How thorough should I sandblast old rust/paint before applying POR15/primer?

   / How thorough should I sandblast old rust/paint before applying POR15/primer? #1  

pclausen

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Location
Nelson County, VA
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JD 5085M, Ford 1700, JD GT235
So I got one of those 40 Lb. pressurized abrasive blasters from Harbor Freight to restore a number of implements. I have never used a sandblaster before, but it seems to work quite well (I got a 7.5HP 24 CFM compressor behind it). I'm using Black Diamond fine media (20-40 I think) from Tractor Supply.

I plan to prime and repaint my implements after removing all the rust. My question is how thorough I need to be in stripping the old paint before proceeding to the prime stage?

I'm working on a Woods RB850 blade first. Here are a couple of shots of the pieces after taking it apart:

RB850-7.jpg


Car dolleys are handy for moving these heavy pieces around!

RB850-8.jpg


I started with the blade itself, and here's what it looked like after working on one side of it. (the blasted areas on the other side is where the labels were)

RB850-9.jpg


And a little while later:

RB850-10.jpg


Should I keep going until the entire surface is completely smooth (as can be seen in the areas where there were labels), or will leaving it like this be good enough? (I do plan to hit those areas that still have solid paint). What I've done so far consumed 1 50lbs bag.

I picked up some grey sandable implement primer from Tractor Supply as well as this stuff:

por15.jpg


For the Woods implements, I went to an auto paint store, and he was able to look up the Woods Burnt Orange in his computer and mixed me some Imron high gloss polyurethane as seen here:

imron.jpg


So once I'm done sandblasting, I figured I'll hit everything with the Marine Clean and Prep and Ready. After that, I'm wondering if I should hit only the areas that had heavy rust with the POR15, and the rest with the Tractor Supply primer, or just hit everything with the POR15?

I was planning to brush on the Imron paint, but perhaps I would be better off picking up some thinner and using a gun?
 
   / How thorough should I sandblast old rust/paint before applying POR15/primer?
  • Thread Starter
#2  
I think I figured out the answer to the last question myself. Reading the warning label on the back of the can of Imron paint, it would require a positive pressure, supplied air respirator to spray it. After looking up the cost of such a system, I think I'll be brushing it on using my $30 Tractor Supply respirator (which is NIOSH and organic vapor approved, which it must be based on the warning label).
 
   / How thorough should I sandblast old rust/paint before applying POR15/primer? #3  
i would be very careful about sandblasting close to hydraulic cylinders... or am i being overly cautious?
 

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   / How thorough should I sandblast old rust/paint before applying POR15/primer?
  • Thread Starter
#4  
That's a good point. When I lowered the cylinder to re-position the blade, I head crunchy sounds. I stopped right away and cleaned the rod and blew off the sand from around the seal. Seems to be ok still. Nevertheless, I'll likely put the pieces on blocks from now on and only use the engine hoist to transport the pieces in and out of the shop.

It started raining, so I'll have to wait until at least tomorrow before continuing.
 
   / How thorough should I sandblast old rust/paint before applying POR15/primer? #5  
thanks for the pictures
 
   / How thorough should I sandblast old rust/paint before applying POR15/primer? #6  
Your Imron will only be as strong as whatever you put under it. I would take back the por15 and tsc primer and get some epoxy primer. The best epoxy I have ever used is made by southern polyurethanes. Look them up on the net, they will ship it to you for free. Putting Imron over tsc primer would be a complete waste IMO.
 
   / How thorough should I sandblast old rust/paint before applying POR15/primer? #7  
i would be very careful about sandblasting close to hydraulic cylinders... or am i being overly cautious?

your being overly cautious. There is no possible way your gonna hurt that cylinder on the engine lift. You would have to be intentionally spraying at it directly but even so, you would have to be shooting it at one spot for awhile. I have one of those lifts that i have removed and installed about 10 engines and the thing has been smacked by everything in the book and still going strong.
OP- beutiful dog! i thout you didnt have to go that crazy with prep with POR. It is what it says paint over rust. A little is understanding but overkill would allow you to go with another product other than por
 
   / How thorough should I sandblast old rust/paint before applying POR15/primer? #8  
One caution on the POR 15. I used it successfully...the second time I tried it. The first time I tried it I screwed up on the process and I was taking the stuff off in sheets. Second time, being very careful it worked out really well. Be careful. I kinda like the epoxy primer for this application. I wonder if the clean, etch, paint of the 15 will take well on the rough cylinder. Good luck
 
   / How thorough should I sandblast old rust/paint before applying POR15/primer? #9  
I'll be interested to see how this turns out. I want to do the same thing to my box blade but don't have a sandblaster. I'd like to have someone blast it for me but I have no idea of what that would cost. Good luck with your project.


OP- beutiful dog! i thout you didnt have to go that crazy with prep with POR. It is what it says paint over rust. A little is understanding but overkill would allow you to go with another product other than por
I've looked through the pics multiple times and I don't see a dog anywhere???? Am I just blind!
 
   / How thorough should I sandblast old rust/paint before applying POR15/primer? #10  
I've looked through the pics multiple times and I don't see a dog anywhere???? Am I just blind!

chk the avatar. :laughing:

btw, i agree... beautiful dog.
 

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