Removing E-coat from Masks

Question:

Do you have any suggestions on how to clean e-coat off of used masks? We are having trouble cleaning the masks in order to get a tight seal on the part. Thank you in advance. R.E.

Answer:

The cleaning method for masks will vary depending on the size and type of mask used. If metal masks are used, burn-off, blasting, or solvent type stripping can be used like cleaning defective parts.

If inexpensive masks are used, it may be cheaper to throw them away after a few uses than trying to clean them. If you are using expensive silicone rubber masks, consider changing to vinyl masks and throwing them away.

The best method that I have heard of for cleaning small silicone rubber or high-temp vinyl masks is to put them in a small tumbler with a mildly abrasive media. Tumblers can be obtained from a rock polishing shop. Media used to deburr parts may also be used. If you do not have a media deburring operation, take some masks to a source that deburrs parts using media.
Large silicone rubber masks can usually be rolled or twisted to remove the electrocoat from the masks after curing. If the e-coat is not brittle enough after a single bake, try re-baking the masks at a higher temperature before trying to remove the e-coat. A larger version of a tumbler can also be used on larger masks if large quantities are involved.

If masks can be removed between the post rinse system and the oven, soaking them in permeate may also clean them. Ask your e-coat supplier for a solvent that will dissolve uncured electrocoat.