OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Tech Talk Rust converter questions

Hi all,

I've been using some rust converter on some surface rust spots on various bits and pieces. A couple of questions:

• Do I need to do anything to it before I spray paint over it? I think it has turps in it, I was simply going to wipe down with methylated spirits and/or car wash detergent (and rinse) to clean the surface before using a top coat directly. I might have to sand them back because some are within painted, some within chromed areas. Is this ok or should there be another procedure?
• If I have some surface rust inside a B&S mower fuel tank, is it ok to treat with the rust converter and leave it for use? Will it last or be affected by the petrol? Do I need to perform any other treatment?

Thanks!

I guess it might depend on the brand, some are designed to be painted straight over. Can't remember which one it is, one of the major brands like Loctite or something, turns purple when it is converting the rust and then you just paint straight over it.

hi pitrack 1
there are a couple of different types of rust converters
one which after application turns the rust black and after its dried should be wiped down with a damp cloth and can be top coated as is , but I would recommend first a under coat in rich zinc paint which is available in a spray can.

other type is phosphoric acid
after applying when dry rub down with a damp cloth, this type of converter some times dries with some white powder on the surface , rub all powder off before painting.
again i a would recommend using a rich zinc under coat before finishing with a top coat.
both types of rust converter can be top coated over after they have dried but the use of the rich zinc is extra insurance against the rust returning and bleeding through the paint

would not recommend using rust converter in a fuel tank, if its a common tank best to get another clean tank
if you really need to use the tank you can buy from auto shops a fuel tank cleaner repairer.
I have used this product myself ,they sell tank repair kits for cars and motor bikes
motor bike kit will repair two or three mower tanks
first it removes , converts rust , then tank is relined with a rock hard ceramic coating, will fill rust pin holes leaks ect no more rust problems, but its not cheap at around $80 for a motor bike fuel tank repair kit .

hope that helps damo

Hi and thanks for the replies Aussietrev and damo.

Petrol Tank
I'll hold off on the petrol tank. I had considered the motorcycle tank repair stuff, might do it later for the learning experience.

Rust Converter
A couple of further questions:
- Does zinc gal paint form a bondable layer for topcoats (i.e. like a normal primer)?
- Would a chrome-finish paint benefit from a white or grey primer/undercoat?

Otherwise I've been playing with the rust converter (Ranex rustbuster- a phosphoric acid solution) and found the following (ain't experience something? )

• The item I'm using it on has at least three different metal types which were hard to tell apart, although I think I understand now the thinking behind their usage.
• The rust converter works well with the chromed metal rust spots
• Aluminium doesn't like the rust converter- I should have known this
• The galvanised/plated (I think) metal really doesn't like the rust converter- which identified it to me as galvanised/plated

More info...
Unfortunately this phosphoric acid recommends against being near zinc-gal type paint (which I had bought a can of) no doubt for the reasons outlined above. But maybe once wiped down post-application it will be OK, will give it a try.

Some of the rust spots are/were in allen key/bolt heads so will no be able to be sanded before some coating- this is where I think I'll use the zinc gal paint.

I did find some info online about painting over chrome- basically sand back to the nickel underneath, followed by priming, resanding, top coating then clear.

The rest of the item I was going to sand and use a metal etch primer (then maybe normal primer) followed by top coat (or two) and (perhaps) clear (or two).

The topcoat is to be a chrome-finish-type paint. But if the fit takes me, I think it'd look great in hammertone blue...you might wish to 'egg me on'!

And the item? Well that will have to remain undisclosed for the moment. It's a cheap test/learning experience before I learn by damaging something I shouldn't!

Thanks again,

hi pitrack 1
sounds like your having a lot of fun building something.
the phosphoric acid type of converter I have used has only stated not to use it on gal-zinc or painted surfaces as it wont dry , it only dries on the rust , after drying it can be top coated, but I always use zinc with no problems as a under coat first. the rich zinc paint is also sold in auto paint stores for use on rusted car bodies guards ,doors ect followed by top coats .

for me the best rust converter is the other stuff that turns the rust black, you can apply it over paint and it dry's to form a tough under coat, easy to use and does work stopping rust from returning .

rust is a real pain, having spent time painting no one wants to see signs of rust coming back through the paint again.
you can be real fussy and the rust comes back or at times do a car yard special and slap the paint on over the rust and have a long lasting paint job, o the joy of painting

very hard to get a good finish with a chrome paint most for me anyway look more silver than chrome.
it sounds like you want to do a good resto on whatever your fixing up.

its fun mucking around with things its the best way to learn things , hands on is better than staring at a pc or phone all day long .
ps hammer finish hides lots of things and looks great in blue

good luck with your project, and looking forward to see it finished
damo

Thanks for the hints and encouragement damo,

As usual it's 90% prep and 10% real stuff...what I thought would take me an hour turned into an all arvo sanding job- only two passes (roughly 120 and 240 grit). Aluminium, chrome and galvanised materials. The chrome did sand back, copper was exposed underneath, this makes sense as as far as I remember it requres copper plating on the base steel, folowed by nickel (the shiny surface) and lastly chrome which forms a clear hard oxide protective layer on top. The aluminium sanded easily except for label removal (white spirit) and the gal metal was sanded easily without disturbing too much. So I got multiple learning experiences

Started the painting this evening. 2 different primers- high zinc gal and etch primer, 2 coats of each on their respective pieces. And yes, I got the hammertone blue so 2 different topcoats, chrome finish ( more a shiny silver as you say) and the hammertone blue on their respective pieces. And going to try 2 coats of clear over all, except bolts, etc.

Only one major hiccup with the painting- second coat of primer had big drops spray over multiple pieces with both primer cans. Couldn't figure out why, had cleaned nozzles after first coat... Then when I put down the can I discovered a big gob of paint on my gloved button finger- the glove was loose at the fingertip and had been trailing into the paint spray. A drip would then be blown onto the pieces. Aaargh!

Off to do the clear coats. Will try for 2 if the can lasts. Hope it's not a bridge too far, i.e. doesn't damage the finish. Wish me luck- late night!

Oh well, the clear enamel did affect the colour coats. It muted the hammertone effect, altered the chrome effect and caused both chrome and hammertone to run somewhat. Should be ok hopefully. Apart from that everything seems to have bonded well so far.

Main large bits total of 6 coats- 2 primer, 2 colour, 2 clear.

Bolts/screws/nuts 4 coats 2 primer, 2 colour for expediency and clearcoat comparative/benchmark purposes.

Did find one recidivist bolt+nut lurking that I missed- that got 1 primer and 1 colour topcoat only, for further comparison.

Should give me an idea of what I need to do in future, and how.

Will allow a couple of days to dry before assembly.

Live and learn!

Patrick, with many of these paints you need to leave them for about 7 days before you clear coat them, even though the paint feels dry, it takes quite a while for it to harden fully

Hi NormK,

Thanks for the tip re: clearcoat timing. I really value people passing on that type of experienced knowledge, it helps stop newbies like me making newbie mistakes (next time)!

7 days is more than I expected; I did know it could take a few. If I let the colour dry 7 days, do I need to lightly sand the surface before clear coating?

The cans said recoat in 1-2 hours ( or after 24). I thought the clear would have to bind to a slightly soft colour coat...obviously wrong! And I was driven by expedience to get the job done in one day (night) before the missus came back and politely enquired what I thought I was doing..!

Also, the small, intricate and curved surfaces of this object have been good practice.

You'll all laugh (definitely off topic) when you see what I've painted anyway! Assembly in a day or two...when paint has hardened, at least somewhat!

Hi Patrick, regarding sanding back, all depends on the finish you want, if you want a mirror finish you may have to wet rub it back several times till all imperfections are removed, depends on what you want

Hi NormK,

Thanks again for the info, much appreciated. Hadn't even occurred to me to vary the sanding by output.

Durability takes precedence this time due to usage. I think I've spotted a couple of runs and thin colour areas - I painted at night under bad backyard lighting but ideal weather conditions.

It's been 2.5 days since final coat in an external metal-roofed garage in mild-warm weathe, i.e. gets warm in the sun, but it is draughty. Do you think this is long enough to risk assembly?

Thanks,

Hi Patrick, bit hard to tell not knowing what it is and how much assembly is required, thick paint takes longer to harden. I guess if you are careful you should be ok

Again NormK, your sense to my nonsense...

Just remembered there's one small external lever to touch up (sanded when I should've left it alone) with a couple of coats. Doing it tonight, assembly tomorrow.

Thanks again.

Almost finished, but...
Hmmm, ever had one of those days you swear the gremlins were out in force to getcha?

Well, thzt's how my assembly was...although completed finally, the dents, dings, scratches, marks, paint dissolution (yes!), stray drips ( of dissolved paint), etc have really made a mess. Tidy up require before photos. And one or two items to finish.

The hammertone stayed robust, no problems there (apart from scratches/stains), the 'chrome' finish paint didn't- clear coated or not. Hmmm.

In fact, I actually removed paint on one item back to the etch primer with a lubricant (the solvent in it did the damage).

Item actually doesn't look too bad...from far away!

Pics soon, Stay tuned...

Patrick, still not knowing what you are doing makes it hard, also not knowing if you are spray painting or brush painting changes the situation.Brush painting due to the extra thickness of the paint means it will take much longer to harden even though it feels dry to touch. This is why you need to leave things to really dry before clear coating. Anyway you sound happy with it and that is all that matters

NormK,

Apologies. Some info:

Substrates: Galvanised steel, aluminium and chromed steel

Method: Spray paint cans

Materials (cans used- all 'fresh' from Bunnings except where listed):
Dulux Metalshield etch primer light grey
Dulux Metalshield hammered finish blue
Dy-mark Zinc Gal
White Knight super chrome
Polycraft Quickcoat emamel clear (old- maybe even up to 10 years I think)

Application/Method:

Prep-
Rust convert where neccessary and sand back (except gal surfaces, these were affected by the rust converter)

Paints-
zinc gal on gal steel, then hammered blue or 'chrome' finish followed by clear, 2 coats each.

Otherwise etch primer, hammered blue or chrome then clear, 2 coats each.

Some exceptions were some bolt heads- no clear. This seems to have gone ok but still a bit soft.

Pics soon, item smaller than a mower, quite a few smaller parts with crevices, shapes, nooks, crannies, etc) don't want 'em laughing too early!

Firstly, thanks to Aussietrev, dodegy (damo) and NormK for their advice. Your experience in these matters is much appreciated and has helped me a lot.

Assembly was a bit of a disaster for the finish but I was able to mostly clean it up. Quick-'n'-not-so-dirty resprays of some 'chrome' and hammertone blue- clean, slight sand, one topcoat only came up solid and fine. Hmmm, overthought (and oversprayed it seems) before. Lesson learnt!

Note in the below the before model has different details and the steering reversed from what it should be.

A gross waste of hammertone blue perhaps? Well I think it looks much better...and the most important thing is my daughter loves it!
You may laugh...now!


Quick-'n'-not-so-dirty repainted deck and brake


Probably last thing to do is paint the hinge covers black. The extended handle is actually the etch primer alone and I think I'll leave it that way, it looks good, the topcoat was soft and came off way too easily. Also, forgot to paint the handle extension clamp so it remains (mostly) chrome.
My daughter insisted on a glow-in-the-dark fluoro-yellow grip strip. That'll teach me to take her to Bunnings!

hi pitrack 1
that scooter came up a treat, better make sure your daughter chains it up well if she takes it up to the shops,
it looks to good to use, hope your daughter doesn't scratch it.
I find with painting after the hard works done, in the excitement to see it finished that's when the damage is done , still soft paint, best to leave it to harden up for about a week first,
damo

This is for your daughter Patrick, gee it won't be long before I have to do one for my great grand daughter, makes me feel really old when you can say your daughter is a grandmother
BTW good job and you had us going

Thanks for compliments Damo and NormK!

Damo, the photos hide some defects it must be said, so not really too good to use and I'm aiming for a paint durability test anyway! What better way than giving it to a kid? However the colour stands out, may be interesting to see what other parents/kids say when they see it. But before my 4 y.o. gets her hot little hands on it, I need to 'test ride' it first to ensure it's safe!

NormK, you're only as old as you feel...the fact you're on here says you're still bright and active! As for me, I've started late, as I do with most things.

Overall I'm actually pretty impressed with the scooter's engineering and design. It is relatively simple overall which enhances its durability I think.

And how many toys today can you buy that are almost exclusively made of metal (the plastics are truly only decorative) and made to be pulled apart and serviced?

When you try to 'pull it down' you find a surprising number of parts, some quite fiddly/intricate and none as simple as they may first appear. For example the base plate has fluting on the top, a box section underneath and rolled edges; the tubes have internal threads, springs, buttons protruding, cutouts and even lengthwise narrow channels; the headset/neck/hinge area has several parts of differing materials with narrow crevices to be accessed.

I also 'fish-oiled' the inaccessible internal bits. A mechanical check/lube also- that's all it needed. I even used at least 4 different lubricants in different spots- general bearing grease, MoS2 grease, white lithium grease and 'dry lube' w/ PTFE.

And The Cost?

• $5 - Used, working scooter from recycling centre
• ~$120 - lots of spray paints- primers, topcoats- but none are emptied so I get to use 'em again
• $0 greases- already on the shelf

I'll try posting some photos of the actual painted bits soon.