gun power?

[randygrapes218]

what is the purpose for having the power be adjustable on the pro guns? does more kv mean it would be easier to powder coat over chrome powder? if so why would you not just crank the power up as high as you can and leave it? thanks randy....

[DALE]

To truly appreciate the advantage of adjustable voltage you would need to see it for yourself. If you crank it up and leave it, there is no way you will be able to powder inside tight corners. As the voltage increases, the faraday cage effect becomes much larger.With a low voltage you can easily shoot into tight places and then turn up the voltage for a more efficient surface coverage of your larger areas.This also allows you to dial in your coating thickness.

[randygrapes218]

thanks for the reply dale.... randy

[sdold]

Does this mean a 16 KV gun would get into tight spaces better than a 70 KV gun?

[Popeye]

Yep

[sdold]

Has anyone here added a connector to the HV cable, to let you remove the gun for cleaning? If so, what kind of connector did you use?

I want to add this to my gun.

[mcaswell]

We asked our supplier to design this into the gun. Their response was that there is no connector safe enough to ensure you don't get a stray current hit you from this very high voltage.

We recommend you don't do this.

[Popeye]

I agree, we tried all different types of high voltage connectors and it leaked every time.
We did finally find one that could possibly work but it was well over $200.. I can live with the cord

[customandsound]

like caswell stated ..I would not do it. They buit the gun that was for saftey and messing with the factory work is just a problem waiting to happen.. So don't try that at home!!!!

[sdold]

LOL...My gun was built for anything but safety (I should point out that it is not a Caswell gun). The braid around the cable stops at the bottom of the handle, on a wire terminal that loosely fits over the air supply nipple. The unshielded part of the cable continues up the handle so that you have to hold onto it while you spray. I have been shocked so many times by this ridiculous design (while spraying and touching ground with the other hand) that I took the terminal off the air nipple and reattached it up at the top of the handle, so that my hand is not in contact with it. I run the cable along the top of the gun where it's taped about in the middle and hangs down from there, so that the cord is not near my hand. It's much more pleasant now without the shocks.

I'll let you guys know if I come up with anything that works.

[customandsound]

Yep i got the same gun i don't like the way they built it ,, anf the braid at the nipple is the wrong way to do it..

I got a gun from one of the members of the board that caswell sells i am going to give it a try this week... it is good to have a back up.. But i been using my pro gun more in the pass few months..

[Zpider]

When my cable broke off a tried some military high voltage connectors that was supposed to carry 60 kv, no luck at all, even a minor leak in the connector made the gun useless. So i dropped the iade very fast... but i agree it would be nice though..

[sdold]

I'm guessing a lot of these guns use the same power supply. Anybody know what powers the supply? 12V or so? I think it is, because the foot pedal switches 12V (it says).How about mounting the supply to the side of the gun? The power supply in mine is small, only about 3" x 1.5" x 1".

I believe there may be a Frankenstein gun coming, I'll post pictures if it appears.

I bet it'll have a removeable connector to the supply, since it'll only be 12V

It might even have a switch near the trigger that turns the HV on/off.

[seanc]

I had to take my gun apart recently to clean it (the trigger would stick open), so I decided to check the rest of the unit out while I had it on the bench. I've also gotten frustrated with the tangle of cords, and wanted to see what could be done about it.

Here's a crude schematic of the Caswell hobby gun:

Powder Gun Schematic

As you can see, AC is fed directly to the HV transformer, as well as to the DC control board. The foot switch simply activates a relay which turns on the HV, and activates the HV LED.

This wire, and the ground clip, could easily be made removeable.

I had considered plugging this unit into a variac, so that adjusting the incoming AC would result in variable output HV, but since the DC control board is also fed by this, it may either not operate at too low AC, or burn out at high AC.

The best way to make it variable would be to run a separate AC line to the HV transformer, and control that by variac. Since the HV transformer is fully encapsulated, there's no way to know what it's maximum input rating is, so there's still the chance of overloading it. But it sould work fine at reduced AC, to get lower HV for getting into tight spots.

Sean

[sdold]

Thanks Sean. I see a lot of HV supplies that run on 10-18 VDC, one of those might be the answer. I think mine might be the same as yours, because I think I saw a relay on the board.

Do you (or anyone) know if the HV output to the gun is positive or negative?