Things NOT to do with a nicely blasted cylinder barrel...

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Fast Eddie

Fast Eddie

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Number 1...

Put them in the dishwasher... They come out in a beautiful light brown coating of rust...!

When I get them cleaned up, what's the consensus re paint, I'm planning on using VHT silver, is an etch primer a good idea prior?
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

Ouch. Should have taken them to the dry cleaners instead! LOL
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

Eddie, I've never heard of the dishwasher method. As far as the rust coating, try some contact cleaner, denatured alcohol or brake cleaner. You might have to give them a quick bIast again. I use VHT brand paints for everything, with good results. You can use "Flameproof" on the head. I use their caliper paint on the cylinders. Chassis and Roll Bar on the frame. When installing new chrome pipes, I do the inside with several coats of "Flameproof". As long as you get your bike running properly from the start, it prolongs the bluing to the chrome for awhile. As far as prep goes, clean everything with contact cleaner or denatured alcohol prior to painting (after blasting). No etching primer needed. When the head and cylinders are off the bike, I do bake them in the BBQ after the paint is dry to the touch. Instructions on the can for on or off the bike process. I'm sure you will get all kinds of replies, but I thought I would post since you mentioned VHT. Good Luck!
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

I did nearly the same thing, after I had it blasted and then I power washed it in the sun with water and it immediately flash rusted. I just cleaned it off with WD40 and then some alcohol and it didn't seem to suffer. If I did it again, I think I'd take it somewhere it could be sonic cleaned in some kind of solvent.
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

Fast Eddie said:
Put them in the dishwasher... They come out in a beautiful light brown coating of rust...!
Click to expand...


The answer to treating this light coating of rust = is phosphoric acid, industrial strength. (rust remover).
It converts and eats the rust coating right away, back to clean steel (iron).
BTW, phos acid is one of the active ingredients in Coca Cola, so its not terribly dangerous (bit diluted though in Coke).

This is an iron head (dommie) that was rather rusty, after several blastings, and then been treated with phos acid.
Things NOT to do with a nicely blasted cylinder barrel...


This head will need another treatment before painting, the rust is not entirely gone yet.
hth.

BTW, I believe that the better powdercoat shops always treat/derust steel/iron things with phos acid after blasting and before powdercoating,
it helps stop them rusting under the powdercoat for much longer than if left untreated... (??).
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

I have never worried about that flash rust on freshly cleaned parts. Just prime and paint. No worries.
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

Thats called the POR system - Paint Over Rust. !!

For a few cents for phos acid, bubbles of rust under the paint are less likely to appear in a few years.
Especially on tanks and mudguards/fenders (if they are painted, of course)

Citric acid, oxalic acid, pool acid etc all do a similar job, but are slower or more hazardous.
Phos acid is literally a brush on / wipe off process.
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

Re the last post.
Oxalic Acid is easily available, most DIY shops/ paint supplier.
It is commonly used to clean cement stains off bricks, lime stains and watermarks off oak etc.
It is a natural product, I believe made from Rhubarb!
Mask and gloves as it burns a little and the fumes can be a little noxious.
Perfectly safe if used carefully.
Hope this helps.!!
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

Phosphoric acid does some nasty things to cast iron, it etches it and brings the graphite to the surface, it will some times attack larger areas of deep rust, like its ment to ,removing very large areas of cast iron, if those ex threads were rusty but still sound they would possibly disappear, makes brake drums useless, you end up with graphite polished shoes
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

Hi Eddie, I blasted my barells a few years back, then tried several full of promise well known high temp paints which each required re painting after a riding season, then I found Halfords high temperature engine enamel and it's still going stronger than ever after several years, I brushed mine but last time I looked it's available in spray cans now, hope this helps.
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

splatt said:
Phosphoric acid does some nasty things to cast iron, it etches it and brings the graphite to the surface, it will some times attack larger areas of deep rust, like its ment to ,removing very large areas of cast iron, if those ex threads were rusty but still sound they would possibly disappear, makes brake drums useless, you end up with graphite polished shoes
Click to expand...

The phos acid is only on it for a minute or less, its only to inactivate/remove the last vestiges of rust after being blasted.
You don't soak things in it for weeks, or anything.

BTW, panel beaters and body shops use phos acid for steel body panels, very widely used for this purpose - they buy it by the drum full.
Again, its only briefly wiped over the steel panels, and then the panels are cleaned off and painted.
Its recommended the paint is applied within minutes...

And Nortons used a phosphate type process to treat steel frames after being blasted, did this for decades and decades.
As did most brit motorcycle makers, prior to the frames being enamelled...

BTW2, the acid products of combustion would do similar things to cast iron. (??).
And for longer, and under much higher temps.
Why wouldn't that do similar things to cast iron - they'd fall apart if it was really a problem.
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

DogT said:
I did nearly the same thing, after I had it blasted and then I power washed it in the sun with water and it immediately flash rusted. I just cleaned it off with WD40 and then some alcohol and it didn't seem to suffer. If I did it again, I think I'd take it somewhere it could be sonic cleaned in some kind of solvent.
Click to expand...

Not sure what good WD40 would do to parts you are prepping for paint other than leave an oily residue behind that could be under your paint. Sorry, but anything with oil or lubricating properties is not a good suggestion when prepping for paint even if you clean it afterwards. Don't think alcohol will remove it completely either.
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

Yeah, I know about the WD40 and paint, but I didn't have anything else handy at the time and didn't want the rust to stay on and get worse. I guess I cleaned it off good enough because the paint has been on since 05 or so. I may have used acetone or lacquer thinner to remove it too, can't remember.
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

brxpb said:
Hi Eddie, I blasted my barells a few years back, then tried several full of promise well known high temp paints which each required re painting after a riding season, then I found Halfords high temperature engine enamel and it's still going stronger than ever after several years, I brushed mine but last time I looked it's available in spray cans now, hope this helps.
Click to expand...

That's a good recommendation, thanks.

BTW did you use black or silver?
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

Just FYI, VHT Flameproof is good for headers not for cylinders and heads. Flameproof paint slows heat transfer, the VHT engine paint is better it allows heat transfer.
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

Halfords engine paint, in silver, is now on the barrels. Thanks for the recommendation.

And good tip ref the flameproof stuff being a barrier Mark, I've read that before somewhere.

Anyway, rusty barrels now restored!
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

You guys need to read Jim C's thread on barrel heat transfer. Convection loss will overwhelm the radiant loss by orders of magnitude.
 
Re: Things NOT to do with a nicely blasted cylinder barrel..

DogT said:
You guys need to read Jim C's thread on barrel heat transfer. Convection loss will overwhelm the radiant loss by orders of magnitude.
Click to expand...

Have read it, with much interest!

The point about some modern, fancy manifold paints is that they (allegedly) contain insulators. As in the 'wrapping' fashion, its specifically designed to keep heat IN.

As far as I recall, Jim didn't test this kinda paint.

Paint tech seems to change constantly, it wasn't many years ago that I painted barrels in 'Smoothrite' silver with great results, but when I used it recently it went a naff shade of greyish yellow ! Clearly the ingredients of it have changed somewhat.

We'll see how the Halfords silver engine paint fairs.

If this doesn't work then I'll simply HAVE to buy some Maney alloy barrels...!
 
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