Galvanising

:cool:The process of galvanising is 1st Wire items 2nd Caustic tank to remove paint & clean , 3rd Water tank, 4th Acid tank to remove serface rust & mill scale, 5th Another water tank to hold ready for galv 6th quick dip into acid to flux the job , 7th Into zinc where it stays in untill the zinc comes back up to tempurature 8th Into water tank to quench. ( the quench usually has a chemical in it to prevent white rust , this chemical will give the galv a yellow tint which will fade away after being in the sun a couple of weeks) 9th Is cutting off wire & dressing usually with a air grinder or body file . The air grinder can some times take too much zinc off if they are not carefull. This is why i prefer to pick up still on the wire & un dressed so nothing gets lost & so they don't grinde through the zinc. If they have ground through the zinc you can buy zinc sticks which looks a little like solder , by heating the area you can melt zinc in then work it in with a wire brush . It takes a little practice but works well. The other way is to touch it up with cold galv then touch up with aluminum paint it is the closest I have been abel to get to the colour of calv. The reason they charge double for stripping is the zinc weakens the acid & they have to replace it sooner , They usually wont strip if they have new acid & you may have to wait longer if stripping is required :DWayne

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Originally Posted by brendanm

Picked up the bits that went in for galvanising today. All the bits were there and no warping or distortion. $138 all up that's doorframes, hinges, all cappings, tailgate pieces and a couple of fittings. I don't think the price would alter much if more components like the windscreen surround went in as it is well under minimum weight, so it would only be 75cents per kilo extra for the acid bath.

I knew when putting them in they would do their best with tying up as they have had wire break before and the component then becomes part of the gal bath. I have enough spares that this is not debilitating just would be annoying given the welding and sand blasting that went into preparation. I was more concerned with distortion.

The coating was thicker than I thought with some inconsistencies. I touched up some of the dags with a file. The surface texture on some components was rough. I will attempt to sand down, though not through the Zinc coating to achieve a better finish. Maybe this is where a centrifugal galvaniser may be better as excess zinc is spun off the metal after dipping.

I am not convinced that I have gone about this the right way. Initially I though that painting with a cold gal would be like spray painting an asterix on a hubcap and calling it a mag wheel. Given it was originally gal I was keen to reproduce this. I will post some more photos that give a better look.

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:cool:In the old days they used to sprinkle sale on the pieces , the salt would make the zinc run better giving a smoother & thinner zinc coating . They are not allowed to use salt now because of polution ( fills the plant up with smoke) Also if they leave it in the zinc too long the zinc will build up on its self & become thicker & it also depends on the silcone content of the steel as to the finish, silcone will give dull patches in the zinc .:eek: Wayne

Next installment. Galvanised door frames being reskinned. The old ones are worn through. Thanks to the Royal review thread for the ideas.

Couple more images. One of the doors frames had one end out of square by about 4mm. I would have thought that these would have been jig cut and welded in a template. Will have to wait and see how the alignment looks when fitted. I also used 2mm to skin the doors as the left over sheet will be the tail gate. The original was thinner though I figured a thicker panel is less likely to dint given it is a single skin.

You will need to etch prime the galv where it is going to touch the alum as you will get a reaction between the alum & galv . Wayne

Thanks Wayne
Would I still need to etch prime the Gal if I etch prime and paint the panel before fitting? I like the look of the fresh Gal against the darker paint. Most doors I have seen are just all one colour, probably having a fresh coat at some time without removing or masking the frame.
My intention was to paint both sides of the door skin. The skin is already a press fit to the frame where I have bent the edges at 90 degrees, then fit to the frame. I was going to use some variant of silastic /metal adhesive to reduce any potential rattle, then tap the edges over to complete the frame and touch up any paint where required on the inside lip.
There must be many ways to go about painting and keeping the raw Gal against the paint. This way wet paint will not be sprayed near the Gal, though I had not thought of reaction between metals. Makes you think again of those aluminium finished vehicles. They must have some kind of clear coat.

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Originally Posted by brendanm

Thanks Wayne
Would I still need to etch prime the Gal if I etch prime and paint the panel before fitting? I like the look of the fresh Gal against the darker paint. Most doors I have seen are just all one colour, probably having a fresh coat at some time without removing or masking the frame.
My intention was to paint both sides of the door skin. The skin is already a press fit to the frame where I have bent the edges at 90 degrees, then fit to the frame. I was going to use some variant of silastic /metal adhesive to reduce any potential rattle, then tap the edges over to complete the frame and touch up any paint where required on the inside lip.
There must be many ways to go about painting and keeping the raw Gal against the paint. This way wet paint will not be sprayed near the Gal, though I had not thought of reaction between metals. Makes you think again of those aluminium finished vehicles. They must have some kind of clear coat.

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The silastic should keep the two metals apart . A few years ago when our company was building marina gangways the people we were building them for left the galv pivots on the alum ramps & they reacted & etched into the alum .

On IIAs a grey mastic type material was used between the door skins and frames. When I refitted the skins to my gal IIA door frames back in 1994 I used brush on sound deadener. That was almost 20 years ago and so far so good ;)

Had a go at constructing a tail gate today. It was a best guestimate using what was left of two fogged out tail gates that had pretty much collapsed. The internals frame that were spot welded to the sheet were fairly thin and ripped.To complicate the dimensions I am using 2mm sheet left over from the doors for every component. This I would expect to add to the longevity, given the fatigue of the thinner original sections.
It fit though needed to be forced over the rear latches. The sides could really do with an extra couple of mm. I measured the internal of the back though forgot to subtract the extra internal frame(4mm) . This would have made the width right. The depth needs an extra 3mm as the Gal brackets are not sitting quite right. The bottom gal strip is just rubbing on the hinge when the top Gal capping aligns.
There is enough sheet left over so I might have another crack at it tomorrow. It will be finished for a long time, so no point settling for something that could be improved. When Iam happy Iwill also add the middle upright and the tie down cleats.

Can I adopt you?