What the Hell Am I doing Wrong
 

I'm not a painter but I've painted several cars and many panels with good to great results. However, I recently bought a set of HVLP gravity feed guns and started primering my latest project with SL-2K with poor results. I followed the mix instructions (4:1 paint to activator) and am painting at the recommended 10 PSI. New primer gun has a 1.8 tip. Ambient temp around 58 degrees.

The paint is laying on quite rough, seems to be too dry, and with quite a bit of overspray and "sandpaper" texture. I tried adjusting the fan, paint volume, and pressure but nothing really seems to help. I added a bit of reducer, per the the product instructions and that helped, but not really enough,

I need to find out my problem before applying topcoat, a single stage arcylic enamel.

Any advice would be appreciated.

jmd_forest

Try mixing it 4;1;1 primer, hardener, reducer

As Axiom stated, you might try using some more reducer in the primer and just lay on an extra coat. Also bear in mind, coatings flow out much better between 75-85 degrees. If you have the ability to heat the work space, that will help alot on smoothing the texture as you spray.

Hold the gun closer, 10-12".

Your pressure should be 10psi at the cap which really means 25-35psi at the gun. I had similar problems. Basically you should be setting your gun pressure so you get a nice fan 8-12 inches from the gun.

Thanks for the replies. I was painting at about 8-10 inches and still getting the "sandpaper" texture. I guess I'll wait for a week or 2 for the weather to warm up before trying again while adding the 1 part reducer (I already have the fast reducer, rated 60-70 degrees). I wet sanded out some of the primer today and had a hell of a time getting it smooth, it was "micro-pitted" all over the place after sanding.

I hope outlaw912 can explain the pressure issue further. I have a regulator right at the intake to the gun. The standing pressure was about 25 psi which translated into about 10 psi (per paint can instructions) when the trigger was pulled.

Thanks again for the help. any further tips would be appreciated.

jmd_forest

almost all urethane 2k primers must be reduced before spraying. sounds like your problem is not enough reducer.

I should preface this by saying that I'm not an expert, but here is what worked for me. I was having the same problems as you with polyester primer. The primer p-sheet says 10 psi at the cap, which doesn't necessarily mean 10 psi at the pressure regulator. I assume there is some pressure lost inside the gun. I set my pressure higher at the regulator, 20-25 psi with the trigger wide open. I think it's more feel than anything else.

Maybe someone with more experience can clear this up, but anyway thats what worked for me.

Hope that helps.

Erik

Boy, that all goes against what is the norm... cold temps mean 'wet' paint film, the solvent doesn't flash fast enough. Low air pressure and thick paint usually gives you a very orange peeled finish not a sandy one. With the three conditions you are discribing I'd have thought the paint would be running off.
Are you positive you mixed the proper ingredients? Sounds also like it could be seedy paint. A quick test is to take some paint and pour a little onto like a piece of flat smooth metal. Take a squeegy or something and smooth it out If you can see 'bumps' it may be kicked out. We use grind gages for this to check the grind of pigment.

Finish was a horrifying combination of orange peel and sandpaper, in different spots. The ingredients mixed: Transtar 2K Kwik Prime and Transtar 2K Kwik Prime Activator. A review of instructions does allow for "up to" 1 part reducer. I originally didn't use reducer since the instructions on the previous Starlite SL-2K primer and SL-2K activator I was using noted to use reducer only if being used as a sealer (That primer job sucked too but I was attributing this new suck job more to the new gun and my inexperience with it). Things improved a little when I mixed in some Urethane Fast reducer, but by then most of the damage was done.

So... I've wet sanded it out with 220 and finished up with 600 grit but still have many pinpoint sized micro pits. Can I reshoot a few good coats and sand out or should I continue sanding MORE before shooting.

Thanks for the help. I seem to need it.

jmd_forest

I've seen that before with those kinds of primers, if you really want to save yourself a lot of grief, I suggest sanding it with 150 grit and start all over, those pinholes never go away.

Good luck

I will take that advice and sand out all pinholes before reshooting. I'll also reduce the primer and wait for warmer (65-70 degrees) and dryer weather. It's around 70 today but raining. I've always heard humidity and auto paint don't mix.

jmd_forest

So... sanded out and reshot the primer but it still didn't come out as smooth as it should so I wet sanded again to a perfectly flat surface. Started applying the finish coat, single stage acrylic enamel, using the new gravity fed HVLP with 1.4 tip gun. I followed the mixing instructions exactly (8 paint: 2 reducer: 1 hardener) and did some research on the gun setup resulting in upping the inlet pressure to 40 PSI and painted on a 70 and 65 degree day. I'm getting much better results but there is still some orange peel. I seemed to alternate between applying the paint too dry or too heavy and running the paint. However, after wet sanding out the initial finish coats and reshooting, the finish is pretty good (some minor orange peel in a few spots) or at least "good enough" for my son's first project car ($500 86 944 + $1000 parts).

Since all of the finish coat so far is on panels removed from the car (hood, sunroof, bumpers) I'm hoping I can get some advise on improving my results on the main car body. Again, I think I'm putting the paint on too dry but It seems to run when put on wet. (Note: I'm using "fast reducer 60 - 70 degrees)

Any help would be appreciated.

jmd_forest

Can you show us a few pictures? Don't feel too bad either, HVLP's are very hard to work with unless you're a pro like Axiom.

If it's orange peel you can reduce the paint further but still using the same air pressure. That should get it to lay down better. If it's dry spray you'd want to lower the air pressure and thicken up the paint. In any event hold the gun about 8 - 12" from the substrate staying perpendicular to the work. End your strokes off the panels then come back overlapping 50%.
I'm not familiar with the brand you are using. Maybe the paint also just sucks?

I'll give your suggestions a try. How much do you suggest I further reduce the paint? I'm concerned with over
thinning since my initial work on the valence resulted in many runs. I've watched a few YouTube auto painting videos and these guys fly with the gun. I'm moving at maybe 1/2 their speed or I can't maintain a wet edge. I do keep the gun about 10" or so from the surface and try and always maintain a perpendicular angle to the surface by following the contours of the body and never arcing the gun. I do always start and end the spray into the air before and after the edge of the panel.

I'm using Restoration Shop Acrylic Enamel from TCPGlobal. Acrylic Enamel because the PO noted he had a MAACO paint job done and I didn't want to risk lifting the paint by using incompatible paint (been there, done that before). The Restoration Shop brand because it's cheap and this is (supposed to be) a cheap project.
Some pictures are below:
This is the hood. Very tough to see any orange peel
http://i256.photobucket.com/albums/h...t/pc120017.jpg
This is a better closeup. If you look just below the reflection of the garage windows you can see some orange peel.
http://i256.photobucket.com/albums/h...t/pc130018.jpg
Some of the other panels after wet sanding and reshooting the original finish coat on the valence.
http://i256.photobucket.com/albums/h...t/pc110007.jpg

Any help would be appreciated I'm damn tired of wet sanding the initial finish coats. I've actually sanded off my fingerprints.

jmd_forest

Forgot to put in previous post: Would it help to wait for warmer weather (75-80) and use medium temp reducer?

jmd_forest

It's tough to see the OP but certainly can see some type of defect. Is it just not wetting out? Almost looks like it. And that hood being a horizontal surface should just about look like glass. With the right reducer I wouldn't worry about the temp. as long as it's within reason. Try another 5% reduction.
I'm sure you have thought of this and have done it but was the surface good and clean? Did you tack cloth it? If so did you VERY lightly run the cloth along the surface? They can sometimes leave a residue that will effect the surface tension of the substrate and cause finish problems.
Good luck and please post results and or any more questions you might have.

Thank you for your responses. I wish I could attribute the problem to surface contamination. The surface was wet sanded the previous day using a bit of dish detergent. Immediately prior to painting I lightly wiped it with reducer followed by light tack cloth. The finish of the hood prior to finish coat was absolutely smooth. (320 followed by 600 grit wet sand). I was concerned at first about wiping with reducer but I had the same problem on the sunroof and that was simply tacked off before shooting.

Sorry to sound stupid, but what is "wetting out"

jmd_forest

Wetting out...hmmm... Uhhh...Think of a freshly waxed car vs. a car that hasn't been waxed in years. The water on the car that hasn't been waxed flows over the surface, it wets out. The water on the freshly waxed car beads up, it doesn't wet out the surface. You want that when waxing but not with your paint. (And there are no stupid questions, maybe some stupid people asking questions :D ).
With the surface prep you've done it sounds like it's either technique, paint or a combination there of. But what does sound strange is the different surface quality, (OP & dry spray), on the same parts. That's what makes me think something is still weird with the surface.
This may sound stupid but work on your technique until you get one or the other. Then you can adjust the paint and or air pressure/fluid flow accordingly.
Wish I was a bit closer I'd certainly come down to have a look. See if possibly you could get better pictures of the OP & dry spray.

Ok guys, this is what I gather so far, any paint nowadays is reduced 4 to 1 to 1, with the exception of CLV, your paint is being reduced 8 to 2 to 1, economic paints do that, because their pigments are weak and won't achieve hidding with the normal reduction ratio. try a 4 to 1 to 1, but I also thought about this: is the fluid needle on your gun all the way open, a 1.4 is a minimun for some medium solids, make sure it's all the way open. Don't get discouraged, if this was easy, everybody would be doing it.

Thank you for your contribuitions Mark.

Boy there's a thought!! maybe the needle is not seating properly, sometimes pulling all the way back sometimes not. Maybe take the gun down to the bare minimum give it a good cleaning and try try again. Good call Axiom, (that's why you make the big bucks! ;) )

Ax and Buck,

Thanks for the replies. Regarding the reduction: 8 paint : 2 reducer == 4 paint : 1 reducer. The "1" part of 8:2:1 is the hardener. Per your suggestion, I would only be doubling the hardener and I'm not sure that was your intention. If so, that's what I'll do.

The gun being used was brand new (different from the 1.8 gun used for primer described earlier in the thread) and I mean brand new. The finish coat was the first time used. I simply ran a few squirts of reducer through the gun before painting. Regarding the needle setting, Unfortunately I'm not sure what you are saying. I did turn down the fluid control a bit to help control the runs I experienced earlier. How do I adjust the needle setting? This gun (Advanced Tool Design Model 6900) has three adjustments: 1) spray pattern knob on side of gun 2) Fluid adjustment - big knob at back of gun 3) Air Adjustment small knob at bottom of handle next to where the air inlet is.

I've adjusted the pattern and fluid to try and get a wet edge while minimizing runs. You can see some test patterns in the background of the picture of the hood posted earlier. I did turn in the fluid control to help minimize runs.

Again, than ks for the replies. From compiling the replies it seems I should: 1) reduce the paint an extra 5% 2) reduce the pressure a little 3) Double the hardener (hopefully Ax will clarify first) 4) open up the fluid needle, I'm assuming by using the fluid control

Any further help would be appreciated, thanks again for the suggestions.

jmd_forest

Do a test panel first, with very little mixed paint using the ratio I gave you, with regards to the fluid needle, adjust as follow, with empty gun, unscrew the big know almost all the way out, then press the trigger and start screwing the know in, when you feel some resistant at the trigger, stop and lock it, if lock is provided, that is open all the way.

On your test panel, do a medium pass first, follow by a wet one, and see how your paint flows.

DON'T double the hardener!! won't do any good for this problem and will, down the road, cause issues. Ax will confirm this. I also wouldn't reduce the pressure at this point. Just start by reducing the paint that 5% and see what that does. You'd be defeating the purpose by lowering the air pressure with reducing the paint.
A quick painting 101...

Problem; Dry spray
Solution; Heavier coats, turn down the air pressure, move gun closer to the work, don't thin paint out to much, turn up fluid flow, use slower reducing solvent.

Problem; Orange Peel
Solution; Lighter coats,turn up the air pressure, reduce the viscosity, back off from work, turn down the fluid pressure.

Problem; Sags/Runs
Solution; Lighter coats, faster reducing solvent, move gun distance back from work, turn down fluid flow, turn up air pressure.

These are not all inclusive but they are a starting point. Have you used this brand of paint before? You've had 'great' results in the past. Wondering if the paint isn't the issue.

Correct again Mark, doubling the hardener on a acrylic enamel is not a good idea.

8 to 2 is the same as 4 to 1. Follow Mark's guidelines, they will get you there.

Thanks for the tips. I have never used this brand of paint before. I couldn't get acrylic enamel at either of the local auto body shops, and since I didn't want to chance crazing/lifting the existing acrylic enamel paint, I found this stuff on the internet from TCPGlobal/Restoration Shop. Paint I've used previously: Dupont Centuri Acrylic Enamel, Dupont Acrylic Laquer single stage, Dupont Acrylic Laquer Base/Clear, Dupont Chromasystem Base/Clear, Sikkens Urethane, Akso Nobel (U-Tech) Base/Clear,and some currently unremembered brand of "fleet" acrylic enamel. (some of this goes back 15 years). All previous paint done with traditional siphon feed high pressure guns.

Thursday is supposed to be a 75 degree sunny day. I'll try an additional 5% reduction and adjusting the gun per Ax's post. I'll also start with a test panel. I'll wet sand out the sunroof and use that.

Thanks again.

jmd_forest

Let us know how you make out.

So, in this case you are only unfamiliar with equipment and product, AH! we will get to bottom of this, it might be a conbination of both.

Yes, unfamiliar with both equipment and product. What am I gonna do? I paint so infrequently (1 car every 4-5 years, and a couple panels every year or so) that much changes between instances. I'd have used my old pressure siphon gun but it started intermittant spitting for some reason and the world seemed to be going gravity feed HVLP.

I taped out the car today and will be shooting tomorrow. As I mentioned earlier, I turned the fluid down on the gun to help control runs and as a result wound up moving the gun pretty slowly to keep a wet edge. Since ti will be warmed tomorrow, I'll adjust the gun per Ax's post and probably be moving faster, Hopefully the warmer weather will help evaporate the reducer faster and take car of the runs.

jmd_forest

Get some cheap mis-matched paint similar to what you have and practice on an old fender first. It's not easy to paint, it takes a lot of practice. Even painters with years of experience often have problems when switching paint brands. Sometimes a guy with 20 years experience has problems with the same material that he's been using for a long time. It's not reasonable to expect yourself to get it right the first time after watching a video.
Most paint (at least in low VOC areas) needs to be reduced more than they recommend on the can. They recommend that amount of reduction because that amount allows the manufacturer to meet the VOC regulations.

I followed the tips above but still wound up with an absolute unmitigated disaster. I put a light coat on top of the sanded out test panel and that went well so I started working on the car body. I put on a light first coat from a further distance (12-16 inches or so) that seemed to smooth out well and let it flash for the recommended 15 minutes. I could tell the 2nd coat was not going as well for some reason and to top it off I tripped on the air line and the lid popped off the gun and paint splashed all over the driver's side fender. (but no other body panel). Let it flash for 15 minutes and put a third coat on everything but the DS fender. Much orange peel all over the place. Guess I'll wait a day or 2 for it to harden and wet sand it out.

Either I bite, the gun bites, the paint bites, or all three.I'm going back to the pressure siphon gun. I spent several hours cleaning out the gun and that fixed the spitting. I compared the guns side by side and the pressure gun definitely atomizes the paint better (or at least with me working the guns). Time for several beers and much crying.

jmd_forest

Man I am sorry to hear. I'm with you, I'd use the conventional gun. If things still go wrong, I'd suspect the paint and or surface. What do the directions say about application? How many and what type of coats?
You get it!!!

Sorry to hear about your frustating times with this project, What was different between the test panel and the car?

Application instructions say 2-3 medium wet coats or until full hiding is achieved. The difference between the test panel and the car is that I had painted the test panel last week with minor orange peel results. I wet sanded it out with 320 followed by 600 and put on a single light coat. It didn't need to hide the new primer or old paint. Without a doubt, if there was any surface contamination anywhere on the car there isn't any more. I wet sanded out the hood and a bumper (both are off the car and had minor OP from my previous attempt.) and will try and reshoot these today using the old gun. I'll let the car harden up another day or 2 before wet sanding it out.

Had to order another gallon paint kit, I don't have enough paint to redo the entire car. Hopefully I'll finish the car next week if we get some 70+ degree weather (and the old gun give me decent results.)

jmd_forest

Well...shot the hood and bumper with the old gun today. It came out better than the car body but still had "orange peel". Actually, it's more like HUGE OP (1/8 " or so) dimples under a glossy surface. I've been reading on the web regarding this and similar cheap AE paints and the consensus seem to be to really thin it out as low as 4:2:1. I read the Dupont Centari AE spec sheet and they recommend 3:1:1. Never again with the cheap paint!! I was just afraid of applying the urethane over the MAACO AE and I really didn't want to strip the body on a $1500 car. This was supposed to be quick and easy.

At least I got 3 medium wet coats on with no runs and should be able to color sand it smooth and buff it glossy

I'm going to try a much thinner reduction on a single car panel once I get the new paint in and see how it goes.

jmd_forest

Ax will know better than I but I don't think there would have been any issue with going over Maaco's paint with urethane. Moot point though. Yes thin the crap out even further till it lays down. Then call and complain!! Please show us pictures when it's all said and done.

Spent 6 hours today wet sanding out the OP on the body. Took it down with 320 grit and dishsoap in a bucket of water and a hose. My 16 yr old son (whose car this is going to be) spent about 4 hours with me sanding also. My fingerprints are gone. Pictures are below.

http://i256.photobucket.com/albums/h...t/pc170020.jpg

You can see the front fender where I tripped and splashed the paint has been aggressively sanded out. I'll need to apply a coat of primer and wet sand before painting again. As a side note, the driver's side rear corner panel had been crushed in and the driver's side door had a strange split in the metal above the door handle. I hammered out the quarter panel and reinforced and brazed the door before bondoing it smooth. The body work actually came out perfect.
http://i256.photobucket.com/albums/h...t/pc170021.jpg

I'm going to try and find a local painter to take a look and see if he can provide some guidance but I don't have much hope since I suppose they would want me to bring in the car for them to shoot. Maybe I'll find a sympathetic ear.

jmd_forest

Mark is right, one of the major issues with those types of paint jobs is to the quality of paint, but the prep work that those shops do to the cars, they just scuff it and shoot. Paint quality and type were a big problem in the the days were lacquer was king, being that acrylic enamels were largely use by these shops. Paints are stronger now, but still, without a proper base, you can put the best on top, if the bottom shifts, you can bet, it will surface.

Now that you don't have any more fingerprints, what about getting some decent paint to try it with, all this work deserves a good finishing.

I've had more than one instance in the past where I unknowingly painted lacquer over acrylic enamel and it crazed/lifted and I had to strip the whole car. Way way too much work for this project so I wanted to be sure it wouldn't happen and chose the AE paint. If I was confident that a urethane wouldn't lift eiither the old paint or last week's AE I applied I would think about it. On the other hand, since I finished up the original gallon of paint I ordered another gallon kit a few days ago (Wish I hadn't done that).

It's killing me since I previously (20 years ago) painted a 69 911 Targa and a 68 Jaguar XKE 2 door coup with the cheapest fleet red AE I could find and they looked absolutely great when done; not a run, no OP, just a great looking job. 15 years ago I painted my wife's Toyota 4-Runner with Dupont Centari AE and again it came out great also. I'm coming to the conclusion that this paint sucks and I've lost a step or 2.

jmd_forest

What color is that? Guards Red?
I'm with Ax, you've done to much work and body work not to put a quality paint job on it, (like you were trying to do). Let me know what color it is and maybe I can help with the paint.