I need a good downstreaming recipe

[Jhignutt 14]

I have been use to xjetting and not put much thought into downstreaming but tommorrow i plan on trying it. My situation is a pre paint prep painted cmu block building. My equipment is (2) Hydrotek hot/cold pw @ 5.5 gpm 3000 psi. Im thinking 12% shc and TSP. What kind of ratios would you downstreamers suggest?

[John Orr 206]

The two most important (other than the shc) factors in downstreaming are: the size of the injector and the diameter of the tip. Make sure the injector is rated for your machine and that you replace the little steel ball inside with a ceramic one. For the tip, your chem tip will work nicely for lower/close-in work, but I like either a drilled-out 0 degree tip or one I make myself using a 1/4" male quick connect with female threads and a 1/4" male thread hose barb. Buy several, including air fittings, and find the one that works best for you. Nothing beats a nice, tight, stream for reaching 2 and 3 stories.

I have found Northern Tool to be a good, local source for all of the above - with the exception of the ceramic ball.

Running 12.5% through an injector will eventually rot the spring inside, so always either have an extra spring/ball or an extra injector. I pay about $25 at NT.

One way to prolong the life of the injector is to suck some water through it after running shc. I take the pick-up hose and put it in the supply tank for a few minutes; this also helps to flush the hoses faster and speeds rinsing.

I use a length of pvc pipe (3/8"?) and stick the pick-up hose into it. This will keep the hose from coiling around in your wash mix and having the strainer float to the top. If your chem tank is clean, no strainer is really needed, but you can add one to the bottom of the pipe with a 2" piece of hose.

As far as your mix, I think yours is fine for paint prep. Rinse, rinse, rinse.

Personally, I like about 110 to 125 degree water.