I went shopping at Walmart last weekend to buy alcohol.
I noticed they now stock both 70% and 91% isopropol alcohol, and I now see why people have been asking about the stronger 91% and if it should be mixed the same.
The 70% has a blue label and the 91% has a red label.
Here is what I am going to do. I bought both 70% and 91%
I will use 2 quarts of 70% for a 40 gallon mix.
Big roofs that will need 50 gallons I will use 2 quarts of 91% alcohol.
That should give me about the same percentage alcohol for both mixes.
I thought I mentioned that to you last week Sullivan. My brain must have slipped! My chemical supplier wants $132 for 5 gallons of IPA! I told her I could buy it at Wally's for $30.
Roof Cleaning Pro Greensboro NC (336)362 7659 wrote:
Yes, Wallyworld is cheap! They've gone up a little, since the last time I bought it.
70% alcohol is about $1.80/quart $1.80 x 4 = $7.20/gallon
91% alcohol is about $2.40/quart $2.40 x 4 = $9.60/gallon
The nice thing about it is when I go in and buy it...AT LEAST FOR NOW.....they are both the same price here in Georgia so I just bought the 91% instead and just use less of it.
By the way, I tried the M>S> CIDER SAUCE mix on the big 3,500+ sq. ft. house we did this last weekend and used the 91% and thought it made the mix dry and evaporate quicker (maybe too Quick) off the roof surface.
I have a feeling the evaporation qualities increase substantially as the free isopropol alcohol volume increases.
On a hot 12 noon day, I think I will go back to the 70% as it doen't seem to evaporate as fast once the cleaning agent hits the hot roof surface.
Just my observation?
Has anyone else noticed this occurring?
-- Edited by Roof Clean USA Georgia 229-227-0000 on Tuesday 14th of April 2009 09:36:38 AM
-- Edited by Roof Cleaning Pro Greensboro NC (336)362 7659 on Tuesday 14th of April 2009 12:24:55 PM
I have had great results with the 70% Isopropol. I will try the 91% while the weather is still cool hear in Richmond Virginia and post my results with the outcome. For those in warmer climates(Temps already in the 80's) please let us know if evaporation problems are an issue when using the 91%. It will be May before the Mid 80's and up hit Richmond allowing me the opportunity to do a hot roof test run. Thanks Scott