I posted up in another thread about how powdercoating bullets can lead to toxic decomposition products. Another member called me out saying I was full of it... I do not want to publish my name but if a mod wants I will give it to him and a quick google search will prove my credentials.
So lets start a scientific study to see if I am. If at the end the hide determines I am truly full of it, I will apologize. However I expect the person who called me out to be an honorable person and do the same.
Here was my post:
I would avoid powdercoating bullets, under combustion the coating degrades into very toxic carcinogenic chemicals. Read the sds for the coating and look up combustion products. Using and baking the powdercoat also contains toxic materials.
I am a chemist and have been inventing paint for 35 years have many patents and dozens of published technical papers, so do know coatings.
Their reply:
Nope. That theory has been postulated and disproven a number of times already, going back long before you ever heard of powder coating. You're missing two important facts:
- The coating is a thermoset polymer, and behaves differently once cured than the powder does prior to curing.
- The coating does not combust at any point during the firing process. This is plainly evident by looking at recovered bullets. There are no "combustion products" of the coating from firing powder coated bullets.
I don't care what your degree is in, there's always room to learn about a subject from people who've been doing it for years, before you come in and try to "teach" them about it.
SO here is my proof.
He is correct that powdercoat systems are thermoset, 2 or more reactive coatings raw materials react forming the thermoset. However, being a thermoset does not make it indestructible.
There are several different chemistries used in powdercoat and not all are equal... You have the resin and the crosslinker.
Most powdercoat use polyester resins.
The crosslinkers for polyester resins are TGIC (triglycidyl isocyanurate) or Isocyanate. TGIC is most common in the US.
Epoxy based powdercoat is the next most common and account for about half the volume of polyester powdercoat systems. They have great adhesion to metals, provide good corrosion resistance and have very poor UV resistance.
On rare occasions acrylic resins may be used instead of polyester resins with the same crosslinkers. They are small volume and used where better chemical resistance is needed (such as the top of washing machines because they resist soap residue better). They are more expensive than polyester resins.
Fluorocarbon based powder coatings are specialized for extreme UV resistance, and very expensive. I doubt these will be used on bullets since they are rare.
Primid systems use HAA (β-hydroxyl-alkyl amide) as a crosslinker with polyesters to reduce the toxicity of the TGIC crosslinker, they are often called TGIC-Free. They were developed and are used in Europe more than here due to the regulations banning TGIC for health reasons.
The last group of powder coatings resins are called hybrid because they are a blend of different systems (polyester and epoxy or polyester and acrylic).
So lets look at the systems and health effects of the most used tones - Polyester/TGIC and Epoxy. I will link in safety data sheets so you can read them. Look at section 2 hazardous ingredients. Section 4 refers to first aid when you come into contact with the unreacted powder. Section 5 fire fighting refers to complete combustion of the material in a fire. The big issue is the temperature range from where thermal decomposition starts to the point where complete combustion takes place, between these 2 temperatures the thermoset polymer breaks back into the components, and at that temperature the components volatilize into gases we breathe.
Polyester TGIC
SDS for polyester TGIC system
Epoxy
SDS for Epoxy Powdercoat
In my next post I will get into published scientific articles on thermal decomposition byproducts of powder coatings.
So lets start a scientific study to see if I am. If at the end the hide determines I am truly full of it, I will apologize. However I expect the person who called me out to be an honorable person and do the same.
Here was my post:
I would avoid powdercoating bullets, under combustion the coating degrades into very toxic carcinogenic chemicals. Read the sds for the coating and look up combustion products. Using and baking the powdercoat also contains toxic materials.
I am a chemist and have been inventing paint for 35 years have many patents and dozens of published technical papers, so do know coatings.
Their reply:
Nope. That theory has been postulated and disproven a number of times already, going back long before you ever heard of powder coating. You're missing two important facts:
- The coating is a thermoset polymer, and behaves differently once cured than the powder does prior to curing.
- The coating does not combust at any point during the firing process. This is plainly evident by looking at recovered bullets. There are no "combustion products" of the coating from firing powder coated bullets.
I don't care what your degree is in, there's always room to learn about a subject from people who've been doing it for years, before you come in and try to "teach" them about it.
SO here is my proof.
He is correct that powdercoat systems are thermoset, 2 or more reactive coatings raw materials react forming the thermoset. However, being a thermoset does not make it indestructible.
There are several different chemistries used in powdercoat and not all are equal... You have the resin and the crosslinker.
Most powdercoat use polyester resins.
The crosslinkers for polyester resins are TGIC (triglycidyl isocyanurate) or Isocyanate. TGIC is most common in the US.
Epoxy based powdercoat is the next most common and account for about half the volume of polyester powdercoat systems. They have great adhesion to metals, provide good corrosion resistance and have very poor UV resistance.
On rare occasions acrylic resins may be used instead of polyester resins with the same crosslinkers. They are small volume and used where better chemical resistance is needed (such as the top of washing machines because they resist soap residue better). They are more expensive than polyester resins.
Fluorocarbon based powder coatings are specialized for extreme UV resistance, and very expensive. I doubt these will be used on bullets since they are rare.
Primid systems use HAA (β-hydroxyl-alkyl amide) as a crosslinker with polyesters to reduce the toxicity of the TGIC crosslinker, they are often called TGIC-Free. They were developed and are used in Europe more than here due to the regulations banning TGIC for health reasons.
The last group of powder coatings resins are called hybrid because they are a blend of different systems (polyester and epoxy or polyester and acrylic).
So lets look at the systems and health effects of the most used tones - Polyester/TGIC and Epoxy. I will link in safety data sheets so you can read them. Look at section 2 hazardous ingredients. Section 4 refers to first aid when you come into contact with the unreacted powder. Section 5 fire fighting refers to complete combustion of the material in a fire. The big issue is the temperature range from where thermal decomposition starts to the point where complete combustion takes place, between these 2 temperatures the thermoset polymer breaks back into the components, and at that temperature the components volatilize into gases we breathe.
Polyester TGIC
SDS for polyester TGIC system
Epoxy
SDS for Epoxy Powdercoat
In my next post I will get into published scientific articles on thermal decomposition byproducts of powder coatings.
