Painting your “Otter” Frame.

Or any Other...




OK ,

So I have decided to paint the next two “Otter” frames instead of having them powder coated, Why...

Well you know when you have supposedly finished building your bike up and you think every thing is in the right place, then you jump onto the bike, and find that this, and that, is not quite to your liking. Exhaust run, wrong. Need a bracket for that, and another to reposition the ignition coil as it hits the tank, and the tank could do with moving up a 1”, I could keep on.


Now your precious powder coated frame is not going to look the same with welding torch scorch marks on is it? So you spend ages, and I do mean ages, looking for ways you can hold this and that onto the frame, without damaging the powder coat finish.

I have come to the conclusion, that there are two alternatives. You either build the bike up without any paint on the bike at all and ride it until you are satisfied every thing is right. Dave Wood is doing this with his bike. Or you sand blast and paint the frame when you think you have every thing in the right place, and if there is need later for modifications, it is not too difficult to remove a small portion of paint to weld on a bracket, and then make the paint good again.

So what paint do I use? Well after a short investigation to what is available. I have come to the swift conclusion, to use an epoxy based fast black paint. There are a couple or three on the market. So you makes yer choice.


 I will probably go for the one marketed by PJ1 Fast Black frame paint.

Here is a tip from PJ Harvey himself. And it looks like there is no need to use an undercoat, unless you want to.


[Make sure that you get your work-pieces warm enough to allow the paint to flow out properly; a couple of heat lamps in clamp-type light fixtures work great, and you can easily adjust the temperature by moving the lights closer or further from the work piece]


I will attempt to do a frame this next week with pictures and we will see how the job turns out.

Firstly I will sand blast the frame using only standard "play pen" type silica sand, with a cheap spray gun type gun appliance, but you will need a good respirator type mask, and a compressor that can keep up the 100 plus pounds constant pressure.

Now most of my frames and the ones from Faber, are bronze welded, these frames need extra care when blasting, to make sure you remove all traces of borax type welding flux from the joints.

If you do not do this job thoroughly, it will penetrate your new paint finish and ,more importantly encourage rust onto your frame. so pay extra attention to these areas of the frame. OK...


Here below are the pictures of the three stages of painting a frame.


Number one,

Shows the frame's sand blasted with the gun in the picture. The abrasive element was only silica sand (dry).

I might add during all days of painting the frames the temperature out side was about 75F so more like a oven temperature.

Picture two,

Shows the frames sprayed with a good grade of red oxide primer, mixed with cellulose thinners.

And picture three,

Shows the John Husband frame painted with the PJ1 epoxy black paint. this was sprayed in the middle of the day when the sun was hottest, and to be quite honest, it baked the paint on, and was dry by five thirty. We will see how good a finish it really is, and what it stands up to, but it looks good at the moment.



The SQ frame is going to be finished with a different paint and then 2K lacquer, picture later.




One thing you always need to check is that there is no moisture left in the steel tubing .


So leaving these frames in the mid day sun more than helped the situation.



Now with a good coat of chromate red oxide primer the steel should be sealed from the elements and be ready for the top coat.


I remember my CoTTon "Telstar" frame all those years back 1965 had this treatment and stayed on the frame event after event and  being in several "OFF'S".



The "Hubbo" frame above had several coats of the PJ1 fast Black paint, in fact there was only just enough paint in the can to do the job.


After another twelve months on the bench after the frame was painted, the paint seems to have stood up very well to getting moved about with occasional knocks.

It is not one of the best finishes on a frame I have seen, but is quite up to the job.




Most of the bolt on parts are going to be plated with our new plating kit.


I will run a page for this for you when we do it.


The Square tubed frame was sprayed as suggested above, and then given a coat of two-pack clear lacquer on top of the paint. it seems OK but did go slightly dull.


OK I have decided to use a well thought of paint system for the Super Cub Trials frame to try something new and see if all the praise about the product system is true.


You know me by now, I have got to try every thing once.


The New Paint system being used is the American POR15.

I have it on order and will start the process in a couple of days.


This is what I am using.







Firstly you clean the frame and then use the POR15 Cleaner degreaser.


There is a specific time to leave this on the frame before removing it. with water!


Then the Metal Prep is applied, and the same again leave and then rinse.


Now coats of POR15 Black Rust Preventive is applied.


Before finally coating with the Top Coat below.


I will go into more detail about the more technical side of this product

as we use it.


POR-15 Technical Information



POR-15 Inc. brings the powerful technology of polymeric isocyanate derivatives to the consumer rust prevention market for the first time, a technology vastly superior to competing products currently on the market.

POR-15® is easier and less expensive to apply than epoxies, since it doesn't require mixing: and POR-15® dries to a high-gloss or semi-gloss finish just like paint, except that it cannot be scratched or peeled off.

Since POR-15® chemically bonds to metal, the underlying surface does not have to be sanded before application. As long as loose or flaking rust are removed from the surface, an application of POR-15® will not only cover up the rust and prevent it from spreading, but will also strengthen the underlying metal and seal holes by forming its own membranes.

POR-15 is a rust-preventive paint designed for application directly on rusted or seasoned metal surfaces. It dries to a rock-hard, non-porous finish that won't chip, crack, or peel, and it prevents rust from re-occurring by protecting metal from further exposure to moisture. POR-15 is sensitive to UV light (sun) and must be topcoated before prolonged exposure to sunlight. POR-15 is cured and strengthened by exposure to moisture and will dry faster under extreme humidity, but moderate to dry atmospheric conditions are most desirable when applying this product,because extreme humidity may cause an immediate surface cure, trapping carbon dioxide gas below the surface. When this happens, bubbling may occur. Extreme humidity at the time of application may also interfere with proper adhesion of the POR-15 coating to metal because it's almost impossible to keep metal dry under such conditions.

POR-15® is a paint-like substance which acts as a total rust inhibitor and also very effective as a metal filler. Its consistency is approximately that of paint and it has very good spreadability (one quart covers 96 square feet). POR-15® chemically bonds to rusted steel to form a rock-hard, nonporous coating that won't crack, chip, or peel. It works by isolating metal from moisture; without moisture present, steel can't rust. Thin, covering coats are best. Apply second coat when first coat is dry to touch with slight "finger-drag" remaining.


Solids - 74% 
Vapor Pressure - 38mm 
Hg: Boiling Point - 232°F 
Specific Gravity 1.05 
Percent volatile by Volume 25% 
Weight per quart - 2.25lbs. 
Solubility in water - insoluble.

Appearance: Glossy or Semi-gloss (black only) finish.
Application: Brush, roller, spray
Spreadability: 96 sq. ft. per Quart, 384 so. ft. per gallon.
Recommended Temperature Application: 45°F - 95°E
Drying Time: Varies according to humidity; average is 4.5 hours.
Shelf Life: Unopened can - 2 years or more. Opened can - up to 6 months.
Abrasion Resistance: Using Taber Abrasion Test, POR-15® passes 200 cycles with a 100 gram weight on a CF17 Wheel.
SolubilityPOR-15 is readily soluble in esters. ketone's, and aromatic solvents.


Surface preparation: 
Rusted surfaces are best; seasoned metal and sandblasted surfaces are also good.

To coat smooth metal surfaces: 
Use POR-15 METAL-READY to prepare surface before painting. Surface must be dry and free of grease, oil, or other foreign substances. Use of 'rust converter' products is not recommended as they may affect bonding of POR-15 to metal. POR-15 likes to adhere to surfaces with 'tooth' rather than smooth, glossy surfaces.

Do not shake. 
Refrigerate unused portion of POR-15 for longer shelf life.

Apply in thin coats, 1 to 2 mil thickness. Minimum 2 coats. 
Topcoat when first coat is dry but with slight finger-drag remaining, usually 4-5 hours.

Use 30-35 lbs pressure for normal gloss. Reduce pressure for lower gloss (20-25 lbs). Thin only with POR-15 Solvent, if necessary, but do not thin more than 5%.

Wet sand with 320 grit until gloss is dull, then paint, or use POR-15 Tie-Coat Primer directly on the cured POR-15 surface, then topcoat as desired.

Use POR-15 Solvent or lacquer thinner for cleanup, which must be done before POR-15 dries. NOTE: Organic vapor particulate respirators, NIOSH/MSHA approved, must be used when spraying POR-15.

Moisture will shorten the life of unused POR-15. See our 'Residual Moisture - Little known Facts' page to learn some little-known facts about residual moisture.

Seal can or jar immediately after using. We recommend placing plastic wrap between lid can and storing in a cool dark place.


For proper adhesion to aluminum, galvanized metal, and smooth steel surfaces, prep with POR-15® METAL-READYT Rust Remover/PrePrimer. Keep surface wet for 15 minutes, then rinse off with water and dry thoroughly. This process will leave a zinc phosphate coating on the metal and insure perfect adhesion.


  • Use as a primer or finish coat
  • Automobiles: fenders, floorboards, bumpers. trunk areas, engine compartments, rockers
  • Trucks, trailers, agricultural equipment, snow removal and highway equipment
  • Storage tanks, bridges, boats, factory machinery
  • Outdoor sign supports, fencing, metal roofs, fire escapes
  • Use to waterproof insulation or wood
  • As a filler for metal
  • Use as a bonding agent on wood or styrofoam
  • Prevents rust in refrigeration units where moisture corrodes metal
  • Use on lawnmower housing to prevent rust; keep grass from sticking and clumping in wet weather.


  • POR-15® SILVER contains metal filler and should be used on badly rusted steel to fill small holes and pitted areas.
  • POR-15® BLACK is used on frames, floorboards. under fenders, engine compartments. trunk areas, etc.
  • POR-15® CLEAR dries to a perfect satin gloss, used on exterior surfaces before painting. Excellent for "touch-up".
  • POR-15® GRAY is ideal for use on concrete.


Better chemical resistance, better adhesion to metals, greater ease of application, strengthened by exposure to moisture. Reasonable pot life, non-shattering, great flexibility. No catalyst required for curing.


  • Pint
  • Quart
  • Gallon
  • 5 Gallon Pail
  • 55 Gallon Drum


POR-15® is sensitive to UV light (sun) and must be topcoated for prolonged exposure to sunlight. Failure to do this may result in long-term damage to the POR-15® coating. Topcoating is not required for areas not exposed to sunlight.


POR-15® was tested for 168 hours at 97°F in a condensing humidity salt spray (ASTM B117). At the end of the test period, coated steel was free of rust or pitting. Acid and alkali resistance tests performed found panels coated with POR-15® to be impervious to gasoline, oil, chromic acid, hydrochloric acid, phosphoric acid, sodium hydroxide, caustic soda, 50% sulfuric acid, and 50% hydrofluoric acid. POR-15® was applied over a rusty substrate as a finish coat (approximately 23 mils dry film thickness). The coating showed essentially no undercutting at the scribed area after 2000 hours in a weatherometer*.

A 2 mil thickness of POR-15® was applied to lightly rusted steel and then exposed for 1000 hours to a salt spray. At the end of the test period, no undercutting was observed at the scribed area. Recoatability is excellent. Laboratory tests have shown very good adhesion when applied up to 14 days after application of the first coat. In an actual Field test, a topcoat was applied 6 weeks after the first coat had been applied, and the intercoat adhesion was excellent as determined by a crosshatch tape test. A metal box used as a filter for raw sewage was coated with POR-15® and placed in service within a few hours after the interior and exterior were coated. No visible rusting occurred at the welded areas after a six month exposure.

POR-15® coating was subjected to 450°F for 10 hours; it remained hard and showed no apparent loss of adhesion. A panel subjected to elongation was pulled beyond the yield point of the base metal without affecting the POR-15® coating.

    Dew cycle XWR with corex D filter, cycle is:
       1. 30 minutes sun, 135°F, 30% relative humidity.
       2. 30 minutes dark. 75-80°F, 100% relative humidity 
           (achieved with water spray on panel backs)
Video of work done with this product.
More Later with photos of the Super Cub Trials frame painted with POR15.R
Super Cub "Mini"Otter Frame,
Cleaned with POR Cleaner.
Then coated with the metal prep to the instructions on the can.
Then coated with the POR coat, and finally the POR "Top Coat" this one in Matt Black.
Brian with the finished bike, Dec 2016...
And job done, a good hardy finish to the frame.
More later on other paint finishes.
I have decided to investigate the possibility of doing some powder-coating at home.

Well I have all these small parts that you forget to send off with a finished frame


the powder-coaters we always use at Redditch..

 and thought I will just have to paint the bits again.

 But with a volume of bikes now on the verge of getting put together,

(yes I know it has taken a long time).

There will be an awful lot of parts to paint.

 So it would be far better if we could powder-coat them.

 I find on the market a couple of interesting home Powder-coating kits, and the

are a reasonable price. 

Easy Coat Powder Coating System from electrostaticmagic on Vimeo.


The only down side is that you need some sort of oven to cure the finished powder

rich frames and these need to get to a temperature of 180-200 degrees C...

 So it is time to investigate the possibility of making an oven to at least the

size of a swinging arm...

A three foot cube seems about the right size ,and perhaps robbing the parts from an

 old electric oven is the way to go?

If you have built an oven or have any ideas please let me know...


 So More when I have plans for that. 




Well today with the frames back from Redditch, it was time to try out the

powder coat gun. the sun was shining and the World looked Good...

 I am sure a lot of what we do is in the head...

Anyway I assembled the gun to instructions an set the 50 lbs pressure on

the control gauge.

 The canister was filled with the black powder coat. and the parts set on

tig wire hooks on the back of an alloy  chair, in front of the

workshop infra-red workshop heater.

( The eldest has got to still swap his oven in his house so that we can do

the job properly)

I left the parts to heat up a while, and then one by one, connected the

earth lead to each length of wire in turn and covered them with the Magic dust...

Each one was hooked back onto the chair in front of the heater...

But I was impatient and wanted to see a result...

 So the workshop heat gun, was cracked up...

 And one by one the parts had the added attraction of the heat from the gun.

And has if like Magic the dull powder suddenly turned into this

shiny black finish that everyone would be proud of...

 I even gave the engine mounting a second blast with the gun. and this time

the result was even better...

 Why did I not buy one of these a long time ago.. Great Stuff...

 Photos below.


What a Gun...Magic...



Warming up on a spring like day...



First attempt at this art of powder coating... And parts ready to go....

Nice one..



I am going to try and do a frame with mine next... we will see how it goes...


More Later...