fluidized bed

[zgcfab]

is thar iny info out thar on this and why not use it for powdercoating at home

im new to this and am looking to start doing this at home on some of my show cars.

sorry for the spelling guys im not good at it so please dont flame me for it

erik

[Popeye]

Re: fluidized bed

Erik,
No problem with the spelling... you might download iespell, that's what I use

http://www.iespell.com/

[zgcfab]

Re: fluidized bed

no one has Any info come on please. ehheheh

hay that Ispell works good

Erik

[machone]

Re: fluidized bed

I have no idea what it even is LOL! I've heard the term, but......
BTW, I just noticed there's a spell check button right next to the preview post button down below!
mach

[Popeye]

Re: fluidized bed

That button wasn't there yesterday )

[zgcfab]

Re: fluidized bed

hehehehehe

[dlaery]

Re: fluidized bed

I have a fluid bed that I use to use for fishing lures.

[lcaswell]

Re: fluidized bed

That button wasn't there yesterday )

You're right - it's new!!

[zgcfab]

Re: fluidized bed

i need info on how to build one in one?

[baz]

Re: fluidized bed

here is an article about building a fluidizing bed

http://www.pcfpowder.com/doit.html

[zgcfab]

Re: fluidized bed

this is what i have found so far


FLUIDIZED BED POWDER COATING


Fluidized Bed Powders are applied by dipping heated metal parts in an aerated powder bed . The powder melts on the hot part and results in a smooth continuous plastic film encapsulating the metal.

The fluidized bed has three main sections. A top powder hopper where the powder is held, a porous plate which allows air to pass through, and a sealed bottom air chamber. When pressurized air is blown into the air chamber it passes through the plate and causes the powder to float or "fluidize". This allows the metal part to be coated to be moved through the powder with little resistance.

[zgcfab]

Re: fluidized bed

thank you for that info

[dlaery]

Re: fluidized bed

is thar iny info out thar on this and why not use it for powdercoating at home

im new to this and am looking to start doing this at home on some of my show cars.

sorry for the spelling guys im not good at it so please dont flame me for it

erik

I have used a fluid bed for 3 years to paint fishing lures. It is 14" x 12" x 3'
The trouble I had with it was inconsistent results. I had "fish eye" (no pun intended) on the finish. I guess this was because I use silicone molds to cast the lures and it left a residue on the lures. So I washed them in 180 temp vinegar to remove silicone contaminates. Next problem was not getting even air flow, so some lures had pin holes and this would be where I had more air flow in the fluid bed and where I had less air flow the eyelets would fill up where you put the fishing line through. Fishermen don't like that.
Next problem was inconsistence in powder. One batch would fluidize good and the next batch would not. It would just blow dust in the air. The good would look like water when fluidized and no dust in the air. A friend brought some steel parts he wanted PC, they turned out perfect.
Now I purchased a hobby gun.
I don't have to preheat the lures.
I don' have to wash in vinegar, no "fish eye" problems.
It does not fill up the eyelets.
The fluid bed is a lot faster if it fluidizes good.
I am not impressed with a fluid bed at all.
It may be ok for some parts, but parts with small details in my opinion, would have too much paint on them.
The biggest problem I'm having with the hobbly gun is controling the dust in my booth. Still working on ventilation.

[zgcfab]

Re: fluidized bed

what i would be doing would be large parts for cars.

i just liked the idea of no wast

erik

[BigDog]

Re: fluidized bed

A "fluid bed" is an open box with a "plenum" chamber underneath, separated by a porous membrane. Air is introduced into the lower chamber, which then passes into the upper box uniformly. The density of free flowing powder in the upper box is reduced by the air, such that 24 inch deep powder in a "dead" bed rises to 28 or 30 inches deep. In a properly moving fluid bed you can reach your hand all the way down the bottom of the box. Depending on the powder in the bed, there may be a substantial amount of dusting coming out of the box. Powders designed for fluid bed application generally have larger particle size than the "thin film" eletrostatic powders, and are ideally spherical in shape to allow easy free flow properties.

The two main uses of a fluid bed are 1) for coating large irregular items
such as dish washer baskets or pipe fittings. The part is pre-heated at a
higher temperature than the melting point of the powder (since the powder
'quenches' or cools the part right away) then dipped into the fluid bed and
moved around under the surface. The retained heat in the part and the time
immersed in the fluidizing powder determines the thickness of the coating.
When the part is pulled out, there may be immediate melting of the coating,
or it may have a "sugar coating" on the surface. Usually the part is then
post-heated, ideally in another oven at a lower temperature, perhaps at or
just above the melt point of the powder. Too high of a temperature will
cause the coating to sag or even drip. The post heat is simply to flow out
the coating, since most powders used with this method are "thermoplastic"
(needing to melt only for property development, and able to re-melt if it
sees heat again) as opposed to "thermoset" (cross-linking and chemically
changed after the cure cycle, and will not re-melt). Common materials used
for this method are Vinyl (PVC), Nylon, and Polyethylene, and in some cases thick-film epoxies (which do need a cure).

The other use for a fluid bed 2) is with an electrostatic gun. The powder
is put into the upper box, compressed air is supplied to the lower box and
adjusted so the powder just moves without dusting too much. In this case
the top of the fluidizing box is closed to contain the dusting, with some
sort of filtered vent. The powder is then drawn up to the gun when the
trigger is pressed. This is generally a superior method for preparing the
powder for the spray gun compared to the "vibrating table, auger feed"
method, where an aerated suction hose is dropped into the open box of powder and the powder is drawn up to the gun. The suction is easier in application of high volumes of powder, since the coater just has to set up the box once until it is empty. With the fluidizer, the powder is scooped or poured into the upper box as needed. With conventional homogenous powders, there is probably no difference in application, but with some "complex" powders such as Veins, Metallics, and some of Polychem's unique compound mixes, the fluid bed technique assures a uniform application. The suction feed method does not allow for any settling or striation variations which the box may have developed in transit or use.

Fluid beds may be purchased from electrostatic gun manufacturers for an arm and a leg. Most Vinyl powder coaters ( less common anymore, since there have been health related questions raised in using Vinyl) used to make their own fluidizers. The walls of the bed can be made from sealed wood or coated sheet metal, then flanged to the lower chamber. Fluid beds range from a few inches on a side to several feet on a side. I know of one coater
who would dip sixteen foot long light poles into a fluid bed filled with Nylon.