Laser engraving / etching on mason jar lids

Laser
#1

Hi Everyone,

I saw that we can etch onto metals when we pretreat with CerMark or equivalent. I wanted to know if there would be concerns with etching on the metal side of brand new mason jar lids, they are steel coated with a thin layer tin. The underside, however, is steel covered with two coats of tin and then a BPA free chemical. The seal itself they told me is a ‘plastisol’ coating. which helps keep everything inside fresh.

Is there a safe way to etch the top of metal lid?

Thank you,
Michael

#2

Dry moly isn’t what I would call food safe. If you were to seal with maybe a low melt wax, perhaps cover the underside completely with blue tape… I would still be worried and scrubbing the underside of a new lid, since they are single use items. However… nothing says you couldn’t use a smaller disc of metal to perm label, and hot glue it after sealing a container. Then that label is reusable.

#3

Hi @dougemes,

What’s Dry moly? If I were spraying on CerMark then all the lids would be face down with the metal face up. Are you suggesting that the laser would introduce unsafe chemicals on the underside?

#4

Dy Moly and its Safety Data Sheet. I think of mason lids like petri dishes, and would exercise extreme caution with anything coming into contact with them. Please read the sheet.

#5

Molybdenum disulfide is the chemical in Ceramark that makes the marking possible. It is also used as a lubricant so there are some diy’s that show how to use dry moly to mark because of CerMark’s very high price.

To be clear when marking with CerMark you dont actually etch any metal. You basically end up leaving a thin film sintered to the surface of the metal (like a metal ruler)

The plastisol itself would be an issue since it is PVC based (releases chlorine). The BPA-Free coating could be an issue as well since it is there primarily to protect the metal from acidic foods. The possible issue I see is that heating the top side of the metal might damage the coating underneath and damage the seal or protection of the surface.

If you are dead set on trying I would seal the bottom side with a mask to keep any airborne moly off of the underside of the lids and run a batch through at least heat cycle to make sure the coatings aren’t damaged by the heat of the laser from the topside.

Actual CerMark MSDS: https://d3ciwvs59ifrt8.cloudfront.net/9fb95566-a02f-4efe-9777-6c15dbe18ad6/4a39e6a6-e477-4da0-9804-e7f5ba0e7b25.pdf

Summary: Silica is bad for your lungs, Moly is a heavy metal, and Nickel iron chromite, black, spinel is a known carcinogen

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#6

Thanks for the helpful info, I am completely abandoning this idea, I really appreciate your guidance.

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#7

Hi Jacob,

Based on your thorough answer I am abandoning this idea while feeling like I just accomplished something.

Thank you for sharing your knowledge!
Michael

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#8

Is the markings you need to make on the food side of the lid? Cermark and dry lube works by leaving a layer that is thermally bonded by the heat from the laser. Other marking methods like vinyl or chemical etching may work for you.

My son made me some customized Mason Jars using vinyl masking and glass etching paste on the outside of the glass. They are really cool.

#9

Hi Lampy,

The plan was to do the visible side of the top if the lid is closed. I think we’ll need to go the glass route, seems much safer.

What’s vinyl masking? Have any pics to share?

#10

They make vinyl specific for masking purposes. Usually has low tack adhesive, it’s thinner and more flexible. I’ll see if I have some pics.

https://www.amazon.com/VViViD-Low-Tack-Adhesive-Stencil-Masking/dp/B07PVC8J43

#11

As an alternative, you could etch and cut similarly sized disks out of posterboard and place them under the canning ring after you have waterbath-sealed and dried the jars. You’d have to deliver the jars with the rings intact, but it might accomplish something close to your original vision.

Metal disks cut by waterjet (elsewhere) and Cermark would possibly also work if it must be metal, but I’d worry about dielectric effect between the disk and the lid leading to corrosion.

#12

As an aside this is not quite right. The process through which it is sintered actually does erode into the surface and depending on the material and settings can be quite notably recessed even with the film leftover.

Here’s the best photo I could get from my phone using my inspection magnifier on a stainless tumbler I have lying around. The raised lip of the bare stainless is there; you can even catch your fingernail on it. This isn’t even the deepest I’ve run.

PXL_20210223_190450052
PXL_20210223_1904500523024×4032 1.85 MB

As for the OP’s question, I think engraving the top of the jars is fine but they’d need to be sterilized even if you covered the inside section because none of our equipment is clean enough for food stuffs.

An autoclave might solve that problem but I’m unsure how BPA handles it. There may be a more adequate procedure.

Additionally one doesn’t have to spray the moly, it can be applied with a paste in a thin layer.

I’ve done plenty of food stuffs with the process but they’ve all been things I can adequately wash and seal out the insides during the process.

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