How is Resin produced? What exactly is it?

[vinnie]

Can someone explain to me exactly what resin is? I know it's a form of liquid polymer, that when hit with light/laser hardens into a plastic material. However, does anyone know how the resin is produced? Is it possible to make your own resin at home, or are too many dangerous processes required?

One of the benefits of filament printers is that you can basically reuse your filament, and practically create your own. I'd like to know if there is an affordable way of obtaining resin (perhaps by creating it yourself). I love the resin printers, but I hate how I am always going to have to rely on others for the raw materials.

[Feign]

I'm pretty much a noob at this myself, but from what I've found you've got two main components: Monomer and catalyst.

With some monomers, the catalyst is oxygen or nitrogen, making them unsuitable for photoresins because they'll simply cure on contact with the air. Others use more exotic catalyst, like Magnesium or fluorine, etc. For these you can use a chemical that either contains one of these in a way that either passively lets it interact with the monomer, making a two-part casting resin, or one that must be energized to allow it to interact with the monomer, making a photoresin. In general, simple monomers are generated by mixing an oil, a gas and a precise heat.

The tough part of photoresins is figuring what monomer will work with what catalyst, and what catalysts are photoreactive. And then figuring out what oil and gas to get the monomer and some source for the catalyst. Once you have these three, it's just a matter of cooking and mixing (and hopefully not exploding or getting mistaken for a drug lab).

There's a discussion over in this thread about possibly making Linoleum photoresin from linseed oil and manganese vitamin suppliments.

[JSenior]

Diy resin is very simple to make and can be done at home. The hardest part would probably be sourcing the chemicals cheaply.

You need a monomer (the resin) and a photo-initiator (plus dye if you want it coloured.)

Put the monomer into a container (not opaque!) and put it on a magnetic stirrer at low speeds.
Add the dye and leave for a small duration.
Then add the photo-initiator and let it stir until there is no hard substances (probably 3-5 days.)

Once done it's ready to be used, or stored away.

You'll obviously want to play with the speeds and duration and it will change with how much resin you're trying to make at a time.


This is the standard recipe people talk about:

Monomer: 1000 ml 1,6-Hexanediol diacrylate
Dye: 0,06 g Sudan I
Initiator: 20 g Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide

There's plenty of different chemicals you can use however. Some initiators work better than others for certain frequencies.

You also have to purchase in good quantities to get a good price however.

[Feign]

Monomer: 1000 ml 1,6-Hexanediol diacrylate
Initiator: 20 g Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide

So, are there trade names for either of these chemicals or other uses they seperately might have? Knowing the chemical names of the ingrediants is all good and well, but I think what Vinnie is looking for is a photoresin that can be made with household chemicals, or at least common market-available ingrediants. (Which I realize is a pretty tough request!)

[JSenior]

So, are there trade names for either of these chemicals or other uses they seperately might have? Knowing the chemical names of the ingrediants is all good and well, but I think what Vinnie is looking for is a photoresin that can be made with household chemicals, or at least common market-available ingrediants. (Which I realize is a pretty tough request!)

They're all easy to get (stick them into google.) They'll just cost a lot in small amounts. Ring up your local chemical supplier and they should be able to assist.

The big companies probably aren't spending more than a few dollars a kilo for the materials themselves.

On the flip side, is it really worthwhile making your own resins? If the quality is good enough (and it's presumably going to be at least as good as mixing your own) then by buying in bulk there is resin available which is cheaper than the cheapest filaments. There's also companies which have list prices at not much more for small amounts: http://makerjuice.com/product-category/resins/

[Feign]

Oh, I realize there's not much liklihood of making a cost-effective DIY photoresin. But the proliferation of SLA printers makes the field of home chemistry much more interested in the field of photoresins. It's possible with so many eager minds on the subject that someone might just come up with something new. (not me, I'm pretty far out of my depth with advanced chemistry, but I like to read science papers and tend to be an ideas guy in general)

That said, what kind of photoinitiators are out there? In the thread I linked, Amirjabri mentioned Manganese and Curcumin (though I'm a bit sceptical on Curcumin working very well) but from what I understand, they only act as catalysts for oxidation. Are there photoinitatiors that can catalyze other reactions? Ones that act as bases or acids while exposed to UV?

I'm sure I'm sounding like a school kid to anyone with a chemistry degree, but I'm very curious about all this.

[JSenior]

There's a huge amount of them. Have a search for resin photoinitiators. There's a lot of research papers on them.

SLA tech has been around for 30 odd years. The machine tech has hardly moved on, it's all very simple, but the resins are ever improving.

Read about brand names such as irgacure 784, 250, 369...

[4Unow]

Is it safe to mix the chemicals to make the resin, if we were to get large amounts for a decent price? I know that the raw materials for making filament is extremely affordable compared to the price that filament typically sells for. Is it the same case with the chemicals needed for resin, or are they expensive as well?

[JSenior]

Wear gloves and you'll be fine. You mix it at a very slow speed, so there is little to no chance of spilling. Some resins may smell, but you'll want to leave it in a dark place, out of the way while mixing, so there shouldn't be any problems.

The ingredients can be very cheap. But I haven't done enough research into what they are and where to get them. I have talked to a chemist from one of the big resin companies, and he says the material is throw away to them, a couple of bucks a kg to make. The cost is in the research, after-support and machinery. The cheapest company I've found selling pre-made SLA resin so far, will do it for less than $25/KG if you purchase 200kg at a time.

I've thought about making my own, but the main thing I worry about is consistency. I don't necessarily mind purchasing a large mixing VAT, but I'm not a chemist and I can't be confident enough that each batch I make will be exactly the same and compliment the previous.

Professional resins can cost $400/kg but when we can easily get DIY resin for $25-50 kg (which is the only level which we can realistically hope to achieve without proper machinery and knowledge,) how much are we realistically going to save by making our own?