Alternate Methods

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soligen

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Joined
May 11, 2010
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1,090
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Sterling Heights, Michigan
Since i'm just starting this, I want to maximize my results without much investment. I want to run a few alternatives by you guys in case there are any pitfalls you know of.

Bubble Removal. Methods posted involve a pressure pot or ultrasonic cleaner. My alternative (yet to be tried) is to use an up-side-down palm sander. I can make a little tray to velcro on so the cups dont vibrate off.

Heat curing blanks. Suggestion is a toaster over. I dont have one and loml may not like using the big oven. Putting the blanks in a hot car helped, but most of the year this would not be viable in Michigan. My thought is to use hot water. Hot tap water seems like it would be about the right temp. My thought is to put blank and not water in a thermos. Change water after 5 min once blank heats up. Leave in thermos for a few hours.

I plan to try this next time, but want feedback first in case there is some wild unforseen safety issue. For example, does partially cured resin explode when put in water?:eek::eek::eek: Create poisonous gas:eek::eek::eek:? I'm no chemist, but I do know not to mix bleach and amonia.
 
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My current PR casting methodology (and I am NOT suggesting that this is the best way, just a way that usuall works in my environment) is four-fold.

First, I use a ultrasonic cleaner with heat to thin and degas the uncatalysed resin with colorant (individual colors all get a seperate container) for 180 seconds with heat.

Second, I add MEKP and stir very slowly with a plastic spoon (I don't use the electric drill as some posters suggest). Then, I pour each mixture into the mold as slowly as possilbe before allowing the mixtures to start gelling. I swirl the colors slowly and stop swirling as the mixture begins to thicken.

Third, I set the mold on the table of a running band saw, scroll saw or whatever tool is close that produces some vibration. I usually let the saw run for approximately five to ten minutes.

Fourth, I put the mold into a Wal-Mart toaster oven at 150 degrees for about 15 minutes.

This usually gives me a nice "almost" bubble-free blank.
 
It won't explode or give off any noxious vapors but I'm not sure how the water would affect the curing of the resin . I don't think it would be a working solution . Toaster ovens are cheap enough and if you have a Goodwill or Salvation Army store near you , you could pick one up for just a few dollars . You could also build a small hot box using several different methods . I made mine by taking a Styrofoam ice chest (a friend gets his medications shipped in these nice cube shaped Styrofoam boxes but any kind will work) I lined the inside with aluminum foil (spray glue works well to stick the foil to the insides) and laid it on it's side so the top works like a door and put an Aquarium heater through a hole in the bottom (now the back) . I can adjust the temperature on the heater to get the inside temperature up to 150 degrees , but I usually keep it at 125 degrees . Since the heater has a thermostat built in it keeps the inside at a constant temperature and because the heating element is enclosed in the glass tube there is no worries about fire or explosion . It works great for preheating the resin and molds and post curing the blanks . Plus it doubles as a wood blank drying kiln .
Someone else on here did a hotbox using a cardboard box and a couple of light bulbs a couple of months ago . Do a search for "Hot box"
 
I found my little "cheapie" toaster on sale a while back for $14.99. I already had the ultrasonic cleaner, but it recently died and I just bought a pretty nice one. It was $79.99 at HF before the 20% discount.
 
Ok, scratch the heated water idea. I had no clue toaster ovens could be obtained so inexpensively. Thanks. There is a good will near my work - I'll check it out, and in the mean time the hot car method should still work reliably for the next 6 - 8 weeks or so.

I don't hear any issues with the sander for vibrations, so I'll try that. I'm sure I'll end up with an untrasonic cleaner at some point - just not ready to spring for it yet. I spent my little bonus from work on the basic materials to get started, and a wood-chuck, so ultrasound will have to wait.

Thanks for all your input.
 
For per-heating resin and post curing blanks I use a large crock-pot. In the center of the lid I drilled a hole to insert a temp. Probe. When the resin temp. comes up to 150 degrees I remove the lid wipe the probe on a paper towel then add the catalyst and pour slowly. After the blanks come out of the mold I put them back in the crock pot for about twenty minuets then turn off the power and take them out the next day.
Mark
 
+1 on the toaster oven from Goodwill!

A $4 lamp timer from the BORG, but the oven on bake, set lamp timer for 1-2 hours- walk away...

Of course if you want to watch it, you could reset the :30min timer 3-4 times too...

-Doug
 
HF coupons

If you have an email address you don't mind getting a little junk to, go to HF site and sign up. I get sometimes 2-3 e-flyers a week from them with coupons.
I use the same email I request for catalogs from so it isn't an issue. You can make a 'throw away' email at yahoo.ymail etc for free. And I can wipe it all out with one click. I haven't gotten spam from anyone I didn't ask to send me something.
 
If you needed a taller heating area one can be made with either wood and lights or wood and stove elements. Look up powder coating oven plans....plenty of reading there. I like the crock pot Idea though.
 
The only problem with the toaster oven is you shouldn't use it for preheating your resin . PR is very explosive and any spark or glowing element could cause a fire or worse .
 
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