 Ospho over primer? |
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| KaptKaos |
 Aug 29 2009, 06:00 PM
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#1
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Family  Group: Members Posts: 4,009 Joined: 23-April 03 From: Near Wausau Member No.: 607 Region Association: Upper MidWest  |
I have some surface rust peeking through some spots that I have primered. What happens if I brush some ospho on those spots? Will it seal?
Or, am I better off just going down to bare metal and applying it? |
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| 993inNC |
Aug 29 2009, 06:02 PM
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#2
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Member Group: Members Posts: 194 Joined: 14-August 09 From: at the beach Member No.: 10,676 Region Association: South East States |
go back to bare! its great stuff when used correctly. going over primered rust is not the right way
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| Katmanken |
Aug 29 2009, 10:41 PM
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#3
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You haven't seen me if anybody asks... Group: Members Posts: 4,738 Joined: 14-June 03 From: USA Member No.: 819 Region Association: Upper MidWest |
Is it a grey or red primer???
It's porous... (IMG:style_emoticons/default/barf.gif) Per the primer, you would be degrading the primer with the acid in the ospho and it may affect the color coat adhesion or disintegrate the primer under the color coat. Use self etching or epoxy primer as a base coat. They are NOT porous. Then you can add primer surfacer later..... |
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| IronHillRestorations |
Aug 30 2009, 08:30 AM
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#4
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I. I. R. C. Group: Members Posts: 6,813 Joined: 18-March 03 From: West TN Member No.: 439 Region Association: None 
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You need to take it back to bare metal and treat the bare metal.
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| Mikey914 |
Aug 30 2009, 02:23 PM
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#5
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The rubber man Group: Members Posts: 12,767 Joined: 27-December 04 From: Hillsboro, OR Member No.: 3,348 Region Association: None
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Bare metal - self etching primer (IMG:style_emoticons/default/biggrin.gif)
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| KaptKaos |
Aug 30 2009, 02:25 PM
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#6
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Family Group: Members Posts: 4,009 Joined: 23-April 03 From: Near Wausau Member No.: 607 Region Association: Upper MidWest |
QUOTE(Mikey914 @ Aug 30 2009, 01:23 PM)  I thought Ospho did the etching???? |
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| scotty b |
Aug 30 2009, 04:54 PM
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#7
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rust free you say ? Group: Members Posts: 16,375 Joined: 7-January 05 From: richmond, Va. Member No.: 3,419 Region Association: None |
OSPHO IS PHOSPHORIC ACID !!! You do the science. The stuff is made for bare metal only adn should be put on bare metal ONLY !!!! You used a cheap primer that does not etch and you either need to strip it and apply an etching primer or spot strip it, re-prime those spots and get a good sealer on it. You get what you pay for (IMG:style_emoticons/default/shades.gif) IF you do use Ospho FOLLOW THE FREEKIN DIRECTIONS. It is not a brush on and paint over product. It WILL cause you problems if not properly neutralized.
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| charliew |
Aug 30 2009, 05:14 PM
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#8
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Advanced Member Group: Members Posts: 2,363 Joined: 31-July 07 From: Crawford, TX. Member No.: 7,958 |
All the above. But I like to go ahead and put the sanding primer over the non sanding epoxy so that it will be ready to start the sanding and filling process if it's going to be a long term process. Epoxy primers are meant to be used only as a base primer. They do seal very good but they are not meant to be sanded later and then the sanding primer applied. If the epoxy primer is sanded then more epoxy primer should be put on before the sanding primer is applied. If I'm going to immediately start using filler I will put that ontop of the epoxy primer then after leveling use more epoxy primer to seal the filler up and then use the sanding primer to get the scratches out. Epoxy primer is not meant to set more than about 12 hours without adding the sanding primer or more epoxy must be put on after it is sanded or scuffed which is just more work.
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| Rand |
Aug 30 2009, 05:34 PM
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#9
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Cross Member Group: Members Posts: 7,411 Joined: 8-February 05 From: OR Member No.: 3,573 Region Association: None |
Strip all paint, primer, and other contaminents away before using Ospho! The stuff rocks, but it needs to work on rust/metal only, not a bunch of other surface crap.
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| KaptKaos |
Aug 30 2009, 05:59 PM
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#10
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Family Group: Members Posts: 4,009 Joined: 23-April 03 From: Near Wausau Member No.: 607 Region Association: Upper MidWest |
QUOTE(scotty b @ Aug 30 2009, 03:54 PM) OSPHO IS PHOSPHORIC ACID !!! You do the science. The stuff is made for bare metal only adn should be put on bare metal ONLY !!!! You used a cheap primer that does not etch and you either need to strip it and apply an etching primer or spot strip it, re-prime those spots and get a good sealer on it. You get what you pay for (IMG:style_emoticons/default/shades.gif) IF you do use Ospho FOLLOW THE FREEKIN DIRECTIONS. It is not a brush on and paint over product. It WILL cause you problems if not properly neutralized. I wouldn't be in here asking for help if the directions had this information on it now would I? I read the bottle's directions 5 times, trying to make sure I use it properly. I AM SORRY IF THEY CAN'T ANSWER EVERY QUESTION ON A QUART BOTTLE!! Geez.... who pissed in your Wheaties this morning. |
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