Author Topic: Galvanizing  (Read 748 times)

astat1

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Galvanizing
« on: December 12, 2018, 09:32:43 AM »
I'm looking to get the rear license plate bracket on my 1969 GT500 redone in its original finish which appears to be a "hot dipped" galvanization. It seems most shops will only do large runs and charge $250-500.  Does anyone know of a shop that will do small part runs? Or does someone have an NOS/great used bracket gathering dust for sale? Thanks

Bob Gaines

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Re: Galvanizing
« Reply #1 on: December 12, 2018, 01:17:46 PM »
I'm looking to get the rear license plate bracket on my 1969 GT500 redone in its original finish which appears to be a "hot dipped" galvanization. It seems most shops will only do large runs and charge $250-500.  Does anyone know of a shop that will do small part runs? Or does someone have an NOS/great used bracket gathering dust for sale? Thanks
FYI if you plunk down your money you better know what the finished product will look like . For example ,the redone ones that I have seen have come out looking like a shiny silver spoon. They looked nothing like the original galvanizing look .
Bob Gaines,Shelby Enthusiast, Shelby Collector , Shelby Concours judge SAAC,MCA,Mid America Shelby

CSX 4133

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Re: Galvanizing
« Reply #2 on: December 12, 2018, 02:56:52 PM »

You might check out the ZRC line of cold galvanizing, they offer several finish grades with up to 95% zinc. They are available in brush on and spray on application.

http://www.zrcworldwide.com/products/zrc-cold-galvanizing-compound
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Bob Gaines

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Re: Galvanizing
« Reply #3 on: December 12, 2018, 03:43:32 PM »

You might check out the ZRC line of cold galvanizing, they offer several finish grades with up to 95% zinc. They are available in brush on and spray on application.

http://www.zrcworldwide.com/products/zrc-cold-galvanizing-compound
I know you suggestion is meant as a helpful one but apparently you do not understand the difference in appearance that will are looking for. It is supposed to be like the original part. The "paint" product you suggest goes on as a one tone/shade appearance. Battleship gray in the case of the suggested one. There are many products like it most of which go on a brighter silver shade/color. What is important in the context of the question is how it looks compared to original and not how good of protection the product provides. If you compare the finish of a product like that (a paint) to a original part (even a dull one) you will see a night and day difference in appearance details. It has many patterns in the silver appearance.It kind of looks like frost crystals on a window glass as far as a pattern. If you can't tell the difference after comparing then I will not be able to make you understand.
Bob Gaines,Shelby Enthusiast, Shelby Collector , Shelby Concours judge SAAC,MCA,Mid America Shelby

Dan Case

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Re: Galvanizing
« Reply #4 on: December 12, 2018, 04:32:45 PM »
I worked with galvanized sheet metal and parts made from it for almost four decades. The appearance is called 'spangle'. I hope this link works to a description of spangle.

https://galvanizeit.org/education-and-resources/resources/technical-faq-dr-galv/controlling-spangle-influences

Sheet steel wise material is run through a reservoir or tank of molten alloy as very wide stock. After 'galvanizing' the manufacturer can add all kinds of surface treatments like corrosion inhibitors or mill work lubricants. Such coatings are also usually applied before the stock is slit down to a width somebody ordered. Buyers can specify what alloy and spangle pattern and size of pattern they want, usually for some visual cosmetic reason. The last manufacturing step for the mill is to slit the wide material down to final ordered width.

One thing possible with doing sheet steel off large coils is that the final thickness of the galvanizing can be controlled very tightly. The end user will want enough to provide the amount of rust through projection they want without being so thick that the coating cracks and or flakes off as parts are formed. The coating could be just a few ten thousandths of an inch thick on each side.

Note that the outside edges of the ordered strip are bare steel. When an end user die cuts and forms parts from parts from this strip all the cut edges will be bare steel. Some end users will add some type protective coating to exposed edges but most donít seem to.

As Bob indicated reworking a used part to look just like parts made as describe above will not mean any kind of simple spray on and walk away paint on product.  If you did find somebody to hot dip an old part and get a good facsimile of the original spangle the cut edges will also be coated unless there is a way to mask them in some manner.  Sanding or filling of edges to remove galvanizing wonít leave the same surface / appearance as the original slit and die cut edges.
« Last Edit: December 12, 2018, 04:54:29 PM by Dan Case »
Dan Case
1964 Cobra owner since 1983, Cobra crazy since I saw my first one in the mid 1960s in Huntsville, AL.

J_Speegle

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Re: Galvanizing
« Reply #5 on: December 12, 2018, 04:38:41 PM »
A few years ago we went through this for a 69 restoration and I gave up on getting the original look with today's processes. We have a number of the parts galvanized by a couple of platters that do it all the time and we ended up with a finish unlike any of the originals. It was thicker, caked on product rather than the thin plating with clear large geometric shapes we were looking for. So instead I had them stripped then zinc plated which I used as a base to do faux plating with multiple layers of different colored shapes which IMHO turned out well and was acceptable to judging and people looking at the car, ie passed the eye test ;) 

Multiple people have used the technique to redo or simply repair sections on a fairly nice original plated part with success

If your the same astat1 as the one on CMF check the Library there for an article on how we did this process. ;)

Pictures are not a true representation of what the finish looks like in person or from different angles like the real galvanizing

On a couple of the larger pieces we reproduced the ink stamp that was applied to the sheets of galvanized metal used to stamp some of the larger pieces from, for an extra detail found on some original panels





Creating one of the layers





Hope this helps

« Last Edit: December 12, 2018, 04:43:35 PM by J_Speegle »
Jeff Speegle- Mustang & Shelby detail collector, ConcoursMustang.com babysitter :) and Judge

JD

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Re: Galvanizing
« Reply #6 on: December 12, 2018, 10:55:20 PM »
Dan & Jeff - thanks for the ed-u-ma-cation.

'67 Shelby Headlight Bucket Grommets http://www.saacforum.com/index.php?topic=254.0
'67 Shelby Lower Grille Edge Protective Strip http://www.saacforum.com/index.php?topic=1237.0

TLea

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Re: Galvanizing
« Reply #7 on: December 13, 2018, 06:51:18 AM »
 The reason the galvanizing will never come out the same and thicker as Jeff pointed out is the sheet of metal was galvanized before the parts were stamped out. Once the parts are stamped out all the bends nooks and crannies will cause a pooling effect on the plating material that will leave it thicker and uneven.

Rodster-500

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Re: Galvanizing
« Reply #8 on: December 13, 2018, 10:56:13 AM »
I worked with galvanized sheet metal and parts made from it for almost four decades. .........
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Great information from someone directly involved in galvanizing for quite some time.  ;) Thanks for sharing!