diy stir bar

well I made myself a stir plate from crap I had in my garage didn't have to spend a cent then I need a stir bar and the prices for those things are crazy unless you buy a bag of them. so I made my own. here's what I did.
I used a piece of an old plastic racking cane I had from my first brew kit. cut a 1" piece off and cut a screw that fit tight inside to just under 1".




I then put the screw inside the plastic tube.




the I cut a small piece off the racking cane to melt into the end of the stir bar.




I let the plastic burn for just a few seconds to let it melt into the stir bar and push it in with a screw driver. be careful not to let it burn to long or the plastic will turn brown.




then I carefully grind off the extra plastic.




then I use a file and by hand file it into an egg shape so the ends are narrower than the middle. I made one without doing this but it did not spin well.




I then insert the bar into the end of my drill adapter tape it in and center it as much as possible.




with it in the drill I carefully grind it against a file to round it as perfect as I can into the egg shape and then sand it with 400 sand paper and finally wet sand all while the bar is in the drill.




here's the finished stir bar. made two because the first one I cracked while making it because I put it directly in my drill and tightened it to much. took me about 20 minutes to make the second one and now my total cost for my stir plate is still $0.




here it is spinning up a nice vortex inside a 1L jar I had on top of my DIY stir plate.

A+ for effort. How do you intend to sanitize them? I don't think they will hold up in a boil.

tasq,

Stir bars don't go in the boil!

I'm going to try this.

Great idea. Buying stir bars is a PITA.
snake10

Snake10 said:

tasq,

Stir bars don't go in the boil!

I'm going to try this.

Great idea. Buying stir bars is a PITA.
snake10

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Uhm... they do in my house. I boil the bar right along with my starter. Stir bars are notorious for causing infections if not boiled. Look around for some threads.

Wow. Nice DIY, but they're $4. That's shipped
http://stirstarters.com/

tasq said:

Stir bars are notorious for causing infections if not boiled. Look around for some threads.

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Not if clean them and soak in starsan.

bja said:

Not if clean them and soak in starsan.

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Again, not true. I'm trying to find the thread now where a guy ended up cutting his open. It was disgusting and a starsan soak wouldn't do a damn thing for what he found.

Many bars are not a single piece of plastic, but rather 2 sandwiching a hunk of metal. The tiny gap allows crap to collect inside the stir bar. The only way to kill it is heat.

In the OP's case, all the nooks created by melting the plastic would be a nice place for the critters to hide.

tasq said:

Again, not true. I'm trying to find the thread now where a guy ended up cutting his open. It was disgusting and a starsan soak wouldn't do a damn thing for what he found.

Many bars are not a single piece of plastic, but rather 2 sandwiching a hunk of metal. The tiny gap allows crap to collect inside the stir bar. The only way to kill it is heat.

In the OP's case, all the nooks created by melting the plastic would be a nice place for the critters to hide.

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Good stir bars are a magnet overmolded with teflon. There are no tiny cracks unless the stir bar has been damaged. I suppose there are cheap ones out there, but I've never seen any.

bja said:

Good stir bars are a magnet overmolded with teflon. There are no tiny cracks unless the stir bar has been damaged. I suppose there are cheap ones out there, but I've never seen any.

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I have seen several with seams on them. If yours are truly sealed then you are right.

My point still stands about these DIY ones though. Melted plastic is a porous material. I think they'd work fine in a pinch, but I certainly wouldn't consider using these long term. A $5 stir bar is cheap insurance for an entire batch of beer.

Food for thought.

I plan on cleaning them and using starsan. should be fine. this is the same plastic I use for my racking cane which i have never had a contamination problem with so I see no problem with sterilizing this way. I also polished this thing up really well by wet sanding it so it's only as porous as the original plastic. if it does start growing funky stuff I will be able to see it because it is clear.

You have microscopes in your eyes? Nifty! Where can I get some?

I wonder if letting the stir bar spin around in your flask with some sanitizer would help get the sanitizer into all the little nooks? You could also see what happens if you boil it. After all, it's just a little bit of racking cane and a screw if it does melt.

Quite honestly any gram negative bacteria could be clinging to the inside of your glassware (which looks like a jar) if you don't properly sanitize it. They are hydrophobic which is just like it sounds. They don't like to be in liquid, so they clump and stick to the glass. That is why a good Pyrex flask that can be boiled or steamed or even autoclaved is best.

IrregularPulse said:

Wow. Nice DIY, but they're $4. That's shipped
http://stirstarters.com/

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Thank you for this. I've been trying to find a good source for a stir bar and flask and this is it!

boil them to sanitize. I wouldn't think you would have to do it for too long, just a min or two, and try not to let then sit on the bottom of the pot and get melted. I would be kinda worried that starsan would not get into every little knook and cranny, i could be wrong.

-edit just realized how old of a post this was

This post might be old and resurrected and shot to hale but I really like the OP's DIY ingenuity.

Did you ever have any contamination problems using this stirbar Buzzardman?

Seems like a lot of work to make a stir bar. Try using 2 bic pens, pull the endcap out of one, cut the back off the other, add small magnets into the tube (google buckyballs), and plug the tube with the second end cap. Use an O-ring around the middle or the tube to let it spin.