Seems like some extremely random spots under the lacquer that are full of pits. If it was one area,, I'd cut it out, but it's not an option here - what's the best way to treat / seal this ?
speed blaster, then epoxy primer, filler primer, then paint https://www.tptools.com/Speed-Blast...MImty2x6OG5AIVjq_ICh1ttAs8EAQYAyABEgIbYPD_BwE
Looks like surface rust/pitting has formed under the paint/primer. Is there rust through pin holes etc? Stripping the finish to bare metal will be the way to look for more. Once uncovered a rust converter can be used and/or careful grinding can remove some or all of the rust depending on how deep it has penetrated the steel. Once dealt with repaint is in order.
Well that thing looks handy... works pretty well ? I also need to figure out what epoxy primer or sealer to use now that I live in a paint challenged state..(maryland)
It's strange, it is in many different random areas, none are through, they all look like patches as in the pic. Rust converter like Ospho ?
REALLY a good tool, I have been using mine for 25 years and depend on it regularly. it can be used with or without the recovery system.
Epoxys have no isocyanates in them so shouldn't be any issue with VOC laws. Sent from my SM-G950W using The H.A.M.B. mobile app
Depending on a lot of things you could strip the surface with a appropriate abrasive to uncover these hidden rust spots then sandblast just the spots. There is small hand held sandblasters meant for these small rust situations. The problem is if you get after a spot like this and keep going until all the surface rust is gone - you often enough end up breaking through the panel with lots of little pinholes of rust. The rust holes end up looking like a piece of lace table cloth with all the pinholes poking through. Then you are forced to weld in some sort of patch . But sometimes you don’t break through the panel which then you can apply some body filler to the perfectly clean but pitted sections.
Good point. I'm not opposed to welding in patches where needed, hopefully most of these spots clean up without becoming patches...
Hopefully these spots don’t breakthrough but you must use whatever way makes the most sense to get these surface rust spots completely clean. Others here may disagree but I have no faith in putting quality refinishing products over any of the various rust converters. I have never used it as a step in the exterior refinish process - I always hear stories of it blistering and such. I have used it on frames and floor pans and things like that. Perfectly clean dry steel is the best substrate there is to apply fillers and appropriate primers over.
The roof panel on my 66 F100 had spots that looked like that under the lacquer paint and primer that I applied in high school. The paint was on there 30 years before I redid the whole truck. I used NAVAL JELLY which is just a thick phosphoric acid which clings real well. I first used a da sander to strip all paint and the rust that I could off, then a 3M paint buster to remove more rust. I applied the jelly and let it sit wet for an hour or so and wiped off the excess and used a drill and wire wheel to scratch at the rust that would come off.Iknew it needed to sit longer to work, so I then applied the jelly and covered it with plastic to keep it wet overnight for the best results. I kept at it and it completely removed all rust and left a nice coating. As far as the SPEED BLASTER, and recovery bag, I have been using one for 25 years and love it, but you need to use caution as it can warp the panel. In fact, I just used mine today to do this very thing on a door that had rusted under a moulding and made sure to monitor it as I went, so as not to put a big bulge in the middle of the door.
This is the reason I started my own coatings line 30 years ago. Soak a rag or paper towel with a quality rust remover. You can use mine or Ospho or jelly after an hour you should be down to white metal. Scrub it with water and a maroon scotch bright pad and then immediately dried off. Then you use my permanent rust sealer or you can use the epoxy. In my opinion I would use both ,my sealer with an epoxy surfacer over it I hope this helps
Thanks a bunch ! I had forgotten about naval jelly, that stuff is magic ! Sent from my iPhone using The H.A.M.B. mobile app
I've seen rust like that created where the paint wore thin and the metal was allowed to rust. When buying your blaster don't cheap out and get the Harbor Freight one. They are night & day different. The Speed Blaster lets you adjust the abrasive flow with the valve while allowing full air flow/pressure. The HF valve restricts air flow. It also doesn't blast as well. The Speed Blaster recovery system works great and is a big plus if you're working inside. I use coal slag for blasting as it cheap. I use Southern Polyurethane Inc epoxy primer. Its the great quality at a great price.
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