- Thread starter weldwise
- Start date
Hello WW,
the rule of thumb I was told is you can spray anything onto cellulose but you can only spray cellulose onto cellulose. (i.e spray cellulose onto another paint and it will react)
Normally a flat finish should flat out then polish as long as there is enough paint thickness? It could have been too hot when you sprayed as the paint needs to flow to get a good finish (so a wet coat as well) and if it flashes off too quickly then that gives a poor result.
Alec
the rule of thumb I was told is you can spray anything onto cellulose but you can only spray cellulose onto cellulose. (i.e spray cellulose onto another paint and it will react)
Normally a flat finish should flat out then polish as long as there is enough paint thickness? It could have been too hot when you sprayed as the paint needs to flow to get a good finish (so a wet coat as well) and if it flashes off too quickly then that gives a poor result.
Alec
pedrobedro
Man at Matalan
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Clear coat it with lacquer then cut the lacquer to make it shine more.
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Cellulose over synthetic will usually (always?) react very badly, it will 'pickle' and lift. One way of avoiding this is to spray the existing paint with an isolator coat ('barcoat') which will stop the reaction, that way you can safely spray cellulose even if you are unsure of the type of paint that has been used previously.
Made that mistake once when painting a mate's MG Midget, never again, it was peeling off faster than I was applying it!
Chickenjohn
Morris Minor and Porsche 944 fan
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Celly is fine over 2-pack, its 2-pack that will crack and lose adhesion over time when sprayed over celly. Celly can wrinkle over synthetic, try a dust coat for the first few coats- anyway, the only really good way to restore a car with out risk of paint problems is go back to bare metal.
As for dull finish- either you are using poor quality thinners or spraying too dry. Keep a wet edge going during spraying (without getting runs) is the key to a glossy finish out of the gun with either celly or two pack.
BTW, don't even think about spraying 2-pack at home unless you have a professional spray booth and an air fed mask. Celly is the way to go for the home sprayer.- much more forgiving than 2-pack for the amateur. Much easier to get a good finish at home.
As for dull finish- either you are using poor quality thinners or spraying too dry. Keep a wet edge going during spraying (without getting runs) is the key to a glossy finish out of the gun with either celly or two pack.
BTW, don't even think about spraying 2-pack at home unless you have a professional spray booth and an air fed mask. Celly is the way to go for the home sprayer.- much more forgiving than 2-pack for the amateur. Much easier to get a good finish at home.
Synthetic doesn't always react, I've got 2-pack primer over synth on my Landy. The synth is fairly old and well cured though, and I'm careful to mist first coats. For experiments I tried really hot mixes to provoke it, but the synth stayed fine. Amazing how un-reactive it was, how well it must have cured.
Two-pack over celly, I know of a custom car builder who 2k clears over celly.
Two-pack over celly, I know of a custom car builder who 2k clears over celly.
thanks guys well ive been spraying motorcycles with 2 pac for years at home and yes i do use a respirator mask and have a well ventilated spray booth and i get very good results just thought id give cellys ago now im put off using it ..am thinking of getting some lessons from pro sprayers but thanks for the advice guys....
mike os
just a little insane.....
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celly must be the easiest of all the paints to get a good finish... perhaps just because I started with it, well there were no other options LOL. Must admit it is far less forgiving than more modern paints.
most has already been covered, my tips:-
prep is everything, must be perfect.
good quality thinners, not gun cleaner.
make sure there is no moisture in the air supply and that the day is dry, dampness will dull or blush.
Consistency:- work on it, again needs to be wet enough to recombine the droplets on the surface and let them "flow" slightly to form an even layer.
air pressure.... low, very low 18-24psi, & try an old gun rather than hvlp
wet colour sand between coats is essential.
more thinners in the last 2-3 coats will help shine
elbow grease
most has already been covered, my tips:-
prep is everything, must be perfect.
good quality thinners, not gun cleaner.
make sure there is no moisture in the air supply and that the day is dry, dampness will dull or blush.
Consistency:- work on it, again needs to be wet enough to recombine the droplets on the surface and let them "flow" slightly to form an even layer.
air pressure.... low, very low 18-24psi, & try an old gun rather than hvlp
wet colour sand between coats is essential.
more thinners in the last 2-3 coats will help shine
elbow grease
series2
Member
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- Cheshire, UK
I'm not a professional by any stretch of the imagination, but the following works for me.
IMHO, if there are no problems with the previous coat, it is not nessacary to flat before the next, so long as the paint has not completely flashed off. If you do need to flat back for any reason (runs, orange peel etc.), leave it for at least 24 hours or it will go pear shaped. Frost sell a fantastic tool for shaving runs off, saves a lot of time rubbing!
When I painted my Landy, I gave it 3 coats at 50/50, left it a week then 1000's the gloss off, followed by two coats at 75/25. It looked good as gun finish, compounded it about a month later, still looks fantastic two years on.
Just a last thought, always use the correct colour primer for your topcoat. Putting a dark colour over a light primer will require more top coat to cover it adequately.
IMHO, if there are no problems with the previous coat, it is not nessacary to flat before the next, so long as the paint has not completely flashed off. If you do need to flat back for any reason (runs, orange peel etc.), leave it for at least 24 hours or it will go pear shaped. Frost sell a fantastic tool for shaving runs off, saves a lot of time rubbing!
When I painted my Landy, I gave it 3 coats at 50/50, left it a week then 1000's the gloss off, followed by two coats at 75/25. It looked good as gun finish, compounded it about a month later, still looks fantastic two years on.
Just a last thought, always use the correct colour primer for your topcoat. Putting a dark colour over a light primer will require more top coat to cover it adequately.
pedrobedro
Man at Matalan
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The thing for runs is a denibber or run razor. If you rub them by hand you tend to take the paint round them down more than the run. If you spot them while the paint is still wet you can catch them with a thin brush dipped in thinners and shaken to lift some of the paint off and it will run back together.
series2
Member
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I've never tried painting metallic, personally I don't think they look good on anything! couldn't agree more about adding colour to the primer, it's available in enough suitable colours anyway colours anyway.
One question I do have:- should etch primer be flatted before covering with primer? BTW it's not the high build stuff.
