First experiments with HVLP (Fuji MM4, BM Advance)

[Tim Booher]

After taking some advice here, I found that I love the MM4.

I've learned some things and have a question.

First, I've made a spraybooth in the garage -- spraying outside was a mistake. It was easy for dirt to get on my workpiece and things dried too fast in the sun. Second, I was super glad I bought the whip hose and also a remote to start/stop the machine. That has been great. I've had to dilute the advance to about 15% to get the 30 second run rate from my #4 ford cup recommended by Fuji for the 1.5mm head.

Questions:
1. Cleaning -- I am obsessive about cleaning right after spraying. Every time I fully disassemble the gun. I'm curious about how much I could wait -- could I leave the advance in the MM4 cup and clean later? Could I just run water through the cup and then do a full cleaning the next day? How much does waterborne vs oil-based matter?
2. Final finish. After spraying the advance, it didn't match the sheen of the factory finish on the cabinets I got. I'm thinking about general finishes topcoat to get a bit more of the sheen of the factory finish. I also ordered EMTECH HSF5000 WB Primer/Surfacer/Filler and EMTECH EM6500 (custom tint). I am hoping that might work better.
3. Primer -- I used BIN which I found I could easily spray and sand (using LVLP gun) I didn't want to use BIN in my Fuji gun. But the local BM dealer recommended Zinsser Oderless primer, which I will try on on my next piece, does this make sense?

[Jim Becker]

1) I don't leave finish in my gun overnight, but I'll keep it in there all day long when I'm spraying multiple coats on one or more projects. (I only use waterborne products, primarily Target Coatings) For any non-bleeder setup, the gun is "sealed" when the trigger isn't depressed. So the finish will be fine unless there's an additive being used that has a "use by" time that's short. Just clean off anything around the nozzle before you start your next coat. Be careful about thinning...10-15% is the max you can do with a waterborne finish. Better to switch to a larger N/N if necessary to accommodate the viscosity.

2) Was it too glossy or too flat? Most common is the former because of flatting agents not getting fully mixed into the product prior to application. They tend to settle in the container. But sheen is also subjective and one manufacturer's "satin" may be very different than another manufacturer's "satin". That, combined with using a finish that's not the same as a factory finish means you may need to tweak it. If you want to try topcoating tha Advance, you really need to let it fully cure for a long time first. Advance is an alkyd product emulsified in a water carrier, unlike most waterborne products which are acrylics. You can use the HSF5000 primer under the Advance, under Target Coatings products and even under General Finishes Milk Paint. (which isn't "milk paint"...it's an acrylic in traditional milk paint colors) Do note that it's a thicker product, so again, you may need a larger N/N to spray it acceptably. Even with my pressure assisted gun, HSF5000 is better served by my 1.8mm N/N (my largest). The tinted EM6500 is also thicker consistency, so be prepared for it.

3) I already mentioned that you can use the HFS5000 for a primer. Target's EM1000 is great, too...clear with some nice fill and sanding properties. I use a it a lot now with my guitar building thing because it's also an excellent clear for tinting to do things like transparent color bursts before layering clear coats on top.

BTW, for buying Target's products, be sure to get on their mailing list so you get the discount codes...they save typically 20% and sometimes 25% on your order.

[John TenEyck]

You can buy flatters for WB products from Hood Finishing for not much money; like $30 for a gallon, and that will last a really, really, long time. I find many products end up more glossy than advertised, hence the need to add flatters.

John

[Jim Becker]

I find many products end up more glossy than advertised

Come to think of that, I've noticed that too.

[Bernie Kopfer]

I have the Fugi 4 also and spray BM Advance thru it regularly. Other than having to overthin I am satisfied with the results that I get. And my favorite primer is BIN. As far as cleaning goes the only thing that counts is the inside of the gun. As long as nothing accumulates there you are fine. Alcohol water and ammonia are cheap and when used in quantity the inside of the gun is Clean.
I’m with Jim I don’t leave paint in the gun overnight. But I’ve never tried so that is strictly a abundance of caution statement, but I have just run some water thru 5he gun until it spayed quite clear and left it for the night. Curses on the long redcoat time required for Advance.

[Tim Booher]

Bernie -- how much do you water down the advance and what tip do you use? What runout time do you hit on the #4 ford cup?

[Bernie Kopfer]

Bernie -- how much do you water down the advance and what tip do you use? What runout time do you hit on the #4 ford cup?

I thin it down until I get 45 sec thru the cup. Tip size would require me to dismantle the shop to get to the unit. But I think it’s the 1.0

[Tim Booher]

Great. Thanks

I thin it down until I get 45 sec thru the cup. Tip size would require me to dismantle the shop to get to the unit. But I think it’s the 1.0

[Jim Becker]

What you have to be careful of is when you thin beyond a certain point, quality of the finish with a waterborne can suffer. The reason for that is that water is the carrier, not the solvent. So you have a coalescing finish with its molecules suspended in water. "Out of the can" there is a certain density of those molecules per some volume of finish. When you add water to decrease viscosity, you are putting more space between the molecules so when you spray the finish, there's more water and less finish hitting the project in a given interval of time. The manufacturers pretty much all agree that minor thinning is fine. Most specify 5-10% is permissible. So when you go beyond that with thinning a waterborne finish, your risk of a poor finish increases. BM Advance also adds the element that it's an alkyd finish emulsified into a water carrier rather than the typical acrylic. That may or may not be meaningful in how it cures...I don't know.

So the best practice is always going to be to use the N/N that's best suited to the finish you are using with the particular gun you are going to apply the finish with. There are a lot of balls in the air here! I actually just moved to a smaller N/N setup on my particular gun for EM6000 and am getting even better results. My previous gun would not have tolerated that.