How to paint parts [right, so that it doesnt start chipping after a month]???
03-15-2011, 03:05 PM
#1
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How to paint parts [right, so that it doesnt start chipping after a month]???
So I need to paint my fender and a few other parts. Paint place quoted me $600
I know how to paint auto parts well (I have an air gun too) with the typical body fill, sand, primer, base coat, then clear coat, but the last times Ive done parts always ended up starting to chip from things like road rocks after only a few months.
Is there any diy, or any kind of special tricks to get the paint to not chip after only a few months? also any trick to getting the surface nice and smooth after the clearcoat on a touchup and to blend with the rest (always looks like an orange?)
Any DIY or advice would be helpful (other than something like take it to a shop)
I know how to paint auto parts well (I have an air gun too) with the typical body fill, sand, primer, base coat, then clear coat, but the last times Ive done parts always ended up starting to chip from things like road rocks after only a few months.
Is there any diy, or any kind of special tricks to get the paint to not chip after only a few months? also any trick to getting the surface nice and smooth after the clearcoat on a touchup and to blend with the rest (always looks like an orange?)
Any DIY or advice would be helpful (other than something like take it to a shop)
03-15-2011, 04:52 PM
#2
first lay down your self etch primer (I suggest taking it back down to bare metal before this). probably 2 coats as etch is usually thick. This primer is needed to ensure a good bond is set to the metal (high build will not set right on the metal and will eventually chip)
next lay down 2-3 coats of high build primer. this is the primer that is needed to set the base coat on (base coat will not set properly on etch alone, high build also helps to smooth out the surfaces.
after both primers are laid and set its time to wet sand before the base is laid down.
Once you have wet sanded (probably 600-800 grit or even higher) and it has dried DO NOT TOUCH IT! the oils in your fingers will set on the paint and cause for a weak bond between the primer and the base
Base coat should be laid down in 2-3 coats and should be as even as possible, especially on the first coat.
You can almost go right into the clear coat process (probably a good 4-6 coats will do it but after each coat you need to wait longer to reduce orange peel and allow for proper flash) right after the base coat has been laid (you need to pay attention to the flash times laid out by the paint manufacturer, this actually goes for all steps above and below as well)
Once the clear has been laid down its time to buff, this is critical to the overall finish, including how long it will last against chips.
stolen from another forum:
^I really recommend reading what is in red. It really helps to lay out the buffing process
One of the biggest suggestions is to take your dear sweet time. It is a long process to get a good solid result that wont chip and rushing in any of the above steps will cause a week bond or a week finish.
Hope this helps a bit and makes sense.
next lay down 2-3 coats of high build primer. this is the primer that is needed to set the base coat on (base coat will not set properly on etch alone, high build also helps to smooth out the surfaces.
after both primers are laid and set its time to wet sand before the base is laid down.
Once you have wet sanded (probably 600-800 grit or even higher) and it has dried DO NOT TOUCH IT! the oils in your fingers will set on the paint and cause for a weak bond between the primer and the base
Base coat should be laid down in 2-3 coats and should be as even as possible, especially on the first coat.
You can almost go right into the clear coat process (probably a good 4-6 coats will do it but after each coat you need to wait longer to reduce orange peel and allow for proper flash) right after the base coat has been laid (you need to pay attention to the flash times laid out by the paint manufacturer, this actually goes for all steps above and below as well)
Once the clear has been laid down its time to buff, this is critical to the overall finish, including how long it will last against chips.
stolen from another forum:
I like to wait at least 4 days before wet sanding. I tell n00b's to use 1500 wet paper to be safe..Then go to a wool pad and buff. I like Presta polishes like the ultra 1500 for first buff. You can buff before that like production shops do it next day but I like to let my clear cook in the sun a couple 3 or 4 days to outgas well.
I just re-read your post. You need a buffer to buff the paint out. By hand won't work worth a crap. Look at something like this:
http://www.harborfreight.com/7-inch-...der-92623.html
And this pad:
http://www.summitracing.com/parts/SHL-175C/
And read this if you like...
http://www.nastyz28.com/forum/showpo...09&postcount=8
I just re-read your post. You need a buffer to buff the paint out. By hand won't work worth a crap. Look at something like this:
http://www.harborfreight.com/7-inch-...der-92623.html
And this pad:
http://www.summitracing.com/parts/SHL-175C/
And read this if you like...
http://www.nastyz28.com/forum/showpo...09&postcount=8
One of the biggest suggestions is to take your dear sweet time. It is a long process to get a good solid result that wont chip and rushing in any of the above steps will cause a week bond or a week finish.
Hope this helps a bit and makes sense.
03-15-2011, 04:53 PM
#3
this is copied from the above link
Now, ready for the real way to do it?
First off, BURY the base color with about 4-6 coats of clear-minimum. Be sure to follow your flash times per the manufacturer so you do not get solvent pop. You want under 10 mil of finished product and the more you start with as far as clear, the more you can cut and buff to get to a perfectly flat finish.
(And have left to re-buff later.)
Let it cure for a week minimum. Get a bucket (Clean) and do the dish soap water mix. THEN, depending on how much peel you have, start with 1200 or 1500 grit and sand in one direction only, using a pad under the the paper, like a durablock on flat surfaces and a sanding pad like 3M makes and sells for woodworking use at Wal-Mart for curved surfaces. Paint stir sticks work great also as they bend. Check it every 20 strokes or so with a California blade or other pure silicone squeegee. THEN go to 1500 or 2000 and repeat, only sanding in a 90 degree pattern to the first paper used. This way, you can tell how much sanding scratch remains from the previous grit. After 1500 or 2000 you can use a wool pad like a Schlegel 175C Twisted wool pad. Do NOT use a non-twisted wool pad. They suck. The Schlegel is only about $17 and worth every penny. Then read this carefully:
DO NOT GET IN HURRY WITH A BUFFER! GETTING GREEDY AND TRYING TO BUFF ALL IN ONE SHOT BURNS MORE PAINT THAN ANYTHING ELSE.
I use this to cut with but I know how much to lean on the buffer without getting in trouble so I advise you to take it easy. Only do a 2 foot square section at a time. STAY AWAY FROM EDGES!
Apply a ribbon of cutting compund to your pad and place it on the panel and work it around a little before turning the buffer on. Then work back and forth KEEPING THE BUFFER MOVING and work one section 2 X 2 FEET AT A TIME.
After you are done with cutting, go to this pad as it works great and is way cheaper.
And this works as good as anything to finish on the foam pad. You can go to a waffle pad after that, but for now, what I have posted here will work fine for you.
Repeat in 30 days. By now you are pretty much cured. (Your paint that is, not you. You will now see the reuslts of your work and have the painting bug!) RESIST IT!!! You will want to paint everything from your mailbox to other peoples' cars!! Then you will open a shop and quit your day job!! Then you will be posting on internet message boards about the "Right Way" to cut and buff paint!
And then......ARRRRRRRRRRRRRRRRRRRRRRRGGGGGGGGGGGGGGGG GGGGGGHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!
Anyway.....Here's what you will end up with from a garage job..And I used this buffer for home work...
First off, BURY the base color with about 4-6 coats of clear-minimum. Be sure to follow your flash times per the manufacturer so you do not get solvent pop. You want under 10 mil of finished product and the more you start with as far as clear, the more you can cut and buff to get to a perfectly flat finish.
(And have left to re-buff later.)
Let it cure for a week minimum. Get a bucket (Clean) and do the dish soap water mix. THEN, depending on how much peel you have, start with 1200 or 1500 grit and sand in one direction only, using a pad under the the paper, like a durablock on flat surfaces and a sanding pad like 3M makes and sells for woodworking use at Wal-Mart for curved surfaces. Paint stir sticks work great also as they bend. Check it every 20 strokes or so with a California blade or other pure silicone squeegee. THEN go to 1500 or 2000 and repeat, only sanding in a 90 degree pattern to the first paper used. This way, you can tell how much sanding scratch remains from the previous grit. After 1500 or 2000 you can use a wool pad like a Schlegel 175C Twisted wool pad. Do NOT use a non-twisted wool pad. They suck. The Schlegel is only about $17 and worth every penny. Then read this carefully:
DO NOT GET IN HURRY WITH A BUFFER! GETTING GREEDY AND TRYING TO BUFF ALL IN ONE SHOT BURNS MORE PAINT THAN ANYTHING ELSE.
I use this to cut with but I know how much to lean on the buffer without getting in trouble so I advise you to take it easy. Only do a 2 foot square section at a time. STAY AWAY FROM EDGES!
Apply a ribbon of cutting compund to your pad and place it on the panel and work it around a little before turning the buffer on. Then work back and forth KEEPING THE BUFFER MOVING and work one section 2 X 2 FEET AT A TIME.
After you are done with cutting, go to this pad as it works great and is way cheaper.
And this works as good as anything to finish on the foam pad. You can go to a waffle pad after that, but for now, what I have posted here will work fine for you.
Repeat in 30 days. By now you are pretty much cured. (Your paint that is, not you. You will now see the reuslts of your work and have the painting bug!) RESIST IT!!! You will want to paint everything from your mailbox to other peoples' cars!! Then you will open a shop and quit your day job!! Then you will be posting on internet message boards about the "Right Way" to cut and buff paint!
And then......ARRRRRRRRRRRRRRRRRRRRRRRGGGGGGGGGGGGGGGG GGGGGGHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!
Anyway.....Here's what you will end up with from a garage job..And I used this buffer for home work...
03-15-2011, 06:18 PM
#4
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Olllleeyyy crap, didnt think there was quite that much, I mean I knew there was a good amount but thats a heck of a lot. I wonder if normal paint shops do all that or if they just primer, base, sand, clear, sand then clear n buff.....
03-15-2011, 06:31 PM
#5
^That was a short version too because I am no expert painter, just a hobbyist
your typical shop will only do what you have stated. To get a good result though you really do need to go through more steps thats why when you see low quotes for paint work they are low for a reason, usually the body shop is skipping out somewhere.
Now you dont have to wait a full week for the paint to cure before buffing but I would suggest it, makes it a little harder to cut/buff but the end result is better. Unless of course you have an oven to bake your car in then you dont even have to worry about total cure time, just throw it in for a few hours and then your done.
One more thing to note is that the gun you use and the pressure at which you spray will also directly relate to outcome of the paint. The gun will mostly just cause more cut/buff work if its a cheaper gun (more orange peal) but the pressure can really mess with the consistency of the paint and once again that will cause the bond to break down and not be as well as it should.
I'd recommend getting a carboard box and practice spraying on it EVERY TIME you switch paint to ensure that your gun is properly calibrated for that specific consistency of paint. (make sure you are using appropriate tipped gun as well according to the specific paint tech sheet).
your typical shop will only do what you have stated. To get a good result though you really do need to go through more steps thats why when you see low quotes for paint work they are low for a reason, usually the body shop is skipping out somewhere.
Now you dont have to wait a full week for the paint to cure before buffing but I would suggest it, makes it a little harder to cut/buff but the end result is better. Unless of course you have an oven to bake your car in then you dont even have to worry about total cure time, just throw it in for a few hours and then your done.
One more thing to note is that the gun you use and the pressure at which you spray will also directly relate to outcome of the paint. The gun will mostly just cause more cut/buff work if its a cheaper gun (more orange peal) but the pressure can really mess with the consistency of the paint and once again that will cause the bond to break down and not be as well as it should.
I'd recommend getting a carboard box and practice spraying on it EVERY TIME you switch paint to ensure that your gun is properly calibrated for that specific consistency of paint. (make sure you are using appropriate tipped gun as well according to the specific paint tech sheet).
03-15-2011, 06:40 PM
#8
Oh just a note because I just re read your first post and if you are going to be using bondo or another form of body filler lay down etch primer FIRST. bondo is better designed to stick to a self etching primer than to bare metal or old paint. What this means is you will need to lay down 1-2 coats of self etching primer, sand/bondo and sand some more the area where you are applying body filler then spray another 1-2 coats of etch primer.
For paint recommendations I would highly recommend souther polyurethanes
start here: http://www.southernpolyurethanes.com...ct%20lines.htm
Use a waterborne was/grease remover beforehand to ensure a solid paint bond: http://www.southernpolyurethanes.com...%20remover.htm
use epoxy first: http://www.southernpolyurethanes.com...y%20Primer.htm
Use Bondo here (brand does not really matter as far as bond goes but brand will effect how much it builds up on the sandpaper and whether or not it causes a lot of work or not, BONDO works alright).
then this 2k high build:http://www.southernpolyurethanes.com...ild%202006.pdf
SPI Does not dabble in base so I would highly suggest Dupont (excellent cohesion with SPI, mixing brands can sometimes cause paint to not stick right together, you need to know before hand what primers/bases/clears will work with each other)
and finish it off with this universal clear: http://www.southernpolyurethanes.com...ech%202006.pdf
Then follow up with the buff products listed above.
^^^
Do all of this and you cant go wrong even if you paint it outside in the backyard
For paint recommendations I would highly recommend souther polyurethanes
start here: http://www.southernpolyurethanes.com...ct%20lines.htm
Use a waterborne was/grease remover beforehand to ensure a solid paint bond: http://www.southernpolyurethanes.com...%20remover.htm
use epoxy first: http://www.southernpolyurethanes.com...y%20Primer.htm
Use Bondo here (brand does not really matter as far as bond goes but brand will effect how much it builds up on the sandpaper and whether or not it causes a lot of work or not, BONDO works alright).
then this 2k high build:http://www.southernpolyurethanes.com...ild%202006.pdf
SPI Does not dabble in base so I would highly suggest Dupont (excellent cohesion with SPI, mixing brands can sometimes cause paint to not stick right together, you need to know before hand what primers/bases/clears will work with each other)
and finish it off with this universal clear: http://www.southernpolyurethanes.com...ech%202006.pdf
Then follow up with the buff products listed above.
^^^
Do all of this and you cant go wrong even if you paint it outside in the backyard
03-15-2011, 06:46 PM
#9
+1 if all you are doing is a fender it may be better to have a shop do it, if its something you want to maybe get into as for a hobby or something or just want the satisfaction of saying you did it then its not bad, but good paint will cost you and a good gun will run you 400+ (all I use is a cheaper 250 dollar set so my results arent the best until after I buff.
Just running thinner through the lines will not be enough all the time either, I know this one from experience, by gun jammed up on me after I had all of my base mixed because that was all I did. You really need to dismantle the gun and clean it thoroughly as often as possible.
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