Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: philward on February 17, 2018, 07:51:48 PM
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Just bought a spare swing arm to replace the Metmachex swing arm on my next project 750 cafe racer (Metmachex will be sold). Its powder coated but a bit dull and needs touching up. I tend to spray things myself so have little experience of powder coating.
Can I just spray over the powder coating?
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Its a misconception that powder coat is something special. It is just a very economical way of painting the biggest advantage with it is it can reach where a wet spray can't.
Just rubdown and repaint with paint of your choice. As always prep is key
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Powder coat can be treated like paint you can flat it with wet and dry use rubbing compound or Tcut then polish for a perfect finish.
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There was a 'Restoration Theatre' talk at Stafford a year or so back on restoring Yamaha FS1E's and the guy there said he powder coats frames, stands etc. and then paints with correct factory finish paint. My worry with powder coating is that, if the prep isn't done correctly, it can crack or chip and you can get water ingress leading to hidden corrosion underneath.
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I had a visit from a member yesterday that knows his paint and we were discussing the finer points of satin black and it seems that it is variant from powder coater to powder coater. The guy I use now does a lot of corporate equipment and matched me a batch of two of the blacks that Honda used in the early years.
I would not like to guess how many variants of black that Honda used over the years ;D
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I talked to the guy who does my painting some time ago on this subject. He is a professional custom painter and knows his stuff. He informed me that it was fine to paint over powder coating but the item needed to be warmed in an oven to a low temperature first to get the paint to key. However this was some time ago and I'm not sure if that is relevant to water based paints we use now. On another note proper powder coating is not just ordinary paint. It's a lot tougher and takes harder knocks. If yours doesn't then you're using the wrong guy.
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Allowing for the fact that I'm Heaven's 'Unlucky' Experiment, the last two powder coated items that I've had, have convinced me that if I'm ever stupid enough to do another restoration, I will have the frame sprayed with two pack. Powder coating is knock resistant but mine seems to go 'soft' when it gets hot; not tricky with an exposed engine. It also 'spirals' when I tighten nuts, bolts or screws onto it; especially when it's hot. As a result I've had small sheets of powder coating around fixings come loose and separate from the frame. I know a good sprayer in Gt Dunmow and he explained to me that it's a form of 'Plastic Paint', which melts into a smooth finish when it goes into the oven. I know other 'restorers' that swear by it but my advice would be the same as above (firet49), rub it down with fine abrasives and then polish it. If you have any small marks, a dab of Smoothrite works well for me.
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So yours sounds like nylon powder coat Mr Sheene. I have had sooooo many frames and parts powder coated over the years and I can honestly say I have never had the coating lift, peel, pickle, melt, go soft or anything else. Yes, I have scuffed and chipped frames and parts accidently but never has the damaged area got any bigger. These days, if I get a small chip or whatever, I just touch it in with Matt or Satin black nail varnish, works a treat.
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Thanks Julie, I didn't know that there was different forms of Powder Coating. The Commando was Powder Coated by a firm specialising in Motorcycles in Birmingham, via a reputed Norton specialist. I'll have a word with him next time I go to see my sister. How do you tell the difference until it deforms? I have been 'bitten' three times and will still avoid it in future but I did start my last reply as, Heavens 'Unlucky' Experiment. I don't know what's on my CB750, as it came Powder Coated but judging by the rest of his work, it won't be the best. To get back to the origin of this piece though, Powder Coating does polish up well in my experience with a bit of effort.
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Powder coating like everything else doubtless comes in many forms and qualities......unfortunately for me; every experience I have had with this stuff has led me to hate it with a passion; it dulls and can't be polished properly, the surface changes colour at random giving a nice piebald effect, it's not as tough as it's made out to be and when it chips, make sure you touch it in or you will be peeling it off in sheets later.
I suspect it is popular because it gets into every nook and cranny, and it's cheap.......the problem is, when it does get in everywhere, it's the devil's own job to get rid of it later on. Don't let a leaky fuel tap drip on your black frame or the affected section will turn pale grey.....forever....DAMHIK. >:(
I sold this Norton five years ago and bought it back last week.....unfortunately, Norton powder coated the frames on these from new and they are a box section affair with a built in oil tank.....oh and the wheels....which started out as silver I'm told, they are now pale battleship grey.
[attachimg=1]#
Just in front of the rear mudguard on the faired models is a mud trap, the owners club forum has a number of threads which involve the powder coat failing at this point, rampant corrosion taking root under the coating and the first the owner knows is when he gets an oil leak from the tank.
Repairing that damage makes most tasks on our Hondas look like childs play. Go look at some street signposts or garden furniture that has been permanently exposed to the elements, you will likely as not see the powder coating flapping in the breeze and the underlying metal rotting for all it's worth.
I think powder is probably good for crash bars and lots of other applications, and it's probably fine on a classic that will only get dry weather use, and admittedly the stuff I experienced was a good few years old, so perhaps it's improved, but as a choice for a regular use bike instead of paint?....no....just my opinion of course.
Mick.
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New Norton Rotary thread please. I’ve only ever seen these in museums.
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So you bought it back Mick...What's next .... the Royal Bomber perhaps? :D
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Just a sucker for punishment........doubtless this will bite the hand that feeds it. ::)
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Powder coating like everything else doubtless comes in many forms and qualities......unfortunately for me; every experience I have had with this stuff has led me to hate it with a passion; it dulls and can't be polished properly, the surface changes colour at random giving a nice piebald effect, it's not as tough as it's made out to be and when it chips, make sure you touch it in or you will be peeling it off in sheets later.
I suspect it is popular because it gets into every nook and cranny, and it's cheap.......the problem is, when it does get in everywhere, it's the devil's own job to get rid of it later on. Don't let a leaky fuel tap drip on your black frame or the affected section will turn pale grey.....forever....DAMHIK. >:(
I sold this Norton five years ago and bought it back last week.....unfortunately, Norton powder coated the frames on these from new and they are a box section affair with a built in oil tank.....oh and the wheels....which started out as silver I'm told, they are now pale battleship grey.
(Attachment Link) #
Just in front of the rear mudguard on the faired models is a mud trap, the owners club forum has a number of threads which involve the powder coat failing at this point, rampant corrosion taking root under the coating and the first the owner knows is when he gets an oil leak from the tank.
Repairing that damage makes most tasks on our Hondas look like childs play. Go look at some street signposts or garden furniture that has been permanently exposed to the elements, you will likely as not see the powder coating flapping in the breeze and the underlying metal rotting for all it's worth.
I think powder is probably good for crash bars and lots of other applications, and it's probably fine on a classic that will only get dry weather use, and admittedly the stuff I experienced was a good few years old, so perhaps it's improved, but as a choice for a regular use bike instead of paint?....no....just my opinion of course.
Mick.
I have to say I've had the exact opposite. I first used powder coating nearly 30 years ago. I still Have that bike and it still looks good after nearly 80,000 miles. It still shines and only a few wear marks. I have always used TripleS at Bingley except for one job after I moved from West Yorks, I thought I would try a local coater on a Harley belt guard. I asked for A deep shine black and got a grey orange peel. Lesson learnt and I have since done the journey back to Bingley for my coating. It seems quite clear you get what you pay for.