Powder coating is bridging over the masking materialsadv.
A discussion started in
1996 and continuing through 2018
Q. We have a small custom powder coating company that has secured a contract to coat satellite decoder casings. Our customer has very exacting masking requirements for the metal casing components and we are experiencing problems getting it right. We have tried special heat resistant low tack tapes, silicone rubber and numerous other masking methods without success. The problem is that the components have slots and holes that become "bridged" with cured powder when the masking medium is removed after curing.
It would seem that the answer would be to remove the mask prior to stoving. Do you perhaps have any ideas as to how this might be economically achieved?
Many thanks.Paul Abbott
A. Unfortunately I have not fully visualized your problem, but if it is just a case of powder that has already cured catching in the slots would it not be possible to blow them out with an air line. Otherwise, we have had limited success in removing masking prior to stoving by using specially shaped thin magnetic strips which are easily removable/reusableL. Tattz
A. Michael, my father discovered Saran in 1933 and spent much of his 47 year career at Dow Chemical working on all aspects of Saran and the machinery used to produce Saran products. I would suggest that you contact Dow Chemical in Midland, Michigan and talk to the researchers in the Saran lab. Good luck.Richard Wiley
October 8, 2012
A. Hi Paul.
I am perhaps not fully understanding the problem, but if the hole plugs are substantial and you are using electrostatically sprayed powder, the powder should not be sticking to them and allowing bridging, should it? Maybe you need silicone plugs that are deep and stick out so they won't be covered with powder?
Ted Mooney, P.E.
Pine Beach, New Jersey
May 23, 2018
A. Trying to fix bridging can be tricky & time consuming. One of the most efficient solutions to help reduce bridging is to implement a custom mask that provides protection around the grounding area of the transitional spot. There are several designs to achieve this protection, but a common solution is to design a mask with a flange wrapped around at an angle like an umbrella or a skirt.
We get this question pretty often, so we made a recent blog post about it. You can find images of what happens that's causing the bridging and examples of what it takes to prevent it here:
- Indianapolis, Indiana
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