02GF74
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 posted on 3/4/06 at 11:41 AM |
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spray painting - what am I doing wrong?
I have srayed the nose cone but my finish is not as smooth as I would like.
I think this is because the psray gun, 1.2 mm, is not adjusted to give out the irght amount of paint or I am moving the gun to quickly os thge paint
does not build up enough.
What I think should be happening is that the paint sprayed onto the surface should build up to the point where it almost starts to run so it has a
nice smooth surface; not enough gives a dimpled effect and even less results in a gritty finish.
I ma doing about 2 or3 passes over the same strip.
Is that where I am going wrong?
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bernie955
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| posted on 3/4/06 at 11:52 AM |
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Sounds like the flow isn't set properly or you are moving too fast (or both). It's very hard to tell without being able to see what you
are actually doing.
The first thing to do is set the spray fan of the gun. Once you've done that then set the paint flow. Do this on some scrap. Adjust the fan till
it's at its maximum size and then back off a little bit. Then practice spraying and increasing the paint flow till you are getting pretty good
coverage without causing runs etc. The paint doesn't have to be put on flat as you can always buff out any orange peel.
Also check that the gun nozzle isn't clogged with old paint. The shape of the fan should show this. It should be an even oval shape.
With acrylic paints most pros but it on fairly dry and buff it out as this reduces the amount of paint wastage and, therefore, their costs.
2 paks generally should go on and sit flatter as they dry slower than acrylic does.
Try and overlap each gun pass by 50 to 70 percent for best results.
Finally, spray painting is a skill that can only be perfected with practice. It is rewarding when it turns out great and you get complements from
people on your work.
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02GF74
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| posted on 3/4/06 at 12:50 PM |
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cheer for trhe info.
the last coat is pretty good but not quite as good as the cycle wings - they have a nice almost glaqss like finish (but not 100% perfect as the
f/glass surface was not prepped as good as I oulwd have done it).
I did 3 coats; the first 2 were really to lay down some colour and were flatted wtih 600 and then 600/1000 wet n dry.
Guess I need to look set up the spray gun properly.
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Peteff
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| posted on 3/4/06 at 07:45 PM |
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even less results in a gritty finish.
What paint are you using and what kind of gun? That sounds like your gun is too far from the work with cellulose.
Practise on the back of the garage door or get a sheet of cardboard to set the gun up so you get the pattern right. Buy some cheap thinners and white
paint to have a go with to perfect your technique. Don't be scared of wasting a bit, start the trigger just off your panel and finish just after
to cut down the chance of blobbing it.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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k33ts
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| posted on 3/4/06 at 09:29 PM |
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not enough paint or going to fast could also be your air set up, depends on what sort of gun your using.
youll need to get a better finish than above before flat and polish that will never look any good by the time that is flat youll have no paint
left.
what type of paint are you using.
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NS Dev
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| posted on 3/4/06 at 10:57 PM |
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As Peteff says, what paint are you talking about? I presume cellulose.
If this is the case you need more thinners and to get closer to the panel.
Don't be afraid to use 80% thinners for the final coats to gloss up the surface.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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02GF74
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| posted on 4/4/06 at 08:07 AM |
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quote:
Originally posted by NS Dev
As Peteff says, what paint are you talking about? I presume cellulose.
If this is the case you need more thinners and to get closer to the panel.
Don't be afraid to use 80% thinners for the final coats to gloss up the surface.
yep, cellulose. the last coat was about 1/3 paint, 2/3 cellulose. Big compressor, 30 psi.
I am guessing not enough paint so eithere bump up the flow or move slower.
Yep, I'll have to practise.
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MikeRJ
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| posted on 4/4/06 at 12:43 PM |
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Cellulose is a bugger for showing every imperfection in a panel as it sinks whilst drying, so your prep work has to be that much better. Two pack is
much more forgiving.
I had simmilar problems spraying the front end of my Citroen AX GTi in cellulose, and it was all down to a cheap and nasty spray gun (which gave quite
an irregular spray pattern) and not setting it up properly. No excuse for a crap spray gun as you can pick up professional quality ones on Ebay for
peanuts now everyone is moving to HPLV equipment.
[Edited on 4/4/06 by MikeRJ]
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DEAN C.
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| posted on 9/4/06 at 05:12 PM |
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30 psi ?
I dont agree with thinning the paint down too much,certainly not 80% for the final coats because with cellulose it just tends to encourage sinking by
softening the paint too much. 2 pack yes I would thin more on final coats.
I've done a lot of spraying over the last 25 years and never usually drop below 60 psi even with cheap spray guns.
I agree with some of the other comments and would mix to the consistancy of milk as a rough guide,usually about 50:50 mix.
Also you must get an even fan pattern and a nice steady movement overlapping each pass so that each pass will blend with the next.
If your paint is too thin and pressure too low you will not get enough paint on the item,also remember as you put paint on it should look slightly
dimpled and flow smooth within a few seconds.
And wear a good mask.
Good luck.
Once I've finished a project why do I start another?
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wilkingj
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| posted on 9/4/06 at 05:43 PM |
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Just remember if you start using 2 pack paint, you should take ALL the necessary safety precautions. 2 Pack Paint gives off nasty toxic fumes which
are hazardous to your health. My mate sprays it all day, and has to wear and Air Fed Mask so he has clean air to breathe. ie check the hazard angle
before spraying with anything.. you only get one set of lungs.
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
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02GF74
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| posted on 10/4/06 at 10:57 AM |
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ah, too late; maybe the low pressure was the reaon?
nevermind; I got a good enough finish by spraying neat cellulose to make the slightly dimpled surface run plus it helped to spread out the couple of
paint runs. It is amazing mow mcuh air borne debris seems to trun up when you start painting!!
good enough; will take on board the comments made for next time.....
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emsfactory
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| posted on 10/4/06 at 11:00 AM |
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What kind of gun are you using. it makes a big difference. Gravity or suction?
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02GF74
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| posted on 10/4/06 at 11:10 AM |
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suction. (from machine mart a long long time ago).
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NS Dev
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| posted on 11/4/06 at 10:13 AM |
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quote:
Originally posted by 02GF74
ah, too late; maybe the low pressure was the reaon?
nevermind; I got a good enough finish by spraying neat cellulose to make the slightly dimpled surface run plus it helped to spread out the couple of
paint runs. It is amazing mow mcuh air borne debris seems to trun up when you start painting!!
good enough; will take on board the comments made for next time.....
Do you mean spraying neat thinners on?
I have used this to gloss up before and whether good practice or not it does work well.
I'm no expert but have sprayed 3 full road cars including 1 that wasn't laughed at in a concourse competition, though I will be the first
to admit spraying is NOT my strong point!!!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Peteff
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| posted on 11/4/06 at 10:43 AM |
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The quality of your thinners will make a difference to a home job. Don't get too fast a flash or it will dry the wet edge before you get your
next pass on and look like a stripey blanket but you will get a better shine with top coat thinners on a cellulose paint.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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02GF74
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| posted on 12/4/06 at 08:47 AM |
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quote:
Originally posted by NS Dev
Do you mean spraying neat thinners on?
yes; standard thinner; guess it would have helped if I bought some better quality stuff.
Don't care if is not be good practise but I'm sure it smoothed the coat down; and that is what counts.
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docter fox
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| posted on 2/6/06 at 02:03 PM |
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sounds like what happened when I sprayed mine, the compressor wasnt building enough pressure and I didn't notice until afterwards, try upping
the pressure, how close are you when spraying? the first time I tried i was too far away got a very nice sandpaper effect, after sanding it back down,
the second attempt with a new compressor at a higher pressure and with the spray gun a bit cloer it came out ok 
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David Jenkins
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| posted on 2/6/06 at 02:05 PM |
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As a matter of interest, how close is "close enough"? I realise that this is a "how long is a piece of string" type of
question, dependent on spray gun, compressor pressure and paint type, but a rough guide would help.
David
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Spyderman
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| posted on 2/6/06 at 05:57 PM |
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If using cellulose then you want it to go on as a heavy dusting. Too far away and it looks like sandpaper, too close and it is too wet and will sag
and run. When right you will see it it flow out smooth within seconds of it hitting the panel.
How close depends on the spray gun and compressor. Between 6 and 10" should be about right.
Spyderman
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