Spray Help Needed!

[Ed Gibbons]

Using my earlex spraying Target’s em8000, finish looks “bumpy.” I did not put too much down. I’m hoping as it dries it will self-level. Any advice would be appreciated.

[Prashun Patel]

Can you post a picture?

Don’t fear. It will level.

[Ed Gibbons]

Looks like it leveled. Phew!

473810

[Ed Gibbons]

Prashun,
This will be used for a heavily used tabletop. I did add the crosslink. How many coats would you suggest?

Thanks,
Ed

[Prashun Patel]

That looks great!

I usually do about 3. The key to durability is letting it cure for a long time. Just be gentle with plates and standing objects for a week. Be diligent about spills for a month. Try to always be diligent with hot objects. You prob already know all that...

Isn't it cool how hard it is to mess up?

[Ed Gibbons]

Prashun,
Ten years ago my daughter bought a nice oak table. The top was veneer oak ply. I didn’t have the heart to tell her that the beautiful kitchen table would not stand the test of time. 3 kids, and literally thousands of meals later, I knew it was time for me to come to the rescue. New top is solid 1/4 sawn oak with what I hope to be an almost bullet proof finish. Good advice on how to protect it. I’m going to let it sit for a month before I attach it.

After the second coat, I can see minor “alligatoring”. I put more finish down this time. Should my final coat be very light?

[John TenEyck]

If by "alligatoring" you mean orange peel, then you sprayed too heavily with the gun settings you had. You could either spray thinner coats, turn up the air pressure, if that's an option, or add some Extender. If you are using a turbine unit, adding Extender is almost always a good idea.

It's best to follow TC's guidance on coating thickness and number of coats. Most importantly, never exceed the maximum dry film thickness on the Tech Data Sheet.

John

[Ed Gibbons]

John,
If I scuff up top with 400 grit, and put down a couple of light coats, will the orange peel disappear? I’m hoping I don’t need to sand to bare wood and start over.

Ed

[Prashun Patel]

The second coat can do that. Does the surface look crackly? Did it happen immediately and then get worse?

If it is indeed orange peel, I would let it dry well for a good day and see if it levels.

Either way you may be in for some level sanding.

[Ed Gibbons]

The finish never went on smooth. I’m going to wait a day, then sand. I will try a much thinner coat.

[Prashun Patel]

How long did you wait between coats and did you do anything to the surface before putting on the 2nd coat? Last, was the 2nd coat thicker than the first?

[Ed Gibbons]

How long did you wait between coats and did you do anything to the surface before putting on the 2nd coat? Last, was the 2nd coat thicker than the first?

Waited 2.5 hours. Scuffed surface with 320 grit. Second coat was heavier than first.

[John TenEyck]

Oh, I hadn't considered that the finish might have cracked, as Prashun suggested. In any case, whether alligatored or orange peel, you need to sand back to a flat surface before spraying a new coat.

John

[Jim Becker]

Based on the description, I'd be concerned that the gun setup may not be ideal for the viscosity of the finish. Did you spray test pieces before going to the real project? (all the steps) That's something that's a really good idea when working with a new product and/or tool just to be sure proper atomization and fan pattern is being achieved. I've avoided that a few times myself and, um...paid the price.

[Ed Gibbons]

Based on the description, I'd be concerned that the gun setup may not be ideal for the viscosity of the finish. Did you spray test pieces before going to the real project? (all the steps) That's something that's a really good idea when working with a new product and/or tool just to be sure proper atomization and fan pattern is being achieved. I've avoided that a few times myself and, um...paid the price.

I did a small test piece. I’m beginning to think my earlex can’t handle this finish. I will try a light coat tomorrow. If it doesn’t work out, back to my sander.

[Prashun Patel]

I doubt it’s your gun. I had once the second coat craze up within minutes of application. I scraped it off, let it dry, then went on with the product and it worked.

[Warren Lake]

what the temp of the room when you are spraying
what are the working temps of the material, there is a range
do you have the P sheet on the material
whats the temp of the coating you are spraying
whats the temp of the top you are spraying
what is the viscosity of what you are spraying, furniture factories use a viscosity meter and adjust the time so its the same all the time and they get the same results, they dont gamble when doing volume
do you you have the right needle nozzle combo for that material, Too big is better than too small,
what is your pressure
how open is the gun, full or turned in some amount, what is your fan set to,
did you spray a test pattern
what is your air flow are you pulling air in to the room when you spray, if you are pulling warmer air it may not level or you might get solvent pop, I see non of that there,

I dont know that finish or your spray gun but you have peel there. The parameters above all affect your finish plus whatever didnt come to mind. Then if you have that together Murphy will participate and you will find a beard hair in the finish or water might drip from your spray mask. You would think with covid and all going on the in the world he find a new occupation.

If you have a soft block and sand it with that you might not level that peel. Pay attention the grit and type of block you use.

[Ed Gibbons]

Update

I did a lot of sanding to smooth out the orange peel. Grit sequence was 180, 220, 320. 000 steel wool, 1000. Followed up with 3 very light coats about 1.5 hours apart. Came out nice. This was the first time I sprayed a large flat surface (60” by 36”). That was part of my issue, learning how to spray on a surface that large. This time I also held the spray gun closer to the surface with the nozzle pointed directly at the surface.

Thanks everyone for the help and encouragement.

[Prashun Patel]

Ok, so it indeed WAS orange peel. Because if it was crazing or alligatoring, the finish would have been crackly and wouldn't have bonded well with the first coat; it would scratch off messily when sanded.

Sounds like your issue was just too thick a coat. The Earlex and the HF/Rockler/Woodcraft HVLPs are tricky because you can't really throttle back the air. This makes balancing the flow and the speed of movement a little tricky.

In the interest of diagnosis: did you by any chance go over the finish a couple times on the 'bad' coat? In your room, is the air flow high? Was the temperature of the room or the finish kind of low? These things can impede the flowing out of the material.

[Ed Gibbons]

Did not go over bad finish. Shop is in basement and I’m guessing temperature is approximately 65. Not much air moving. I think I may upgrade my sprayer. Any recommendations on that would be appreciated.

[John TenEyck]

Did not go over bad finish. Shop is in basement and I’m guessing temperature is approximately 65. Not much air moving. I think I may upgrade my sprayer. Any recommendations on that would be appreciated.

EM-8000CV should spray fine through an Earlex with a 1.3 - 1.5 mm N/N set. It's viscosity is pretty low at about 35 seconds in a Zahn #2 cup which is just about the same in a Ford #4 cup, and that's low compared to many WB finishes. I really doubt you need a new/better gun to spray that stuff well. What you need is good technique, which only comes with experience, and maybe to add some Extender because turbines produce hot air and that often causes problems with finishes setting up before they have a chance to flow out.

On large surfaces it's important to spray from end to end, overlap your passes about 50%, and work from front to back, towards the exhaust fan. The gun should be close to 90 deg to the surface. I set the fan wide open on my gun, almost always, and hold it 8 - 10" from the surface. Lighting is critical to success. If you can't see the wet line you are doomed. If you don't have a wet mil gauge spend the $3 or 4 and get one and use it until you know what 3 - 5 mils looks like.

John

[Warren Lake]

sometimes hard to tell from photos but the peel showed in that photo. Id have to question your sanding process. Why so many grits? Normally depending on the finish its one grit and whatever 280 - 320. Id normally sand once with 320 before a second clear coat on a pre or post cat. If it was a really hard coat and heavy peel maybe drop down a grit. Why the steel wool? and 1000 grit? Sometimes steel wool can leave shards and you have a pretty open pore wood. Most finishes want tooth and need sand scratch there. Thinking back to Nitro when the next coat burned into the one below. The good old days :)

[Ed Gibbons]

sometimes hard to tell from photos but the peel showed in that photo. Id have to question your sanding process. Why so many grits? Normally depending on the finish its one grit and whatever 280 - 320. Id normally sand once with 320 before a second clear coat on a pre or post cat. If it was a really hard coat and heavy peel maybe drop down a grit. Why the steel wool? and 1000 grit? Sometimes steel wool can leave shards and you have a pretty open pore wood. Most finishes want tooth and need sand scratch there. Thinking back to Nitro when the next coat burned into the one below. The good old days :)

Definitely overkill on the grit sequence. I wanted to take off as much of the finish as I could without scratching the wood. Definitely the lower grits took off more but the higher grits appeared to help. Bottom line I need to improve my spraying technique and not rely on post spraying sanding.

[Warren Lake]

not just overkill might work against you. I would look at the sheets for that finish.