Monday, March 28, 2016

The Problem-Solution Series: Part 4


Streaks, Spots, Solution?


Problem: 
The pretreated part appears to have streaks and spots, but I thought I did everything right. How do I get rid of them or stop this from happening?

Origins/ Causes: 
There are several reasons that these spots and streaks could begin appearing. Here is a handy list of just a few of the causes:

  • Soils are not being efficiently removed
  • Parts are not fully rinsed, or the rinse is contaminated
  • Drying off of the coating is occurring between stages
  • The phosphate coating weight is too low

Solutions: 
If…

  • It seems that the soils are not being removed, you may need to test the cleaning stage. This means that you should determine if the proper choice of chemicals and process conditions have been chosen (remember: acid conditions clean inorganic soils and alkaline conditions clean organic soils)
  • The parts are not fully rinsed or there is contamination, orient the pars for maximum coverage. Also, clean and adjust the spray nozzles for maximum coverage. As always, ensure that you are maintaining high rinse tank purity.
  • You notice that dry-off is occurring between stages, allow sufficient time for adequate drainage, yet not enough time for dry off. If possible, reduce the temperatures, and utilize the fog nozzles and adjust them for maximum coverage.
  • The phosphate coating weight is too low, adjust the processing conditions. Make the necessary adjustments by either increasing the temperature, lengthening the time, or both. In addition, increase the phosphate and/or accelerator concentration.

For additional information on powder coatings, visit our website at tcipowder.com. Feel free to Contact us today to have someone with our experienced team answer your powder coating questions or to see how we can help you with your powder coating needs.

Thursday, March 24, 2016

The Problem-Solution Series: Part 3


What To Do When Parts are Being Picky: Little or No Adhesion

Problem: 
For some reason, little or none of the coating seems to be adhering to the part. What should I do to fix this.

Origin/ Cause: 
In most cases, coating will fail to adhere due to excess soils.

Solution: 
First, check that all soils have been identified. Next, test all of the stages. Determine if the proper choices of chemical and process have been chosen in order to remove all soils. Lastly, orient the parts for the maximum amount of coverage and clean, and adjust the spray pressure for maximum part coverage. Throughout the process, be sure to maintain high rinse tank purity.

For additional information on powder coatings, visit our website at tcipowder.com. Feel free to Contact us today to have someone with our experienced team answer your powder coating questions or to see how we can help you with your powder coating needs.

Tuesday, March 22, 2016

All About Grounding

What it is, When it's Good to Go, and How it's Measured 

 

What is Grounding? 
Grounding is providing a sufficient path for the flow of electrical charge from the object to the ground. An adequate path allows the charge to dissipate faster than the speed at which the charge is accepted to the part. NFPA 77 states the electrical resistance of such a leakage path may be as low as 1 Mega Ohm, but as high as 10,000 Mega Ohms, and still provide an adequate path. For powder coatings specifically, 1 Mega Ohm or less is used as working ground to ensure proper discharge.
An ungrounded part will accept some voltage and attract some charged powder, but at some point it will begin to repel the charged material. Smaller parts will show these effects more quickly than larger parts. Some difficulties related to poor grounding are:

  • Halos around hooks
  • Inability to penetrate Faraday areas (fields generated inhibiting electrostatic application, mass of particles cannot penetrate field)
  • Inconsistent or low film build
It is very important that powder coaters have good grounding. If the parts are isolated from ground, they can build up voltage to a point and then discharge to ground, creating a potential arc that could ignite powder in the air-stream. So, before using your equipment, take that one extra step to ensure your safety, and check that the parts are not isolated. 

What is a Good Ground? 
As we stated before, it is important to have resistance less than 1 Mega Ohm to ensure your safety. Most equipment companies use this measurement as a standard. 
How is Ground Measured? 
You guessed it! Mega Ohms are measured with an ohmmeter! How does it work? One cable is attached to a known ground, and one is attached to the rack content or part. If the resistance to conductivity is greater than 1 Mega Ohm, the system needs to be cleaned.
 
Additional tests will show specifically where the loss is occurring:

  • House ground rod to rail
  • Rail to conveyor
  • Conveyor to hanger attachment
  • Hanger attachment o rack
  • Rack to part 

For additional information on TCI’s powder coatings, visit tcipowder.com. For more on powder coating hazards and safety, click here to see the troubleshooting guide.

Wednesday, March 16, 2016

Combustion Precaution


What You Should Know About Combustion

Nobody likes thinking about possible combustion or ignition risks. Yet, it is very important to be aware of these risks and take precaution when handling powder coating and curing equipment. To keep you safe, we’d like to supply you with two helpful lists. See the chart below for a visual representation. 

Elements That Should Be…

Controlled
  • Powder to Air mixture: keep powder concentration outside the explosion (flammability) limits
  • Compressed air supply
  • Booth air flow
  • Sparks from poor grounds 
 
Eliminated

  • Electrical equipment
  • Matches
  • Cigarettes

How to Control Powder to Air Mixtures...

  • Engineered powder systems
  • Quality spray guns
  • Exaggerated powder output
  • Size of openings
  • NFPA and OSHA exhaust guidelines
  • System expansion factors
  • Reduced efficiency factors




For additional information on TCI’s powder coatings, visit tcipowder.com. For more on powder coating hazards and safety, click here to see the troubleshooting guide.

Tuesday, March 8, 2016

More on Powder Coating Safety

Safety Issues During the Powder Coating Process


Handling of Powder Coatings
Our last blog post provided readers with details on hazards, protective practices, and safety measures. For your safety as an end user, we would like to remind you of a few additional precautions and safety tips.
  • Read the material safety data sheets (MSDS) Available on TCI’s website: Link to the website where to get them: https://msds.tcipowder.com/tds.aspx 
  • Avoid excessive skin exposure
  • Wear proper respiratory equipment
  • Wear proper clothing and eyewear


Fire Risk
Powder coating is very different than everyday painting, not just in form, but also in quality. One of the most hazardous differences about powder coating is that users may be exposed to heat and flame. Here are some things to keep in mind when working with powder coating materials and curing ovens.
  • Maintain a safe concentration of powder in air-outside the explosion (flammability) limits
  • Eliminate any sources of ignition
  • Maintain a good ground on everything in the powder coating system
  • Maintain a good ground throughout the racks
Pretreatment Chemicals
As a powder coating user, you should become aware of the chemicals associated with the process (such as iron phosphate, acid salt, nitrate, chlorate, and others). Some tips on how to stay protected from these chemicals are listed below:
  • Read the MSDS
  • Avoid skin contact
  • Wear recommended safety clothing
  • Maintain good ventilation
High Temperature Environments
Both potential flames and high temperature environments pose a risk to you and those around you. Here are a few ways to stay safe in these hot environments.
  • Limit access
  • Never open washer or oven during operation
  • Disconnect power before entering
  • Use good lighting when entering
  • Wear a hard hat in areas where it is necessary to stoop
  • Know the hazards inside the equipment
Always follow the manufacturers written procedures when handling risky materials.

For additional information on TCI’s powder coatings, visit tcipowder.com. For more on powder coating hazards and safety, click here to see the troubleshooting guide.

Wednesday, March 2, 2016

Powder Coating Safety


Hazards, Protection, and Safety

TCI Powder Coatings strives to provide our customers with ample information so that you can get the best use and superior results from our products. More importantly, we also hope to ensure that our products are used in a safe and effective manner so that you may maintain a secure environment. The safety of our staff as well as our customers is extremely important to us. Although our website includes a user manual and troubleshooting guide, we want to extend a reminder to you that every organization should examine and develop their own coating operation, safety program, and specified procedures.


Health Hazards of Powder Coating Materials

All chemical manufacturers, according to the OSHA, must evaluate chemicals produced and determine if they are hazardous based on:
  • Carcinogens
  • Toxins
  • Irritants
  • Danger to human organs
  • Flammability
  • Explosiveness
  • Reactivity



This information is available to workers in the material safety data sheets (MSDS).



Respiratory Protection: What mask should I wear?

For small particles (powders), legally the Threshold Limit Value (TLV) of occupational exposure is 10mg/m3. In regards to the TLV, below is a list of the masks that should be worn for specific exposures.



  • Outside of a spray enclosure: disposable dust mask
  • TLV higher than 10mg/m3: half mask with cartridge filter
  • Fully inside of spray enclosure (high powder concentration): full-face mask



Personal Safety

Here are a few reminders to keep you safe during the powder coating process:

  • Use coating and protective eyewear to limit eye and skin exposure
  • Do not wear gloves unless they are specially designed for electrostatic application
  • Make sure all equipment is in proper working order
  • Hold the spray gun in its proper position to ensure grounding
  • Do not blow powder off of the skin using compressed air (it can force abrasive particles into skin and eyes)
  • Practice good housekeeping to reduce accumulation of powder in the area and personal exposure



For additional information on TCI’s powder coatings, visit tcipowder.com. For more oven designs and troubleshooting information, click here to see the troubleshooting guide.