This is from the PPG "Reporter" news letter. It is a very interesting technique that really does cut down on overspray. It is for spot priming only and has nothing to do with priming complete panels.

One of the reasons I wanted to post this is the warning on turning down the air pressure creating trapped solvents. I beat this atomization thing to death as you may know. Here is PPG rattling the same cage.

Solvent and what it does AFTER you have sprayed your primer, paint and clear should be a concern of yours. If you think you are "building up" primer to fill more for you. If you think you can build up clear to make it "flow" (man I hate to even say that word when talking about modern products) you are kidding yourself.

You need to have a LOT of respect for how you apply your primer, paint, clear. Atomize the product correctly, use the proper temp solvent, do NOT pile it on, and leave the proper flash time between coats.

Sorry about the large image. My scanner is not working so good anymore and the thing harder to read if I shrank it any more.

Click HERE (http://members.aol.com/basicofbasics/reverseprimer.jpg) to see the tech tip.

This technique was demonstrated 4 years ago by one of the ppg reps in my area. The technicians (including me)unfamiliar with the Global system at the time were having trouble with the high buildup of oversparay on the outside edge of primer areas. By applying the first coat larger than the next overspray was cut down. The newer primers don't melt the overspray like the old primers so if this technique wasn't used the fuzzy build up was great. Same basic thing happenend with the old laquer primer if the temperature and humidity was really high so nothing new really.

Bob, an interesting thing you just mentioned. "The newer primers don't melt the overspray like the old primers". That is very right, and neither does the clears or SS urethanes. That is something that comes up every once and a while here on the forums. You can not put the old "tack coat" on using these products, you will be fighting that dryness in the last coat that you started with the first.

EVERY coat should be a med wet COMPLETLY covered coat. No holidays, the first coat should look like it is done.

With primer it is not critical, but it sure is with the top coats.

A question for MARTINSR, when you refer to top coats is that the clear coat or does it include the base coat? Recently I painted my 69 convertible and had a few problem (bugs) show up in the last base coat. After trying to remove them I finally gave it about 2 hours, then wet sanded that area with 800 to smooth it out. After drying it I misted two coats over that small area - didn't paint the whole panel. There was certainly a rough edge around it and I had to clean it with a tack-rag. It immediately disappeared with the first coat of clear and I have looked it over pretty good and can't see any sign of it. Any reason to think this would be a problem??? I have never noticed anything I can contribute to trapped solvents, but I am concerned that I have "hurried" a few base coats recently since they seem to dry so fast.

A light tack coat with clear is ok as long as the texture is smooth-although with some of the high solid clears it is impossible to put a thin coat on anyway-so?

EVERY coat should be a med wet COMPLETLY covered coat. No holidays, the first coat should look like it is done.
Try this on a blend panel on a light colored metallic and after you razor blade the runs you'll be reshooting your blend panel and the panel next to it.
A buildup of clear WILL darken the color!!Always had a problem with the high solids clear on blend panels,as stated the overspray edge will not melt in given the proper flash time.Over reducing helped but sometimes would get solvent pop. I switched back to normal clear and if 2nd coat is applied before 1st coat sets up (like a couple minutes) the edge will melt in.

edurando, that problem is very common. The overspray from the base doesnt melt into the existing base, be it your NEW base or the old paint on the car. If you DONT remove that the dry spray will look grainy and the metallics will not match so you'll be able to see the blend area. The way to rid that is use a tack rag before each coat like you should anyway. That will pick up any loose base that didnt adhere to the existing paint.

Also another way is to use a blend solvent, PPG's is DBC 500 or DBU 500. This helps that edge melt into the existing paint. I like to shoot my color coats and before I make the final blend shoot DBC500 over the areas to be blended. Also say am blending on the hood, I spray the ENTIRE hood with that DBC500, it gives the clear something to stick too. But I dont spray on the panels that are not on the blend area. Go back to the blending hood again, only spray on the hood since am BLENDING on the hood, no need to spray the fender.

I agree and dont agree on the EVERY coat should look like the last coat. When using PPG 2055 which is their Glamour clear, you spray the first coat like it was the last it will be on the floor :mad: The trick is spraying it inbetween a tack and wet coat. Then second coat can be the heavier coat sprayed on smooth.

Now when using PPG's new DC 3000 clear you apply a tack first coat that tack coat will show thro the second coat as orange peel. You need to apply that clear on this clear as if the first coat is the last...Eric

"If you DONT remove that the dry spray will look grainy and the metallics will not match so you'll be able to see the blend area. The way to rid that is use a tack rag before each coat like you should anyway. That will pick up any loose base that didnt adhere to the existing paint."

Sevt, Man, I gotta hand it to you. I've never, ever been able to wipe with anything, including a tack rag between or after a base coat that contains metallics without causing streaks. Damn! I thought I was above the shade tree level. Maybe not.

Vette, I wipe the car down between each coat of base whether its a solid or metallic and YET to recieve any type of streaks. This is just not something that I came up with on my own, the PPG rep SAYS to do this along with the other reps that tought a PPG class that I recently took back in July.

Just simply stating that when using PPG products, have noticed this with both DBU and DBC that if you dont tack rag the area off before and after the final blend you WILL see that edge.

Vette, I really dont care for your never ending sarcastic comments. Just because someone does something that you dont do or YOU THINK is wrong doesnt make them wrong or an idiot all it makes them is different then you

"Vette, I really dont care for your never ending sarcastic comments. Just because someone does something that you dont do or YOU THINK is wrong doesnt make them wrong or an idiot all it makes them is different then you"
-------------------

Shucky darn, Dood! We all have stressful days. Today must have been yours.

It will be interesting to see any further responses from experienced painters concerning using a tack rag on base coats/between base coats. I will admit that it's been a looong time since I've used PPG, but in the meantime, I've used a variety of other brands. By way of repeating myself...I've never, ever seen any brand of paint that wouldn't streak the metallic ESPECIALLY when spotting the base within a panel.

If that's being sarcastic or doing something that "I THINK" is wrong, I just dunno what to say.

In the future, any comments or responses I might consider where you are concerned, I will double think about what I say and how I say it so that you won't think I'm being unduly sarcastic. If questioning a technique or action that is totally alien to anything I've ever done or learned from major suppliers(other than PPG), I'll speak up. If that hurts your feelings, I'll try to get over it. How about you?

I always tack my base and i dont have any problems.I mostly use Chromabase. If your getting streaking your probably putting it on to dry which is common on a blend.Thats what the basecoat blender is for so you can step your blend out without having the dry edges.But honestly i dont use it.If you tack the whole panel off good you should be ok,only time i could see a problem is if you just took a swipe or two on a part of the panel.Also a quality tack rag is a must.I use Crystal tack cloths.I have used others that leave a messy lint behind.Never had a problem tacking the base with the Crystal brand cloths.

I had great day no stress what so ever.

"Damn! I thought I was above the shade tree level. Maybe not."

Its this little statement that I dont care for not the part of streaking left behind due to tack rags.

Hey if someone disagrees with me so be it, really dont care, no skin off my back. Its when you disguise calling someone an idiot or whatever you meant under a flurry of words that tends to rub me wrong.

My now Ex fiancee told me this once and now Ill tell you since you like play on words (but Ill sum it up since this is a family site)
A donkey is still a donkey no matter how you look at it.

70isfine, I too am most experienced with Chromabase. I'm also experienced with Sherwin Williams, Sikkens and Spies-Hecker(Now owned by Dupont). In situations where I absolutely had no choice but to re-spray the entire panel or blend, I would attempt the blend. It is true that the most likely way to get streaks is if the base is sprayed too dry. In that case...as you know...there will be a fine overspray dust that includes metallic. To wipe/tack that will for sure result in streaks regardless of the brand of tack rag...and there is definately a difference in the quality of tack rags. I rarely use them, but I'm familiar with which is good and which is not so good.

Even using the proper temp basemaker with Chromabase, blending the base within a panel will almost always result in at least some of the overspray dust. Frankly, I've never seen any of my painters or myself who could tack the base coat without getting streaks. If you've done it and/or you do it on a regular basis without streaks, hats off to you.

I've not attended any seminar or class nor had any jobber rep nor paint rep recommend tacking the basecoat whether a blend was involved or not. I'm including all four of the brands that I mentioned earlier. Correct me if I'm wrong. Just because I attended the seminars/classes and spent a bazillion hours with paint reps doesn't mean I got it right or didn't misinterpret something.

It is rare for experienced painters to disagree on major issues. Ordinarily we get hung up on the teeny tiny specifics and procedures. I consider this issue a teeny tiny thing. Too bad Mr. Sevt_Chevelle doesn't.

Vettefella, my issue is NOT and I repeat NOT tacking off basecoat, its your attitude.

Everytime you got to throw in some little remark that degrades someone then they stat something that you dont agree upon.

Think am wrong, the statment of "boiling lacquer in water to make sprayble" ring a bell to ya? I sure do recall your reply graemlins/sad.gif

I must apologize to Martin, great post sorry for the trouble...Eric

I also spray ChromaBase on a near daily Basis......tack between every coat of base......recently I've had the chance to start using Duponts Sontara final tack cloths Info here (http://www.sontara.com/productpages/sps/finaltak/fin_home.html) and thay are very very nice.....no chance of leaving tack streaks with them.....but before them I used the normal Crystal Tack cloths and only had streaking problems if I boneheadedly applied to much pressure or paused and let the cloth stop moving graemlins/clonk.gif

Peace

Boy, some times these threads go off into another galaxy. smile.gif

I "have" tacked base coats with success many times. I say "have" because it isn't a common thing to do. If there is something in it or it has to be scuffed because of dirt nips or something like that, tacking is needed.

If the base is applied in a med wet application there is no "dust" on it. Most quality bases can be applied in this way without any worry of metallic mottling or streaking. On a blend, if you use a "colorless basecoat" on the blend area, again, it will not leave the dust (at least not as much).

This is do to the very same conditions as the reverse priming technique.

Hey, here we are back at where this thread started out at. http://www.rodder.com/ubb/graemlins/rockband.gif

Everyone seems to agree that there can be a dry edge when blending a basecoat right? And there is often a dry overspray that settles on the panel.I just can't see clearing over that dry 'dust' and trying to bury it with clear, when it can simply be removed. A light tacking will pull it off without ccausing streaking of the base below it. I've never had any problems,and like Ratluvr stated i'm also spraying everyday.I'm also using U-tech(Azko Nobel,) and BASF/Diamont with no tacking problems.

I'll agree that there are times such as when the base requires nibbing/scuffing that tacking may be necessary. Other than that, I don't tack or wipe between base coats...period. Until now, I never knew anyone who did that on a routine basis when doing blends or otherwise. Never knew a discussion on that subject would make me akin to a donkey either. smile.gif smile.gif

MartinSr, you have something there. Doing blends in the same manner as reverse priming should work like a champ.

This is the plain and simple fact, you SHOULDN'T ever have to tack the base. If you do, it is because of poor air movement in the "booth" or improper air pressure or something. A light dust on the surface is fine "under" the clear. The whole question is, is that "dust" being SEEN in the final finish. I have never, routinely tacked blends. In fact, I did everything I could to NOT have to. If there is one thing I can be proud of is an INVISIBLE blend. I do it by clearing over that "dust", just as the manufacture says.

If you ask five painters how to paint a car you will probably get five different answers,none may be wrong.Everyone does things their own way and as long as the end result is good i guess it doesn't matter.Whatever works for you.

70, you are right about this subject. I have to assume that all in this discussion produce a nice job. Yet, we have some differences in OPINION. smile.gif

However, if you ask five different painters and they give you five different answers, it does NOT mean that all five are "right". Believe me, there are PLENTY of guys painting (and for that matter doing every other trade on earth) and they do things WRONG every day. I am not talking "opinion" wrong, I am talking WRONG, WRONG. I am talking, against the manufactures recommendations, against basic science, against common sense!

THEY will tell you it is just "their" way and there are many different ways to do something.

Believe me, you can't say there are these different ways to do something when it is WRONG.

Opinion, sure, there are lots of that and it is quite harmless. But don't think EVERY "different" way is just another option.

Originally posted by MARTINSR:


However, if you ask five different painters and they give you five different answers, it does NOT mean that all five are "right".
Martin, I didn't say all five would be right, I said you would probably get five different answers and none MAY be wrong.I'd say we are splitting hairs now.I'm done here.
smile.gif

Not "slitting" hairs 70, just clarifying.

Boy, for some reason a simple post on a priming technique has sure brought out the sensitivity in you guys.

I agree with you, these are "opinions". IN THIS PARTICULAR CASE, THEY ARE OPINIONS.

I just feel that a clarification was due because the old "just another way to do it" comments are USUALLY a way to "Mask" a WRONG way to do it as "just a different painters way".

That's all I meant 70. graemlins/beers.gif

Everybody does things alittle differently-that's OK, no need to get excited. As far as tack wiping basecoat I've done it many many times. Sometimes I tack wipe between coats of base or just before the last coat. Heck sometimes I de-nib with ultra fine if needed. Solid colors can be totally wetsanded before clear without any problems and increased gloss and depth. I do not tack rag final coats of metalic base colors unless they are covered with midcoat clear. The midcoat clear is nice to use over the metalic base's as it provides a surface that is easier to keep clean without disturbing metalics. graemlins/beers.gif

Originally posted by baddbob71:
Everybody does things alittle differently-that's OK, no need to get excited. As far as tack wiping basecoat I've done it many many times. Sometimes I tack wipe between coats of base or just before the last coat. Heck sometimes I de-nib with ultra fine if needed. Solid colors can be totally wetsanded before clear without any problems and increased gloss and depth. I do not tack rag final coats of metalic base colors unless they are covered with midcoat clear. The midcoat clear is nice to use over the metalic base's as it provides a surface that is easier to keep clean without disturbing metalics. graemlins/beers.gif Bob, you had me until the "solid colors can be totally wetsanded" part. That is where it changes from just "opinion" to wrong. It depends of course on what base you are shooting. But you can't just make a blanket statment like that. There are many base coats out there that specifically say DO NOT SAND in the tech sheets. They say that for a reason. You WILL loose adhesion. It is not designed to be used that way. It is not an "opinion" it is science.

I am totally with you on the rest. I don't want to sound like it is not to be done. Of course sometimes you do tack the base. But honestly, if your booth has good air movement and your gun is properly set up you really shouldn't have it covered with dust. If there is overspray falling back down on the car do to poor air movement, well of course you will need to remove it before clearing.

All I can say is you really have to have a knack for tacking base without making some sort of marks. These marks are many times not seen until after the clear is applied. That is all I really was saying.

Dupont Rep told us nothing more than nib sanding between coats because the base has a built in adhesion promoter that you will sand off .....

and as far as good booth LMAO I could only wish.....I work in a low production (3 techs) dealership shop :( our booth is a 8 year old brewco down/side draft that was ONLY purchased because OSHA were gonna shut his (the owners) bodyshop down.....currently we have one shop supplied Sata NR95 and 2 Binks model 7's :eek: the other 3 paintguns in the shop I personally bought :rolleyes:

I would probably enjoy my job alot more if I got to use the correct tools/equip....as it is now it's just a job until my wife gets out of school so I can go back and get into computer IT/web design

Martin I envy your co-workers, it would be a treat to work with you I think.

Peace

just to stay on topic a little.....I try to always use the reverse technique....makes sanding much easier normally ;)

Originally posted by RatLuvr:

Martin I envy your co-workers, it would be a treat to work with you I think.

Thank you very much. It is funny you should say that. I just had a discussion with a co-worker as I left last night. I had stopped what I was doing and went to help him out of a jamb he was in. He was just finishing one of those cars that beats the crap out of you. You know, the ones that make you feel like you have been physically wrestling it. Anyway, he had made one last mistake for the day smile.gif He closed the hood on this 2002 Mercedes ML320 BEFORE he hooked up the cable for the hood latch!!!! :eek:

It looked like we may need to cut the hood open with an air chisel for a while, no kidding. Well, we finally got it open using a long mirror, a flash light, a long Snap On hose removing tool (a bent, pointed "screw driver" looking tool) and a LOT of luck. He was so relieved that after he came over to me and told me how great it was to be working with all the guys he does at this shop. Now mind you, he has been with the company for about 8 years, much longer than me.
It was really touching because he is a hard as nails street guy from the nearby "big city" ghetto! We are talking spent time in jail more than once and has a tear drop tattooed on his face which I am told is something to do with KILLING someone or the amount of years in jail or something like that. Anyway, he is a tough guy none the less.

We joke about gangs and the inner city and it is a very "light" subject around the shop. We joke about race and all the screwed up things that people do in the "hood". After living DEEP in the heart of the ghetto for all his life, he recently moved out, way out to the middle of the valley in a little farming community. He had enough of that crap and moved his family the heck out.
Anyway, I just wanted to try to paint a picture of this guy for you.

He said, (and I digress) something that was real touching. He told me Thanks for helping him and said "I really mean it, no joking, no gang talking ghetto stuff, really, thanks"

We then talked about this place where we work, it really is special. There are about 25 people on the payrolls between paint, body, detailing, and office. In the two and a half years I have worked there, only ONE guy ever went over the line with his anger towards another employee (he did it to a few guys over the years, the last was me) he was fired and that was the end of that. Everyone else will help anytime you need it. There is NO back stabbing, we are all business don't get me wrong. But we all work together. I personally have never worked anywhere like it.

The funny thing is, my "new employer" said something to me the day he hired me. He said "whether you work here six months or six years, you will enjoy it". I thought that was the strangest thing to say. It only took a short while for me to understand.

One more smile.gif We were at the Christmas party (a big event at a hotel with DJ and more) and this same tough guy was sitting next to me. He said, "This sure is fun" after we had just danced to the "Disco Inferno" smile.gif and I looked at him and said "Hell, it is just like at work". smile.gif No kidding, we really do have a blast there.

Boy, it sounds like I am talking about my kids smile.gif It kinda is, you want to spank them sometimes, but you still love them. smile.gif

I've sanded and tacked when ever it was needed for more that 40 years. Right or wrong it worked. Just have to use some common scense.

Not every thing in a body shop can be done by the book. Seat of the pants works pretty good. graemlins/beers.gif

Originally posted by Vettefella:

"boiling lacquer in water to make sprayble"I wondered why that laquer wouldn't spray !!! graemlins/clonk.gif

Rat, I forgot to tell you about the equipment.
Two Sprayback Full down draft booths
Three Dataliner frame racks
Chief bench rack
Car-o-liner robotic computer measuring system
Rotory four post lift
Laser Four wheel alignment system
Three Trisk short wave infared curing "lamps"

I have worked without this stuff and you can get it done. But, I have to tell you, it is much better with it!!!

I have only sprayed Sherwin Williams Ultra 7000 recently, but I found that tacking between base coats improved my results without creating other problems (solid colors). It didn't take long to realize that doing it between clear coats was a bad idea. A comment from RatLuvr made me realize that I created a problem about 3 years ago by stopping the rag for 3-4 seconds and later noticed an odd spot during the next coat at that point. At the time I was unaware that this could cause a problem - do I understand correctly that the technique is a very light touch without allowing the rag to stop? Any other warnings about tacking??

Originally posted by MARTINSR:
Rat, I forgot to tell you about the equipment.
Two Sprayback Full down draft booths
Three Dataliner frame racks
Chief bench rack
Car-o-liner robotic computer measuring system
Rotory four post lift
Laser Four wheel alignment system
Three Trisk short wave infared curing lampsThanks Martin :( smile.gif

Iam in the same boat as Rat, right now I dont enjoy my job, hate getting up in the morning. Not having the equipment that makes it easier or co workers that give a crap makes a HUGE difference. I Agree with you Martin 100% yes the job can be done without them but it sure does make life easier, especially when the guys care for the stuff also.

When I started painting full time this June gave up doing metal work, the former painter thought that since my tools were no longer going to be used he can use them :rolleyes: That lasted about a week, my stuff was scattered all over the shop laying on the floor, my friggin brand new Spitzangel spot weld remover was on the floor covered in dust with a broken bit graemlins/angry.gif . I flipped out, came back that night with the truck and trailer loaded my box took it home, I think he got the point. Anyway that had nothing to do with the topic, just venting...Eric

Martin....all I can say is tongue.gif

Sevt......as you know I can relate......heh ever catch yourself sitting in the corner out of everyones view thinking of ways to get yourself fired? LMAO graemlins/clonk.gif in all reality the only reason I've stayed at this job as long as I have is because I like most of my co-workers....the job itself I've come to hate. It's gotten bad enough lately I have to force myself to do general maintenance on my own stuff...I used to love tinkering :(

Eduardo thats about the only things I can think of......lightly without stopping smile.gif

Peace

Originally posted by sevt_chevelle:
I Agree with you Martin 100% yes the job can be done without them but it sure does make life easier, especially when the guys care for the stuff also.

...Eric [/QB]Boy did that hit a nerve! That is ONE thing that will ruffle my feathers. And in fact it reminded me of a few tools I forgot to mention.

Prospot STRSW (Sqeeze Type Resistance Spot Welder)
Three dent pullers (I forget the name) you know the ones that use the stud gun technology. You "weld" the tip onto the panel and then using a leverage tool you pull the metal out where the tip is welded and then twist the tip to remove it from the panel.

three Miller 135 Mig welders.

The Prospot is a GREAT tool. One problem, the guys beat the living crap out of it. One guy will put it on "coated metal" and tear the tips all to hell twisting it back and fourth trying to rub the paint off under the tips to make contact for a weld.
Jeeeeeez, all you have to do is REMOVE THE PAINT off both sides and you don't have to do that. But all in all, the tools last as long as can be expected with so many guys using them so as much as we do.

heh ever catch yourself sitting in the corner out of everyones view thinking of ways to get yourself fired? Oh yeah its called 8-5 graemlins/sad.gif
I work in small shop WAS 4 guys, one(body tech) hurt his back and retired this may,the owner has had several operations from heart, back and knees in the past 2 years, which in turn keeps him home. So the work of 4 guys is now put on 2 guys, me and the owner's son, and its true when the cat is away the mice will play. He spends more time on the internet playing Texas Hold-em poker then time out in the shop, and whos arse is it when cars arnt done??

I keep telling him he needs to find someone you just cant run a shop with 2 guys. Am getting feed up with the never ending crap and pretty soon (new job or not) he'll be looking for 2 replacements instead of one :eek: Sorry to get off topic but I could go on and on about this friggin dump hole and how I look forward to the day I say "I quit" graemlins/hurray.gif graemlins/waving.gif