Masking For Powder Coating

What about wax or mold release?

Inner and outer magnetic foils? Maybe that should be over and under . You are dealing with a flat surface? A pic would help

How hot do you have to bake it? May limit your choice of mask. Could you have a mask that you remove before baking so that it takes the powder away from the area in question?

Are you sure that powder is the best method? You will have to bake the powder at a fairly high temperature & this could damage your moulding.

As the moulding is clear you could spray paint on the inside or outside to get the finish you need.

And there's the problem.

"As the moulding is clear you could spray paint on the inside or outside to get the finish you need."

How do you mask it? Either process requires masking.

Still need masking, yes, but if the powder finish is chosen for durability, spraying inside the clear moulding could achieve that.

No argument there.

Another reason lots of plastic moldings are painted is for visual consistency.

Molded plastic parts don't always have the same exact surface appearance.

Painting/coating is more consistent.

Perhaps in the morning you could call the supplier ! Sometimes they know these things ! Paint supplier and masking supplier, and perhaps plastic supplier.

In addition to the wealth of experience here, you might tap the people in the business, perhaps those who apply the powder coating for a living.

Try www.pfonline.com they are the premier trade magazine and have Q & A columnes for all types of finishing, including all types of power coating.

Powder is applied by an electrstatic process and may not attract/adhere to your plastic surface. As you have already been told the powder gets cooked on, although the temp is quite low it still may distort your plastic.

The cooked powder is stiff, i.e. not flexible, certainly not as flexible as the plastic component and will flake of the first time you pick it up.

The powder coaters will not be happy with you if there is outgassing from your 'bits' that alter the colour or affect the surface of other peoples 'bits' in the oven.

If your plastic is polypropelene you need to know that virtually nothing will stick to it.

However; if you really want to coat your 'bits' with a masked section see if you can locate precut peelable paper labels in the size you want. Apply paper label, spray with plastic etch and then apply a flexible paint such as an oil modified acrylic in as thin a coat as you can.

Jim

There is company in India (Global Applied Materials) makes polymeric binder in two version conductive and non conductive for masking before plating. This I have used to protect area I do not want to coat. After that Just dipped in Solvent (acetone) and cleaned this off.

We automated using roll coater. If I know drawing I may be able to help you out

When I was policing, our armorer/gunsmith used gas pipe tape to mask off areas for metal finishing/coatings. It worked. Black vinyl, 10 mils thick.

The most cost effective way, while initially more expensive, may be to make the lens separately and glue it into place with adhesive afterwards.

Once the molds are made, you will never have to mask anything.

But you still have that nasty problem with color and surface consistency from batch to batch of molding compound.

Tell me, is your cell phone painted?

The inside is likely painted with some type of conductive paint for EMI shielding, and I'll wager the outside is painted, too. All done by robotics.

Nope. Just cheap white plastic. It doesn't even take pictures.

Speaking of pictures...........if the OP was to show us one, it would probably lead to much better solutions.

Here is a Link to take a look at the 3D model of the part.

You can rotate the model by left clicking the mouse & moving. The Green area has to have NO texture. But the rest of the part will have to be textured. Texturing straight from mold is little expensive. So I am wondering if this could be cheaper to mask & have a secondary operation.

Thanks

C1

Might i suggest a plywood board with an epdm ( foam rubber ) sheet glued to it that is the shape of the inner part. Attach a vacuum cleaner hose to the board and you will be able to mask and manipulate the part at the same time.

I am assuming you are smart enough to realise that you will need a hole in the board and channels in the foam rubber etc.

This solution will enable future automation with a pick and place type m/c.