Does your product come with a warranty?
Our stir plates ship with the following
warranty and this warranty is in effect regardless of who you
bought your stir plate from. Warranty repairs can be handled
through the retail outlet you bought your stir plate from or
directly through us.
This product is covered by a one year workmanship defect
warranty. Your stir plate warranty extends one year past
your purchase date or 18 months from the manufacture
To claim your warranty, ship your defective stir plate
along with a note explaining the defect and a copy of
your purchase receipt to the address listed on the
web site. If returned without a valid receipt, the
manufacturing date code will be used to determine
stir-plate.com is not responsible for warranty
return freight but will cover freight back to you.
Repaired and / or replacement product will be returned
as shipped to us. For example, a stir plate shipped in
without stir bars will be returned without stir bars.
This warranty does not cover user abuse, damage from
incorrect power supply or unreasonable product
expectations. For example, expecting a SP-2000 to spin a
5 liter starter as well as a SP-3000 spins a 5 liter
- Does your stir plate have a weight limit?
Our stir plate housings are made of high
impact high strength polystyrene plastic and there is no known
weight limit. I've actually stood on one of the assembled
housings we use to see if it would hold up to my weight and it
did. But like everything else you should be reasonable. You
might figure out how to put a 5 gallon carboy of beer on our
SP-2000 stir plate, but why?
Does your stir plate have a size limit?
We have set-up a starter in a 5 liter
flask on our SP-2000 model stir plate just to see what would
happen and the starter spun fine, even though the 5 liter flask
overlapped the sides of the stir plate by quite a bit. But the
overlap worried me - it just didn't seem safe. This test and requests
from customers for a stir plate that would reliably spin a 3 to
5 liter starter led us to design the SP-3000 stir plate. Then
during most of the summer of 2011 we worked on the Black MAXX
Stir Plate, the only low cost stir plate we know of designed to
spin a 5 or 6 gallon carboy of beer.
Here are our recommended flask size
ranges for each stir plate:
SP-2000 - 250 ml to 2 liters
SP-3000 - 1 liter to 5 liters (our most flexible stir plate)
Black MAXX - 2 liters to 6 gallons
Do your stirplates come with Speedsafe?
Speedsafe is a term used by a competitor
to show that their stir plates will not over-rev and destroy
themselves. And although we can't use their term in our product, our
stir plates are also RPM limited and will not over-rev and it is
perfectly safe to remove a flask from one of our stir plates,
even at full RPM.
Does your stirplate make noise?
All stir plates can make noise depending on
the RPM you run them at, the type of stir bar you choose, the
type of flask or jar you use and how well the flask is centered
on the stir plate. The noise is caused by the stir bar wobbling
inside the flask and the noise can also be caused by a stir bar
that's too long. Our stir plate is no exception, but we
carefully chose the correct length stir bar and other components
to minimize this effect.
One competitor falsly states that PWM is
noisy - it's not. Our stir plate does make a slight humming noise
at some speeds - It's
inherent in the design of a PWM stirplate. But we chose a PWM
frequency and components to minimize the hum and the volume is
low enough that you can't hear it over the stir bar. And
anyways, you aren't going to be running one on your night stand!
I built a stir plate using one of the LM317 regulator plans on
the net. The stir plate spins the stir bar fine at slow speeds but
when I try to speed it up the stir bar throws off every time. Did I
do something wrong?
Probably not - there are issues with the
simple LM-317 design that's floating around the net. The biggest
issue is that at anything remotely approaching full speed, the
motor is spinning way too fast. A LM-317 regulator based design
will work but you need to build a smarter regulator circuit that
limits the voltage to the motor to about 6 VDC. Also, no-one
discusses magnet spacing in detail and the type of magnets you
really need to be using. One of the worse magnets to use is a
used hard drive magnet because a used hard drive magnet does not
provide the two concentrated magnetic poles you need to keep the
stir bar captured at all speeds. Also, because of the shape of a
hard drive magnet it's impossible to have the weight centered
and the two poles centered. To keep your stir bar captured
at all speeds, you need two opposing magnets with a flux density
of at least 2500 Gauss, the poles must be under or just outside
the ends of the stir bar and the magnets need to be very close
to the ends of the stir bar.
Note: Some people try to play down
these design flaws by stating something like "you don't need
to spin your stir plate at high speed anyway, just a dimple
on top will do". This does little to explain away an obvious
defect in their design!
Not seeing your stir plate I really cant
tell what's going on but maybe I can help anyway.
I'd suggest placing the stir bar in a
flask full of water and then lower the flask towards the top
of the stir plate. If the magnets don't grab onto and center
the stir bar within 1/4" of the top of your stir plate with
some force then I can say for certain that your magnets are
mounted too far from the top of the box or they are not
If the stir bar does center but you
can't run full speed then start slow and slowly turn the
speed up. If you can generate a vortex that reaches at least
1/4 way down the flask but the stir bar is thrown at faster
speeds then the regulator is driving the motor too fast for
If you can't generate much of a
vortex before throwing the stir bar then it's a magnet
problem. The drive magnets aren't strong enough, you are
using a used hard drive magnet, the spacing isn't correct
(this could be center to center spacing or distance from the
top of the box) or the stir bar is bad (not likely).
With any well designed stir plate,
you should be able to place your flask on the box, turn the stir plate on,
then adjust the speed to high. The stir plate
should spin up to full speed and pull a strong vortex
without throwing the stir bar.