A review of correspondence from NOC-L
A review of postings on powder coating and other paint types
"I have a frame that may be powder coated soon. Can other parts be done as well, e.g. oil tank, battery cover, petrol tank, sidestand, and centre stand?"
Powder coating costs
I did over a number of parts in my Mk.lll restoration - the
battery tray, side and centre stand, swinging arm, engine cradle, etc. (the
swinging arm needs to be removed).
Most powder coaters will charge by the job and the size of pieces is not the determining factor. My 24 total small and medium size pieces cost ~$200US for preparation and powder coating. I didn't do the frame in powder coat as powder coating doesn't have the 'depth' of color that comes from other techniques. I had it sprayed with urethane and hand rubbed. It's quite beautiful. You might give some thought to the oil tank - it's designed for cooling the oil, so less paint is better than more. Mine has a single thin coat of flat black so it dissipates heat as efficiently as possible.
John S. Morris (email@example.com) on NOC-L 31st. Mar 1998
More on powder coating
I had my frame powder coated last year. You have to remove the
swinging arm and also the metal/rubber bushings in the swingarm. If you don't
the rubber will separate from the metal and you will have to replace them. I
think the cost is close to $100.00 for new ones.
I also had the triple trees, centre stand, tool tray, battery box, rear brake lever & backing plate, and oiltank powder coated. You will have to plug (I use corks and tapered dowels) any hole that is threaded or is a tight fit (fork tube holes in triple trees). If not you will have to run a tap or drill into the part to be able to put the thing back together.
John Mead (firstname.lastname@example.org) on NOC-L 31st. Mar 1998
Problems with powder coating
The only problem with powder coating parts like oil tanks is
that powder tends to leave an 'orange peel' finish on larger flattish surfaces.
Oil tanks, fenders and that kind of stuff tend to look like a poor paint job,
otherwise, I find powder to be a great finish on bikes that see service as
riders. Be sure that your powder coat shop knows what kind of surface finish you
expect to see and what type of finish you will accept.
Powder coat was designed to provide a durable finish on items like lockers and heavy-use equipment, not on concours restorations, although it can be done delicately. What I mean is, it needs to be applied by some one with a deft hand, if you as the customer expect to see a 'paint-like' sheen type of finish, ask them if they are capable of providing that for you! Some shops will load the powder on - I've seen frames where the serial numbers are barely visible through the thick finish. I've also seen fenders, chainguards, and oiltanks done in so ugly a finish that the parts looked dipped and the finish was heavily 'pebbled'. I don't know if powder can be block sanded and repolished but it would seem frivolous to do that kind of work when the idea is to avoid it.
Personally, I don't like to powder coat large flattish smooth items like oil tanks or petrol tanks. I use powder coating for frames, ancillary mounting hardware and round tubular things like kickstands, centre stands, footpegs etc. Powder is difficult and frustrating to repair and to remove - except where your wrench slips! Then it chips - the more visible the area, the easier and uglier the chip! (The Inverse Law Of Damage And Visibility applies dramatically at these times).
Be specific when you talk to the shop guy and ask to see some of his finished items. Deal with shops that have experience with non-industrial customers. If they work with custom car, hotrod or restoration people then they can do the job that you require. A guy who powder coats playground equipment may break your heart.
Joe Michaud (email@example.com) on NOC-L 31st. Mar 1998
Masking off and hole blocking is important when powder coating
Watch out for the thickness growth associated with powder
coating. You may find things like tool box and battery box lids no longer fit
due to the increased thickness of coating; also threaded holes are difficult to
mask effectively. The masking either gets sand blasted away in the preparation
or causes the powder to creep back from the edge of the hole leaving bare metal
I leave things unmasked and retap the holes, which means you have to have a set of taps for all the threads. Don't leave any rubber bushes like Metalastic Dommie swinging arm bushes in place as the high baking temperature will destroy them.
If it's an oil tank be aware that the preparation is always a grit blast operation so be sure that all the grit is cleaned out before you use the item.
Angelo (firstname.lastname@example.org) on NOC-L 2nd. Apr 1998
A URL for powder coating FAQs
Some of you may not have seen the FAQs I did on powder coating,
especially as it relates to cycles - www.execpc.com/~davewrit/.
Let me know how you like it and if you have any comments or additions to the coater list.
Dave Wright (email@example.com) on NOC-L 2nd. Apr 1998
Powder coating as a primer/undercoat
Powder coating has also been used as a kind of primer, since it
does tend to be thicker than paint, which helps to smooth out old parts that are
pitted and banged up, and the prep (sandblasting) helps to ensure good adherence
and durability. Once on, the powdercoat can be sanded smooth and sprayed with a
conventional paint. On tanks of any kind, be sure the various orifices are well
sealed as the blasting grit can cause all sorts of headaches.
I still like how Classic Bike characterised powder coat some years back - 'cheap and cheerful'.
Wayne Bratt (firstname.lastname@example.org) on NOC-L 4th. Apr 1998