When I did my build, I installed all my new suspension parts just prior to removing the tub...to make sure that with the (planned) 1" BL that the Cage mounts would fit, etc.
Then I pulled the tub, see photo1. Then I stripped it all down and took it to a local place to have it blasted. It was March, I believe, so there were still intermittent snow issues/salting, so we wrapped the frame and loaded it to take to Nashville, TN. I have a buddy from HS who now runs the plant, but at the time was their sales guy...they dipped it and then we hauled it south to their "paint shop" about 45 miles south-west and they sweep-blasted it. Another guy, not on staff, but at an adjacent building shot it with some Sherman Williams "Industrial" primer and two-part urethane. I paid $125 for the hot-dip and the sweep blasting...friend pricing.
The charge to galvanize for a bronco frame should/would be basically a "minimum" similar to a setup fee at a powder-coater. Its at the minimum size kind of thing, so its pretty cheap...should be in the $250-300 range, depending on what the price of zinc is at the time.
For best results, the frame should be pre-blasted. The process includes a dip in a hydraulic acid bath (pickling), this is a cleaning step to get to bright steel. Each plant differs a little in the steps, but there is usually 3 dips with a rinse, then the work goes into the kettle, which is liquid zinc at about 800-900 degrees. The zinc chemically bonds and fills on the steel depending on how long its left in the bath. They then hoist it out and its allowed to slowly cool.
A couple of very important things. At the temp of the kettle, any enclosed air pockets will explode. All the tube that you may add to your frame needs to be vented. The vent holes should be in a certain proportion to the diameter of the tube. So, all the cage mounts and my frame tie-ins were all drilled (, started with a 1/4 then opened up to 3/8"). We did this in the yard, ran out of battery on the last hole... The holes need to be done at "top" and "bottom" of the work, so that any super-heated air can escape as the work goes into the kettle...otherwise, the piece can/will explode. My buddy said he has seen it happen...not good and dangerous too.
I definitely think if you are taking the frame down all the way, its a great way to preserve the frame. It also coats inside, which is good. The caveat is you really need to make sure you do all your welding ahead of time. Welding on galvanized steel is not healthy. I added my bumper reinforcements after the fact...I dindt originally think I was going to (be able to approval from the boss-lady to) get the Protofab bumpers--which pretty much require some frame reinforcement on the horns). The body-already in Line-X was already mounted too...so I warpped all the adjacent areas with thick HD aluminum foil, ground down the zinc as best as I could, turned up the heat and used flex-core. It turned out OK...but the gases produced are toxic and you really need good ventilation.
Anyway, here are a couple more pics of the process. If you are considering hot-dip galvanizing, look in your local phone book and a google search can turn up a galvanizer near you. If you dip, you really need to 'sweep blast' (a quick sand blasting process using larger grain and high volume to etch a clean 'bright' tooth for optimal adhesion) prior to painting, powder coating or whatever. And the painting/coating needs to be done very quickly after the sweep-blast. Even though mine was "technically" done correctly, the Sherman Williams product still lifts and cracks every once in a while. I hit the bare spots with rattle can...just to keep it black, cause thats what I was going for. If I had it to do again, I would have contacted a powder-coater in Nashville and had an appointment to take it in the same day. Powder-coating, while more expensive would bond better and look better. At the time, my PC-shop in Indy was not doing their own in house blasting on items of that size, so it would have been difficult to organize...additional transport, etc...logistics were already a pain.
Sorry to be long-winded...figure its better to get the whole story/process out there and answer as many Qs as possible.
