This might fall under the category of over-cautious, but are cups like these ok for mixing resin in? It feels like there is a slightly waxy surface inside. Would that be a source of significant contamination? I have only ever used plastic containers previously.
I would think it's fine with epoxy resin. Definitely wouldn't use it for polyester resin.
Why use paper cups? Water cooler plastic cups would be better for the environment.
And cheap ..Ebay
100x200ml $12 inc del
100x450ml $18 inc del.
They work fine...
... except when you mix too much in one and then also heat it in a cup of hot water to make it less viscous, and then realise that it has already started to gel and starts smoking and you have to quickly run outside with a rapidly heating cup.. not that that would happen to me 
They work fine and I use them all the time now that plastic cups are verboten.
It's obligatory for Americans to use these cups for mixing epoxy
My daughter had a pen pal from Austria who came to stay with us and was surprised that red Solo cups were actually a thing and not just a movie trope. fwiw, I use the paper cups, too. Haven't set one on fire, though. Yet.
It's such a hoodwink to replace plastic cups with petroleum wax coated paper cups. And what's worse is those wooden knife and fork packs that are covered in colored wax coated paper to make them look natural. Have you eaten with those? It's like licking a blackboard. Not to mention replacing plastic straws with crappy paper ones that you need at least two to get through a drink. Don't get me started. If the government really wanted to help the environment, they would improve the public transport system. Stop picking on the poor straws. That one pic of a dead turtle with a straw stuck in its nose. Which the whole world saw and started the ban on plastic straws. It was probably a kid that poked it into a dead one. I would have when I was young. Where I live, they have a turtle graveyard. One a week on average in the passage from boats and jet skis. Do they lower the speed limit, no. They ban straws. FFS !
I like to be accurate mixing epoxy resin so I get the cups with measurements on the side.
Or as Tardy a straight can and then marks on your stirring stick for the 4:1 (or what ratio it is).
Having seen plenty of "Hot Brews"! 
I then pour it into a 2l ice cream container 
Select to expand quoteImax1 said..
It's such a hoodwink to replace plastic cups with petroleum wax coated paper cups. And what's worse is those wooden knife and fork packs that are covered in coloured wax coated paper to make them look natural. Have you eaten with those ? It's like licking a blackboard. Not to mention replacing plastic straws with crappy paper ones that you need at least two to get through a drink.Don't get me started. If the government really wanted to help the environment, they would improve the public transport system . Stop picking on the poor straws. That one pic of a dead turtle with a straw stuck in its nose. Which the whole world saw and started the ban on plastic straws. It was probably a kid that poked it into a dead one. I would have when I was young. Where I live they have a turtle graveyard. One a week on average in the passage from boats and jetskis. Do they lower the speed limit , no. They ban straws. FFS !
Top rant 
Select to expand quoteazymuth said..Imax1 said..
It's such a hoodwink to replace plastic cups with petroleum wax coated paper cups. And what's worse is those wooden knife and fork packs that are covered in coloured wax coated paper to make them look natural. Have you eaten with those ? It's like licking a blackboard. Not to mention replacing plastic straws with crappy paper ones that you need at least two to get through a drink.Don't get me started. If the government really wanted to help the environment, they would improve the public transport system . Stop picking on the poor straws. That one pic of a dead turtle with a straw stuck in its nose. Which the whole world saw and started the ban on plastic straws. It was probably a kid that poked it into a dead one. I would have when I was young. Where I live they have a turtle graveyard. One a week on average in the passage from boats and jetskis. Do they lower the speed limit , no. They ban straws. FFS !
Top rant
I feel better now 
Well, I'm going to have a massive mix-fest in my paper cups now. Environ-"mental" issues I will leave to Imax to straighten out.
I cut the bottom out of soft drink bottles to mix my epoxy resin. You can reuse many times by just letting the remnants harden. The hardened remnants actually ballast the container and stop it from being accidently tipped over during use.
^^^ +1
Doing numerous a day means half a 2L juice bottle is great
Little medicine cups for the 15ml mixes..... leave a tiny bit in the bottom with the stirring stick so itseasy to rip it out later and reuse
But yeah the paper cups are good... plastic ones like Paducahs pic melt with many solvents like paint and found out the hard way...
Select to expand quoteImax1 said..
It's such a hoodwink to replace plastic cups with petroleum wax coated paper cups. And what's worse is those wooden knife and fork packs that are covered in colored wax coated paper to make them look natural. Have you eaten with those? It's like licking a blackboard. Not to mention replacing plastic straws with crappy paper ones that you need at least two to get through a drink. Don't get me started. If the government really wanted to help the environment, they would improve the public transport system. Stop picking on the poor straws. That one pic of a dead turtle with a straw stuck in its nose. Which the whole world saw and started the ban on plastic straws. It was probably a kid that poked it into a dead one. I would have when I was young. Where I live, they have a turtle graveyard. One a week on average in the passage from boats and jet skis. Do they lower the speed limit, no. They ban straws. FFS !
It seems like the straw thing was highly dubious. I don't really care for straws anyway but yes the paper ones are absolute crap.
Interestingly enough it seems like fishing line, rope, and other garbage is more of a problem than others. At least, at this place apparently in the same country as Luderitz:
Ya cups are fine Shifu. Used them for yonks on all the stuff you've seen of mine using poly, vinyl & epoxy. They don't like acetone, thinners etc... for any length of time.
Friday's interesting side notes
round mixing vessels are better than square, simply better for the mix, Less chance of unmixed stuff being caught up in the corners and ending up on the job. Same issue with cleaned out everyday containers, they often have weird shapes in the bottom that hinder a thorough professional grade mix.
Never wipe out the container with ya brush to use the last of the resin. If there's any unmixed resin its on the surface of the container where that devil mix will be.
If you want to be pro, get some mixing cups from a paint supplier. See through to see you've mixed proper good and with all the mix ratios you'll ever likely to need on the side. Plus they tend to allow epoxy to pop out and can be reused.
Happy mixing bro
Select to expand quoteMark _australia said..
But yeah the paper cups are good... plastic ones like Paducahs pic melt with many solvents like paint and found out the hard way...
I'm on Team Paper Cup, fwiw. 
Red Solos are for "beverages".
Select to expand quoteMark _australia said..
^^^ +1
Doing numerous a day means half a 2L juice bottle is great
Little medicine cups for the 15ml mixes..... leave a tiny bit in the bottom with the stirring stick so itseasy to rip it out later and reuse
But yeah the paper cups are good... plastic ones like Paducahs pic melt with many solvents like paint and found out the hard way...
Have you ever used Coke cans? The method was to file around the top edge to take off the cap. No lip. It is a bit of work but, once upon a time Coke cans were plentiful.
Select to expand quotedecrepit said..
I use the bottoms of yogurt containers, both large and small.
Me too. I have a stash good to go.
paper cups are good for coloured resins, can mix 3-4 different colours in cups.
I like to use silicon cup cake baking trays. I cut one out and use it many times (cured epoxy remains are pealed out of container, then I wash container out using boiling water to remove residue). I can get the heat gun under the container and heat the epoxy for 5min in order to accelerate curing time. If the epoxy goes into thermal runaway (if it ever does) - no problem !
Coke cans are the best for pinching a really small spout in the top edge.
Tinyyy dribble possible
Select to expand quotejn1 said..
If the epoxy goes into thermal runaway (if it ever does) - no problem !
Back in the mid 80s I worked in a factory building trailer yachts and other fibreglass products. We used a mix of polyester resin and iron sand to bed lead ingots inside centreboards. One day we over mixed by a litre or two and left the excess in the pot while attending to other jobs. Ten minutes later the pot was pumping out a fumarole of black smoke in a jet about 12 feet heigh. We got that thing outside quick smart!
Select to expand quoteShifu said..jn1 said..
If the epoxy goes into thermal runaway (if it ever does) - no problem !
Back in the mid 80s I worked in a factory building trailer yachts and other fibreglass products. We used a mix of polyester resin and iron sand to bed lead ingots inside centreboards. One day we over mixed by a litre or two and left the excess in the pot while attending to other jobs. Ten minutes later the pot was pumping out a fumarole of black smoke in a jet about 12 feet heigh. We got that thing outside quick smart!
LOL, no solution is going to be completely fool proof. I've only ever had thermal runaway once when I didn't follow the mixing instructions.
Select to expand quoteImax1 said..
Why use paper cups? Water cooler plastic cups would be better for the environment.
We are talking about mixing epoxy resin. Probably shouldn't use the words "better for the environment" in that context.
What I meant was , producing plastic cups is better for the environment than paper cups. Once contaminated both are bad. So , if you were to buy cups , plastic would be better. Re using what you have would be best. But in the grand scheme of things , if you drive a car to go windsurfing, cups will make no difference at all.
Worked in an aviation composite repair shop, clear round cups are only used to ensure you can see you have perfect mix. Most of the adhesives and resins are coloured different from their hardener so you can see a uniform mix.
Also a good freezer, mixed adhesive/resin will keep for several days before thickening, great for repairs and multiple applications.
Select to expand quoteairsail
Also a good freezer, mixed adhesive/resin will keep for several days before thickening, great for repairs and multiple applications.
Interesting, do you loose any qualities doing this ?
Select to expand quotedecrepit said..
I use the bottoms of yogurt containers, both large and small.
Me too. Yummy and they don't have corners on the bottom
