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Old 10 March 2009, 18:45   #1
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Galvanising question

I've got a trailer I want to modify. The old galvanising is looking pretty tired, plus I want the new bits galvanised. If I modify it and send it to the galvanisers, will they accept it as a mix of old and new? Is there any special prep you need to do to previously galvanised steel?
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Old 10 March 2009, 18:55   #2
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I've got a trailer I want to modify. The old galvanising is looking pretty tired, plus I want the new bits galvanised. If I modify it and send it to the galvanisers, will they accept it as a mix of old and new? Is there any special prep you need to do to previously galvanised steel?
The galvanisers are usually ok with that. They will send it for blasting to remove all the dross and old zinc. Cost you tho. Phone em and ask.
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Old 10 March 2009, 18:57   #3
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I've got a trailer I want to modify. The old galvanising is looking pretty tired, plus I want the new bits galvanised. If I modify it and send it to the galvanisers, will they accept it as a mix of old and new? Is there any special prep you need to do to previously galvanised steel?
Yep and charge extra to sort it out

No rust
no paint

You will probably need to shot blast the whole thing, then any galvanizing left on will be sorted by the pickling treatment pre galvanizing

All box tube sections to be drilled for draining + to allow the air to vent

After galvanizing you will need to clean out(drill) any holes + re tap any threaded holes before refitting of bits

Oh and blow out any shot blasting dust with an air line( before its galvanized)

Also any pigeon crap welds will often blow apart during galvanizing so they need to be done by someone who knows what they are doing

Jim
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Old 10 March 2009, 19:00   #4
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Shouldnt need blasting, it gets dipped in chemicals to clean and degrease. Double dipping is a known process used for extra protection so the old zinc wont be a problem.

If its only smallish areas then you can buy these sticks of zinc which you can apply on with a little blow torch. Or even just give it a good coat of galvafroid, should get a year or 2 before the rust comes back.
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Old 10 March 2009, 19:05   #5
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Also any pigeon crap welds will often blow apart during galvanizing so they need to be done by someone who knows what they are doing
Galvafroid it is then
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Old 10 March 2009, 19:10   #6
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Shouldnt need blasting, it gets dipped in chemicals to clean and degrease. Double dipping is a known process used for extra protection so the old zinc wont be a problem.

If its only smallish areas then you can buy these sticks of zinc which you can apply on with a little blow torch. Or even just give it a good coat of galvafroid, should get a year or 2 before the rust comes back.
We've done some big stuff that needed to be double dipped, one end then the other with an over lap no problems but as soon as we have welded new to old or clean to galv, even with cleaning back first the local guys make us shot blast the crap off + any rust or paint
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Old 10 March 2009, 19:10   #7
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Also any pigeon crap welds will often blow apart......

Jim
By 'pigeon crap' are you refering to 'seagull shit' welding?
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Old 10 March 2009, 19:12   #8
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Galvafroid it is then
the thick hand painted stuff works the best ,but the spray on looks better in the short term if your tying to move it on
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Old 10 March 2009, 19:13   #9
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Just had a big pair of fancy entrance gates delivered back to us from Wessex Galvanisers. After spending hours and hours cleaning every bit of spatter off the whole thing is covered in lumps and bumps and runs etc. Great big drips off every single finial, several areas where the galv reacted or something its been sanded down then sprayed up with silver paint!!

If they were my gates I certainly wouldnt accept them but they know theres not much we can do once they've been shipped back across the Channel.

And dont get me started on the shipping companies! One finial has been broken off and dissapeared and the 2 next to it were bent over almost 90 degrees!
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Old 10 March 2009, 19:13   #10
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By 'pigeon crap' are you refering to 'seagull shit' welding?
This far inland it's Pigeon shit
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