Por15 and Chassis Black question, what would you do and what have you done

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broth9640

broth9640

10 Year
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Golden Colorado
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Ok I am nearing the completion of sandblasting of my frame and plan on using POR15 along with POR15 Chassis Black as a top coat. I am not looking for your opinion on POR15 products. I have read the debates and I am fully aware of the pro's and con's. My question is this:

The product sheet gives directions for applying chassis black over a fully cured POR15 base coat by sanding the base coat then applying the Chassis black. The instructions on the can of chassis black say that "it can be applied over a fully cured POR15 at any time" Nothing about needing to sand it. So my question is has anyone done this? Either way? My gut tells me that I need to sand it, but that is going to be a royal pain especially with all the nooks and crannies. Again I am looking for anyone that has used POR15 base and then top coated with Chassis Black. What did you do and what results did you get?
 
Why POR over a sandblasted frame? A quality epoxy primer will offer far better adhesion and corrosion resistance than POR will. POR is meant to be used as a band-aid to be applied over rust. There's no benefit to applying it over a sandblasted surface unless you leave a lot of rust left after sandblasting.


I know you didn't want opinions on POR, but a lot of people confuse it's proper use.


I'm not a big fan of Eastwood Chassis Black paints, but I have used them over POR15. I followed POR's recommendation of spraying etching primer and then surfacer over the POR15 before topcoating with paint. It stuck like glue.


I don't think you'll find too many people that would disagree that the best possible automotive coatings applied over properly cleaned steel surfaces are 2K epoxy primers and topcoats. I would skip the POR and Chassis Black and head straight to your local Jobber for some epoxies.

For chassis applications, I recommend PPG Omni MP170 primer and MTK paint. They're inexpensive and offer excellent chip resistance because of their thin build.
 
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^ Agreed

I used POR-15 on my axles and parts of my frame after completly stripped/cleaned/prepped ect. It started to flake off in sheets, It needs the "pores" of rusted metal to adhere.
 
I personally prefer Eastwoods chassis paint. Pretty spendy stuff comparatively but seems to hold up well. I use a couple coats of DP 90 epoxy primer/sealer then a couple coats of Eastwood chassis black. Looks good and is bullet proof.
 
Alright here we go!
Reasons:
1. No matter how well you blast a frame there will still be rust in the seams, below rivets, etc. Using POR15 with a brush will allow it to flow into those seams and react with the remaining rust. If I just prime and paint that hidden rust can spread and eventually wreck the paint.

2. POR15 will not flake off unless you didn't prep it right. A sand blasted surface is very coarse and POR15 will adhere to it just fine. If you painted your axles after just wire wheeling and cleaning you missed the other prep steps.

3. I will have some pitting when I am done blasting and the POR15 will help to reduce these dimples.

4. I like the powder coating look of the finish compared to just straight chassis paint.

5. Powder coating would be nice, but I may add Siginaw or FJ60 power steering or perhaps a 3bt later down the road and will need to weld the frame. POR15 will grind off and not wreck the entire job and I then can touch it up after I weld.

6. it is extremely chemical resistant after it has cured. Probably far greater than just a Eastwood chassis paint.

And to be clear the Chassis Black paint I am talking about is the topcoat made by POR15 not the Eastwood.

Can someone chime in who has used just an epoxy primer and a chassis black more than 5 yrs ago? How well has it held up? Most of the complaints I hear about POR15 in my opinion come from improper use or prep. If
 
POR 15 is awesome paint. i have used it for years. I even use it on my motorcycle frames. Durable as any other, if not better! I would blast the frame and spray on the POR-15. People say it does not spray well, that is incorrect. It sprays fine and does not need any dillution. You just have to spray it a bit closer than normal because it dries fast when it hits air! Just watch for clogging on the spray tip and keep clean. Spray the first coat, let dry, sand, spray top coat. Sanding not necessary, but the appearance will be much more professional looking if you care about that.
 
broth9640 said:
Alright here we go!
Reasons:
1. No matter how well you blast a frame there will still be rust in the seams, below rivets, etc. Using POR15 with a brush will allow it to flow into those seams and react with the remaining rust. If I just prime and paint that hidden rust can spread and eventually wreck the paint.

2. POR15 will not flake off unless you didn't prep it right. A sand blasted surface is very coarse and POR15 will adhere to it just fine. If you painted your axles after just wire wheeling and cleaning you missed the other prep steps.

3. I will have some pitting when I am done blasting and the POR15 will help to reduce these dimples.

4. I like the powder coating look of the finish compared to just straight chassis paint.

5. Powder coating would be nice, but I may add Siginaw or FJ60 power steering or perhaps a 3bt later down the road and will need to weld the frame. POR15 will grind off and not wreck the entire job and I then can touch it up after I weld.

6. it is extremely chemical resistant after it has cured. Probably far greater than just a Eastwood chassis paint.

And to be clear the Chassis Black paint I am talking about is the topcoat made by POR15 not the Eastwood.

Can someone chime in who has used just an epoxy primer and a chassis black more than 5 yrs ago? How well has it held up? Most of the complaints I hear about POR15 in my opinion come from improper use or prep. If
Click to expand...
I did the POR 15 thing over my sand blasted frame. That is not a misuse of the product as they have special directions for that. They say you do not have to use the metal etch prep step after sand blasting. I did do it anyway as you mentioned there is still a bit of runs hidden away here and there.
I then scuffed it with a pad and painted the Chassis Black later. The truck is still being built so I can not speak to how well it will hold up but there was no issue with adherence. I have had adherence issues when I did not properly prep a piece.
That being said, I also rebuilt an M416 and painted it with POR15 after sandblasting. No issues. I painted it with Chassis Black as suggested and have discovered that the Chassis Black is fading to a dull flat black and turns my hand black when I run across it. This is what POR15 says will happen with the bottom coat (POR15 paint) if left uncovered.
I have installed sliders on my 40 that I POR15ed and did not paint over. They have remained bright and shiny for about 6 months with no noticeable UV issue. I was going to scuff them and paint them with Rustoleum but had to install them for a run and never took them off to spray them. I will if they get really banged up or discolored.
 
I used the Master Series Silver Primer, like por 15 but much easier to apply, and much less likely to fail. It has a lot of aluminum in it to help fill pits and can go over any metal condition and under any primer or body filler if done within about 7 days. Like por15 it is a moisture cured paint so it sucks the moisture out of the metal, it can even be put in your gas tank to help seal it, chemicals and gas do not mess it up once cured.

I put some on the body when I did my gas tank, used up what I had on the brush. It was on some clean, rusty metal. With a rope wire brush on an angle grinder my son had a hard time getting it back off the body. real tough stuff, I am very impressed with it.

Plus unlike por 15 it says it can be applied over marginally prepared surfaces, that sold me, but seeing how tough it was to get off I am now really sold on it.

Worth looking at in my opinion, I will use nothing else from now on,

MasterSeriesCT Coating Line Rust Prevention - Product Info
 
I reckon the key POR15 product is the primer (basecoat)....

I'm not a fan of their topcoats. (I had a bad experience with one so I've never touched any other.)

So ... for chassis painting I solve my adhesion issues/worries by spraying regular "gloss black" (from rattle cans) directly onto the brushed-on primer after just 1 to 2 hrs primer-curing-time have elapsed.

That way the topcoat "bites into" the primer leaving no possible separation issues.

:beer:
 
I painted an axle housing with POR15, let it dry, sanded lightly and top coated with Chassis Black. I didn't spend much time sanding, just scuffed up what i could. I followed the prep directions religiously and 3 years later is still looks good.
 
No offence to anyone but does anyone else notice that everyone form CA , AZ etc... find POR15 to be great , well of course its gona last in those climates , bare metal would probbly take a year to start rusting. I live in the harshest climate for damp salt air and salt on the roads that you will find anywhere . My friend used $5000.00 worth of it on his semi that he uses to haul lobster boats out of the water and you wouldn't believe how it sucked , he did prep correctly and used all the cleaners and metal ready etc...the stuff was flaking off rust comming through only after one year while his epoxy coated trailer (that gets submurged in salt water has held up great) I always thought it was the best stuff out there from reading about it so much untill I saw this first hand. If I even mention the word POR 15 around him and he looses it . :bang:
 
I've used Por 15 and it works well enough. I did some testing to maximize adhesion before coating my chassis and axles. It likes sandblasted or scuffed surfaces and always use a degreaser before the metal ready as this works 9 times out of 10. After 6 months of various conditions including salty roads it seems to be holding up well with minor peeling.

I wouldn't use it again due to the amount of prep involved and the fumes. I did a lot of first hand commercial research into the masterseries product and I am impressed. I just bought a can so I have yet to test it out but I would recommend you do some serious research into this product or just go the epoxy route. Check out this test: Side_By_Side_Comparison. I wouldn't put too much weight on the results but it is interesting.
 
broth9640 said:
Alright here we go!
Reasons:
1. No matter how well you blast a frame there will still be rust in the seams, below rivets, etc. Using POR15 with a brush will allow it to flow into those seams and react with the remaining rust. If I just prime and paint that hidden rust can spread and eventually wreck the paint.

2. POR15 will not flake off unless you didn't prep it right. A sand blasted surface is very coarse and POR15 will adhere to it just fine. If you painted your axles after just wire wheeling and cleaning you missed the other prep steps.

3. I will have some pitting when I am done blasting and the POR15 will help to reduce these dimples.

4. I like the powder coating look of the finish compared to just straight chassis paint.

5. Powder coating would be nice, but I may add Siginaw or FJ60 power steering or perhaps a 3bt later down the road and will need to weld the frame. POR15 will grind off and not wreck the entire job and I then can touch it up after I weld.

6. it is extremely chemical resistant after it has cured. Probably far greater than just a Eastwood chassis paint.

And to be clear the Chassis Black paint I am talking about is the topcoat made by POR15 not the Eastwood.

Can someone chime in who has used just an epoxy primer and a chassis black more than 5 yrs ago? How well has it held up? Most of the complaints I hear about POR15 in my opinion come from improper use or prep. If
Click to expand...

caper said:
No offence to anyone but does anyone else notice that everyone form CA , AZ etc... find POR15 to be great , well of course its gona last in those climates , bare metal would probbly take a year to start rusting. I live in the harshest climate for damp salt air and salt on the roads that you will find anywhere . My friend used $5000.00 worth of it on his semi that he uses to haul lobster boats out of the water and you wouldn't believe how it sucked , he did prep correctly and used all the cleaners and metal ready etc...the stuff was flaking off rust comming through only after one year while his epoxy coated trailer (that gets submurged in salt water has held up great) I always thought it was the best stuff out there from reading about it so much untill I saw this first hand. If I even mention the word POR 15 around him and he looses it . :bang:
Click to expand...

That's because a properly applied coat of POR15 is inferior to a quality 2k automotive coating on a properly prepared surface. Period.
 
I used POR 15 on my PW frame after I sand blasted it , I had a problem with it flaking off where i didnt sand blast and used the spray bonding/ etching agent. Had to wire brush the flakes and paint again. I am out in the desert so the big problem is the sun , the sun turned it from a nice shinny gloss black to a flat black in about a month. But thats my fault it says on the can to keep out of direct sun light. Inside on the floor in my 60 Plymouth that I started to work on it looks great and should hold the entire floor together for years. Just keep out of sun light , dont know if it is worth the cost my old man used a regular ole can of primmer and then again with black spray paint on his frame and his looks great and they are sitting side by side in the sun
 
Ive used por-15 and powr liner bedliner, you can put your topcaot on the por-15 as soon as it gets a little tacky they call it a slight finger drag. No sanding needed!

I am very pleased with the product
 
I bought the whole kit: etching primer, cleaner, metal ready, and POR-15 paint...

Followed the directions- parts were sandblasted, some flapper disc'ed, and some wire wheeled; ALL of it acetoned, metal prepped, then painted.

Directly from can of POR-15
"POR-15 is a rust prevenitive coating designed for application directly on rusted or seasoned metal surfaces."

Application Procedures
"Surface Preperation: Rusted sufaces are best, seasoned metal and sandblasted surfaces are also good. Smooth Metal Surfaces: Use POR-15 METAL-READY to prepare surface before painting."

I'm not saying POR-15 is an inferior product, It is AWESOME! I own three Cruisers and NEED it, some spots/applications there is no better option! But, for bare clean metal, there are better options.

I discovered a paint called "ZERO RUST" about a year ago, I've never seen anything like it!? You can dent, scatch, bend, whatever to it and stays stuck!? I painted a test spot on a tie rod a year ago and still looks good? I'm sure there are others out there? I'll save the POR-15 for floorboards... no affliation to either

last of my $0.02 :meh:
 
I did my FJ75 18 months ago with 3 coats of POR15 silver and a couple of coats of chassis black over the top, its still in the shed and hasnt really seen much direct sunlight yet but theres no sign of fading or discolouring so far although I've heard of it going chalky and fading? I painted a few bits on my 40 series with POR15 black without anything on top of it and thats starting to strip off now

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