Ospho treated metal

O

Oramac

Hay everyone, Just getting started on the latest project, 41 Lincoln Zephyr Convert. The owner diss-assembled and stripped the car, so it's all in bare metal. Now, after stripping, he wiped/sprayed on Ospho, which is a phosporic acid based rust inhibitor/protecter. I'm not crazy about epoxying over this stuff, thought I would 80 DA, clean w/ Simple Green, then use WB W$G before epoxy. Don't want any failures later.:confused::confused: Any thoughts, suggestions? Thanks C
 
myself i would reapply ospho and rinse well. when you get no black residue it's pretty much gone. but it has to be reactivated. just my opinion. sheet metal shops use it all the time. just don't paint over it.
 
shine;10208 said:
myself i would reapply ospho and rinse well. when you get no black residue it's pretty much gone. but it has to be reactivated. just my opinion. sheet metal shops use it all the time. just don't paint over it.
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Exactly!!!
You must rinse with water before the Oshpo dries or it does no good.
You CANNOT sand the dried film off as metal is porous and it will in-bed in the metal.
May work if you do sand but very risky, only other way I know is sandbast with sand.

To spot test when done--let epoxy set 24 hours mix a 1" ball of filler and set in a couple of different spot over the epoxy, wait ten minutes and with a flat head screw driver try to pop off, if their is an acid film the filler will melt the epoxy and just fall off, epoxy although hard on top will never cure on bottom.
If you applied filler to an acid film metal it will do the same thing, harden outside but by the metal will still be gummy.
 
Thanks guys, re-activate and rinse seems risky, the water and bare metal thing, probably will just sandblast to remove any traces of this stuff. Barry do you think, I should do the "test" after the sandblast, or should it be good? Thanks again to both, C
 
Oramac;10220 said:
Thanks guys, re-activate and rinse seems risky, the water and bare metal thing, probably will just sandblast to remove any traces of this stuff. Barry do you think, I should do the "test" after the sandblast, or should it be good? Thanks again to both, C
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Whats so risky about water and bare metal? Some people do it all the time with no ill effects, flash rust is not much of a problem when you consider that the SPI epoxy has etching properties too, the epoxy takes care of it without problems.

If I remember correctly Shine washes the bare metal with dawn soap and water, then dries everything real good and goes to town with the epoxy.
 
i have seen more paint failures because of people being afraid to wash a bare car. blasting with sand will cause more rust problems than water and just how do you get the sand out ??? ever seen them dip a car ? out of the vat then into the wash rack . you have to reactivate the acid to remove it and neutralize it.

phosphoric acid has 3 uses in metal work. rust removal , metal etch and metal preservative . the first 2 are for refinishing. both are applied wet , kept wet and rinsed. as a preservative it is left to dry. this helps keep it clean while metal work is being done as in a sheet metal shop. but it has to be reactivated and rinsed before top coating. call any paint mfgr's tech line and ask them . you will get the same answer from each one.
 
I would reapply the phosphoric acid in the shade on a cool morning, just wash it off , then take the weed blower and dry it off.
 
What in the sand causes the rust issues? I am scared myself to wash a bare car with water after blasting.
 
i have a blasting business. more for me than the public but i did a lot of research before investing the money . what i found through my composite supplier was that using sand creates chloride ions and caustic salts. not real sure what that means but it was enough for me. that and sand is just too aggressive for me. no mater what you use you still have to clean the car. you cant vacuum or blow out the media. soap and water cleans the metal and rinses the dirt and media out. if it turns orange your good to go because it is clean. most flash rust is from iron deposits in your water instead of rust. i can rinse one , blow it dry and leave it for week with no problem. but i usually epoxy the next day.
 
I have one getting blasted this week, i am leary but may have to give this a try..

Only issue i've ever had was the pinch welds. seems like no matter what I do it ends up getting a light rusting in those areas.
Basically usually only get if welding new rockers on. or something to that effect. But it drives me nuts. I can't seem to get rid of that.
 
just think of trying to get acid out of those pinch welds . especially after it dries. rinse the car then get it inside asap and start blowing. what little rust you see will not be a problem under epoxy. as soon as it is dry hit it with epoxy.
 
shine;10241 said:
most flash rust is from iron deposits in your water instead of rust. i can rinse one , blow it dry and leave it for week with no problem.
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A person could put in a DI water system and have clean water, a guy nearby did that to wash his cars with, no water spotting.

Your air is soo dry you can't lick a stamp and have it stick. Do hope you guys get a bunch or rainy weather sooooooon.
 
hell it's do dry the trees are bribing dogs. this treatment thing would not be such a big problem if the info given on web sites matched the paint mfgr tech sheets. unfortunately there is some real bs going around. i've been collecting tech sheets this week . :)
 
by the way. if any of you have your tech manual from classes do me a favor. scan the metal treatment page and send me a copy at crazyhorserodshop@gmail.com . i still have my ppg book but my others went south in the flood.
this is the page ppg tech.jpg
 
Hay all, Been reading a 11 pg. thread over at HR, wow, a few of those are really set on painting over ospho directly, without sanding,rinsing etc. Good luck with dat. I think alot of the phosporic acid treatments were developed back when we were using lacquer primer on the bare metal,( before epoxy days), remember after that they were pushing the yellow zinc chromate primers? stunk bad. On this car, all the panels are off, so it won't be a problem to retreat and rinse, which I'll do. Some of the panels have deeper rust in them which will require blasting in some areas. Thanks everyone for all the input on this. I've done many cars over the years, and theres always something the owners do to screw you up (make more work for you). This car will be over 125k, so just want to be sure on these different procedures. Thanks again, c

http://s128.photobucket.com/home/OramacRestos/index
 
naval jelly works good on pits as it stay wet longer . i prefer it over ospho. you can mist the jelly and keep it moist longer. i no longer use any of it as i now have a blasting set up.
 
i have ospho on my car in some spots also. can i still wash the car even tho i still have some exposed areas of bondo on the car? and some areas the ospho did not rinse off good. what should i do?
 
Any areas that have not been neutralized must be retreated and rinsed with water.
I would wash with the acid and wipe with another clean rag with water and spot clean, staying away from the filler.
Let dry and buzz over it with an 80 grit DA.
 
i would put some 2 in tape over any filler close. you get ospho in any filler it will be a nightmare.
 
gotcha. so just spray on more ospho on the areas that has dried ospho on it and then immediately rinse with water?
 
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