balance scale

[OneWithWood]

I would like to acquire a good scale that I can use to measure moisture loss via the oven drying method (actually I plan to use a microwave) and for measuring ingredients for brewing bio-diesel.  I have been looking around and I have found a Boreal balance at Edmund Scientifics that might work but I am not sure what size I should get.  I think I need something that measures .1 gram but I am not sure what the upper limit needs to be.  Any suggestions?

[Tom]

If you aren't into buying new, a mail scale might work.  When electronic scales came out, a lot of companies got rid of their manual scales that operated on a weight slide.   You can find these at flea markets, sometimes.  they go from fractional ounce to several pounds.

There are companies that specialize in mail scales if you shop for a new one.

To be very accurate, I would think that a company that sold to school system's chemical departments would produce a good scale.   Perhaps a call to the local school might find one of these companies.

[Ga_Boy]

What are you going to dry?  In terms of thickness?

4/4, 6/4 or 8/4?

If you will dry 8/4 get a scale that can handle up to 20 pounds.    I just picked up a new electronic ballance that goes up to 13 pounds; I had to trim my sample baord. 

For oven samples a Ohous (Spelling) tripple beam ballance works well.  Make sure you get the extra weights, 2,500 grams, this will take care of most 4/4 material.


For accuracy .01 grams is desired, big bucks for these.  $500 or more   
You can find .1 gram scales and ballances in the $150 and less range.




Mark

[Ga_Boy]

I forgot to mention that you can pick up a good used lab oven for $200 - $400.  I bought a Blue M lab oven for $300. 

If you elect to go this route make sure it is a lab grade oven, these have temp controls that allow drying samples.

You will also need a can of BOSS (Bright Orange Sample Sealer) from UC Coatings.  When you order make sure you tell them how much you want.  When my order came I was expecting the Quart size can but received the gallon size can. 

Now I gotta get real busy to use up a gallon of BOSS, that stuff goes alonnnnnnnnnnng way.  It is going to take me years to use a gallon of this stuff.  I sure hope it does not go bad.






Mark

[OneWithWood]

Mark,
I will be doing mostly 4/4 with an occasional 6/4 run and the rare 8/4.  My research tells me the DH kiln is not very cost effective for the 8/4 stuff.  Some of the literature suggests a microwave oven can be used in lieu of the lab oven.  Did you consider this or do you think it would not be very accurate?
Thanks for the tip about the BOSS.  I hope it comes in quarts  :D
The weight capacity and increment is exactly the info I was looking for.  20lbs!  How big are your sample pieces?
Which electronic balance did you acquire?

[Ga_Boy]

I do not remember the name of the electronic ballance I got, I'll pay more attention to night.

As for kiln samples, my books tell me to cut them 30", but I cut mine 18" - 24" .  I was weighing some 8/4 Poplar and Bass Wood and these were too much for my scales.  I have not calculated the density of Oak, I'll ask Dan Shade, I think he knows the density of Oak.  A few weeks ags when were clearing that Big Oak we got to talking about wood density.

As for DH units, I changed my plans to a conventional Kiln after I attended kiln operators school.  Primarely as I can burn wood waste and fire the kiln and heat my shop and house from the same furnance.  Also the economics of conventional drying allows me to dry the thicker stuff quicker and with less energy cost than a DH unit. 

DH units are good units, I just wanted more control over my drying process, I can think and reason; a computer can only do what it is programed to do.  Not to mention the fun I had building the kiln.  I like to build things.

Now for microwaves:  I was taught to use the lab ovens so that is what i bought, I understand microwaves will do a fine job.  I just have not taken the time to determine the times to dry the oven samples with a microwave.  I like my little lab oven, I am teaching my daughter the science behind drying.  This is one more thing I like about a conventional kiln, it is more science than art, a DH unit is follow step 1, step 2, step 3 then you are done.  A conventional unit allows me to make changes in the drying times based on the environment in the kiln; temp and RH.

Yes, BOSS comes in quart size cans.....



Mark

[Don_Lewis]

You should get two sets of scales. One that will measure to tenths of a gram for the wafers and one that will measure at least 5 kg. Get scales that read in metric because this is one place where it makes life easier. You can't get a scale that reads 10 kg and also to tenths without spending a ton of money. The small scale new is less than $150 but watch for Police auctions as they get a lot of them as they are essential equipment for any drug dealer.

As for dh verses conventional, larger dh units do operate schedules like conventional kilns but the smaller ones are simpler to run. That is intentional as most people want that. There are exceptions and both systems provide excellent lumber. Be really careful about coil, fan and pump sizing for conventional kilns with wood fired boilers. I get lots of calls from people who bought the heat coils from the guy they bought their boiler from and they were way too small. There is a derating factor you have to use and the guys selling them do not seem to understand that very often

[Ga_Boy]

Good point Don on the coils and fans.

I picked mine up from a company that supplies kiln parts.  In my 20' shipping container I am running 3 fans and 180' of 3/4" finned copper tubbing as my heat exchanger.  There are four runs the length of the chamber, I did it this way to help with even heat distribution.

There is 4/4 Poplar and Holly in there now. 

If you decide to go conventional let me know and I will share my lesons learned in kiln construciton.





Mark

[Ga_Boy]

I checked my electronic ballance, it is an Ohaus as well.  I ran a Google search to find the best deals for my scales. 

[OneWithWood]

Thanks everyone for the good info.  I just ordered two Ohaus digital scales - one is a 5000g x 2g and the other a 200g x .1g.  I found them online and got both for just under $215 with shipping.

[barbender]

I'm pretty clueless on all of this but balance beam scales for cartridge reloading are cheap and accurate, you'd have to have some pretty tiny samples though  :D