My Bus

[Kelvin12]

Terry,

No its a pretty plain looking tin, I'll get back to you tomorrow, got to find the tin, everything around here is stacked up on anything that will support it in preparation of the past flood and the pending one, maybe.

You should be using 2K thinners in all 2K applications and only a minute amount/as per instructions. Mind you this is one that hardly ever reads the instructions, just a bit of a "glug" will do. You need to go over all the surface, edge to edge, top to bottom with a panel beater quality sticky disc machine with 80 grit paper, (random orbital sander with guts). You aren't removing the zinc you are keying/profiling the surface to give the etch something to bite into. The etch also neutralizes the surface. Weather and age also does the same thing if you can wait for the action to take place. If your paint is breaking away/lifting its down to preparation. Even the bottom shelf 2K is pretty good quality these days. But the top shelf is always better. You also need to clean the surface with some sort of surface prep. different metals and surfaces require different prep. products. Follow the instructions and keep your sweaty maulers off the prep'd surface. Nothing stuffs the surface like body oil and sweat.

Scourer isn't good enough to key the surface. all a scourer is good for is taking the gloss off a previously painted surface when you are adding stripes or doing a repair. You can't paint over a gloss finish it can't key to the gloss surface. Hit the unpainted surface with the sticky disc and 80 grit possibly finer for the likes of fibreglass and aluminium. Previously painted and sound surface then a scourer, proper scourer, NON SOAPED, not the used one sitting under the brides sink.

Was the panel a door skin you saw and mentioned a hatch/bin door. If so they are aluminium, different prep. Hit them all over with 80 grit on the sticky disc, etch, prime the hit them with guide coat. Final rub down will be a 120 grit with the sticky disc as they were pretty rough and needed some TLC to get them reasonable. Guide coat is only to make sure the blemishes and dents are gone as much as possible when you rub down. The rest of the panels are zinc as you mentioned. The bulk of which still need to be etched, primed etc.. Another cause of failure is leaving the etch to long. Should be primed and painted over within a few hours/day at the most.

Dirk.

[T1 Terry]

The tip from my spray painting teacher was, use the same thinners all the way through, from the etch primer to the gloss clear coat, it's the primers that clash and cause frying. I've carried that tip with me through the years, never let me down.
The scourer pad is the brown 3M velcro fix, it would take a lot of work getting 80 grit scratches out, nothing worse than the scratch marks appearing 3 mths after you've finished the job, 2pk isn't supposed to suffer sink back, but no one told the paint that

[BACAMICK]

looking good

[Kelvin12]

Funny my paint teacher told me to only use the appropriate thinners for each product. Industrial for etch, 2K thinners for 2K primer, 2K for top coats including clears. There is quite a bit of difference in acrylic thinners to 2K thinners. 2 or 3 coats of primer more than fills the surface. Sink back is from top coating to early before the primer is dry. Leave primer for a couple of days and you won't get sink back. By the time you get around to rubbing the primer back and re-masking the primer is dry.

Humble apologizes here to, it should have been `120 grit. I got my boxes mixed, should have realized that before I posted.

Dirk

[T1 Terry]

I've used the GP primer with the Wattyl 1k etch primer, Spartan 2k primer, spartan 2k cynoacrylic, Debeers 2k, PPG 2k, never had a problem. Used debeers 2k thinners with the first lot of debeers 2k undercoat and had a flair up from what ever the inside ceiling sheets were sprayed with 20 yrs before, scrapped it all off, clened down with GP thinners and then used GP thinners in the 2k primer filler, no problems.
Unless you are painting show cars where the shine needs to look a foot deep, 2k thinner is an over priced waste of time and effort as far as I can see.
Even the 2k primer filler suffers sink back after a few mths, those deep scratched have to be sanded out before you apply any fillers and top coats unless you are going to wait the mth between coats. Get the subsurface right, then wet on wet, the lot on in one go, bugger masking up 3 or 4 times.

[Kelvin12]

Terry,

Who knows what old surfaces were painted with, emamels probably, should have used a sealer first in an unknown surface. Only problem I have had over coating was on early enamels and I short cutted and just primed over the surface. Seen a lot of surface flaking/crazing but that's been down to not rubbing the old surface down cleanly, or that gods curse of a product armourall, (silicone) being used previously and splashed onto surfaces. I have used a few brands of various paints myself but you pay for what you got back in those days. You don't use a lot of 2K thinners in the mix at the best of times so I reckon it pays to go with what the manufacturer says. At least then you do have a chance of claiming against them if it goes to crap. I did have a problem years ago with Dulux, (longer now than I care to remember). It turned out to be a pigment problem and they compensated me after I complained and they sent a rep. out who actually took samples. Only time I have ever had problems with sink back was with using Regal primers under acrylic. Thank god those days are now long gone. I know masking up is a PIA for sure but you need to get those base coats dry and stable. Sanding back primers wet or dry the tape is going to be damaged regardless so I find it easier to re-mask than take a chance. Every time I have gone ahead without re-masking I have had a lift somewhere, and or paint seep, (3M tapes).

The way we are going here we are going to scare everyone from painting themselves.....Lol.

Dirk

[T1 Terry]

The way we are going here we are going to scare everyone from painting themselves.....Lol.

2K is definitely for those who know what they are doing, no buffing out a minor blemish with that stuff.
When I worked for the crane mob, they used some very heavy duty 2k sealers and top coats, always sprayed wet on wet, they went on off shore oil rigs and building sites around the world, never a corrosion problem or paint lift, all done with GP thinners.
Wattyl polyurethane 2k 9polyU 400) needs it's own special thinners, fantastic stuff to work with but what a nightmare to get back out of the gun if you get the timing wrong, no slow hardener for that stuff

[Kelvin12]

Was thinking of using poly for my engine bay. Used brush on poly for the bins due to all the existing wiring and piping but the brand I have been using isn't UV stabilized and dulls off and really looks shabby, but tough as nails even in its dull look. Will look into your poly for the engine bay. Gun is getting old so can afford to waste it as it certainly have my monies worth out of it. Puts me in mind of a spray bog gun I won at tech. Lent it to my son, who should know better being a panel beater, he left the mixed spray bog in the gun overnight, bloody good idea. One solid lump that wouldn't dissolve/break up with dynamite.

Dirk

[TigerMK1]

While I have the attention of some forumites with spray painting expertise. I used to paint cars etc 30+ years ago. Now have bought a Daihatsu Freoza to use as a toad. The little beastie is great mechanicaly however it is suffering with the dreaded clearcoat failure. You see it on all the 10 year old cars, the clear coat fails on the upper surfaces, the colour below is ok but dull. Now some saleman types said no problem, sand back the clear and repainting the clear.
I am concerned that the crazed edge of the damaged clear will show thru with the recoat? Maybe have to sand ou the complete clear coat to repaint? A bugger

[Kelvin12]

If it was mine, and this is strictly my thoughts. I would paint strip the lot back to bare metal. Its a metallic colour or clear over base, so the base coat will be damaged somewhere along the line. A tart up isn't going to last long. Cutting back the clear is really a bit of a hit and miss, damage the base and its going to show up like your mother in law. My son has a really dark blue metallic statesman where the clear is peeling off like glad wrap literally in sheets. But if you look closely there is damage to the base colour in places so it needs a full paint strip job and a touch up is going to show and the problem is going to persist and come back to bite you on the behind. You have to decide if the vehicle is worth the effort/money involved to get it right, sometimes it is other times...... Being a painter you would know what its like ,lots of effort and birds eyes..... painful little bastards.

Dirk