Hi, wondering if anyone has used Milesi waterbourne finishes. I'm currently using their two component product with a Sata RP 5000, 2.0 tip, and just cannot get the product to flow well. I tried thinning, 5% and 10% and at 10% I had good results with the material laying down, but any time that I thin the product I get small pin holes all over my work piece.

Also, I have to be super close with very tight overlaps to get my material on the piece to flow out right. I feel like I'm using a detail sprayer.

Any help would be appreciated.

Can you give more details on which product, and what you are spraying it on?

They have waterborne products that range from very thin to very thick.

Hard to help without more.

Also would be helpful to know what temperature and humidity are where you are.

I'm using their 2K topcoat, paint. I'm spraying this in a 400 SF shop, humidity is low right now, temp around 70. Everything has been primed with their universal primer. I'm spraying maple and MDF plywood.

Most of the Milesi pigmented water base products require a 2.5 tip for best results. The larger tip reduces the need for over-reduction.
Try to limit your reduction to 5%.
Goes on like pudding, dries like glass.

ronb

Tim,
If this is the HGA11-15 series, then.

A. they make a thinner (LZC97) that you could try.
You can't thin it more than 7% or it will have severe effects on the finish.

Thinning is done as a percent of *weight* of part A.

So if you are thinning based on mixed result volume or something, you are going to severely over-thin it.

B. LTC 5, which should improve flow-out, is also fairly available.

(It can only be used with the water based urethanes, not the solvent ones)

LTC 40 should be similarly available.

(You'd need to call them and ask them which they recommend here)

C. It is meant to be sprayed pretty thick - 4-5 mils. It is also fairly viscosity wise thick.

You probably need a 2.2 tip or to be using a AAA

If you are using the HKA114 or the HKR114 Milesi recommends a 2.1 to 2.5 tip. Max 5% reduction.

The HGA series is a clear topcoat and is not really intended to be tinted.

Ask your distributor for a copy of the Milesi Product Application Guide. A good read... I wrote it.

Thanks guys for the input. I'll give the larger tip a try and see what kind of results I get.

When I thinned it, I only thinned it on part A. When you used a larger tip, just curious, what did you have your air pressure set at?

When I spoke with my rep, they suggested 22 PSI. I did that, I was able to get good results at times, but I felt like the high air pressure was almost drying the material.

With a 2.5 tip I typically used 25 - 30 psi, but it really varies according to how high you hold the gun and how fast you move it. At this size you are capable of moving a lot of fluid thru the tip so you need a little extra air to increase atomization.

When I worked for Milesi I sprayed their water base products in literally hundreds of different shops all across North America and they were very forgiving. Followed the basic rules and the results were always the same...impressive.

ronb

Note that being water based, temperature has a big effect on the viscosity here, especially towards the lower temps

I pulled out my certified ford 4 cup and the difference in material viscosity between 68 and 78 degrees temp is ~20%.

(which is amore than the viscosity difference for water at those temps)

Of course, it will also decrease pot life (but you can spray wet on wet so ...).

I spoke with a technical guy at Milesi. One of the issues it seems that I am having is my rep recommended a universal primer for the two component top coat. He let me know, I really should be using a two component primer as well. With my initial topcoat over primer, it is so porous, it forces the paint to dry very quickly, so you will undoubtedly need to add another topcoat. The second topcoat flows out much better. He also said that the HB1 catalyst is an extremely reactive catalyst, and needs to be added a little at a time when mixing into the paint, bc you can shock the product. I made that change, but didn't feel that it made a significant difference.

Ultimately, I was able to get good results on my smaller parts. One piece, a 5' wide x 5' tall x 13" deep locker, I took to my finisher (been in bus for 40 years) and he sprayed with his airless bc it was impossible to do with a cup gun. Ultimately, he felt that this piece was impossible to spray with this product. I've had great results spraying pieces like this with Milesi's single component top coat and conversion varnish as well, but I agree, I don't see how its possible to spray a piece like this with the two component. It dries too fast, by the time you get to the end, the product is dry and the overspray is all over the piece. I'm gonna end up rebuilding this section of my project bc it now has 6 coats of paint on it.

I'd be curious to know if anyone would ever consider spraying a piece this large with Milesi 2 component paint. I attached a picture of my design.

View higher quality, full size image (1540 X 1520)

FWIW: I have sprayed (with HGA19) and rolled (with HSA6A457) objects larger and more complex than that with 2k Milesi stuff with no issue.

The HGA19 uses the HNB1 catalyst.

I have used their pigmented topcoats (HKR*) but not on objects that large. On smaller ones, drying speed has never given me any issue.

I normally use a pressure pot with a CAT H2O-CPR gun doing the above, but i'll pull out the merkur es when i spray very large flat objects, mainly just to get it done faster.

The only thing i'll note is that I use a precision scale to do the catalyst measurement, because it's very easy to overcatalyze it.

Given what you are saying about dry time, that's really the only thing i can think of that is different. I have the same temperature/humidity you are suggesting.

Note that if you can get it, they have a catalyst for HKR* that is unlimited pot life (HNB11).

HKR* can also be sprayed mono-component. You won't get the same chemical or physical resistance, but the datasheet specifically okays doing this.

That may be useful for you to track down what is going on here.

For any if the two component euro WB coatings you can get better results going to a diaphragm pump. I run Titan 655 sprayers now after years of AAA and they lay it out perfectly. No microshear. Around 700 dollars

If you do high volume then look at the Wagner Cobra. 40:1 pump. Pricy.

I am new to spraying Milesi Waterbourne. I am using a 2.5 tip at 25 psi. I thin the product 5% add 10% hardner and 3% retarder. I am having problems with the product drying in the gun while spraying and also drying on the material quickly. The shop has hvac set at 76 degrees. Any suggestions of what I am doing wrong will be helpful.