Speckles in paint. How do I determine what is wrong?

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danford1

I'm painting a piano and I'm using Black PPG DCC solid urethane. I'm mixing it 4-2-1 with 885 reducer and dcx61 hardener as per instructions. The garage is at 70-72 and has been for the past week. I don't think the 885 reducer would be an issue in 70 degrees but want to mention all I know to make replies easier. I'm spraying it over SPI epoxy that is 5-7 days old. I have a separate thread going on that. All is fine with the primer :)
I'm getting thousands of tiny specs in the finish. They appear as soon as sprayed like they were mixed in with the paint. OR it is like I took a salt shaker and thoroughly salted the fresh paint. There are too many of them to be dust on the piece before painted. Plus they are consistent all over the pieces not just in isolated areas.
I cleaned the wet sanded SPI epoxy primer with SPI water bourne W&G remover, wiped it dry, then let it air dry another 1/2 hour before spraying top coat.
I have a refrigerated air dryer also. Now, the compressor and dryer are in another area of the garage that is maybe 20 degrees cooler than where I'm painting? Could that be the problem?
I'm painting in a garage as I have been doing for many years. Since I'm in a garage I get dust and grit in the finish but this is WAY more excessive than normal.
Here are a couple pictures. One is further away and you can see the specs in the reflections of the florescent lights. It looks local in that picture, but it isn't. It is all over the piece. The other picture is with a flash up closer and it illuminates the specs pretty good. They look white in the picture but in reality aren't white. They appear black.
What could cause this?
Thanks.
Danford1 specs.jpg

DSCI2345-2.jpg
 
Wow. Looks like it has died also. The doctors at SPI need to diagnose this.....
It could be a moisture issue along with other things IMHO.
My first questions are what was the surface temp when you started and what were your flash times.
 
Only thing I can think of is I've seen that happen a couple of times with bad or stale hardener. If it was a full fresh can that would surprise me though.
 
The hardener is seeding or pigments are failing to stay dispersed in the paint. Is is hardening normally? You might just sand it and clear it, if the specks are not a different color when sanded.
 
crashtech;24853 said:
The hardener is seeding or pigments are failing to stay dispersed in the paint. Is is hardening normally? You might just sand it and clear it, if the specks are not a different color when sanded.
Click to expand...

Ok, Thanks for the replies. Sorry I didn't respond quick, I've been painting :)
Of course that means I spent 6 hours sanding and 15 minutes spraying paint.

The paint is drying and hardening just fine.

The paint came out very black, the pictures above make it look cloudy because of the flash on the camera. It is pitch black.

The surface temp has to be 70 degrees or dam close. It has been 70-72 degrees in the garage for over a week now.
I have a digital temp infra red gun but it is in the trunk of the car I lent to my brother for a week or so. I'll probably have the piano done by the time I get the temp gun...

The specs looked like and sanded out like normal dust. That got me thinking................ what did I do different this time?
I came up with what I didn't do and usually do, do. I didn't spray the floor done with water. So, tonight before I pulled the trigger I wet the floor and walls (plastic hanging from ceiling) down good with water. I sprayed a lot of paint today and it all looks fine so far. I'm waiting for the first coat to flash 45 minutes to an hour before I squirt on another coat.
What I could see through the fog looked promising. Super shiny and extremely smooth paint.

I was concerned about the air compressor and refrigerated dryer being in a cooler part of the garage. It isn't very humid this time of year so I turned off the receiver dryer hoping it wouldn't be cooling the air down to much. I don't know if the cooler air caused my speckles yesterday but today they don't appear to be present. It is also at least 10 degrees warmer today in the other part of the garage where the air comes from.
Could cooler air to the gun cause a paint spray issue? I can't be the only one around using air cooler than the "paint booth".

I'll update this thread with more info tomorrow when I can see what the dried paint looks like. Maybe even post a picture or two :)
Danford1
 
Cooler air could if the humidity was right.
Especially with the 61 activator.

My thoughts were, moisture from line or wetting the floor but sounds like may have been from line.
 
Barry;24874 said:
Cooler air could if the humidity was right.
Especially with the 61 activator.

My thoughts were, moisture from line or wetting the floor but sounds like may have been from line.
Click to expand...

With the 61 activator, what temp range and humidity level should I avoid?
Yesterday when I wet the floor and the paint looked good, it was pretty humid in there, probably 85%. How much is too much? The humidity where the air compressor is wasn't as high, maybe 65-70%.
I read somewhere awhile back that urethane Likes humidity. Did I read wrong?
Danford1
 
danford1;24880 said:
With the 61 activator, what temp range and humidity level should I avoid?
Yesterday when I wet the floor and the paint looked good, it was pretty humid in there, probably 85%. How much is too much? The humidity where the air compressor is wasn't as high, maybe 65-70%.
I read somewhere awhile back that urethane Likes humidity. Did I read wrong?
Danford1
Click to expand...

I don't know the range and air temp also plays into it, so could be 90 with 98% humidity and work great or could be 85% and 65 degrees and it blow up, I just can't say. the DAu5 if they still make it was the answer years ago to this problem but I just don't know the product well enough in last 10 years to say.

Yes urethanes like humidity but there is a fine line and like I said temp, gun and solids all play a part.

Easy way to understand is the tin force mates the moisture and air with the iso to make it kick, so if over done that is when a lot of problems can arise, the same as over accelerating a product as that is usually tin. Another reason, allover clears are slower then spot repairs clears.
 
All is well with the piano project. It came out very nice.
I didn't use any clears, this is all solid DCC SS urethane.
The customer seems happy as well which is paramount.
Whatever problems I previously had with speckles were resolved with wetting the floor and walls before painting. I had minimal debris in the final coats of paint. It all sanded and rubbed out well.
Here are a couple photos of it.
Danford1

DSCI2404.jpg

DSCI2392.jpg
 
That speckle condition was weird, you used the same hardener and wetting the floors and walls stopped it?
Glad it worked out, the results look outstanding.
 
Yes, I used the same hardener etc. The speckles just HAD to be excessive dust in the air. No other explanation.
Wetting the floor and walls held dust down and the top coats looked fine.
Live and learn... I'll make sure I don't overlook that small detail in the future.
Danford1
 
A mirror shine and quality products, it should last a lifetime! Wood is funny though-always unstable if the humidity changes so hopefully the owner keeps it in a good environment.
 
Barry;24881 said:
I don't know the range and air temp also plays into it, so could be 90 with 98% humidity and work great or could be 85% and 65 degrees and it blow up, I just can't say. the DAu5 if they still make it was the answer years ago to this problem but I just don't know the product well enough in last 10 years to say.

Yes urethanes like humidity but there is a fine line and like I said temp, gun and solids all play a part.

Easy way to understand is the tin force mates the moisture and air with the iso to make it kick, so if over done that is when a lot of problems can arise, the same as over accelerating a product as that is usually tin. Another reason, allover clears are slower then spot repairs clears.
Click to expand...
Barry just sayin the DAU5 has been moved to the omni or shopline product. Can't remember which line or number. A good knowledgeable jobber can tell ya right off...
I still have some Porsche Red Starthane and my local gave me the info on the move.
BTW looks good Dan!
 
Bondoskimmer;25133 said:
Barry just sayin the DAU5 has been moved to the omni or shopline product. Can't remember which line or number. A good knowledgeable jobber can tell ya right off...
I still have some Porsche Red Starthane and my local gave me the info on the move.
BTW looks good Dan!
Click to expand...


Thanks for the info on the 5, now i know to keep my mouth shut!

The old Starthane was some pretty good stuff, would not waste it if you can use it somewhere.
 
Bob Hollinshead;25125 said:
A mirror shine and quality products, it should last a lifetime! Wood is funny though-always unstable if the humidity changes so hopefully the owner keeps it in a good environment.
Click to expand...

The piano will be kept in a good environment inside a nice home :)
Danford1
 
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