|02-16-2013 08:18 PM|
|ACEgeorgetown||Hey this is the first time using this, I have exactly the same story as the topic opener. The problem is the tack coat. If you do exactly the same thing again it will turn out the same way. It looks like dust in the clear. When it happened to me, I blocked it down the next day and put on two medium wet coats and it turned out perfect, nothing else was changed, temp, hose, gun nothing. I think it's because the clear is cheap, the reducer is cheap etc. This does not happen with expensive clear!|
|03-29-2005 10:22 PM|
Today I finished the bed..
Convinced that it was the deference in temperature between the room and metal, trapping solvents giving my the major solvent pop......
Today we had better wormer weather...I didn’t bother turning on the heater. The room temp along with everything in it was at a steady 65*
I skipped the sealer, and applied 6 light-medium coats of base, with a 45 minute wait between coats, and an hour and a half wait between the last base coat and clear.
The clear was mixed 4:1:1 and not wanted to take any chances, since I used the fish eye eliminator on the front end, I also added a couple drops of it for the bed. Laid down 2 medium-wet coats of clear, with a 15 min. “tack” time in between.
Everything else was done exactly the way the front end was done......I used the same gun, compressor, line, filters, paint products, types of mixing cups, stir sticks..........well you get the point.
It came out GREAT........nice gloss, no runs, and only the minimal of orange peel (like oem jobs) I will still be giving it a light cutting and buffing to match the front end.........which I start cutting tomorrow.....all day tomorrow
This was definitely a bad case of the “planets aligning just right” to give me a major case of solvent pop.
I want to thank everyone who responded to this post. All your comments and ideas were greatly appreciated.
I’ll try to get pics of the bed tomorrow.
|03-29-2005 08:25 PM|
Solvent pop VS Fisheye.
Most painters do not really know the difference between the two. Before you throw things at me read on.
If you paint for a big shop and the paint rep comes in from the factory not the jobber and you say I’m having a fisheye problem, even if he does know the difference do you really think he is going to say no that is solvent pop? If he does say that it now goes from user error to product problem and he does not need that hassle. Thats why you don't know!
First of all fisheyes rarely give you problems in spots, such as a 6” strip down the center of the hood or just the top of doors or fenders, fisheyes will consume the whole panel, so if the top of the door is fisheyes and center down is ok, its not fisheyes with rare exception.
First stage of a solvent pop.
Looks like dirt in hood and top surfaces of car the little speck can be black, white or gray depending how much water the iso took on. These are usually spaced at random so painter thinks it trash and no big deal.
These are caused by unsealed activator, water in line, watering down the booth floor and over atomization on a humid day.
That same speck of dirt with a ¼ moon fisheye coming off the speck of dirt. Same causes as above but more serious water problem.
These can be a full fledge the size of a bad fisheye but the speck of dirt will still be in center. Wetting floor on a rainy day and using a 1.3 tip?
Third type of solvent pop.
Is baby pinholes to full blown fisheye size. These are caused by trapped solvent in primer or sealer loading or solvent trapped in base is the most common and happens the most with black dark blues and dark reds or colors with poor hiding and 6 or more coats to cover. These can show up in clear on first coat as pinheads (gassing) or in the second coat as full blown fisheyes. 90 times out of 100 it happens on second coat of clear within minutes after you spray it.
A true fisheye will almost always go through the clear and leave a small center of the base exposed, solvent pop, there will always be clear covering the base in center.
ANYTIME you get what looks like fisheyes on second coat of clear its solvent pop.
Hope this helps, I keep it short as this is an hour subject to explain in class setting.
|03-28-2005 10:34 PM|
|p8nter||Ive been told by paint reps for years that fisheye killer was silicone and just having it in the shop could cause more fisheyes, like fighting fire with fire.Use it if you absolutely have to then get rid of it. And like baddbob said clean everything afterwords.|
|03-28-2005 10:22 PM|
With the limited information and without seeing the shop it is darn hard to say anything. Barry's info on solvent pop would cover that subject.
Let's go down with the most common.
1. Solvent pop (that is why I mentioned it) it can happen pretty soon. How soon did this occur? Hard to say, one mans "as soon as I applied the clear" is another mans ten or fifteen minutes later. It still could be solvent pop. Look close to see if there is a "volcano" look to the craters formed by the solvents rushing out of the "film" on the top of the clear.
2. Contaimination, DIRT, yep, "bondo" dust can look exactly the same as discribed. As soon as a nice coat is applied the top starts to "film" from the solvents evaporating. The tiny dust particle (too small to see without looking REAL close) falls on the "film" and sets there a while before it falls thru, wham, a "fish eye". These can be seen if you look real close. The spec is sometimes seen at the bottom of the crater. Plus, the top of the crater doesn't have the "volcano" look.
Any other contaiminant such as a wax or something, very unlikely. These flaws appear only on the top surface or mostly on the top surface.
If it was something in the line, water or whatever, it would be all over. This is one of the first misconceptions with "contaiminants". How in the heck could it be only in one area if it was "in the gun"?
3. Towels, again, nearly impossible being it is only in one place.
"When you hear hoof noises think Horse not Zebra".
Start at the most common (likely) and work down.
|03-28-2005 10:01 PM|
|baddbob||And throw that fisheye eliminator away, it will cause nothing but grief on future jobs. Just think about this, any overspray that ended up on the garage floor or anywhere else in the shop has the fisheye eliminator in it. This means every spec of it is now a possible contaminant for future jobs. You may actually need the eliminator again for spraying the bed unless you clean the garage very well so your air movement doesn't pick up any of the contaminated particles. I've never seen solvent popping that bad or had any happen that fast, but I have seen millions of fisheyes appear when spraying in contaminated air- start a diesel up near your air intake or if a squirt of armor all gets sprayed upstream and this kind of thing will happen instantaneously. I hope your next spray goes well.|
|03-28-2005 09:46 PM|
70-75 is a good temp. No reason to go much higher unless your just wanting to help the utility co. out Main thing is to have the metal STABILIZED at that temp.
70 is the "magic" number and any time your shooting below it those planets seen to have alot more alignment issues I've found.
I'd shoot the first coat "straight" and on a TEST PANEL
Just incase "Their Baaaack".
I really don't see the 10% helping that much outside of helping it to run easier.IMO.
Beds are a major PIA to shoot and runs are going to be high on your list of things to avoid.
One other thing. WHAT clear are you using??
IF it is the Nason Selectclear 497,
Better reread the mix ratio.
|03-28-2005 09:24 PM|
Just wanted to thank everyone for the great advice and impute
Convinced that it was a combination of low temp, and fast reducer trapping solvents giving me the worse case of solvent pop I’ve ever had
for the bed I’m going to get the temp as high as I can, which shouldn’t be too hard since we should be getting better weather in the next few days. Depending on how high I can get the temp, will determine whether I spray or skip the sealer. I will be laying down lighter coats of base with plenty of flash time in between. For the clear I will skip the tack coat and just lay down 2 medium coats, and 1 wet coat. Plus I will be reducing the clear 10% for better flow out.
Any other recommendations will be highly appreciated
I will have a 6 pack handy just in case
|03-28-2005 09:18 PM|
|p8nter||Its real hard to see from them pictures, but looking at how bad the top of the hoods looks, it sure seems more like contamination to me. How did the bottom of the doors look. If it was dry enuff to tape the two tone off with out the tape eating in to it or peeling it off, its usually good to go. Then again ,metal temp is pretty critical for most clears to kick properly. Im not familiar with nason brands, but most paint lines I have used do have special hardeners( Polar hardeners) for cold weather shops. Hopefully your bed goes better with warmer temps. If all else fails, sacrifice a six-pack to the paint gods and do alittle dance, sometimes that helps.|
|03-28-2005 09:06 PM|
I've used the "Select" in green /yellow can and it is a nice clear for the $$$ as in cheap. All though, It is a 3:1 mix,which is strange for a cheepie.
The 7500 Chroma series Dupont is a 4:1 and no reduction,Not sure on the 7800,Haven't tried it yet.
|03-28-2005 09:06 PM|
Let me throw this at you!
That Nason is less likely to cause a problem like this than say the good Dupont or Basf or PPG. The better the clear the more sensitive in a case like this.
Be happy thats what you used or you would be 320 and redoing.
|03-28-2005 09:02 PM|
The system being used is Dupont Nason with 4:1 clear.
And yes I know using 4:1 clear is just asking for problems, but I've used it befor with good results
Trust me, if it were up to me I would only use Dupont Chroma series or HOK all the way
But I gata make money, and it is the quick inexpensive jobs that are the most popular around here.
I give my "customers" the choice of what products to use, and always recommend the high end stuff, but all they see is the price deference.
But then again, like I said before........For being a low end product, I am very pleased with the results I have had with Nason in the past, and it is the only low end product I would use.
|03-28-2005 08:58 PM|
Switching to Med. temp red. will help but can give you the same problem all though no where near that bad.
Getting the metal temp up is crucial during this time of year.
That Purple/Flame hood I repaired pulled this on me with the first coat of clear,not as bad as your's but still sad using Med. red.,which I blamed on trash in the clear,there was some fine specks of dust in the cup floating around.I dumped the clear back into a clean cup and installed that little filter which goes between the cup and fluid body back into the gun,restrained clear and layed the second coat which layed fine.
Point being, The hood was still probly 55 or so at the first coat.Beings it was a 'glass hood and the heat running the whole time of the gun rework it had got up to a "shootable" temp and thus the real reason the second coat layed down I'm guessing.
The subsquent jr. dragster I shot was done around the same temp BUT, was kept in the shop at 60 and set to 70 in the morning and shot after lunch.
I had no problems what so ever laying the clear.
|03-28-2005 08:53 PM|
What clear did you use that required no reducer? I'm don't know much about other products except for PPG/Autocolor. I've demo'd others and don't remember not using reducer. I'm sure there are ones that don't require reducer I'm just checking.
What speed/temp of hardener did you use, too?
I think Barry has point is right on.
|03-28-2005 08:52 PM|
Because if you don't have a contaminate problem you will with everything if you keep using it.
So true if your painting in a garage at home (small area)
They also tend to work less than they do work.
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