Oxalic acid, How Long...

M

Michael Cappa

Member
Here is a question for all you chemists out there. lol
If I take 25 lbs. of oxalic acid, mix it in a 50 gallon drum to make 50 gallons of acid, how long will it keep its cleaning/whitening/etc. properties before it is neutralized? Basically, how long is it good for after you ad water?
 
Why would you want to do that? Carry it around in dry form and mix exactly what you need at the job site...it only takes a couple minutes. It's less weight to carry around, and should you ever have an accident, it would not create nearly the mess that many gallons of liquid would cause.

I'm not a chemist, but I have not heard of a particular shelf life for premixed oxalic acid. I would see no reason to mix more than you could use in one season anyway, so figure one year.....
 
Tony,
That's what I was trying to figure if I should do it that way or not. The reason for my thinking was I had a little acid and spayer problem last week. I mixed on the job but the not yet disolved acid clogged up my spray tube and I ended up having to dismantle and re-build my spray tube. (gotta love how I make such and easy job sound hard). But, this made me lose some valuable daylight. Thanks for the info.
 
Thanks Steve,
No, no hot water machine yet. Soon I hope. I am in a dilema wether or not I should get a hot box or save up for a hot water machine.
 
ron p

get a insulated water jug and fill it with hot tap water. It will stay hot most of the day.
Save up for a hot water skid and just use your old unit for rinsing,wood,and back-up.
Once you have heat[unless you just do wood] you will wonder why you did not get it sooner.
The hot water skid will pay for itself in less chem and time savings in a short period of time.
It will also open more markets to you.
Im not big on used equipment but the end of the summer sell off is about to get under way.
 
Go with the hot water machine over the hot box. I bought a hot box first and it works well but the all in one unit is worth the extra money. I keep the hot box in the trailer as a backup with a cold unit. Reed mixes his oxcylic acid the night befor and it works for him that way also.
 
Mike,

If you are using a 1-2 gal sprayer, mix the acid in a 1 gal bottle (I use an old RustAid bottle) and strain or filter before putting in your sprayer. A funnel with screen works fine - you just want to keep the chunks out.

I field mix with cold water all the time and use a 4 gal backpack sprayer. The sprayer has a plastic strainer basket, and I never get clogs. The hot water dissolves the crytals more completely, so if you can mix it at home, do it. If not, filter the chunks.

I keep a gal or 2 pre-mixed for weeks at a time with no prob. A little shake, and its ready to go.
 
For the financially challanged, an old turkey fryer and propane tank works well to heat water, your lunch or make large containers of hot soup on chilli day.

Regards,
 
Regarding the initial question regarding the stability of the acid, you may want to contact the supplier. A couple of thoughts, however. First, most brighteners are 10% or less oxalic, and they are stable for long periods. Second, dilution alone will not "neutralize" the acid as I belive was indicated in the post (may not have correctly interpreted). Third, introduction of CO2 might. Therefore, my guess is that the acid will stay pretty stable as long as you keep in closed container. Ask the supplier.
 
oxcylic acid

Bill, you are right about obtaining information from the supplier. If you view the MSDS of our oxcylic acid ( Deck Brite - powder form)) it will show it is in the 50-100 % range. A refractometer will show how much solids are in different chemicals, that way you can compare the same type of product from different suppliers and see which product will do the most for your dollar. You can also identify the strenght of a chemical if you have diluted it without marking it. P.S., if the homeowner is home you can always ask them to fill a bucket with hot tap water.
 
Not sure what you using oxalic for,if you could replace it with citric,it mixes really easy in cold water,i mean easy.I used to have a problem mixing oxalic too,clogged my sprayer
Johny
 
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