Editing Phosphoric acid as metal pretreatment
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− | The use of phosphoric acid-based products as metal pretreatments is controversial in hotrodding. Proponents favor its low cost and ease of use, while opponents cite the problem of acid film leading to topcoat failure | + | The use of phosphoric acid-based products as metal pretreatments is controversial in hotrodding. Proponents favor its low cost and ease of use, while opponents cite the problem of acid film leading to topcoat failure. |
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==Brands of phosphoric acid-based metal pretreatments used for automotive work== | ==Brands of phosphoric acid-based metal pretreatments used for automotive work== | ||
− | + | *[http://ospho.com Ospho] | |
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==Reasons for using phosphoric acid== | ==Reasons for using phosphoric acid== | ||
*Inexpensive. | *Inexpensive. | ||
− | *[[Media blasting]] has its own set of drawbacks | + | *[[Media blasting]] has its own set of drawbacks. |
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==Reasons for not using phosphoric acid== | ==Reasons for not using phosphoric acid== | ||
+ | *Metal pretreatment manufacturers are economically incentivized to recommend their products. A better point of view might be obtained from the manufacturer of the product that is destined to go on top of the pretreatment. | ||
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*Even a very low failure rate is economically disadvantageous, especially in light of the value of a professional paint job, and the labor required to fix a failure. | *Even a very low failure rate is economically disadvantageous, especially in light of the value of a professional paint job, and the labor required to fix a failure. | ||
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*A manufacturer's tech sheet may specifically advise against using an acid pretreatment. Always follow the tech sheets for the products you are using. | *A manufacturer's tech sheet may specifically advise against using an acid pretreatment. Always follow the tech sheets for the products you are using. | ||
− | *Amateurs and [[First paint job|first-time painters]] are more likely to make errors. Phosphoric acid pretreatments must be used meticulously, and | + | *Amateurs and [[First paint job|first-time painters]] are more likely to make errors. Phosphoric acid pretreatments must be used meticulously, and are thus not recommended for beginners. |
==Specific paint and primer failures caused by phosphoric acid pretreatments== | ==Specific paint and primer failures caused by phosphoric acid pretreatments== | ||
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*Epoxy cracking. | *Epoxy cracking. | ||
− | ==Published | + | ==Published epoxy primer and paint manufacturers' positions on the use of phosphoric acid pretreatments== |
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===Southern Polyurethanes, Inc.=== | ===Southern Polyurethanes, Inc.=== | ||
− | *[http://www.southernpolyurethanes.com/tech%20sheets%20new/epOXY%202006.pdf Southern Polyurethanes | + | *[http://www.southernpolyurethanes.com/tech%20sheets%20new/epOXY%202006.pdf Southern Polyurethanes]: |
<blockquote> | <blockquote> | ||
''"NEVER use SPI Epoxy over a Soda Blasted vehicle, Acid Etch/Wash Primer, Rust Converter or other Metal Treatments. NEVER!"'' | ''"NEVER use SPI Epoxy over a Soda Blasted vehicle, Acid Etch/Wash Primer, Rust Converter or other Metal Treatments. NEVER!"'' | ||
</blockquote> | </blockquote> | ||
− | The owner of Southern Polyurethanes | + | The owner of Southern Polyurethanes has detailed some options that '''should''' solve the phosphoric acid film problem, in [http://www.hotrodders.com/forum/ospho-factory-response-173513.html#post1235021 this post on the Hotrodders Bulletin Board]. |
==Use of phosphoric acid in an industrial setting== | ==Use of phosphoric acid in an industrial setting== | ||
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==References== | ==References== | ||
*http://www.hotrodders.com/forum/ospho-factory-response-173513.html | *http://www.hotrodders.com/forum/ospho-factory-response-173513.html | ||
*http://www.ospho.com/directions.htm | *http://www.ospho.com/directions.htm | ||
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