: LandCruisers@tlca.org
Send reply to: LandCruisers@tlca.org
From: mike@credit.headwaters.com
Date sent: Thu, 10 Apr 1997 14:18:17 +0000
Subject: Re: Powdercoating Strength?
> What is the REAL strength off powdercoating?
> Will it take the abuse?
Way stronger than tremclad, but not magic. It will chip. If the
bumper isn't galvanized first then one chip in the powdercoat will
make it rust in a way that *is* magic. I'm used to powdercoated
motorcycle frames, and they look great, and are easy to clean, but
one chip and you're crying. You can't really 'touch up' powdercoat.
Basically, my feeling on the powdercoating issue is that if it's
seeing moderate use, then it will last forever without chipping, and
you will have no problems and no rust. In heavy-duty applications
(and off-roading counts!) then stick with a yearly coat of paint so
that you'll know what's going on in your bumper (you'll have to give
it a good look every year) and you can keep it rust-free.
> Should I stick with Tremclading it ever year or so?
Unless you're going to galvanize the bumper before powdercoating
it, then yes.
/---------------------------------------------------/
Mike Graham, TLCA #5047
,
1981 BJ42 24V Diesel Land Cruiser "The Chew Toy"
1988.5 Suzuki Samurai JX "Super Smurf"
Find the ORDFAQ at
Diesel Technical LandCruiser list -
FROM: "Stephen Plumb"
SUBJECT: Re: Steel Wheels - Refinish
DATE: Fri, 27 Aug 1999 15:12:27 +0200
ORGANIZATION: University of Natal
NEWSGROUPS: rec.autos.4x4
HITman wrote in message
news:M64x3.1869$H%4.148765@news.uswest.net...
> My girlfriend's 89 Nissan 4x4 has some after-market steel wheels that are
> really corroded. What would be the best way to refinish and paint them?
> I'm trying to make it into a passable camping/scuba ride and don't want to
> spend a lot of bucks.
>
> Ideas? TIA!
>
> -Brian
I am quite intrigued by this one. I agree that sandblasting/galvinizing is
the way to go, but I went and got some quotes from one of the local marine
workshops to sandblast and respray, the quote was about as much as new
wheels. If you are going to be using it as a dive wagon, then maybey it
would be best to get the wheels galvanized even if it does cost a bit, as
they would definitely last better then a new powder coated wheels.
Of course I am not sure what diving entails in your neck of the woods. Out
here we normally use a 6m Inflatable towed by trusty (and rusty) 4x4 and
usually lauched through the surf. This obviously entails much driving on the
beach and sometimes into the water a bit to get the boat off the trailer. If
this is your MO then I would definitely go for galvanized wheels.
Cheers
Stephen
FROM: sbest@TAKEOUTglinx.com (sbest)
SUBJECT: Re: Steel Wheels - Refinish
DATE: Thu, 26 Aug 1999 21:05:06 GMT
ORGANIZATION: Business Internet
NEWSGROUPS: rec.autos.4x4
On Thu, 26 Aug 99 14:49:09 GMT, w.j.markerink@a1.nl (Willem-Jan Markerink)
wrote:
>The only permanent solution against rust is sandblasting, galvanizing
>(torch/spray-style, not dipping, that might come out too
>rough/uneven/unbalanced), and finally powdercoat (paint doesn't stick well
>to zinc).
>With zinc below, no scratch can promote rust further than the scratch
>itself, unlike any other coating/paint.
WJ, I looked into wheel galvanizing locally and they said they are not
having any problem with dipping. I agree with your comments, it goes on
thick and rough, but maybe they have a special procedure for dipping them
or maybe balancing is able to correct any problems? The company's main
product is boat trailers, wheels and all.
Steve Best, Nova Scotia,
4x4 van website:
http://www.glinx.com/users/sbest
FROM: w.j.markerink@a1.nl (Willem-Jan Markerink)
SUBJECT: Re: Steel Wheels - Refinish
DATE: Fri, 27 Aug 99 14:41:32 GMT
ORGANIZATION: A1 Internet news-server
NEWSGROUPS: rec.autos.4x4
In article <37c54463.723955310@news.glinx.com>,
sbest@TAKEOUTglinx.com (sbest) wrote:
>On Thu, 26 Aug 99 14:49:09 GMT, w.j.markerink@a1.nl (Willem-Jan Markerink)
>wrote:
>
>>The only permanent solution against rust is sandblasting, galvanizing
>>(torch/spray-style, not dipping, that might come out too
>>rough/uneven/unbalanced), and finally powdercoat (paint doesn't stick
well
>>to zinc).
>>With zinc below, no scratch can promote rust further than the scratch
>>itself, unlike any other coating/paint.
>
>
> WJ, I looked into wheel galvanizing locally and they said they are not
>having any problem with dipping. I agree with your comments, it goes on
>thick and rough, but maybe they have a special procedure for dipping them
>or maybe balancing is able to correct any problems? The company's main
>product is boat trailers, wheels and all.
Well, there is one more argument against dipping, and pro spray/torch: the
dipped surface looks rough/dirty, but at micro-scale it is much
smoother/more-sealed than the spray-torch surface, which simply means that
the powdercoating sticks less well.
One could prevent the balancing problem by dipping them horizontally,
instead of the most logical way, hanging vertically.
Also, the overall roughness/dirt problem might cause problems at the edges,
where the tire seats....one has to check it carefully to remove 'tears' and
other crap from that area.
Dipping does give a more thick surface, hence more sacrificial zinc, and
spray/torch *must* be followed by some kind of seal, as it is more
porous....it does look pretty snazzy at first (same as sandblasting btw!),
but it will turn ugly pretty soon, unlike hot dipping (over here, entire
trailer frames are left bare after that).
--
Bye,
Willem-Jan Markerink
The desire to understand
is sometimes far less intelligent than
the inability to understand
[note: 'a-one' & 'en-el'!]
From: w.j.markerink@a1.nl
To: dtlc@helios.net
Date: Tue, 09 Mar 2004 01:06:36 +0100
Subject: Re: [DTLC] Hot dip zincing?
Reply-To: dtlc@helios.net
On 8 Mar 2004 at 7:58, griemer1@sasktel.net wrote:
> My son Warren hot dip zinced his frame for his project FJ40. Turned out
> beautiful. Inside and out were perfect because they dipped it in acid for
> the weekend before the hot zinc. Added 180lbs of zinc to the frame, (all of
> which will have to corrode away before any steel rusts because of the
> sacrificial anode thing). Cost him $106 cdn taxes in, (another $200 prior
> to that for the blasting).
>
> Now his truck is just sitting because all his body interior and wiring stuff
> got smoked in the fire.
How does one sandblast *inside* the (closed sections of the) frame
rails?
Or was that where the acid-dip was for?
(for ordinary crud I have been thinging about a sewer-cleaning head,
spraying at a 90 degree angle (or even better, 135 degree, so that it
pulls itself forward inside)
Btw, German TUV does *not* like seeing galvanized
frames....apparently there is a (theoretical) issue of heat-weakened
steel, if only the connecting 'hot-nails' (how ya call those in
English?)
(does one get inside the mating (often nasty from rust bulging)
reinforcement sections, like 3/4 down the rear (spare?) and tow-hitch
supports on the very end?
Bolts with screw thread loose their strength too, have to be removed
(and better in advance than later on, where it would leave an
unprotected area)
--
Bye,
Willem-Jan Markerink
The desire to understand
is sometimes far less intelligent than
the inability to understand
[note: 'a-one' & 'en-el'!]
Date: Mon, 08 Mar 2004 18:43:46 -0700
From: bruce.loewen@prairiedogparts.com
To: dtlc@helios.net
Subject: Re: [DTLC] Hot dip zincing?
Reply-To: dtlc@helios.net
w.j.markerink@a1.nl wrote:
>How does one sandblast *inside* the (closed sections of the) frame
>rails?
Very powerful blasters can do a marginal job of this
>Or was that where the acid-dip was for?
This is much better
>(for ordinary crud I have been thinging about a sewer-cleaning head,
>spraying at a 90 degree angle (or even better, 135 degree, so that it
>pulls itself forward inside)
>
>Btw, German TUV does *not* like seeing galvanized
>frames....apparently there is a (theoretical) issue of heat-weakened
>steel, if only the connecting 'hot-nails' (how ya call those in
>English?)
The word in English is rivet but you made me laugh because hot dipped
nails are what holds most modern North American houses together. The
German engineers better not come here for their vacation.
>(does one get inside the mating (often nasty from rust bulging)
>reinforcement sections, like 3/4 down the rear (spare?) and tow-hitch
>supports on the very end?
You disassemble as much as humanly possible. also be sure to remove all
cast pieces like 40 series steering box towers and 45 series rear spring
hangers. It turns out that their melting point is a little too low for
dipping.
>Bolts with screw thread loose their strength too, have to be removed
>(and better in advance than later on, where it would leave an
>unprotected area)
All fasteners should be removed and replaced with sacrificial hardware
threaded only till they barely protrude from their captive nuts.
From: "Francois Labelle"
To:
Subject: galvanazing steel vehicle frames
Date: Fri, 20 Oct 2006 22:15:32 -0300
I'd like to point out to the neophytes out there thinking about hot dip
galvanizing vehicle frames...hot dip galvanizing consist of dipping
steel frame in 900 degree melted zinc, my experienced with this process
is that the heat will distort the frame, the metal being very soft as it
is lifted out of the zink bath, and any temper in the steel (or carbon
hardenning) will be softenned back to mild steel strenght...(aniled)
including the spring hanger brakets and rivets, bolts etc...not a good
thing to do on a 4X4 vehicle...as well, zinc will not get to the area
where the frame is laminated or sandwiched together by rivets, leaving
the metal in these area bare, thus subject to rust anyway. It is not
recommended to hot dip wheel intended to be installed on a vehicle, one
could get away with having them on a boat trailer or similar
applications, but I certainly would not want to drive a 6000lb vehicle
with them on on a highway! There has been a lot of problems with hot dip
zinc coated steel scuba diving tanks failing the pressure testing
because of the loss of temper in the steel.
Francois Labelle
If you have any question, remark, comment, want to share some
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