HVLP sprayers.

[Sawblade]

I would be very interested in hearing more about the filtration system, and the air control valve vs. varying the speed of the fan (as in the Turbinaire system).

Thanks,

Sawblade

[Mike Marlow]

I'll echo a "me too". I really don't know diddly about turbine systems, so anything that came out of this discussion would be interesting to me.

[Paul Smith]

Hi,

I replied to 'Sawblade' (good name!) by e-mail but it seems others are interested. So here is what I e-mailed to Sawblade.

1A) The filtration system. In the Wood Magazine article, they gave us a B- because of the filter system. They said in a box to the right of the ratings that the filter was difficult to replace because it was inside the case. The filter is not inside the case - it only looks like it is to the uninformed. If the author had raised up the case to look underneath he would have seen that the filter enclosure is completely open from below. You can remove the filter in 2 - 3 seconds - it simply slides out.

It takes a bit longer to replace it because you have to ensure that it fills the whole enclosure - about 10 seconds maximum.

So we really should have received an A rating on the filter but the author misunderstood the facts.

1B) I don't know if the author was marking us on this or not but we use a combination, much thicker fine filter on our Q-Series but 2 filters (they call them dual in the article which is a misnomer) on our less expensive systems.

The combination filter is superior because it allows you to use a thicker filter. That is because the 3 or 4 fans (5.7" diameter) pull in a lot of air into the case. It is inside the case that this air divides up into the air for the cooling fan and the air to the much larger 3 or 4 fans. Usually, the cooling fan has its own separate filter and this restricts air being sucked in. There is absolutely no restriction to the cooling fan with the combination filter, so it is better for supplying more air to the cooling fan.

To avoid restricting the air to the cooling fan, we have to use a coarser filter on our less expensive units. Once again, this is not necessary with a combination filter.

2) The reason you would want to turn down the turbine or psi/cfm is so that you can spray with less pressure. Doing this would allow you to spray with less overspray and bounceback.

If this control is at the turbine and knowing that the turbine should be placed at least 20ft away from the spray area, it means that you would have to walk 40ft to make the change to psi/cfm. Plus, if you didn't adjust it enough, or you went too far, you would have to make the same walk again.

So it's really not practical to have the control 20ft away when you can have it right at the gun for tweaking anytime you want to.The author did mention this and got it right.

3) Although you didn't ask, we (fujispray) were a little perturbed by the fact that with our total ratings being A x 8 and B- x 2 we were not rated a 'Top Tool'. And yet, with 6 x A, 3 x B- and 1 x C- Turbinaire was. When I was in school, if the kid next to you got marks like this, he was placed somewhere down the list behind you.

Oh well, the world is not perfect.

Regards to all,

Paul Smith Fuji Spray

[Sawblade]

Paul,

Thanks for the rapid follow up. I was at the Woodshow in Houston this weekend, and the Turbinaire guy was really touting the benefit of reducing the speed of the turbine instead of just putting a valve in the line. Since you guys chose the valve, I am sure you have studied the pros and cons beyond just the walk to the turbine and I was wondering if there is a tradeoff here. It seems that running the turbine full blast all the time would be worse for it than slowing it down to only produce the pressure necessary for the task at hand. Also is the control that you guys use a valve or a regulator? I know it should not be this hard, but the learning curve is pretty steep at least in the beginning.

Thanks,

Sawblade

[JGS]

[Paul Smith]

Hi Sawblade,

The motors used in all the turbines are not specifically made for HVLP. They are common vacuum bypass motors of the type that you may have in your basement (with hoses you attach to different locations in the house).

When you place a regular vacuum cleaner tight on the floor, you are restricting the air passing through and this causes the vacuum motor to speed up a little and you can even hear the change in pitch. These motors are designed to take that pressure change with no problems whatsoever.

About 10 years ago we spent a couple of thousand dollars to make a prototype speed control for our turbines. When I called the technical people at Ametek-Lamb Electric to ask some advice, they advised us not to do it. They told us that not only does it change the speed of the main 3 fans (on a 3-stage motor), in turn, it also changes the speed of the cooling fan. This is because the small cooling fan is mounted onto the same shaft as the main (much larger) fans. I thought that the motor wouldn't get as hot going slower but the technician assured me that the windings still get just as hot and so do the bearings.

In this same conversation he advised us to simply go with an air control valve and that's when he explained to me that the motors were built to take that kind of change in pressure.

So we've been using the same valve (but from different makers over the years) and never had a problem with it or the motors.

Thanks,

Paul Fuji Spray