Removal of epoxy paint 1

[OrthoTech]

I work for a large orthopaedic company in the midwest; my area of responsibility is in the design of sterilization cases and trays for instruments and implants.

I'm currently working with a vendor to determine the best way to remove the epoxy paint they use to apply silk screened artwork to the case components, and have had little success up to now in finding an acceptable method. What I have so far is basically a heavy-duty stripping compound, but using this product leaves a "ghost image" that I don't find too appealing.

Does anyone have any suggestions of a product / method that could be used that won't degrade the aluminum component but yet be aggressive enough to entirely remove the evidence of existing silk screen?

Any help would be much appreciated!

 

[tickle]

Have you talked to a painting contractor? My first investigation would be grit blasting. A painting contractor will be able to help

 

[sciguyjim]

I don't know about epoxy paint, but I've heard that epoxy glue can be loosened with a chemical called:
N-methylpyrrolidone

It's easy to obtain, doesn't have a very high vapor pressure, has low odor and low toxicity, and can be washed away with either water or organic solvent. By itself it leaves no residue on drying. I wouldn't expect much, if any, reaction with the aluminum, but I don't know for sure.

Epoxies can be decomposed by boiling in concentrated potassium hydroxide solution, but this would attack the aluminum.

 

[chicopee]

Could the ghost problem left on the aluminium be corrected w/ a mild etching treatment. I definitely would not use abrasive blasting as it could wear off the aluminium.

 

[sciguyjim]

Chicopee,
I would not expect a mild, or strong, etch to remove the ghost on the aluminum. It would depend on what the ghost was made of (would it be attacked by the etchant.) Also, all the surrounding aluminum would need to be protected from the etchant aince without the (possible) protection from the ghost, the surrounding Al would etch more than the ghost. I'd recommend finding a non corrosive solvent that could hopefully remove the ghost. Maybe it's some sort of primer applied to help the epoxy paint to stick?

Abrasive blasting can be done gently and would not remove much Al at all. If you could do it evenly, the whole item could be given an even matt appearance. With all the microscopic pits though it could offer places for microbes to hide as it is cleaned.

 

[khorsing]

How about caustic soda (NaOH) solution 30% ? Give it a try.