SFC 750 frame question.

M

Mactriple

Hero member
Location
Wide Bay Queensland
Which process was originally used to galvanize the SFC 750 frames? I think that there are only 2 processes - Hot dip Galvanizing or Electrogalvanizing. Each is a slightly different process and may produce a different appearance but I'm not sure if that is right either. This question will probably end up as a Marnix query I suppose.
Ian
 
I had a trailer hot dip galled and it added a stunning amount of weight so I would be really surprised if they did that.Great idea for a trailer,its 10 years since and zero rust,but I had to add a jinny wheel as its bloody heavy now.
 
hot dip is for fence posts and boat trailers

i'm not familiar with the term electrogalvanizing
but if it is zinc, that's what you want

it is a thin and nearly translucent coating
when finished you can clearly see mandrel marks and such from original fabrication.
so, you can't sandblast the frame and cover the pits in the metal with zinc

how long the frame is in solution during plating process does have an effect on appearance
mostly the level of translucence.

zinc is normally sealed with a chromate; clear or some mil-spec shade
the clear chromates used can tint the color to a yellow or a blue
(like cad plated hardware)
the longer the part stays in the greater the color shift from silver

after a long search, the folks i ultimately used specialize in "aerospace" applications
the rate was very reasonable, i think i spent more in freight than in coating
 
If you use the original coating-version under normal road-conditions the frame will get a grey/white/dirty colour. Not really sexy.

With several frames i have found a perfect solution with a third metode. Chemical zink plating (?) + a pasivation bath protects the frame even in the inner sides of the tubes. Although you will get the original structure of the tubes and the wellding-ropes (sorry, don?t know the right word). This easy methode is not verry well known. 

No rust, everytime shining and a easy cleaning will make you smile for many years.

How it works:
- sand- or better nutshell-blasting
  (wait only few hours between blasting and zink process)
- a little polish with a rotating, soft steelbrush
- short bath against rust
- chemical zink process
- pasivation bath

Prices here in the northern bavaria:
- blasting frame and swingarm about 80 EUR
- chemical zink and pasivation bath about 180 EUR per bike

The result you can see in the aktuell gallerie of the forum (see 750 SFC 18391).

Thomas aus LAU

 
Thanks for the above info. The problem that I have is that the SFC frame has been painted black over the zinc plating. I am not sure if paint stripper will be satisfactory in completely removing the paint and according to Scott blasting the paint will probably stuff the surface underneath for plating a nice zinc coating. It might be that the zinc underneath is quite good if I could get all the paint removed.
After looking into this problem there seems to be an issue with hydrogen embrittlement of welds due to zinc electroplating. There is even a "mechanical" method for applying zinc to metals as well. Maybe I will have to settle with non-original silver paint which is not what I really want to do. Maybe one of the aerospace companies will know. Any  further suggestions?
Ian
 
If fine bead or as has been suggested a soft media like walnut shells is used you will finish up with a platable surface. May be a little tedious blasting though...and don't even try if it's powdercoat.
I use quite a lot of bright zinc on chassis fittings and usually beadblast prior to plating. Fine bead at lowish pressure is the prep for nickel plating frames too. Never coarse grit.
Hydrogen embrittlement is only a problem on very light gauge highly stressed structures...which does not describe a standard SFC frame
 
The aero industry guys strip the coatings slowly in a caustic solution. It will remove the paint and leave the metal substrate intact, including any electrolytic zinc coating. The same place that does the stripping should also be able to do the electroplate if needed.
 
Thanks to all above! I will start to ask around to find a good plater preferably in Queensland. If I can get the other parts I need for the SFC I will probably start in the new year.
Ian
 
Ian,
Will talk when we get home but bear in mind, probably best to restore your SFC and our SFC at the same time.
So look at sending two frames off to be plated.

You do the cosmetics, I'll do the engines.
Sounds like a fair trade to me.

Tchau
Red
 
Red,
I haven't forgotten. I just like to get things organised in advance so that there are less hold ups after getting started. I'm talking with the local plater today to see what he can do in this instance. He was reluctant to take the frame on when I first enquired. He had concerns about chemicals remaining inside the frame and causing eventual corrosion from inside. Now I have been told about drain holes I will see what he thinks.  I've got 2 bikes to get tidied up first before I can wheel the SFC in. I can't wait to get on with it.
Ian
 
redax5 said:
You do the cosmetics, I'll do the engines.
Sounds like a fair trade to me.

Tchau
Red
Click to expand...

Your house need painting, or the garden. I noticed the driveway was a bit ratty. Doesn't the workshop floor need cleaning? :D :D
 
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