Letter 5065

De waxing of parts post electroplating. 

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My company are about to replace trichloroethylene vapour degreasing with an aqueous base process. The "Trike" is also used for final dewaxing of parts post electroplating. We have not found a satisfactory replacement process for dewaxing as yet. I would welcome comments on possible environmentally sound alternatives in use.

Mark Dunphy
- Dublin, Ireland

Actually, perchloroethylene is slightly better for wax removal as it has a higher temperature aiding in thermally removing wax (quicker). Perc is about as bad as trike, but since its vapor point is higher, it is easier for the coils to knock it down. You can reduce your solvent use considerably by putting a higher freeboard on the tank. eliminate crossdrafts as much as possible.

Normally, simple walls can be cheaply installed and removed for maintenance as required and will cut use enough to pay for the addition in a month or so in many facilities. Use a slower hoist speed, both in and out. Allow for a longer drip time in the cold zone. Freeboard chiller coils are a mixed bag. some help but bad for the solution in areas of high humidity that will cause condensation of water into the tank. The excess wax can be removed from the top of the tank on a routine basis by shutting the tank down overnight and using a homemade holey long handled hoe.

For all of the claims made, nothing has replaced the efficient and ecconomical use of a well designed and well operated vapor degreaser.

James Watts
- FL

Mike,

Have you made any progress in your search? Carol Eden (United Airlines) in San Francisco published an article in Plating and Surface Finishing magazine.

Katherine Dougan
- Annapolis, Maryland

Dear Mark-

We at United Airlines Maintenance base have totally removed all degreasers from our shop. We no longer use them for cleaning or dewaxing on engines and aircraft. For cleaning, all our products are aqueous based. For dewaxing after plating, we use hot water (180-190 degrees F) to melt off the wax, which we recover, and then go into Bioact 280 (an aqueous cleaner/solvent), then rinse and into a cleaner and rinse again. This process has been in use for two years and we have the bugs worked out. Either Carol Eden the author of the article the previous writer mentioned or I (the process engineer) could give you more details if you need them.

Jeanne Kitazaki
United Airlines - San Francisco, CA

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