85lebaront2 Posted December 28, 2018 Share Posted December 28, 2018 No, I'm using coal slag. Aluminum castings need fairly heavy abrasive in order to get things off/out of it, and lighter or softer media doesn't do that. Plus, you don't want smooth surfaces for powder. It needs something with "tooth" to grab hold of. If I were doing delicate things, like a carb or pistons, then I'd go to walnut hulls and turn the pressure down. But my experience with soda wasn't good. It was too "soft". Lacked "bite". Yes, it might take paint off, but slowly. And it breaks into DUST on impact, so doesn't seem like it would be good in a cabinet. However, I don't know that as I've not tried it. And, here's what I got done today. Lots of really clean 460 parts. Next up, probably Monday, is to melt some powder on those parts. Gee, that stuff looks vaguely familiar. I thought it had gone into a black hole, or maybe a rusty Chevrolet. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 29, 2018 Author Share Posted December 29, 2018 Gee, that stuff looks vaguely familiar. I thought it had gone into a black hole, or maybe a rusty Chevrolet. Well, it wasn't really a black hole. Or even a Chevy, or a Mopar for that matter. It was a twinvasion. (Get it? Twin invasion.) Speaking of Mopars, I forgot to post a pic of the convertible parts, which I have blasted. Wow, they were rusty. I may run them through the blast cabinet again just to be sure the rust is gone. And, as said in the email, the valve cover is drying from having been cleaned with brake cleaner to make sure that the baked-on oil doesn't get into the media in the blast cabinet. Link to comment Share on other sites More sharing options...
grumpin Posted December 29, 2018 Share Posted December 29, 2018 No, I'm using coal slag. Aluminum castings need fairly heavy abrasive in order to get things off/out of it, and lighter or softer media doesn't do that. Plus, you don't want smooth surfaces for powder. It needs something with "tooth" to grab hold of. If I were doing delicate things, like a carb or pistons, then I'd go to walnut hulls and turn the pressure down. But my experience with soda wasn't good. It was too "soft". Lacked "bite". Yes, it might take paint off, but slowly. And it breaks into DUST on impact, so doesn't seem like it would be good in a cabinet. However, I don't know that as I've not tried it. And, here's what I got done today. Lots of really clean 460 parts. Next up, probably Monday, is to melt some powder on those parts. Well done, looks good! Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 29, 2018 Author Share Posted December 29, 2018 Well done, looks good! Thanks! Just realized that the bowl games don't start until 3 PM Central tomorrow. So, I should at least get the rest of the blasting done, and maybe the 1 hour+ bake at 400 degrees. Then starts the masking off process as we don't want powder in the intake, inside the valve covers, etc. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 29, 2018 Author Share Posted December 29, 2018 Thanks! Just realized that the bowl games don't start until 3 PM Central tomorrow. So, I should at least get the rest of the blasting done, and maybe the 1 hour+ bake at 400 degrees. Then starts the masking off process as we don't want powder in the intake, inside the valve covers, etc. Ok, I did get the rest of the parts blasted today, and have just finished a 90 minute bake on the aluminum parts at 400 degrees to burn off the contaminants. But, along the way I had a couple of a few thoughts I wanted to pass on in case one or more of you start powder coating or even media blasting. RTV: Get all the RTV off before you blast. Media blasting takes off a lot of things, but not RTV as the media just bounces off. Yes, some stragglers can be blasted off, but it is much faster to get the bulk off other ways. My favorite is to soak it in brake cleaner and then hit it with a wire brush. For aluminum I use a brass "toothbrush". Powder Coating: You can blast powder coating off, but it is faster to soak it prior to blasting, and O'Reilly's brake cleaner is my favorite as it will bubble powder coating, making it much easier to blast off. And the Chrysler valve cover had powder on it that was stuck well. (But the 460 valve covers had a thin coat of aluminum paint that almost blew off with compressed air.) Tooth: Mark/Dyn asked yesterday if I use baking soda, and I explained that I don't because I want "tooth" to increase the adherence of the powder. And you can see on the pic below, the surface below the powder is clearly smoooooth. And here's the after-blasting pic, showing that the almost mirror finish is pitted, giving much better adhesion. And, in this pic the valve cover is ready for its time in the oven to drive out the impurities, having been washed with the brake cleaner. Last, just for grins, here's what the under side looks like: Link to comment Share on other sites More sharing options...
85lebaront2 Posted December 30, 2018 Share Posted December 30, 2018 Ok, I did get the rest of the parts blasted today, and have just finished a 90 minute bake on the aluminum parts at 400 degrees to burn off the contaminants. But, along the way I had a couple of a few thoughts I wanted to pass on in case one or more of you start powder coating or even media blasting. RTV: Get all the RTV off before you blast. Media blasting takes off a lot of things, but not RTV as the media just bounces off. Yes, some stragglers can be blasted off, but it is much faster to get the bulk off other ways. My favorite is to soak it in brake cleaner and then hit it with a wire brush. For aluminum I use a brass "toothbrush". Powder Coating: You can blast powder coating off, but it is faster to soak it prior to blasting, and O'Reilly's brake cleaner is my favorite as it will bubble powder coating, making it much easier to blast off. And the Chrysler valve cover had powder on it that was stuck well. (But the 460 valve covers had a thin coat of aluminum paint that almost blew off with compressed air.) Tooth: Mark/Dyn asked yesterday if I use baking soda, and I explained that I don't because I want "tooth" to increase the adherence of the powder. And you can see on the pic below, the surface below the powder is clearly smoooooth. And here's the after-blasting pic, showing that the almost mirror finish is pitted, giving much better adhesion. And, in this pic the valve cover is ready for its time in the oven to drive out the impurities, having been washed with the brake cleaner. Last, just for grins, here's what the under side looks like: FYI, the two small holes on the back side opposite end from the oil cap are for the internal baffle. This "in theory" keeps the oil inside the valve cover. These engines are famous for puking oil into the breather and soaking the air filter with oil. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 30, 2018 Author Share Posted December 30, 2018 FYI, the two small holes on the back side opposite end from the oil cap are for the internal baffle. This "in theory" keeps the oil inside the valve cover. These engines are famous for puking oil into the breather and soaking the air filter with oil. And, there are two tiny screws that go in those holes. Do you want them powder coated? Since that's going to be well-lubed, there's no chance of rust. Link to comment Share on other sites More sharing options...
85lebaront2 Posted December 30, 2018 Share Posted December 30, 2018 And, there are two tiny screws that go in those holes. Do you want them powder coated? Since that's going to be well-lubed, there's no chance of rust. Probably wouldn't hurt, they get a small bead of RTV on them where they go through the cover. Link to comment Share on other sites More sharing options...
Hstrymkrs Posted December 30, 2018 Share Posted December 30, 2018 Probably wouldn't hurt, they get a small bead of RTV on them where they go through the cover. It has been a long and sordid day. I was able to get the flywheel cleaned up and the new clutch put back on the engine. As I was putting everything together, I notice the o-ring was missing from the pilot bearing. I know I didn't do anything to make it come out, and there was a small dent in the bearing surface. Thankfully a new one came with the clutch kit. I borrowed the tool from the parts store to pull the old one out, and like every other time, the tool was work out and didn't work. I had to resort to the bread trick. Let me just say that I am amazed. Eventually, I was able to get it all together and get the engine married to the transmission. Now I can start putting the other stuff back together. I will upgrade the ignition coil and distributor. Any suggestions are appreciated as I do more research. I am also reading and trying to decide on a smog delete. Just not sure yet. I really don't know enough about the pros and cons. William Link to comment Share on other sites More sharing options...
Hstrymkrs Posted December 30, 2018 Share Posted December 30, 2018 It has been a long and sordid day. I was able to get the flywheel cleaned up and the new clutch put back on the engine. As I was putting everything together, I notice the o-ring was missing from the pilot bearing. I know I didn't do anything to make it come out, and there was a small dent in the bearing surface. Thankfully a new one came with the clutch kit. I borrowed the tool from the parts store to pull the old one out, and like every other time, the tool was work out and didn't work. I had to resort to the bread trick. Let me just say that I am amazed. Eventually, I was able to get it all together and get the engine married to the transmission. Now I can start putting the other stuff back together. I will upgrade the ignition coil and distributor. Any suggestions are appreciated as I do more research. I am also reading and trying to decide on a smog delete. Just not sure yet. I really don't know enough about the pros and cons. William Not sure why my I'm ages are flipped. Link to comment Share on other sites More sharing options...
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