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production losses....(the long version)

updated fri 31 may 96


Don Kopyscinski on thu 9 may 96

Hi Tom,

(Clayarters, If you really don't care about production losses, now is a good
time to bail out, this is quite long.)

Jonathan was right when he said your losses are too high. I have had times when
they range from about 7% to upwards of 70% (bad times for sure... primarily due
to raw material problems). High loss levels can be so frustrating and costly.
They can threaten your existence as a potter. There have been times when I have
sold **over a ton of seconds** (literally) in about 4 hours of my seconds sale
weekend (they know a good deal when they see it!) to recoup some of my losses.
I have heard acceptable industry standards of 15-19% but to me, this seems too
high. I discussed this earlier in the year with a production potter who was
accepting a 20% loss primarily in the glaze firing due to application problems,
his partner refused all attempts at standardizing and quantifying the process
(still lurking here I think...I hope you've made some progress on this one) . It
is in this type of situation (consistant loss, far into the process) where the
greatest benifit may be had. Looking at your list I get a 28% loss rate.
Usually when they are so high, there is a predominant culprit. You seem to have
covered all the bases rather evenly. This will make it a bit harder to see
dramatic reductions in your seconds, but certainly there is much room for

When confronted by high levels of seconds I suggest that you analyze the problem
(something you have begun to do quite well), then tackle the problem areas one
by one, starting with those that offer the greatest return for your efforts.
Don't make the mistake of valuing a greenware second the same as a finished
glaze fault. The greater the amount of work that has gone into the piece at the
time of loss, the greater the value of the loss. You should also try to tackle
the higher value items first. If you can solve some warping problem with your
casseroles (with a lid and three handles) you can gain more than by solving a
similar problem in small items such as a small bowl with slight trimming, given
the same incidence. So....attacking those problems farthest downstream first
(the significant ones) will yield the greatest result in the shortest amount of
time. I would then try to get a handle on the items that are strictly a matter
of skill and technique (trimming...yours seemed quite high, some warping
problems, firing faults, poor joining technique, drying related matters,
etc...). Such reductions in loss rates require lots of soul searching and
thinking about the who, how, what, why, when, where of every step of the
process. I have determined that there are some jobs I was deligating to
assistants that were actually costing me ....I was paying people to ruin my pots
(I hate it when that happens). Knowing who is strong at doing what, and letting
everyone concentrate on their strong areas, is a good idea.

I have developed a seconds log sheet for use at times of high loss and it has
helped me zero in on some problems. I don't do it for every piece all the time
but during times of high loss it can sure help you focus on the problems at
hand. I offer a copy of it below (modify to suit your needs). The quick
barometer I have is a kiln value log. Sure there are going to be losses...they
are inherent in the process. Knowing when they get out of hand and acting
quickly can save you a lot. When we unload a glaze kiln we log that load on a
form (for later entry into our inventory). On entering that log into the PC, a
dollar value is taken before and after the entry (calculating this value takes a
few seconds with "Makers Automated Clerk") and a dollar value for that kiln
noted on the form. For me, hitting below a target value of ($300.00 wholesale
for a 10 cubic ft. kilnload is a big red flag to look closer at the
problem...your mileage may vary). Tripping over piles of seconds in the kilnroom
is a strong clue as well. I hope this helps you and others gain some insight in
your loss problems. I read in a book on manufacturing that the simple act of
logging losses on such a chart in itself reduced the losses. Just knowing that
losses will be analyzed will make everyone more aware of what they are doing
that could contribute to the losses.

Seconds Log

Filled out by-
Item code-
Type of piece- ( )thrown ( )jiggered ( )slab ( )extruded
Wholesale price of piece-
Total cost (Qty. x Wholesale price)
Stage of production-( )greenware ( )bisque ( )finished piece
Clay Used ( )regular ( )other __________
Category of loss-( )Process ( )Raw materials
Nature of defect-
( )Breakage
( )warp
( )crack
( )Junk in clay (obvious lg)
( )Pinholes
( )Lime pop (large)
( )Popout small
( )blow up in bisque
( )glaze ran and stuck
( )lid stuck
( )foot stuck to kiln shelf
( )Handle cracked
( )Joined sections seperated
( )foreign material in glaze
( )crawl
( )burnout of something in clay
( )glaze too thin
( )glaze too thick
( )poor glaze application
( )poor workmanship (explain)
( )underfired
( )overfired
( )wax resist related
( )other (explain)

If glaze related, glaze letter-

Preventable by change in working methods?( )Yes ( )No
If yes, suggested change-

Preventable by other means?( )Yes ( )No ( )Don t Know

Primary cause of loss
( )quality of materials - clay ( ) quality of materials - glaze ( )working
method needs improvement ( )technique needs improvement ( )mistake (

Incidence - ( )isolated ( )recurrent ( )pervasive
Likelihood of recurrence - ( )low ( )medium ( )high


Don Kopyscinski
Bear Hills Pottery
Newtown, CT

Who...... so far thinks that he will have to cancel this year's annual seconds
sale for lack of seconds (only a few hundred pounds under the