I seriously considered having my Camaro subframe galvanized before powder coating. I didn't do it because of the concern about warpage, but I didn't research it enough to confirm that it would be a problem.

The problem with powder coating is that the best shops do an outstanding job of prepping the part inside and out, usually by pickling, and then the coat only the outside. With powder coated parts, then, you can end up with a beautiful frame that's naked and vulnerable on the inside. With galvanizing, the coating is thorough inside-and-out.

Using the right prep and priming takes care of getting good adhesion to galvanized parts for both paint and powdercoating (different process & materials for each though, of course). There are "right" ways to paint & powder coat zinc plated parts.

 

I plan on painting the outside of the frame with the correct primer and paint to use over galvanizing, or even considering powder coating too. The galvanizing was to get to all the inside areas that sand blasting will never get to. Ive done alot of sand blasting on all the other parts that I can get to all areas inside and out but the frame is different. I got the frame back Friday. All dimensions check out so I can rest easy there was no warpage or movement with the 850 degree Zinc. Ill post pictures as soon as I figure out how to.

 

This will show you how to post pic's http://photos.imageevent.com/durango...g%20Images.pdf

 

Yes, when dealing with duplex coatings (paint over galvanizing)the galvanized coating will require some preparation. In the bridge construction industry any galvanized coating is required to recieve what's called a 'brush blast' prior to painting. This is essentially a very quick sandblasing or mechanical abbrasion that removes the top layer of oxidation from the galvanized coating which, if left in place, can inhibit paint adhesion. I strongly suggest taking this step, otherwise you risk having peeling and flaking paint down the road.

I also wonder if, when the frame is dipped in the molten zinc, the sudden temperature change will stress and warp the frame, or possibly crack some of the welds. You'll want to check your welds after dipping for any signs of cracking or stress, probelm areas will most likely be at sharp bends in the frame. Also, the galvanizing outfit may require that venting and drainage holes be created in the frame to allow air to vent from the frame when dipping, and to allow excess zinc to drain out when it's removed from the tank.

If this is something you're seriously considering, a trip to the galvanizing plant may be in order to discuss your plans with their operation folks.

Good luck,
Tim

 

I got the frame back from the Galvanizer. I have to say it came out great. I am sanding the outside to get rid of any lumps of excess Zinc. I verified all the frame dimensions and they are all good. I bolted on a temporary brace on the rear section just so it couldnt flex at all. Im retapping all the threaded holes and nuts on the frame and getting ready for paint. After sanding and detailing the outside of the frame Ill get the primer and paint on to protect any spots that Ive sanded the galvanizing off. Its a relief to know that the whole inside of the frame has a good galvanized coating. Ill spray inside every hole in the frame to get some black color in there. Ill post some pictures as soon as I figure out how. I have the instructions Durangoboy posted about posting pictures, but the computer is definately not my strong point.

 

Good choice on getting the frame done. Will last forever.

Got a steel building that needs paint and the material costs are going to be over $10,000, so I have been researching this a bit to make sure the right materials are being used.
I know that you should not use an Alkyd/oil paint because it will cause “saponification”
And the paint will peel in a year or two.


Your plater is probably a member of “American Hot Dip Galvanizers Association” and if so, get this, ASTM D6386-99, that is the bible. Forward me a copy too, please.

Here are some links
American Hot Dip Galvanizers Association
http://www.galvanizeit.org/images/up...paintsteel.pdf

http://www.galvanizeit.org/aga/onlin...ing-hdg-steel/

http://www.ingal.com.au/IGSM/23.htm

 

Keep in mind that frames rust due to driving them in the rain, driving them in the salt, putting covers on the car that seal the moisture in, having improper sealing in the windshield, running kerosene heaters in the garage in winter, clogged up drain holes etc...

if you minimize these your frame will last you a century, so many people do such massive overkill to protect their frames.. one should do the same overkill to protect their birdcage since it is much more costly to replace..

if you do this to your frame , it will be your pride and joy you will never drive it in the snow, and rarely in the rain anyway...

if the car is your daily driver, think how your heart will sink when you hit a mud puddle and splash that nice underside with mud...

my car has not seen rain rain since it was restored.. how do I know?.. The restorer never set up windshield wipers... ( I put them on it now just in case!)

it is overkilll... just my opinion...


- Joe

 

A lot of people originally plan to keep these cars forever and I'm sure that is a good part of the reasoning.

Down here almost all boat trailers are hot dipped galvanized and regularily immersed in salt water. Hate to guess at how many winters that would compare to.
The hot dipping is so good that my last trailer was over 15 years old with absolutely no rust starting anywhere.
If your frame is already bare anyway due to a body off, I certainly would do it. The cost here locally isn't that bad, but it is very common here.

The birdcage would be nice, but that would be a real chore.

 

I would love to have done the birdcage, but like you said it would be a chore to say the least. I had the frame completely bare, and just couldnt pass up the opportunity to have it galvanized. Just knowing the rust was inside the rails and in every seam and around all the welds was a good reason. The first dip, "pickling" I think he called it took care of the rust, then the galvanizing gives you the future protection. This place also has a third step that they dip it in a chromium based product, but he suggested we skip that process since its getting painted and it would have been harder to prep for painting then. Since I have used this galvanizer for other projects in the construction business he did the galvanizing for me for $200.00. I just couldnt come up with a good reason not to have it galvanized.

 

Galvanizing pics

http://www.flickr.com/photos/1209389...7603198130582/

http://www.flickr.com/photos/1209389...7603198130582/

 

Hi NMT1957,

I am doing a body-off restoration on a '77 Corvette and thinking of having my frame galvanised. I am worried about the body mounts number 2 and 3 hough, the ones that have nut cage and a nut inside them. Would the dipping process fuse the nut inside the nut cage? What was your experience with it? Also did you remove the trans crossmember from the frame before galvanising or left it on to prevent warping?

 

What have you guys done to protect the inside of the frame? Looking forward to lift off the body next weekend.

 

When powdercoating and you not can reach inside the frame?