I am a custom cabinetry and professional refinishing company.

I unfortunately don’t have the funds or the space to do an enclosed booth. I have tried everything I can to keep the dust particles out of the finish from blowing out the shop, letting it settle, coming back the next day to spray, turning on my booth During all of that, wiping the top down with NAPA after I scuff sand it with 400 and even 600. Then blow off the top. I get it to where it is smooth, but I can feel a little pricklies /hairs (maybe dust) but I can’t get it to go away to have a completely smooth and slick surface to apply my next coat with. I am using a 15 to 1 ratio Kremlin and spray acrylic urethane 2K solving based.

I have even tried a tack cloth as well, but nothing seems to get that fine prickly feel off.

I have even gone to the extent of making an enclosure out of two by fours and four mill plastic, along with furnace filters open up in both sides to allow airflow while the booth is on. I am using a magnetic dust door to be able to walk in and out. The problem is, I can’t turn on the booth and close the dust door completely at the same time. I also have a make up bar system, which works independently of the booth and that doesn’t help either but blow more air toward my enclosure.

The problem with having the booth on is it is sucking in so much air that the chemical coming out of the gun is hardly even touching the top surface before it is being whisk away into the booth. I have even tried turning off my booth and closing the magnetic dust doors to see if that would help and it does not. I have also wet down the floor and sprayed liquid fabric softener on the plastic, the floor and the surrounding areas and that still does not work either.

I am at a loss. 😢

What are you guys doing who have open booth to prevent the dust particles from being in the finish? I know it won’t be 100%, but it has to be better than when I’m getting

let me add, from the minute I pull the trigger, I could see the little particles in the finish. I have repeatedly cleaned out my gun and filters to the gun.

Sounds like you have too much fan for the booth size if it's taking the spray away before it can hit the surface. That seems to be causing 2 of your issues. Not letting the spray get to the surface and pulling in dust from the shop.

If you are using a 2K poly I would suggest using denatured alcohol instead of Naptha. DNA will evaporate much quicker and on top of it it'll reduce any static attraction the part may have to the dust.

Good luck.

Leo, thank you for the thought.

I sent a picture off to the manufacturers representative from ilva, along with a still picture of what looked like either dust or bubbles. His thought is that with the colder weather upon us, I need to be thinning out the product more than the normal 20% and also instead of using the normal thinner, use a slow thinner at 20%. He thinks the chemical is trying to dry too fast as it’s coming right out of the gun. I told him the bubbles are pretty much instantaneous as it comes right out of the gun

Take a look

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Leo, regarding the booth. That isn’t the issue, as I think the enclosure I made around the front of it is forcing too much air which is not allowing the chemical to hit the surface. This picture I posted was with the booth being turned off. Therefore there’s no airflow to affect it. I have the heat on in my shop about 68°

That's a lot of grunge in that one area. The other areas look better.

If you think it's bubbles maybe you are putting it on too thick? The only 2K I've used is MLC Polarion.

No. I hate polarian. I ALWAYS got lap marks, but as soon as i switched to ilva, no lap marks

The only thing I don't like about Polarion is the long open time. never had an issue with lap marks.

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Looks kind of like solvent pop. Have you tried using a slow reducer instead of medium? Maybe its a bit too hot. I know 2k can be tricky depending on sheen.

Tyler,

That is exactly what the manufacturers representative is suggesting

get a variable frequency for ur fan motor which will slow down the vacuum cleaner ur exhaust fan

secondly add more intake filters to ur booth, the more square footage of the intake filter the slower the air going into the booth will be.

good luck

herb j

Herb,

Ty for the suggestion

I don't think it's solvent pop, I think it's material contamination, most likely from your hose.!! To know for sure, spray your 2k through a very clean cup gun, with appropriate air cap and nozzle, with normal compressed air output and see if that solves the problem or not..!! If it does, then your culprit is a build up of fine 2k material/particles in your hose, get new hose and keep it clean, and you will be ok..!!

Funny you should say that, because I just ordered a brand new fluid hose and was debating on attaching it up. I also just sprayed a piece of wood using my pre-catalyzed lacquer to see if I don’t have similar issues and if so, then I will know it likely has something to do with the 2K product

I would still spray your 2k through a clean cup gun, to make absolutely sure, but glad you recognized that it was a good possibility that it was inner hose contamination...good luck
Chemmy..!!

Chemmy,

I changed out the hose and while it’s still visible here and there, it’s better.

I posed the question to the manufacturers representative, is it possible that I just did not sand the bumps down far enough, a.k.a. machine sand them with my Festool DA and it is telegraphing through. He said that is possible. I don’t have any refinishing jobs coming up, but I do have some built-in cabinets next and one of them is white paint, so it’s going to be interesting to see if it happens again

Hmmm..?? The fact that they are there to begin with, weather they were sanded absolutely flat or not, is the problem.!! But what I viewed was bump like resin snot, which to me was a dead give a way, that this was coming from the material itself.! Though I never had a problem with any 2k's I personally used, I have had other coatings like conversion garnishes that give me this type of problem, and even occasionally cat acrylics from one company in particular.! It happens when the fluid hoses are not thouruoghly cleaned, and I mean soaked overnight and then have have fresh clean appropriate solvents that will for sure dissolve the coatings that were used in the hose's..... I was using 2-5-20 gal pressure pots from devilbiss at those points in time, and made sure, after the fact to have at least two extra fluid hoses perfectly clean by using a long 25' super stiff base brush to make damn sure there was no build up of any kind left in the hose interior.!!
That said...I hope everything turns out all right after all the time u wasted trying to figure this out, and continued good results when it has been resolved.!!
Chemmy

Funny you should say that, because I just ordered a brand new fluid hose and was debating on attaching it up. I also just sprayed a piece of wood using my pre-catalyzed lacquer to see if I don’t have similar issues and if so, then I will know it likely has something to do with the 2K product

Chemmy,

What is this base brush you talk about that will allow me to clean out the hose thoroughly? How much acetone do you typically run through a 25 foot hose and do you recirculate it or do you just waste it out? I tend to fill up a 1 gallon empty container with acetone and flush it and recirculate it but it’s always possible there is some finish residue in that acetone. I shoot out the main line with as much acetone as possible into another bucket and then start the acetone flush until I see the acetone coming out and then I recirculated into the actual bucket of acetone in the gallon container. Maybe I’m doing it wrong?

The brush is something I bought over 3 decades ago from a company in Florida, where I was working at that time. It was a wooden circular brush that had very stiff natural bristles, I drilled a hole in the center of it and attached a long wire to it so that I could pull the brush through, which would scour the hose interior.
Whether they are still in business or not I have no clue. But if you Google natural bristle round brushes you might find something of the same Ilk.
As to using a solvent for 2k, for cleaning, you need something much more potent than Acetone, you need MEK, (methyl Ethyl Keytone,) and in some cases Methaline chloride and methyl alcohol to remove residue or deposits like or from 2k's or epoxies.The spent solvents can be be strained with ultra fine paint s trainers from any auto paint supply store in your vicinity or online. It will also allow you to see any and all gunk that was in your hose. The filtered solvent can then be saved for future cleaning in cans, etc.
Note: if you have been using the same hose for both cat lacquer "and" 2k, this is most likely where the problem has stemmed from..!! Do yourself a favor and switch hoses when your switching coating material types..ok.???
Chemmy

Hi Mike, I use a 2K poly urethane From Woodwright 6701 For primer and 6700 topcoat and 2800 hardener I have about 9 months of experience in it with close to 500 gallons of it spayed and we spray vertically on a Guffey rail system and I do have an enclosed car spray booth, but I also started in an open area using a kremlin pump always having to mix the 2k and noticed that some of our issues where among pump settings, being consistent and prep, blowing our stuff off wiping it down and then blowing it off again waiting like 10 minutes to let the dust settle gave us really good results, we had a fan blow it all outside didn't have a filter on it but the fan was about 10ft from where we would spray. We don't use cup guns and we don't mix the 2k anymore because of the hassle it gave us we upgraded to a kremlin pump that mixes it for us as we go so we have very little waste, for a cleaning solution we use methyl ethyl ketone which is amazing it's a little toxic but very effective on getting the stuff nice and clean compared to alternatives it destroys the 2k so I don't recommend getting on your finished . if you use a pump with an air and fluid regulator on it, I recommend using 50 psi for fluid and 20 psi for air it gives us the best quality spray, you have to move a little fast, but it gets the job done. For sanding before priming, we go about 180 with and orbital and a jitter bug sander, and after priming we use a jitter bug sander and for grits, we use 220 or 240 paper 3x4 from Surfprep and a 240-320 sanding pad from either Surfprep or Sia abrasives. if you have any questions i would be more than willing to help with what I can.

Riely,

I did some tests and what I mean by that is, I sprayed the 2K solvent based urethane out of my PPS cup gun and ended up with the same crap happening in the finish. It appears as though it is probably bubbles, but I don’t know how to get rid of it.

Alternatively, I sprayed out a big piece of walnut and MDF and a raw piece of MDF using pre-capitalized lacquer and ended up with 100% better results. In my opinion it’s the chemical that is the problem, but my supplier has a professional finisher that has been added for many many years who is going to come by my shop this Monday to find out what the problem is. He’s also going to bring a microscope to see what exactly is going on as well.

I have to have this job delivered back to the customer in two weeks and time is of the essence

I wish you the best of luck with it. I hope the problem is easy to overcome and want to wish you a merry Christmas I will come back and see if the problem was fixed so keep us posted.

When using the Kremlin do you have a tip screen in your gun? The little Oring with a screen in it that fits into your tip. I have the gun screen which is at the entry to the bottom of the gun on top of the tip screen that will take out any crap that makes it past the hose screen.

Tip Screens