| Author | Topic |
|---|
Registered:
May 2002
|
|
Can someone help me with my paint problem?
|
Thu, 27 January 2005 05:39
|
 |
I (tried) to paint my car yesterday. I was painting over a light grey primer, 3 or 4 coats have gone on ebut I can't get a good colour out of it. It always comes out patchy.
http://www.members.iinet.net.au/~cooltim/DSCF0029. JPG
see in that pic how it looks darker at the ends of the patch. I also have had troubles with patches at the top and bottom of the spray fan, You can't see it in that pic though.
The colour has metallic and some pearl I think.
Tim.
|
|
|
Registered:
February 2003
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 05:56
|
|
are you using 2 pac?
A 2 pac base pearl shouldn't have that effect, so i'm guessing it's acrylic. Maybe the mixture is too thin, and/or the pressure is too high (from the pic it looks like that)
try longer strokes too, like go the whole length of one side, very light coats always help with suitable drying time.
|
|
|
Registered:
May 2002
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 06:39
|
|
It's acrylic. Thinned out about 1:1-1.5:1 (thinners:paint), Sprayed at about 55PSI.
Tim.
|
|
|
Location:
cambo
Registered:
May 2002
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 07:03
|
|
|
is there some sort tech article somewhere on spray painting cause im seriously considering giving it ago myself on the sprinter. just want some general info like techniques, masking etc...
|
|
|
Registered:
May 2002
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 07:10
|
|
There's a lot of info around. Just do alot of searching. I tried to start one but there wasn't much feedback on it.
Tim.
|
|
|
Location:
Castlemaine Vic
Registered:
November 2002
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 07:47
|
|
their not over lapping marks are they? from where you have pulled/released the trigger?
also, you gonna fix that dint up the top? 
|
|
|
Location:
Sydney
Registered:
June 2004
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 07:51
|
|
mate thats sink back!!!!!! you got bog under that patch right? what this means is that you did not rub it back properly AND that you sprayed the primer too early on the bog, ie, the bog did not dry fully
there are 3 ways around this:
1 - in the affected arear you need to really pack in the paint but not over do it as it will run. this is NOT easy, as in not easy that professionally spray painters stuff it up!
2 - redo it. redo the whole quarter section. this is the best and absolute perfect way to do it
3 - completely spray the car as per normal with just colour. let it dry over a week to ensure that it is completely dry all the way through. once this is done rub the affected area down again and respray that area and about 15-20cm extra around the affected area. this will not get rid of it but get most of it out. then once its cleared, let it dry for another week and then rub it back with 1200 and buff it, but due to the colour it is more than likely that it will always be there
keep in mind that metalic colours (especially if they have a pearl) will show EVERY little mistake and then amplify it 10x. the metalics shine and finish is the worse for mistakes and iof there is a pearl then any change will show up as you can see
mate sink back is the worst, also from the pic, behind the 2 vents there seems to be a line bout 2" long, you might want to fix that aswell
|
|
|
Location:
Sydney
Registered:
June 2004
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 07:53
|
|
| twincam_ke20 wrote on Thu, 27 January 2005 18:47 |
their not over lapping marks are they? from where you have pulled/released the trigger?
also, you gonna fix that dint up the top?
|
its not overlap as that would be more defined and will usually cause runs
|
|
|
Location:
Vic, AU
Registered:
September 2004
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 08:03
|
|
| fade-e wrote on Thu, 27 January 2005 18:51 |
you got bog under that patch right? what this means is that you did not rub it back properly AND that you sprayed the primer too early on the bog, ie, the bog did not dry fully
|
Not knowing my shit, but that doesn't look like it's been bogged, at least, not by him. That's a good job, very straight, no noticable change in the wheel arch.. If it was him, good job!
I'd say it's more of an improper spread of the original primer. Did you spray the whole car? Let it all dry sufficiently?
If you try to spray and the primer coat isn't even enough, that can happen. Did to me anyway. 
|
|
|
Registered:
May 2002
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 08:05
|
|
| twincam_ke20 wrote on Thu, 27 January 2005 18:47 |
also, you gonna fix that dint up the top?
|
No. I'm sick of sanding. I just want it done. I'm more than a little upset that it wasn't finished yesterday.
No there's no bog under that, just primer over the old paint job.
I think it may just be cause of the gun, maybe doesn't shoot the fan with equal pressure, which would stand out more with the metallic+pearl paint.
I'm going to rub it back a bit tonight and then try painting the whole side again tomorrow, but breaking it down into seperate panels and try spraying the entire length of each panel.
EVOsti I suggest you find a nice, flat colour for your first go 
Tim.
|
|
|
Registered:
May 2002
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 08:07
|
|
[quote title=gr8r-x wrote on Thu, 27 January 2005 19:03]| fade-e wrote on Thu, 27 January 2005 18:51 |
I'd say it's more of an improper spread of the original primer. Did you spray the whole car? Let it all dry sufficiently?
If you try to spray and the primer coat isn't even enough, that can happen. Did to me anyway.
|
The primer coat looked good, I sprayed a few coats but cause it was a hot day it dried a little rough so I rubbed it back before I sprayed the top coat. It had been left about a week in primer before sanding and painting.
Tim.
|
|
|
Location:
Sydney
Registered:
June 2004
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 08:23
|
|
| RA28 wrote on Thu, 27 January 2005 19:05 |
No there's no bog under that, just primer over the old paint job.
|
are you sure no bog under the old paint?
also another issue is that there is old paint under there!
- why did you primer ontop of the old paint? there is no need, primer is only for bare metal and bog. i mean you could primer on top of paint but it is a waste and no benefit at all
- did you rub the old paint first to get the clear off? if not it could crack and peel off in the near future
- when you rubbed the primer did you use a block or by hand? you should use a block as it could cause low spots using just your hand
|
|
|
Registered:
May 2002
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 14:27
|
|
| fade-e wrote on Thu, 27 January 2005 19:23 |
| RA28 wrote on Thu, 27 January 2005 19:05 |
No there's no bog under that, just primer over the old paint job.
|
are you sure no bog under the old paint?
also another issue is that there is old paint under there!
- why did you primer ontop of the old paint? there is no need, primer is only for bare metal and bog. i mean you could primer on top of paint but it is a waste and no benefit at all
- did you rub the old paint first to get the clear off? if not it could crack and peel off in the near future
- when you rubbed the primer did you use a block or by hand? you should use a block as it could cause low spots using just your hand
|
As sure as I can be that there is no bog. The bog isn't the problem though, I get the same effect when I paint my wheelie bin. I primed the paint so I could get a better look at the car, The old jub was a little "busy" and it was hard to find all the dings and runs so I could fix em up. Didn't help much though, when I got the colour on there were heaps more that I missed. I sanded the original paint with P400 and most sanding is using a block, I do all the fiddly bits by hand.
I think it may just be my inexperience and the metallic paint. See what happens tomorrow anyhow.
Tim.
|
|
|
Location:
Sydney
Registered:
June 2004
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 16:50
|
|
if you read this before doing anything tomorrow then try this:
if you have a spare part or large piece of metal then spray that, you dont need to prime it cause its nothing important but just a test piece. also when spraying keep the gun bout 20cm away at all times and spray using your arm and not your wrist. if you use your wrist then it will lay on thick in the middle where the wrist is closest to the car and less where the wrist is turned and furthest away from the car.
also when spraying on the test piece use that to adjust the gun to your hand and spray technique. its always best to spray into the air to get initial adjustment of the gun that way you can adjust pressure, amount of release and spray effect (whether it sprays stright lie or gives the wide angle release).
once you have done that then give the test piece a quick spray to really see how much comes out and how much of the piece gets covered. from there then you do your final adjustments to the gun to your desired rates. once your ssatisfied then spray the piece a few coates to get the hang of it (but since you have done the whole car you should have the jist of it)
also you dont want to go too fast or too slow, keep it an even pace, on a rough estimate i would say cover a 1m length in about:
- first coat 1second, that will give a dust coat and ggive the thicker layers something to bind to
-second and third coat 1.5-2 seconds. that should be enough to lay on properly
-fourth coat IF required will also be 1.5-2seconds to cover a 1m length
dont give it more than 4 coats otherwise it will just get too heavy and cause issues later on. keep in mind although the thcker the paint the better it is but TOO thich will make it chip very easily and may even get too heavy that it eventually cracks and peals off. obviously leave bout 5-10min between coates depending on weather.
with the clear you only need 2 coats, first one being a dust coat and then a proper coat... if she comes up well then leave for a week and then rub it back and buff it
are you going to buff the car yourself? if so then be careful here cause you can burn the paint and you will need to start all over again and i mean from are metal and not just rub it back a bit. also the buffing compound is very viscous and rough. it basically scrastches the paint to shine it and also the buffing pad isnt any help either... buffing is a bit delicate in the sense that you dont want to press to hard or too soft, you dont want to over buff and burn the paint but you also dont want to under buff and leave massive scratch marks everywhere.
once buffing is complete you can use some cust and polich to finish it off and then wash it... she will come up sparkling and shiny AS
good luck and if you need any other tips let me know, iv painted heaps of cars in acrylic and 2PAC also so iv been through it all almost 
|
|
|
Location:
Crapberra
Registered:
September 2003
|
|
|
Location:
c'town, NSW
Registered:
May 2002
|
|
Re: Can someone help me with my paint problem?
|
Thu, 27 January 2005 21:32
|
|
| RA28 wrote on Thu, 27 January 2005 19:05 |
No. I'm sick of sanding. I just want it done.
|
i know how u feel man 
|
|
|
Location:
Bottom of the hill, Sydney
Registered:
April 2004
|
|
|
Location:
Forster NSW
Registered:
September 2004
|
|
Re: Can someone help me with my paint problem?
|
Fri, 28 January 2005 10:47
|
|
| Azrael wrote on Fri, 28 January 2005 08:02 |
Correct me if I'm wrong but isn't 55PSI spraying pressure a little too much? I painted my whole car in Acrylic pearl on about 30-35 psi.
ps. you could also try cross hatching your spraying. Do one coat horizontally, and the next coat vertically (you should be able to turn the nossle on your spray gun to do this). Cross hatching is a good way to blend in pearls and metallics.
|
Indeed, 55PSI is probably a little high. Try 35-40psi.
Too higher pressure causes the paint to heat up as it comes out the tip due to more friction. The results would/could be pretty various...
As for thinning, the last acrylic I used (wattyl supercryl) recommended thinning it to 150%, ie. 1 litre of paint would have 500mL of thinners. With the ratios you guys are using wouldn't it be water thin?
|
|
|
Registered:
May 2002
|
|
Re: Can someone help me with my paint problem?
|
Fri, 28 January 2005 12:37
|
|
I think paint thinning is more about personal preferance and room temperature. Though, 150% seems very thick. I found thinning between 200% and 250% gave me the best results. It didn't seem to run too often and was real easy to get a good "wet" finish off the gun.
Tim.
|
|
|
Location:
Vic, AU
Registered:
September 2004
|
|
Re: Can someone help me with my paint problem?
|
Fri, 28 January 2005 21:20
|
|
| RA28 wrote on Fri, 28 January 2005 23:37 |
I think paint thinning is more about personal preferance and room temperature. Though, 150% seems very thick. I found thinning between 200% and 250% gave me the best results. It didn't seem to run too often and was real easy to get a good "wet" finish off the gun.
Tim.
|
Yes, but did it still look "wet" after it had dried? The high amount of thinners will give it a very glossy look, until it evap's... When I used to spray small sections of internal panels with an air-brush, used to start with a small amount of thinners then increase it until it got the desired consistancy.
|
|
|
Registered:
November 2002
|
|
Re: Can someone help me with my paint problem?
|
Sat, 29 January 2005 12:43
|
|
I might be able to help you with this problem.
Check my site under "Technical Info", I have posted info on painting acrylic there.
http://users.chariot.net.au/~stmezz/celica.htm
Firstly, metallic is not easy to apply perfectly. Especially if painting is new to you. I've painted a few cars now, my TA22 GT is the best I've done, closely behind is Traceys Red Celica which are both on my site as well.
The pressure you should use in your spray gun is around 280kpa. Ideally the gun should also have a 1 litre pot and 2mm nozzle for acrylic.
In 1 litre, I have only around 30% paint and the rest thinners. This works best for me as I can get a very nice wet and glossy coat which needs very little buffing. I ca nget a high gloss straight from the gun.
When you paint metallic there are a couple of tricks. Try putting a couple of small marbles in your paint pot. This will keep the paint mixed. Metallic settles quick and will give you an uneven looking coat. Second, don't spray metallic too "wet". You only do this with base colours. The metallic is heavy and will run if you apply it the same as a base colour, the metallic particles this is, the paint itself won't run. Its not a really dry coat but it just won't have a good gloss. Once you have 4 or so coats on then you use clear coat straight over it. This is how you get the gloss. I sometimes use clear on base colours too to get more depth of colour, but you don't really have to use clear on flat colours, but its a must for metallic and pearl colours.
Also, its important to overlap each coat evenly to get a good result.
I use PPG products, I find then to apply really well. Finally use a AAA thinners with the final colour.
Hope this helps,
cheers,
Simon
|
|
|
Location:
Melbourne - NthSubs
Registered:
January 2004
|
|
Re: Can someone help me with my paint problem?
|
Sat, 29 January 2005 12:53
|
|
can a 2hr compressor do 30psi?
im about to respray the sprinter and need all the info i can get
cheers
|
|
|
Location:
Forster NSW
Registered:
September 2004
|
|
Re: Can someone help me with my paint problem?
|
Sat, 29 January 2005 13:26
|
|
| rthy wrote on Sat, 29 January 2005 23:53 |
can a 2hr compressor do 30psi?
im about to respray the sprinter and need all the info i can get
cheers
|
You mean 2 hp? I don't think so. What you need is a compressor which can supply around 12cfm. They are pretty big compressors and expensive. The best way to go is hire one if you're just spraying one car, unless of course you can borrow one of someone!
|
|
|
Registered:
November 2002
|
|
Re: Can someone help me with my paint problem?
|
Sat, 29 January 2005 13:29
|
|
My compressor is an Ingersoll Rand 8cfm and it does the job fine, hasn't missed a beat in all the years I've had it. Ideally I would have a 10cfm so it wouldn't have to work so hard.
Absolute minimum is a 6cfm. Forget about hp rating, only the amount of cfm counts.
Cheers,
Simon
|
|
|
Location:
Melbourne - NthSubs
Registered:
January 2004
|
|
Re: Can someone help me with my paint problem?
|
Sun, 30 January 2005 13:18
|
|
yea i ment 2hp...
so 2hp would be alright as long as it has 6cfm or higher?
|
|
|
Registered:
May 2002
|
|
Re: Can someone help me with my paint problem?
|
Sun, 30 January 2005 15:17
|
|
Depends on the pressure you're spraying and the gun you're using.
You don't want the pressure in the tank to drop below you regulator's pressure, so you need a compressor that can supply more air than the gun will use. Find out how much air the gun uses and go from there. Also, it's hard work for a compressor to do it's thing, and if it has to continiously pump then it won't last long. the bigger the compressor the easier it's job is.
You could try to paint then stop and let the compressor catch upbut it will be hard to keep laying the paint on wet.
Just prolly best to hire one. Get a good one and it'll make the job that much easier.
I'm lucky, I inherited a big twin cylinder one. Does the job nicely.
Tim.
|
|
|
