how many "rattle can" coats as a minimum on a 531 frame

[greyingbeard]

looks fine from here !

cheapo paints (eg "word corrected to Halfords") are mostly thinners, a proper automotive paint supplier will mix any colour you like, to match if required, there will be more solids in the tin, often no more expensive than H.
Of course, nothing wrong with checking the car boot sales, pound shops etc. The finish is 99% effort.

[breakwellmz]

Thanks.
In appearance it is at least a match for the factory finish on the frame, i`m not saying it will be as durable!
I feel the`knack`is knowing the fine line between putting enough paint on so it flows together to get a glassy finish and not so much you get runs.
A fork is an easy one to start with, you can hold and maneuver it by the steerer in one hand with your can in the other.

[kylecycler]

I feel the`knack`is knowing the fine line between putting enough paint on so it flows together to get a glassy finish and not so much you get runs.

The great American frame painter Joe Bell calls that "running the ragged edge between liquid glass and run city," so even he has the same problem!
http://www.campyonly.com/joebell/How%20 ... 0Crew.html
You've done a nice job on the fork, and that's a good tip about lighter fuel to degrease - I was wondering what it would be best to use. From what I've read up on, grease is your enemy, as well as dust, of course - tack cloths (available in B&Q), are the answer for that.

As well as heating the cans in hot water, does anyone know if it would help (or even be safe) to heat the frame/fork with a hairdryer or hot air gun first, to help the paint to dry from the inside out, so to speak - even to help the paint to dry on the outside after you've applied it, before anything sticks to it and ruins the finish? Just concerned about igniting fumes - don't want to go up in smoke...

I've got two white Raleigh Pioneers to paint. They're both lugged steel, one about 25 years old with 18-23 tubing, the other maybe less than 20, with Reynolds 501. The main tubes are perfect but there's slight rust around the lugs, and on the chainstays and brake bridge on the older one. I don't think I'll need to strip the paint off of either, just get the rusty areas down to bare metal and treat it before priming. I'm just telling you this coz I'm trying to convince myself to make a start! I've been collecting aerosol cans of white 'metal paint' at Aldi for about two years when it's reduced, so I've got enough. It's German - good stuff, I think. Just need the bottle.

For anyone who's interested, here's a step-by-step of Joe Bell's process, painting a Richard Sachs frame from start to finish. I found it intriguing. W-a-a-a-y more involved than any of us are ever likely to attempt, but it just shows you how much work - elbow grease, even - goes into it. Joe Bell uses DuPont Imron paint - what I believe is called 'two-pack' - which is highly durable, although he jokes in the above link that the reason the Imron tins are so big is to allow space for all the health and safety warnings - it's lethal stuff without a full respirator, fume extraction, etc. so it's out of the question for DIY use. It's quite a process, though...
http://www.campyonly.com/joebell/painting_steps.html

[Brian73]

I had a frame 'professionally' re-finished by a local Derbyshire firm about a year ago. 2 pack stove enamel with decals, £120.

There was a decent paint run on the downtube.

I won't be having another frame done there.

[Brucey]

....You've done a nice job on the fork, and that's a good tip about lighter fuel to degrease - I was wondering what it would be best to use. From what I've read up on, grease is your enemy, as well as dust, of course - tack cloths (available in B&Q), are the answer for that.

As well as heating the cans in hot water, does anyone know if it would help (or even be safe) to heat the frame/fork with a hairdryer or hot air gun first, to help the paint to dry from the inside out, so to speak - even to help the paint to dry on the outside after you've applied it, before anything sticks to it and ruins the finish? Just concerned about igniting fumes - don't want to go up in smoke...

Lighter fuel is fine for degreasing but it doesn't remove traces of moisture from the surface of the work. For that, warmth and/or wiping with alcohol works OK.

If you warm the work gently it definitely helps BUT if you get it even slightly too hot then the solvent will spontaneously boil and this will ruin the paint finish. This happens well below the point at which you are likely to get any other trouble, so in a well ventilated area you are not likely to have a fire on an explosion if you use a hairdryer or similar.

Provided the ambient temperature is in the range 20-25C aerosols work OK; if you are getting runs at this temperature then this strongly indicates that the paint is being applied in coats that are too thick.

Note that (unlike two-pack paints) pretty much anything that comes in a rattle can will never 'cure' in quite the same way; this means that the solvent in later coats of paint will always have the capacity to soften underlying layers of paint. This means that it becomes more and more important to spray in relatively thin coats in the latter stages on the paint process.

As others have commented, rattle cans don't contain that much in the way of paint solids. This has two consequences;

1) It is a really good idea to spray the base coats using a spray gun instead of a rattle cans. You can buy automotive paints such as zinc bearing primer and good quality cellulose base coat. It is far easier to build up a base coat that is thick enough to be worth sanding down and durable enough to be worthwhile this way.

2) It is kind of tricky using rattle cans to build up a colour coat that is thick enough to cut back using (say) 400 or 600 grit paper. The kinds of thickness per coat are so thin that you can usually go through one coat in a few seconds using 400 grit paper. Most people therefore try to spray rattle can colour coats well enough that they don't need cutting at all or can just be cut using a mild cutting compound rather than abrasive paper.

The single thing that is the biggest stumbling block to getting a really good finish on bike frames with rattle cans is not runs (these can be avoided once you have the knack, or simply cut back later on) it is in fact more usually 'orange peel'. What happens is that the 'sides' of the tube see a thinner, dryer, spray coating than the part of the tube that faces the spray plume directly. If you treat each tube as if it were a square shape, and paint it as if it had four 'sides' in short order then you can usually make 'dry sides' run into one another well enough. But it isn't easy and the exact method will vary with temperature somewhat.

hth

cheers

[breakwellmz]

As well as heating the cans in hot water, does anyone know if it would help (or even be safe) to heat the frame/fork with a hairdryer or hot air gun first, to help the paint to dry from the inside out, so to speak - even to help the paint to dry on the outside after you've applied it, before anything sticks to it and ruins the finish? Just concerned about igniting fumes - don't want to go up in smoke...

Anything i spray sits in a warm dry place beforehand(The conservatory in this case, or on a radiator in winter)so that it`s warm to the touch(A bit vague i know ).This goes for Waxoyl treatment as well.

Go for it!

[RogerThat]

If I was renovating an older bike just to get out back on the road I'd probably go powder coat, which is lot more finessed and thinner than the chunky coats of yesteryear. The local bloke round my way knows what I expect from a finish and will mask off the bracket ect and do a nice single colour for £35. I just couldn't be bothered with the hassle of all that rubbing down and painting to get a nice, but essentially fragile paint finish which won't last..

[mjr]

If I was renovating an older bike just to get out back on the road I'd probably go powder coat, which is lot more finessed and thinner than the chunky coats of yesteryear. The local bloke round my way knows what I expect from a finish and will mask off the bracket ect and do a nice single colour for £35. I just couldn't be bothered with the hassle of all that rubbing down and painting to get a nice, but essentially fragile paint finish which won't last..

I probably would when I know who locally is any good at it, but I decided a cheap-except-for-time short-lived paint finish would be better than a medium-priced potentially-rubbish powder coat.

[bigbloke]

Well its done!

Not perfect, but daughter is delighted

Would I spray one again ? not a ruddy chance in hell! Straight to a paint shop or frame builder !

The frustrating bits were:

* Having left the paint for a week (working away) in a warm place (next to a radiator) to harden,
I fitted the gear cable stop bracket to the down tube. When I returned a week later the paint had "muffined"
either side of the bracket! (photo to follow)

* Underestimating how hard to screw up the front derailleur I shifted gear and the blasted thing got dragged 10mm down the
frame , scratching the paint and revealling yet more "muffin paint" where it had originally fitted.

* The point where you think youve finished spraying just as the last spits are emitted from the can...only to find an hour later that
youve missed a bit, dinged a bit , or a fruit fly has landed on it and ruined the finish, requiring you to go back to the shop and buy
"just one more can"

I would say I used about 5-6 cans in all. its a very wasteful process with no substitute for practical experience, the choice of rubbing
compound makes a huge difference too.

Photos to follow , thanks to all for your input

regards

BB

[Brucey]

good work, I am sure!

I felt the same way after I'd first painted a bike frame.... but like most things, it is a skill, and it is something that, with practice, you can manage twice as well in half the time.... so my first paint job wasn't my last, even though I said it would be at the time!

BTW I'm guessing that you didn't use a conventional cellulosic automotive primer, from a can (rather than an aerosol)...? If you had done so I do not think that it would have wrinkled when you put the front mech on; it dries very hard indeed by comparison with what you can get out of an aerosol.

cheers

[Vetus Ossa]

BTW I'm guessing that you didn't use a conventional cellulosic automotive primer, from a can (rather than an aerosol)...?

Now this is probably a question I will regret asking when I have had the time to think about it, but what's the difference between the two Brucey?

[Brucey]

well my understanding is that most aerosols contain Nitro-Acrylic paints these days. These paints are not very hard even when they have had plenty of time to cure.

By contrast if you buy cellulose undercoat meant for use with sprayguns, it dries and then cures to something that is much harder. The real strength in a DIY paintjob lies in the undercoat and primer; the top coat is just for show, moreso still if the topcoat comes out of a rattle can, and the undercoat doesn't.

cheers

[Vetus Ossa]

Thanks for the explanation. I guess a spray gun is not an option for most unfortunately.

[pete75]

well my understanding is that most aerosols contain Nitro-Acrylic paints these days. These paints are not very hard even when they have had plenty of time to cure.

By contrast if you buy cellulose undercoat meant for use with sprayguns, it dries and then cures to something that is much harder. The real strength in a DIY paintjob lies in the undercoat and primer; the top coat is just for show, moreso still if the topcoat comes out of a rattle can, and the undercoat doesn't.

cheers

Why would anyone with access to a proper spray gun use it for the undercoat but not the top coat?

[Vorpal]

You can brush cellulose on if you mix it with a retarder thinner (also called a brushing thinner), instead of a thinner meant for spraying. It takes some trial and error to get it right, and it's still not easy to produce a finish entirely without marks.

I hadn't honestly thought of using cellulose paint on a bike, but I on further reflection, I think that what a former clubmate does. He has a business doing painting, inlcuding cars, motorcycles, and pedal cycles.

Restorers of carriages, cars, trains, etc. sometimes use cellulose paints with retarder thinners so that they can restore custom paint work (with brushes).