SFC 750 frame questions.

M

Mactriple

Hero member
Location
Wide Bay Queensland
Can anyone shed light on the reason why the factory didn't paint the frames on the SFC 750s? Also, were the frames hot dipped by the factory or were they electrochemically processed? I asked a local plater about zinc plating a frame and he wouldn't do it for fear of leaving chemicals inside the frame which may eventually weaken the structure. Has anyone restored an SFC using one of these methods? Regards,
Ian
 
Marnix would answer for sure but I believe that the frames were galvanized by dipping, ie the holes on these frames.
 
i can't answer why the factory zinc plated

the genuine frames have holes in blind tubes to drain the chemicals
i've had a couple replated, no problem
simply explain it is an original process for the part
point out the drain holes

longer it stays in solution the thicker the plating gets
but some mixtures may begin to color blue or yellow
it should be pulled while still silver

zinc is also a translucent coating
so the tube surface imperfections are visible
nice when you can see bend lines from the machines in the tubes
not so nice if someone sandblasted and painted or powdercoated

might be a good idea to rattle can a satin or matte clear over the plating
to protect the natural brilliance of the zinc
else over time it will begin to dull to a grey
much like nickel
 

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If it would be Mercedes, I would say it was for weight saving...  :D

Honestly, I absolutely don't know and I do think this is a great question for the next meeting with Mr. Piero Laverda somewhere on this planet (if Marnix can not answer it for sure). My personal guess would be, too, that it was for looking out for cracks and/or it might be easier to modify/weld on a frame that wasn't painted/powder-coated but just zink plated. But I am not an expert in welding, so don't know if you have to first remove the zink if you want to weld on the frame?!?
 
Welding through zinc is horrible, if you are going to do a lot of it drink a glass of milk first, stops you getting sick.


                Keith.
 
laverdakeith said:
Welding through zinc is horrible, if you are going to do a lot of it drink a glass of milk first, stops you getting sick.


                Keith.
Click to expand...

yeah - guessed that this would be the answer, as welding burns away the zinc, which causes it to get into the air and therewith into your lungs. Not good...  :-[ But did they know that 40 years ago? And did they care? Maybe they thought that this would be less of a problem than having first to grind away the paint?!? Who knows?!?

Maybe zinc is easier to remove than paint before welding? can you sandpaper it away? Or maybe it is because it gets INTO the tubes, too, and coat the inner side also - opposite to painting? Who knows... Maybe it was just for the great look of it...  8)
 
Can I suggest that like so much else in motorcycling these frames were zinc plated because they had access to the equipment ...

An awful lot of agricultural machinery is zinc plated.

When you plate a frame - either zinc or nickel - it should either be sealed (ideal) or free draining.
In neither case do you want plating bath fluids left inside.
If your frames have drain holes I'd suggest a good squirt of fish oil or duck oil from time to time as there will be no protective coating inside the tubing.
 
I picked the brains of quite a few people including Piero. I am pretty confident that the drum brake SFC frames were cadmium plated and that the disc brake versions had zinc plating.
Fact is that the few unrestored/untouched drum brake SFCs that I saw all had a thin layer of matt silver paint to make an even finish.

Marnix

 
Laverdalothar said:
laverdakeith said:
Welding through zinc is horrible, if you are going to do a lot of it drink a glass of milk first, stops you getting sick.


                Keith.
Click to expand...

yeah - guessed that this would be the answer, as welding burns away the zinc, which causes it to get into the air and therewith into your lungs. Not good...  :-[ But did they know that 40 years ago? And did they care? Maybe they thought that this would be less of a problem than having first to grind away the paint?!? Who knows?!?

Maybe zinc is easier to remove than paint before welding? can you sandpaper it away? Or maybe it is because it gets INTO the tubes, too, and coat the inner side also - opposite to painting? Who knows... Maybe it was just for the great look of it...  8)
Click to expand...

The answer to that is easy, yes they would, I learnt it 31 years ago and I knew nothing, it would have been common knowledge from the 1st week of the 1st person welding Zinc plated steel. It's very dangerous, yellow ash and thick smoke, I was off work for 3 days. It is easy to grind through with the use a Soft pad and the welding is much better, but cutting mezanine was where we got ill using a gas axe !

Welding Aluminised car exhausts is the same procedure in preparation ( usually thinner coating) but doesnt appear quite as toxic although I wouldn't argue that point.
 
Mactriple said:
Can anyone shed light on the reason why the factory didn't paint the frames on the SFC 750s?
Click to expand...

I asked Piero this question and his response was straightforward and quite surprising. He told me they went for the silver finish [Cad/Zinc/painted/whatever] to make the bikes look more 'technical' and sporty.
I'm guessing its a very durable finish so it's perhaps suited to a race machine which might start to look a bit shabby once the engines been in and out a few times.
 
not only horrible but actually poisenous, and yes it can, does and has killed, especially if welding (or more likely demolition oxy/acet cutting) of hot dipped galvanised, which is after all only molten zinc, no electroplating involved in that at all, just acid cleaned and then dropped in a tank of molten metal (zinc) very dangerous process, if there is a closed (box) section without a drilled hole, then that part of the section will become a bomb and it will explode, blowing the molten metal every where, that is the main reason for the holes, so that there can not be any presssure build up inside a closed section when the room temperature article is dropped into the tank of (very hot) molten metal.

If you cut and weld something that is zinc coated it can give of arsenic, under certain conditions, you know what they say about arsenic? no one knows what it smells like, since if you have smelled it, you are about to die..

I think they zinc plated the SFC's because it stopped them rusting and is cheaper than paint.
CLEM
 
If its hot dipped gal I doubt its for weigh saving,I had my box trailer done and it ended up so heavy I needed a jinny wheel to push it around,must have doubled its weight.No rust parked in the open for 10 years but its very heavy
 
CLEMTOG said:
If you cut and weld something that is zinc coated it can give of arsenic, under certain conditions, you know what they say about arsenic? no one knows what it smells like, since if you have smelled it, you are about to die..

CLEM
Click to expand...

Smells of Almonds!  UuuuuuAgggggggHhhhhhhhhhhhh ................................................................ uh!


















Uhhhhhh!






























UhhhhhhhchhhhhhHuuu!  (I was a Hollywood actor in my previous life) ;o)

Julian
 
I think that's Cyanide Julian...
I worked with Potassium Cyanide and had to have a 2-part antidote to hand at any time. Any whiff of almonds and it was too late... :o
 
Chemistry book says,

Arsenic tarnishes in air, and when heated rapidly oxidises to arsenous oxide which has a garlic odor.

J

What's that Garlic and Almond pie you are cooking for me dear?  you said you had a meeting with the insurance agent and you would be late home today  :P
 
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