looking for thoughts on what/why I am observing... I have been a hobbiest painter for 20 years. I have painted or assisted painting 10+ cars over the years. I have used most major brands I think....PPG, DuPont, Matrix, Nason, 5 star.....dependent on what we wanted to spend on the paint job. I love to paint. I tell people I paint because I love it, and do everything else because I have to because I can't afford this hobby otherwise. Anyway, my last 2 paint jobs I have experienced a lot of shrinkage after the paint job is finished. They were budget jobs so I used 5 star acrylic primer (which requires a catalyst) and Nason base coat with 5 star urethane clear. Both were sanded with 400 grit for final sanding prior to paint. Both were allowed to cure in 70+ degree temp for at least 24 hrs prior to base coat. (This is how I have always done it......but this is the first time I used an acrylic catalyzed primer......I have always just used a lacquer based primer) In both cases the paint and clear went on smooth, but after a few days I started to see sanding marks show up. One of the cars I let cure for 1 week, then cut and buffed the marks out. After about 2 more weeks I start seeing sanding marks showing up on that same car in the same areas! I waited another few weeks and sanded and buffed the entire car again. Sure enough......after a few weeks, sanding marks were back! The car looks great in the sun, but if you get it under flourescent lights you can see the sanding marks. I was asked to show the car at a big indoor car show next year but don't want to given these issues. I am hesitant to sand and buff again. I put 4 coats of clear on......and it has to be getting thin in places.....I don't want to cut through. It reminds me of that Simpsons episode where Homer tries to wear the speedo....puts one on......gets sucked up.....puts another on......gets sucked up.... 1. Anyone ever experience this? 2. Why is this happening? 3. Anything I can do to stop it? I talked to the paint shop....".of course they swear the products are fine, nobody ever has this type of issue and the shops around town use this stuff all the time.
First problem is the primer, use only top shelp primer K36 is my Favorite when budjet allows I use Matrix high build every day and it Performs fine, Second its always best to use a catalyzed urethane sealer before the top coats, third 400 is a little rough for Base clear although I myself spray over 400 on occasion 600 is better. And remember primer is primer not filler body work should be finished in 180 or 220, priming ontop of 80grit will only cause issues
1. I did use a sealer.......forgot to mention it. 2. Did not know about the 400 vs 600 grit for base and clear coat. I will use 600 for final sand from now on. 3. I will definitely stay away from that primer and use something better from now on. I am not seeing any body work sanding.....just the fine scratches from the final sand.....all over the car.
We used 500 for the final sanding at the shop I worked at. I did a "cheap" job recently on a later model car. I was told 320 would be fine enough, and it was in a lot of places but not others. I've also seen differences in grit - I.E. 500 Mirka is more course than 500 3M.
I have been painting cars for 30 yrs. dont get me wrong. far from perfect. and my work . $$$$ USE THE BEST PRODUCT FOR BEST RESULTS. I HAVE ONLY USED EUROPEAN PAINT! GO FIGURE I LIVE IN PITTSBURGH!(PPG:eek2I use only spies Hecker (germans) GO figure Dupont buys Spies hecker/Standox and PPG buys ICI and Max Mayers
Eric b I think people tend to use product like a crutch! ( not you) What I'm saying is. I always look at a paint job as a four stage application.(1) epoxy over bare metal then mud on top of epoxy. ( if you paint a car , you should start with bare metal . never put product over old materials.) (2) high build primer. Witch should be 3-4 application. then sanded off until metal almost showing. (3) Then primer (sealer) surfacer. Witch is tighter nitched product . Not pourous like high build primer. So when you paint over it the solvent does not get sucked into the product like a( high build ) primer would do . I think a lot of people paint right on high build primer. Then all the solvent goes in primer and swells it up like a loaf of bread. that's why a surfacer should go on high build primer so when you paint it solvent goes out of paint slowly up out of paint instead of absorbing in the primer. (4) Then the paint. don't forget high solids clear have no / or very little reducer ( solvent ) mostly just high quality resin w/ hardener. unlike the cheaper less(quality paints lie (omni) that uses a lot of reducer to water it out! or enamel clear coats of back in the day. no offence to omni users. It's just the old Delclear of the 80's .Point being. when you use paint that's extremely expensive sometimes you get better results. But believe me this hobby we have and love is not for us MIDDLE class people anymore! most of the people restoring these cars today that pay shops to do so are wealthy people! that have $$$$$$$$
Also Eric b I have learned over the years . And watch people at work. When they prime something , and the humidity is through the ROOF! they use a fast reducer in their primer! HUGE mistake. Eric when you put 3-4 coats of thick heavy primer on a car w/fast reducer and temp outside is 85 degrees. On the forth coat of primer how fast is the crust(shell) outer layer going to dry ? long before the primer underneath ! think about it. So if it is hot and the outer skin drys first your trapping solvent. and if solvent stays there to long it attacks the plastic work. Sometimes even Auto Painters don't realize SLOWER (solvent) is faster dry time. Slower is faster.
The 5 Star high build primer is probably what is shrinking. It sounds like you did this fast. I usually prime and block for a month before I paint which gives the thicker layers (the first coats) of primer more time to shrink before final sanding. The later coats of primer are thinner (and don't shrink as much) since, as the blocking process goes on, I'm focusing on smaller and smaller details. I painted a car 20 years ago with 5 Star and Nason and it still looks great today. I have two friends who are retired body men and they can't believe it's Nason and how good it looks after all this time. It does chip easily. On that paint job I shot two coats of Montana epoxy primer instead of sealer before my base coat and it worked well. I've had no shrinkage. I would finish sand with 600 not 400. You cold probably save that paint job by scuffing it with 800 and shooting 3 or 4 more coats of clear then color sand and buff. It should be done shrinking by now.
Out of high school (late `80s) I was in the body business and then into the paint and body supply (PPG) where I really learned the ins and outs that I put into practice at my own little shop. First, sand paper has changed from US to Metric sizing. P600 is equivalent to traditional 400 grit. P1500 = 800. So if you used P400 that would equal 320 grit. Keep in mind that if it does not have the P prefix it is traditional designation. Next, that is average grain size, which means you will have grains that cut deeper and those that cut less. Meguiars sand paper is rolled so that no grains are larger than spec. Wet paper should be stored in water for best performance. Use plastic bins for each grit size. You will get much better results and life from them. Also use tons of water when sanding, almost a continuous flow. For instance, I used to use a Hutchins waterbug. When using body filler, stop short of final feather when sanding dry and final sand with 600 wet. Ensure that you dry the filler thoroughly before priming. To avoid heavy scratches, do not use grinding grits. Most DA (dual action) sanders can be locked to single action. Use 80 grit or finer in single action for stripping.
Dave thanks for serving! We Appriciate! And yes NASON blows my mind excellent product!!! Painted a 80 ft. triple car trailer in 93 degree black top parking lot! airline was so hot could not hold ! to hot for hands! man o man what a paint job! for the money what a product! that sold me.
I Love Nason "fulthane" cheap , and once you cut it just a little it lays FLAT , I use it on mostly heavy duty apps Fire trucks,Ambos,Tractors etc
In the 70s (when I was in the Air Force) I painted a lot of cars. Now I paint one about every 10 years or so, and, every time I need to learn everything from scratch because things keep changing. Now when I go into an auto body supply store I say "this is how I used to do it, how do I do it now"? It seems the products keep getting better and more expensive. At what point do they price themselves out of the market? How good does paint need to be?
Most is due to environmental and health reasons. The mix bases and other products through my time (up to `93) still had lots of cadmium, thallium, zinc, chromate, and even some lead not to mention the solvents and isocynates. In `08 I helped a friend run his collision shop in Upstate, Central, NY. The industry had totally changed and was near impossible to turn a profit with all of the legislation and codes while having your hourly wage dictated by the insurance companies.
It's amazing how America handicaps ITSELF. Pretty soon we will have to load our cars in storage containers and ship them out of our country to be painted! Cost of paint is ridiculous and like gasoline and many other commodities, it is American greed that has inflated the price. I plan on painting my car in a home-built booth when the time comes, because I want to be able to say I built and finished the car myself. I just hope I can afford the stock and pray nothing goes wrong to inflate the price more! Jim/Rott
Up in NY you fellas were making big money I bet, albeit cost of living is higher but we just got raised to $44body $55frame $48mechanical and a whopping $30 material, average body tech makes $12hr highest paid are $18, sucks for the amount of work,frustration, and skill involved. Luckily im able to average 60hrs aweek and sometimes tickle 100, but not often
Upstate, Central, NY is one of the most depressed, "used to be" places in the country. It has nothing in common with the NYC area (except they send all their prisoners up there) and what they call Upstate which is just West Connecticut. Hourly rate is around $65 and pay rate is similar to what you mentioned. It takes an extremely resourceful and smart shop owner to turn a profit. NY State is notorious for having so much regulation that they can often take over 100% of profits from businesses. In the most recent election, over 80% of the state voted against Cuomo but he got re-elected because of NYC.
VERY true:TU: Insurance companies are cutting refinish times and expect you to do the same quality job!!
