Casting Save ?!?

[hughbie]

Hey all, happy holidays
now on to the subject at hand.
I've only casted three times and loving this. But since i got my mold from Matt, I've used it twice already. Keep in mind that i don't use a pot, yet.
Both times I've mixed my resin and poured, the resin doesn't set up completely. i guess that since my shop is in my basement and rather chilly, that's the main reason of all the stickiness. my second cast, i poured in the mold and realized that i forgot to use the catalyst so i added drops to each blank and stirred.

this seems to be running on and on but here's the main reason of this post.....

since my blanks didn't set up completely and the catalyst generates heat to set the resin, i thought i would heat my oven and 'bake' my blanks to see if they would set up completely.

it does!

has anyone else had to do this? what's the thought of using a small toaster oven or even better, use more catalyst? right?

let me know what ya'll think

 

[doddman70]

Man i can't even imagine the smell from the oven[xx(] that stuff smells bad enough right from the can. i have not heard of anyone heating up the resin in an oven. i would think that you might want to check the flash point on the resin before i did that again. as far as more catalyst i have had some castings take only a matter of a few hours to cure and i have had some that have taken a little more that a week. you just have to be paitent with it some times the best i can tell is that it depends on what kind of dye or pigment i'm using some of them take longer to set that others regardless of the amount of catalyst i ad to try and speed up the process.

SHANE

 

[MesquiteMan]

Be careful, PR is very flammable according to the MSDS.

 

[kevin_f]

I had the same problem last week-end. I poured some casts just as the weather turned cold and wet. I left them in the pot under pressure for over 24 hours and then let them stand for another day, but they were still way "under cooked". I placed a halogen work light about a foot above mine (still in molds) for few hours and that cured them out.

 

[stevers]

My shop is room temp, right now in the 40s and 50s. My last cast for a Friend took an extra 2 days to set up. Should have added more MEKP. No big deal, it still set up and worked fine.

 

[OKLAHOMAN]

Guys,in the winter I have heated my toaster oven to 150 degrees and put my PR in without the catalyst to make the resin more workable. During the summer my shop when not in use will get to at least 120 degrees, so I have no reason to think its going to flame up with the oven @150 as the pr is @40 degrees or so when its put into the oven and the pr itself never has gotten hot only warm in the oven. Just my 2 pennies worth as it works for me.

 

[hughbie]

thanks guys. yea, it stunk up the house a little but after a couple of hours, the wife and i pretty much went numb on it! LOL
i've done this twice, and both times it saved the pour. i agree, it probably shouldn't be the norm, but it worked on blanks that had sat 'curing' for 3 days and still sticky and wet.
thanks guys....HAPPY HOLIDAYS

 

[Blind_Squirrel]

When it is cold (below 45) in my garage I turn on the toaster oven (set at about 150 degrees) that I use for powder coating and place my fresh blanks in there for 30 minutes. They come out set and ready to turn.

 

[RONB]

A little heat speeds up the chemical reaction.
A lot of heat sets it on fire.

 

[maxwell_smart007]

http://books.google.com/books?id=Tt...ts=0iz2ZFKPpI&sig=YwGwYS2Xr3xPJi0b90tDx9eAOfw

Did a quick search...not sure if this is the same TYPE of PR, but it lists the flash points of some PR on page 421 or something like that...not as high as I would have thought...125F to 210F...

Andrew

 

[Phillip]

The oven may not have ignited the resin when you did this. My concern would be with the flammable vapors and air mixture you have with the added ignition source of the oven. When the fuel air ratio is just rite with an added ignition source (your oven) there will be a fire. Three things needed for a fire are heat (your oven), fuel (PR resin vapors) Oxygen (21% in our atmosphere). Sorry this is just the fire fighter in me stepping out. Don't want to see anyone get hurt. There are heat wraps out there that you can adjust the thermostat and are rated to use for this type of service. They can get a bit expensive but will reduce the risk of property loss and personal injury. I have seen them but can't remember what site they were on.

 

[bitshird]

My wife nearly strangled me just for mixing PR in her kitchen, I tried to explain that it was too cold and dirty in my shop, then she aske if it were too cold and dirty for me to sleep in, I got my revenge though, I used her microwave to dry out some deer antler I had boiled to straighten [8][8][}][}][B)]

 

[elody21]

Guys! PR is a dangerous Carcinogen!!!!!!!!!! I live in Illinois and just cannot cast in the winter.[V][xx(] Keep it out of the house!!!!!!

 

[Blind_Squirrel]

Originally posted by elody21

Guys! PR is a dangerous Carcinogen!!!!!!!!!! I live in Illinois and just cannot cast in the winter.[V][xx(] Keep it out of the house!!!!!!

According to the MSDS (http://www.delviesplastics.com/msds/Casting-Resin-MSDS.pdf) There is no evidence that "CLEAR CASTING RESIN" is a human carcinogen.

Styrene has been identified as a possible</u> human carcinogen by the International Agency for Research on Cancer (IARC). The IARC determination is based on "limited evidence" in animals and other "relevant data." IARC concedes there is "inadequate evidence" on humans for its findings.

Source: http://www.fiberglassflorida.com/products/datasheets/msds/resins/Interplastic 41 Casting Resin.pdf

I would be more worried about peanut butter, french fries, potato chips or BBQ'd meat than I would be about PR: http://en.wikipedia.org/wiki/Carcinogen

All that being said, be careful and use plenty of ventelation.

 

[OKLAHOMAN]

Guys your heating the toaster oven to 150 degrees NOT the pr just the air around the container the pr is in the pr might reach 75-80 degrees at most. Yes do not do this in your kitchen oven and yes have ventelation.

 

[Glass Scratcher]

The techs at many of the supply companies are good for information. Several of them from different companies have told me to preheat molds or tooling to around 150deg F before pouring resin. One of the techs (I can't remember which company presently) said that if PR didn't set overnight with 3drops of Cat. then to place it in a 150 deg oven for an hour to kick off the chemical reaction. YMMV

 

[bitshird]

The instructions with the PR from MR. Fiberglass recommends 10 drops per OZ on 3/4 thick castings, mine Gel in about 25 to 30 min and are pretty well cured at about 6 hours at 70 degree ambient temperature

 

[stevers]

Great cure time, but you have to remember, the more MEKP, the hotter the cure. When doing some custom stuff, snake skins and label castings for instance, heat is your enemy. Heat softens the glue on the labels. Never cast a snake skin, but I believe I heard heat is bad for casting snake skins. Just a thought. Especially for the new casters out there.

 

[Draken]

The hotter it gets, the faster it sets, and the more brittle it will be. I've had some which were still soft after a day, so I preheated the oven to 125F, turned it off, and put the PR molds in on a cookie sheet lined with foil. That did the trick and they gelled. I've also used a desktop halogen light to add heat near the mold when the temps in the garage dip a bit.

Even without the heat, they will eventually cure, if you are patient enough. Had some pliable ones take about two weeks to reach final cure while sitting in the basement.

 

[bitshird]

Ok I know Don Ward recomends 3 or 4 drops per OZ and when it comes to snake skins I think He Be Da Man, his label pens looked darned good as well.
I was going to try a photo label next week, so I'll back off the catalyst, My casts haven't been brittle, they turn with a steady string of waste (which usualy balls up on my chuck and throws stuff all over) I'll try the lower Cat rate in my single mold, it's made from 1/2 in UHMW so no danger of messing it up, for saftey I'll set it outside in my toaster oven, I guess Gadgets would stand 125 to 150 degrees, or a 500 watt halogen shinning on it,but I hate to take a chance with it, I'll just use the 10 drops on plan PR with colors.
I still think back to my training days as a jewelry caster, there is always a trade off where time and temperature are used as a metric of measure, I was going to look through the Archives and see what YoYo spin says, I thought the 10 drops sounded high, the stuff from Hobby Lobby ony recomends 5 drops for a 3/4 inch cross section per OZ and only 2 for a second layer. But their resin took for ever to cure, nearly 36 hours, but that coukd have been caused by too much colorant, I weigh mine on a tripple beam scale that is pretty accurate. now to get some accurate measures fir the pearl eX, I have a 4 beam scale but thats getting a bit over the top just need some measuring spoons

 

[Gadget]

Did you try pre heating the silicone mold? You can heat them in an oven to a nice warm temp just before casting and that may help. The silicone that i use claims to withstand up to 400f. I would think something around 130f would work. Just a guess on my part. I would heat them, pour and set into a stryofoam cooler to retain heat so they can cure well. Just my 2 cents.

 

[stevers]

Good two cents. Thats a thought.

 

[smitty]

I have been using a toaster oven for casting since I started, Over a year now. I set it at about 125 deg. and it works fine. I do keep the oven in the shop because of the smell.

Smitty