Powder Coating - Powder Compatibility

[chi_boy]

So I've made the decision to try powder coating.  I already have a compressor and a small oven for baking enclosures, so the only thing missing is the gun.  Those are on sale at Eastwood, so in I go.

I don't have the gun yet so I can't RTFM, but I do want to order some powder.  I've noticed that there are different types of powder.  Are they all compatible with each other, or do certain type not mix?


I also have some boxes that were coated by PPP.  I would like to label them and then put clear powder on the box.  If I order clear powder, do I have to worry about compatibility, or is all powder pretty much created equal and able to work together?

[John Lyons]

Once the powder is cured you can coat over it with any other powder.
BUT I have found that a lower voltage works much better to coat over
previous coatings. In fact it does not work at all with the full voltage.
I use a variac to drop the voltage. But that will add
at least $50 to the cost. (buying a "variac" auto transformer).

[artifus]

But that will add
at least $50 to the cost. (buying a "variac" auto transformer).

plus your time, man

*edit* have reread - misunderstood but the sentiment still stands

[chi_boy]

Once the powder is cured you can coat over it with any other powder.
BUT I have found that a lower voltage works much better to coat over
previous coatings. In fact it does not work at all with the full voltage.
I use a variac to drop the voltage. But that will add
at least $50 to the cost. (buying a "variac" auto transformer).

Have you tried the technique of heating the coated enclosure to 200'F before putting on the powder?  I read that in my research somewhere.  To me it sounds like the heat would make the powder stick because of partial melting or at least increased tack, assuming it sticks at all, of course.  I can't say if it works, but it is something that I'm keeping open as an option when it comes time to spray.

I'll keep the variac in mind too, but I'm hoping it won't come to that.  I'm trying to keep costs somewhat under control.  If this keeps up, I may have to resort to selling a few pedals now and again to fund the habit.  Makes me sound like some kind of junkie.  ugh.

Also, I read one of your posts and you said you lacquered after labeling.  If you powder coat already, why not powder clear over the labels?

Thanks again.

[John Lyons]

I have not tried powder coating over decals yet.
Spraying lacquer is much faster and less expensive
so that's what I've been using as a clear coat.
I'll have to try it.

[tiges_ tendres]

Once the powder is cured you can coat over it with any other powder.
BUT I have found that a lower voltage works much better to coat over
previous coatings. In fact it does not work at all with the full voltage.
I use a variac to drop the voltage. But that will add
at least $50 to the cost. (buying a "variac" auto transformer).

Have you tried the technique of heating the coated enclosure to 200'F before putting on the powder?  I read that in my research somewhere.  To me it sounds like the heat would make the powder stick because of partial melting or at least increased tack, assuming it sticks at all, of course.  I can't say if it works, but it is something that I'm keeping open as an option when it comes time to spray.

I'll keep the variac in mind too, but I'm hoping it won't come to that.  I'm trying to keep costs somewhat under control.  If this keeps up, I may have to resort to selling a few pedals now and again to fund the habit.  Makes me sound like some kind of junkie.  ugh.

Also, I read one of your posts and you said you lacquered after labeling.  If you powder coat already, why not powder clear over the labels?

Thanks again.

The heating up the enclosure technique is called Hot Flocking.  Its not an easy technique to master.  This method is not forgiving of mistakes.

I've heard guys powder coating glass with this technique, but most avoid it for metal work.

I have powder coated clear over a previous powder coat with no issues.  As mentioned, the voltage lowering is recommended, but you can kludge it like I did here:

[The Tone God]

I tried hot flocking / coating early on. It does not work well for our enclosures. You have to shoot quick and accurately otherwise the finish gets really uneven from the build up of the passes. Its not like you can do sweeping passes and have it all blend together nicely during drying as with a liquid paint. The cure process is so short little time is availible for the powder to flow out evenly. The other problem is as the piece cools down the powder will have a harder time flowing out when it hits the piece then the earlier shot powder. Not recommend. Let the piece cool down a bit and shoot the second coat under the cure / flow out temperature.

I found if you are going to do multiple coats like a colour coat and a clear coat do not use a special texture coat for the base. There are chemicals that are added to react during the curing process to cause the powder to take on it's texture. If you clear coat this when you go to curing the second coat some of the un-triggered chemical will react and put holes in your finish. The best base coat I found is a simple gloss. If you want texture use a textured clear coat. Actually this is nicer anyways as you can then make custom colour textures more easily then trying to find a custom textured single pass colour.

As for decals I tried vinyl decals and they would not survive the cure. One thing I did try that worked not too bad is the laser transparency toner transfer like for PCBs but on metal then clear powder coating over that. That made for a really tough labelling option.

Andrew

[tiges_ tendres]

As for decals I tried vinyl decals and they would not survive the cure. One thing I did try that worked not too bad is the laser transparency toner transfer like for PCBs but on metal then clear powder coating over that. That made for a really tough labelling option.

Andrew

In the above picture I'm just using water slide decals.  The standard ones we all get from Small bear.  I haven't had any issues with warping or melting.

The toner transfer sounds like a fun experiment for a rainy day.  The only bummer is the surface prep, which is what has always put me off of etches.