Good Ospho (phosphoric) and epoxy Test

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Art Vandelay

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Don’t know if anyone has seen this. Pretty good test and results, especially for those of us without the ability to blast every small part.

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Ricko1966

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He said spi says not use acid under epoxy,I don't think that's right. I belive SPI only recommends ospho and only when directions for using it are followed completely,which is what I think that second test was. I'll look and see. Yep Ospho is the only phosphoric acid treatment,SPI recommends.
 

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Ricko1966

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I'm looking at getting some Tamco Moncoat for axles and small parts but their Q&A says "Do not use any form of rust converters..." but if you neutralize like in video don't see why it wouldn't work.
https://tamcopaint.com/products/monocoat-1-k-direct-to-rust?variant=31399920566352#qamp-a_i1
Some of the paint over rust products use tannic acid as part of the process the tannic acid needs some iron oxide to work( anyway that's what I was told by one of the manufacturers a decade or so ago when I was researching it. I'd ask the manufacturer for more info,not us.
 

legopnuematic

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I'm looking at getting some Tamco Moncoat for axles and small parts but their Q&A says "Do not use any form of rust converters..." but if you neutralize like in video don't see why it wouldn't work.
https://tamcopaint.com/products/monocoat-1-k-direct-to-rust?variant=31399920566352#qamp-a_i1
For Tamco products, the reason they advise against using converters is the likelihood of the product not being neutralized or removed completely before applying product on top of it.

Think of something like a door that has a hemmed edge, phosphoric acid can easily creep into that hemmed area, you prep the panel, it’s still in the hemmed area, spray epoxy, then it starts creeping and bleeding out causing adhesion issues.

And certain products, like Monocoat, 5311, some of their epoxies are DTM/DTR, so they already have the ability to seal the rust on their own.

I’ve used monocoat, I like it, but if you are going for more visible parts and want them to look really good, I’d recommend their HB truck chassis black paint or their underhood satin black products.

I have used their chassis black for the frame and parts of my 79, I have a gallon on the satin to use for the inner fenders and underhood stuff.

79 12 Bolt in chassis black:
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Their 5311 primer is really good stuff too. I primed my trailer fenders with it almost 2 years ago and the trailer sits outside in the elements and still look like the day I sprayed them.

If you reach out to Barry at SPI or the Barney’s at Tamco, they are both receptive to questions about their products.
 

Art Vandelay

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@legopnuematic I was hoping you would respond. I have only done the tank brackets in Acid and there isn’t a lot of crevices so should be able to neutralize them before Monocoat. I’m going to use the 5311 for my frame. Did you do the chassis black over that?
 

legopnuematic

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When I did my frame, I had it media blasted, the chassis black is DTM/DTR, I cleaned and sprayed it, no primer.

I believe it will hold up fine as is, if I were to do it again right now, or if/when I do my 76, it’ll likely get epoxy first, then top coated. Or 5311 would be just fine too. Really just for that extra layer of protection more than anything.
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My trailer fenders in 5311 sprayed as a sealer (4:1:2). August will be two years of sitting outside uncovered, in all the delightful weather Missouri has to offer. That photo was late last year.
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Camar068

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I've used Ospho on my manifolds. These had surface rust on them (LS manifolds). Painted with high heat Rustoleum. Later they did start to flake. But exhaust on a daily who cares.

He's taking what appears to be clean metal and applying ospho......why? If I'm wrong point it out.

I do like the info on spraying Ospho on there and letting it sit for 24 hrs, then reapplying for 5 minutes then washing off. There was a white residue prior to painting the manifolds but thats what the directions said (hell who knows coulda been a utube video that said that and I did it I'll admit).

My point is, if his metal is clean with no rust.....how can you compare clean metal to "rust converted metal" and do that test? Unless I missed a part that said his parts were rusted.

Just a thought for apples to apples. Is the clean metal in the video the same as old ospho treated rusted metal? No. Per the directions, I highly doubt it, with the 2nd "rinse" maybe closer but still different in my opinion.

Why would you make a video like that with clean metal and involve a rust convertor.....when there is no RUST CONVERSION involved?
 

vr1967

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If nothing happens, I’ll work on my daughter’s S10 frame tomorrow and will get some photos (if anyone id interested)

Some has been wire wheeled, and some left natural, and has had Ospho brushed on it. Will show the difference between cleaned and un clean metal. Want to get it out in natural light to see better (yes, I have gotten old) and need to turn over to do the top side.
 
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