Seeking advice on dealing with rust: converter, paints...

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PostPosted: Sun Dec 05, 2021 5:22 am
I'm a DIYer trying to maintain 2 family cars, 2005 Acura MDX and 2008 TL. Both have shown rust spots on various parts. I started learning about rust and paint and came across this wonderful forum. I read as many posts as I could here, learned quite a bit, and developed a real respect for your knowledge and skills.

1. I learned the best way was to mechanically remove rust completely, epoxy prime, urethane prime, color coat, and clear coat. Since I don't have a blaster, I'll miss some of the rust in the pits and tight corners. I wonder if it's beneficial or critical to apply phosphoric acid or one of the other rust converters to convert the remaining rust chemically. I'll then clean any residue off with isopropyl alcohol (Is 70% appropriate?) before applying epoxy primer. Would this method be acceptable?

2. I don't have a powerful compressor to drive a spray gun and wonder if you may recommend a decent paint system that can be applied by spray cans or brushes. The rust spots are small. My goal is to stop or delay rust to extend the life of the vehicles as much as I can at a reasonable cost. Perfect appearance or color match is not important to me. I searched and only found Sherwin-Williams Automotive Finishes in my area. I haven't found a local source serving consumers for PPG, Dupont, Kirker, etc. Of course, Dupli-color is available at auto parts stores.

3. My last question is on the surface rust on brake components: backing plates, caliper pistons, and hubs. Due to high temperature, I plan to use a caliper paint, such as VHT SP734 Gloss Black Caliper Paint, heat resistant to 900°F (https://tinyurl.com/2p9f29p6), or Eastwood Rust Encapsulator, heat resistant to 400°F (https://tinyurl.com/4nun2c2u). Would like to hear your experience on these products or your recommendation of better products.

Thank you for sharing your knowledge and wisdom.
20211203_200205.jpg

Sorry, the system put my image upside down. Backing plate rim: I plan to brush/sand off the rust, treat with phosphoric acid, clean with IPA, and finish off with several coats of caliper paint.

20211203_200237.jpg

Sorry, the left side should be up. The system put my image sideways. Rear hub: I plan to brush/sand off the rust, treat with phosphoric acid, clean with IPA, and finish off with several coats of caliper paint.

20211101_171656.jpg

The inside of the caliper piston was rusty.

20211101_003955_Copy.jpg

Sorry, the system put my image upside down. I did this a month ago before I knew better: sanded off the rust as much as I could, cleaned with IPA, sprayed Mar-hyde 3509 one-step rust converter, heat resistant to 200°F (https://www.3m.com/3M/en_LB/p/d/v000207848/). As the manufacturer claimed, remaining rust turned to black as part of the latex primer sealer. Not sure how long it's going to last as is. I still have an option to coat it with caliper paint. Should I?



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PostPosted: Tue Dec 07, 2021 9:21 am
1st off that Caliper looks like its on its last leg, needs seals replaced its blown out needs to be rebuilt properly with new seals and inspect piston and bore for rust pits if pitted buy new or rebuilt. Don't take chances with Breaks! a car is only safe when it can be controlled Stopping ability is the most important.

As far as painting blast clean with Glass paint with good system stay away from VHT and other 1K products they look great for a while but deteriorate quickly they don't hold up.
Most BC/CC systems holds up well to indirect heat under 400.

Powder coating is best for these parts for long lasting great looking pieces even when subjected to direct heat. Can be done at home DIY but Wifey may not like you using the oven in house but the smell does go away.

As far as rusted panels please post pics
While some rust can be removed with sanding wire wheels and Phosphoric acid some is just too deep and must be blasted or cut out b4 I say anything need to see it.
Dennis Barnett
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.

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PostPosted: Tue Dec 07, 2021 10:47 am
Media blasting is best for parts like these, as it gets all the rust.
Notice the control arm next to the blasted rotor as well.
Rotors Sandblasted.JPG


I painted the blasted parts with black epoxy primer.
Lower Control Arms in Epoxy.JPG


Brake calipers were stripped, painted and rebuilt:
Brake Calipers in Epoxy.JPG
1968 Coronet R/T


ACTS 16:31



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PostPosted: Tue Dec 07, 2021 11:44 pm
Doright wrote:As far as rusted panels please post pics. While some rust can be removed with sanding wire wheels and Phosphoric acid some is just too deep and must be blasted or cut out b4 I say anything need to see it.

Thank you for your help, Dennis! Appreciate your advice!

Attached photos show what I'm dealing with. Here is my repair plan:
1. Remove rear fender cover, fender well trim (rubber strip), and molding.
2. Remove rust inside out as much as I can with wire brush/sandpaper.
3. Apply phosphoric acid or some other rust converter.
4. Apply epoxy primer, filler primer, base coat, clear coat.
5. Skip body filler and fiberglass so that I can see future rust development.

The problem is it's too late for me to execute this plan right now because it's too cold and wet already. Instead, I plan to use a cocktail of automatic transmission fluid, P.B. Blaster Penetrant, and Dawn (https://www.youtube.com/watch?v=Wh2xK7GZqSI&t=167s) to slow down rust till next summer. Should I still remove loose rust and paint chips now before applying this cocktail?
20211119_195048.jpg
The right side of the photo should be up.


20211119_195037.jpg
The right side of the photo should be up.


20211119_194950.jpg
The right side of the photo should be up.



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PostPosted: Tue Dec 07, 2021 11:56 pm
'68 Coronet R/T wrote:Media blasting is best for parts like these, as it gets all the rust.
Notice the control arm next to the blasted rotor as well.
Rotors Sandblasted.JPG


I painted the blasted parts with black epoxy primer.
Lower Control Arms in Epoxy.JPG


Brake calipers were stripped, painted and rebuilt:
Brake Calipers in Epoxy.JPG


I admire the excellent job you did there! Media blast is the best!

Not sure if I'll ever be able to put my hands on it...



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PostPosted: Wed Dec 08, 2021 2:00 pm
That area looks a little to far gone already and should be cut out new piece welded in.

I realize you probably didnt want to here that but it is true. You could go a head and wire wheel it BUT a better way would be to try to use a Minny Spot blaster.

https://www.harborfreight.com/21-oz-hop ... ysEALw_wcB

They work ok at removing some really bad spots use the Glass that they sell as well also cheap. I get a 50lb box for like $25 or so.
Tape off areas you don't want blasted clean! with a good heavy tape.

Forget miracle rust converters Just blast clean and paint with some good Epoxy even with a brush if you have too, That will slow things down and give you some time till you can fix it right.
Epoxy doesn't like to cure under 55 degrees, It slows down and even stops after certain temps so if you could leave a small elect heater pointed at it for a few hours to overnight would be good. just not to close don't wanna burn or melt anything doesnt need to be radical just something to keep it above 55 degrees.
Dennis Barnett
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.



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PostPosted: Thu Dec 09, 2021 8:44 am
Doright wrote:Forget miracle rust converters Just blast clean and paint with some good Epoxy even with a brush if you have too, That will slow things down and give you some time till you can fix it right.

Thank you for your suggestions, Dennis!

Would you please recommend some epoxy primers and paints that are accessible to consumers? I suppose I can get everything from Sherwin-Williams Automotive Finishes. To my surprise they carry SprayMax 2k epoxy primer, not their own brand. I saw SprayMax on Amazon too.

I'll consider setting up a blast cabinet. I'd probably not pollute my yard with glass media. If I do decide to blast outdoors, I'll have to use some media that is environmentally friendly.

Thank you again for your help.



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PostPosted: Thu Dec 09, 2021 9:34 am
Glass is environment friendly its just Glass, Sand if you will but refined.
I blast in my yard all the time it just blows around the yard mixes with the dirt.
That's a small area and wont take much to clean it up a couple of min and you would be done, ts not going to be a Huge mess not for such a small area.
That small hand held blaster is perfect for this job.

As far as Paint retailer look no further Criss's store front on this web sight he sells good products at a good price with free shipping! I don't think you need Gallon kits maybe just a single Pint Tamco can be contacted directly as well they also can provide Base coat and clear to you by the paint code from your car if you want to see the project all the way through.

Good luck
Dennis Barnett
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.

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PostPosted: Thu Dec 09, 2021 1:55 pm
Watch your local craigslist or other publications for used blasting equipment.
I know it is hard to believe but I bought this cabinet for $200 from a local business. The picture is of a new one, but mine looks just like it only slightly used.
BB-1000XLD-1jpgw240h324.jpg
BB-1000XLD-1jpgw240h324.jpg (13.67 KiB) Viewed 604 times
1968 Coronet R/T


ACTS 16:31

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