PR and # 6 polystyrene cups.

[louie]

I have been using the hard clear 9 oz plastic cups (Chinet cut crystal) for mixing PR. I have used hundreds of them and never had a problem.

I was out of these cups one day except for my master cup and I looked on the bottom for the recycle code and it was "6 PS" (polystyrene). The little 3 oz bathroom cups we use were also marked "6 PS", so I thought, PR doesn't eat through polystyrene, I can use them. Wrong!! the PR ate right through the little cup in a few minutes.

Now the bathroom cup is much thinner, but does this mean that the PR would eventually eat through the Chinet cups?

Thanks

 

[Skye]

Only one way to know for sure. I prefer to use the wax paper cups kids use in the bathroom. Cheap, better for the environment, if you're making bottle stopper blanks you can leave the paper on and turn it off.

 

[ldb2000]

Yes it will , you need the cups that say #5 which are polypropylene . PR will dissolve anything Styrene based . I use either uncoated plastic coated paper cups for mixing . Wax coated cups are ok too but if you are doing clear casts you have to be careful that you don't get wax scrapings floating around in your clear casts .

 

[louie]

Yes it will , you need the cups that say #5 which are polypropylene . PR will dissolve anything Styrene based . I use either uncoated prplastic coated paper cups for mixing . Wax coated cups are ok too but if you are doing clear casts you have to be careful that you don't get wax scrapings floating around in your clear casts .

Butch, but I am sure I read in the archives to use the hard plastic cups.

So where can I buy #5 cups?

For larger batches, I used the quart or 2.5 quart plastic mixing tubs from Home Depot paint dept. They are marked "2 HDPE". -- I think they are good as well

 

[ldb2000]

The #5 are also hard plastic just a different make up . I think that some get the #5 clear plastic cups from Wally World . I find that the 5 ounce paper cups from A&P are cheaper and work very well . HDPE should also work , anything but Styrene . PR uses liquid Styrene as one of the chemicals in the mix .

 

[louie]

Wally World, Kmart, Target, Party City, ... I figured they were all the same.

I found the Chinet hard plastic cups at Target. All the other cups were soft, I never even bothered to look at the bottom. I guess I will be making a trip to Walmart tomorrow. Thanks.

Ever use "1 PETE" -- I was thinking of buying the plastic tubes they use for small parts, mailing, etc. The tubes are PETE and the caps are Polypropylene. Only problem with these tubes so far is you have to buy in bulk. Still looking for a supplier who sells smaller lots. (assuming I can use them).

 

[Hardwoods]

I have checked three walmarts here in kansas and they don't carry the number 5 clear plastic cups. I will check the target stores. I don't know who wally world has for their buyers here in Kansas but they have droped the ball on a lot of stuff that they use to carry. Don in Kansas

 

[kevrob]

Don, I am glad to know I am not the only one who cannot find them in Walmarts in Kansas! Louie, I had the same issue with the little plastic bathroom cups, just last night, only I think mine had a 3 on the bottom.

 

[edman2]

Last time I needed hard plastic cups #5 I found them at a Party Store. Might check there if you have one close.

 

[PTownSubbie]

I use the 9oz hard plastic cups from "Sams Club". They actually are a #1 cup and the PR has NEVER eaten through those.

PR has sat for hours while curing and never had a problem....Now I just need a larger cup. Looking for the same thing in 12oz size...

 

[PenMan1]

Wal Mart and all of the supermarkets here carry the RubberMaid "moveables". They are recycle code 5. The come with lids and the 4 oz ones are perfect for pr casting. Eight on them fit in my ultra sonic cleaner all at once.

I have about a dozen of these. That is about the number of different colors that I use. I rarely clean these (although they clean easily after the pr residue cures). I just reuse them for similar colors on the next pour.