finishing.com -- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing

HomeFAQsBooksHelpWantedAdvertiseForum
topic 4281

OUTGASSING BUBBLES FROM CAST IN PAINT


(2000)

WE ARE A POWDERCOATING SHOP LOOKING FOR A LIQUID PRODUCT TO GO OVER CAST TO STOP VAPOR OUTGASSING BUBBLES FROM THE CAST IN THE PAINT.

WYATT BUCHANAN
- BINGHAMTON New York


(2000)

My experience with solving out gassing problems with powder coating is to heat the part to 250 F for 20 minutes to drive the internal gas out, before coating. I am guessing that your system as configured doesn't have heated section specifically for out gassing prior to coating. If the dry off is the only equipment you have to do this, elevate the temperature in that section, and see if you get better results. I am not aware of a liquid coating that will withstand the pressure of the internal gasses to prevent the rupturing or "popping" of the powder coating. There are fillers to smooth the rough surface of castings that will be a good substrate for the powder coating, but I would be skeptical about them holding the gasses in during curing. You might try something like that, but I have my doubts. Let me know if you find something that works.

Randal Rockwell
- Mishawaka, Indiana


(2000)

To degas castings will require a heating schedule GREATER that the powder cure cycle. If that is not viable try a dry-in-place chrome-resin pretreat. I believe Brugal 5TF from Procoat may be available in the states. An alternative would be to dip in PVB based blast primer which will penetrate the surface being based on alcohol/MEK. All solvent must be driven off by force drying to prevent solvent bubbling.

Roger Bridger
- Croydon Surrey UK


(2000)

We have found that the best way to solve the problem of out gassing is to buy a product specifically designed to do just that. This special type of powder stays in the gel state longer, and allows all of the air to escape before it completely cures. The cure times are not much longer either. DuPont has one that works great for us. It is called AGP Black.

Hope Tyburk
- Canton, Ohio



This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Q or A to THIS thread START a NEW THREADView This Week's HOT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices


©1995-2017 finishing.com     -    Privacy Policy
How Google uses data when you visit this site.