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Discussion Starter #1
When you use metal prep acids (Dupont metal prep), are you supposed to rinse it off, or just let it dry?
I always thought you were supposed to rinse it off, but I scrubbed up an old axe head with it, and didn't rinse it off. It's been sitting wedged in a stump in my back yard for about two months now and there's not a spot of rust on it. And I know from experience that if I rinse the metal prep off, I have to dry the part as fast as I can and prime it.
And if I am supposed to leave it on the surface, will plastic fillers and primers stick to it ok?
 

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Sorry I can't answer your question, but wanted to ask one of my own. Where do you get your metal prep? The last time I looked the auto parts stores around here no longer carried it. I'm almost out & need some more. thanks Phil
 

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ya i know what ure talking about, ure supposed to rinse it off and then u use water based wax & grease remover and then you're supposed to epoxy prime it, if u dont treat it you can use self etch primer and then go on with ur topcoats. and u should get it at ur auto paint store or ppg.com or autobodysupply.net
 

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Discussion Starter #4
Figure8,
I haven't bought any of the Dupont stuff for a while, so I don't know about whats at the auto paint stores. But I just bought another bottle of what appears to be the same type stuff at Lowes hardware. I don't know the brand name, but it says "metal prep" on it, looks the same, smells the same, and appears to do the same thing, and a lot cheaper too. Look for it at hardware stores, farm supply stores etc.

Thanks Mitmaks, I learned something. I didn't even know water based wax and degreaser even existed, and I haven't tried shootin any epoxy based primers yet, but it looks like I'm gonna have to learn.
 

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B.K. I'm not sure what type of metal prep. you're talking about but if its the 244 kwik prep you shouldn't rinse it off. Check the label directions or the product sheet. <a href="http://www.performancecoatings.dupont.com/" target="_blank">Here....</a> :D
 

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Thanks Busted Knuckles. We have a Loews & I will try them. I was afraid it might be some environmental thing that the auto supply stores no longer carried metal prep. By the way I also heard it was muriatic acid. Phil
 

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Discussion Starter #7
Thanks tlambert, great suggestion (read the freakin' label) :rolleyes: :D
It's Dupont 5717s and the directions say to just wipe it off with dry cloths. Turns out I've been doing it wrong by rinsing it off.

Figure8, it could be a state to state kinda thing.
Now I'm wondering, if it's muriatic acid, isn't that what concrete workers use to etch concrete?
I'm always lookin to save a buck.
 

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Phosphoric acid. The reason you don't want to wash it off is that it leaves a phospate coating that protects bare metal and even improves paint adhesion.
 

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The metal prep I bought at Lowe's is made by Jasco. Its a green solution in a clear plastic bottle. Cost about 6 bucks for a quart. Its made of phospheric acid. I've used it and like it. Just brush it on, thats it.
 

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Don't have the exact answer to your particular question because I don't know what "metal prep" you're using. Years ago metal prep was a very good product to etch metal with and destroy rust before it began. You definitly rinsed it off if you expected your paint to stick because it is an acid. Then, like all good products that work well, OSHA found something wrong with it and took it off the market. I tried the new "metal prep" then, which was diluted with water and produced such poor results that I stopped using it altogether. If you clean really well and get primer on very soon after opening to bare metal, I have no problems with paint addesion. If there is rust present there are many new rust prevention products out there which can be applied to the area after you've removed all you possibly can. As a rule they can be painted over with good results. Just follow product directions........ by the way, not all the OSHA rules are bad. I was using a plastic I really liked, because it worked easy, called Blue Moon. I went to buy more one day and there wasn't any. I wondered why , when it worked so well, so I investigated. I found out it was a vegetable product, and if you breathed the dust, it started growing in your lungs, and had killed several people!! Changed my mind about OSHA trying to protect us from ourselves, even though their decisions are not always agreeable........
 
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