I guess I don't understand why other people have trouble removing old paint
Doesn't leave a rough surface at all? I've worked for a soda blaster in the past and he and I used to have fun debating this...as in what's a course enough surface for primer to stick to? Epoxy on bare metal the manufacturers like to see at no courser than 180 grit. Is the blasting process equal to that?
A good urethane or primer surfacer should be the same way, a minimum of 180 grit for metal and bone, as the surfacer needs a sand scratch to flow into and lock down on. When you say it doesn't leave a rough surface is it leaving enough surface area on the sheetmetal - that's what sanding does, increases surface area - for the primer to look on to?
Don't get me wrong, I like media blasting. Quick, easy, and in the case of soda, it's biodegradable, making clean up easy - shovel, sweep, wait for a good rain - but I've always felt the need to rough the panel up a little more afterwards with at least 180 grit. It may take a little more time, but it's a peace of mind thing, knowing that I won't have to worry about primer not wanting to adhere.
And please don't think I'm trying to piss in your wheaties. I'm just asking for those who are reading to ask and be informed.
The surface prep needs to be followed by the recommendation of the paint manufacture's p-sheet. As in "prep bare metal by sanding with 180 grit paper." Just need to make sure the media is giving an equivelant.
now that i have a soda blaster i would never take paint off any other way. this chevelle fender i blasted quickly as a experiment. (its not perfect) Doesnt leave a rough surface at all. in fact the bodyshop i do work for just cleans and shoots it afterwards. no prep work at all. (assuming it needs no work)
Doesn't leave a rough surface at all? I've worked for a soda blaster in the past and he and I used to have fun debating this...as in what's a course enough surface for primer to stick to? Epoxy on bare metal the manufacturers like to see at no courser than 180 grit. Is the blasting process equal to that?
A good urethane or primer surfacer should be the same way, a minimum of 180 grit for metal and bone, as the surfacer needs a sand scratch to flow into and lock down on. When you say it doesn't leave a rough surface is it leaving enough surface area on the sheetmetal - that's what sanding does, increases surface area - for the primer to look on to?
Don't get me wrong, I like media blasting. Quick, easy, and in the case of soda, it's biodegradable, making clean up easy - shovel, sweep, wait for a good rain - but I've always felt the need to rough the panel up a little more afterwards with at least 180 grit. It may take a little more time, but it's a peace of mind thing, knowing that I won't have to worry about primer not wanting to adhere.
And please don't think I'm trying to piss in your wheaties. I'm just asking for those who are reading to ask and be informed.
The surface prep needs to be followed by the recommendation of the paint manufacture's p-sheet. As in "prep bare metal by sanding with 180 grit paper." Just need to make sure the media is giving an equivelant.