Better fluidizing in the hobby gun?

[cruizer]

So I have had many problems with the hobby gun, First with the sticky trigger, which I have to put WD40 on every day to keep it working.

I also have problems with consistant flow. It seems like the powder is not fluidizing properly in the cup. I begin to spray, and powder comes out OK. Then is quicky fizzles down to a fine mist. The airflow stays the same by the way. I shake the gun, and more powder comes out again, and them it fizzles down to a mist. To get descent coverage, I have to continually shake the gun (and I mean violently too) while trying to spray my part. This seems to waste alot of powder. Also doesn't help when I am fading colors and trying to be precise and accurate.

I was thinking of drilling a couple more holes in the piece that sticks up the is supposed to fluidize the air. Maybe getting a little more air circulation in the cup.

Anyone else expereince this problem? Have a fix for it?

[sdold]

I did the same thing you mentioned and it did seem to help. A couple of extra holes, about 1/8.

Sometimes my powder seems more "heavy" and clumpy and shoots like you described, other times it's light and extremely fluffy and shoots great. I assume it's the amount of moisture in the powder and the line making the difference.

In fact, that probably has a lot to do with how well the powder clings to the part, since things hold static charges much better in dry conditions.

I only mention this in case you think it might be part of your problem. It's sure caused me some headaches.

Steve

[chromeitout]

Steve, by your reply I have to assume that the extra holes did not fix your problem?

[sdold]

Right, the extra holes seemed to help noticeably, but the fluidization was still not perfect.

Steve

[cruizer]

Were they randomly placed holes? Or strategically placed?
Thanks for your reply, btw!

[mcaswell]

If you are having clumping problems, this may be caused by moisture in the air.

You may need to install a DE-humidifier in the room.

We now install a silica gel packet in every unit of powder we sell, however, this may not cure the problem of a humid powder room, or moisture in the airline, it does insure that the powder is good until the can is opened. Try taking an old silica gel packet and heating it in an oven to 140 f, for 30 mins, and placing it in a plastic ziplock bag. As soon as you open a unit and only use a partial amount, change over the silica gel packet.

You may like to 'fluff up' the powder by using an old fashioned flour sieve, and running the powder through it immediately prior to coating.

It certainly makes a huge difference on a cake!

[Livinincolor]

We are having a custom hopper built for us that we will report on when it gets here. It was built with the hobby gun in mind.
Some of the measures we have taken to insure our powders flow well is
1. Keep all powder in a room that is air conditioned,
2. All powder is stored in air tight containers that have silica gel packets in them
3. No less than 4 moisture filters inline to the gun (including a silica gel cannister that we made).
4. We also tried the holes in the tube for powder pick-up, we are hoping this new hopper will dop the trick. We will keep you posted, should be here next week.
Mike
Sho Me Coatings

[PatrickMcGovern]

Maybe the problem is coming from all of that wd-40 you've been using. The air used for fluidizing the powder has to go through that trigger mechanism and it probably picks up oil off of it.
My trigger is sticky too. Very sticky. I took it apart and switched a few o-rings and got it to work a little better.

[cruizer]

Well it was having this problem well before I had to start spraying it with WD-40.

Thanks for all the replys so far!

[sdold]

My two extra holes were near the bottom of the tube, so that in addition to the air coming from the end (top) of the tube, some also squirted out of the two 1/8' holes on the sides of the tube near the bottom of the cup. Well, air doesn't "squirt", maybe I should say "spray". No, it doesn't spray either. Huh, I don't know what it does. But hopefully you get the idea.

Steve