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When i get ready to paint to engine (im going to do it all when i have to replace the stator and when i replace the dampers) i was thinking about cleaning up the engine using a sand blaster. I have never used a sandblaster on aluminum, only steel. Would this be a good idea? I do have a lot of oxidation on the engine, and a sandblaster would be perfect for it, it is a portable one that kind of looks like a paint spray gun so i wouldnt have to worry about fitting the engine into a blasting cabinet. Just curious if sandblasting the engine is a good idea or not. I am going to sandblast the frame, fenders, and tank to get ready for fresh paint, so i might as well do it all at the same time if i can.
 

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I used a sandblaster about ten years ago on heavy rust spots on an older truck, and made some mistakes. I used sand media which leaves small deep holes where miroscopic droplets of solvent can remain after wiping the panel down just prior to painting. This solvent will eventually evaporate and mar the paint surface.

I think if you are going to use a sandblaster, that you will want to use some sort of bead media which is not so agressive when cutting, and leaves a smoother surface for surfaces to be painted. I would try the beads on the aluminum first too, to see if it will clean the engine satisfactorily, before deciding to use sand media on it.

Others with more painting experience may have other ideas regarding this.
 

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I used to have an '82 Kawasaki 750 LTD which I completely restored. Having had the frame powder coated and the chrome work rechromed I couldn't leave the engine looking like it was. I sandblasted it using sand that was mild, for lack of a better word. The place you buy media from will be able to suggest the right type. Be very careful though to seal, seal, and reseal every possible opening into the engine. Triple check it to be sure you haven't missed anything. Sand under pressure is as intrusive as water and you don't want any of it getting into the engine. I will say though that it came out beautifully. I actually used it to blast the wheels as well and they came out nicely. I borrowed a little portable hopper with the hose and gun already attached. Next I spread out some relatively thick visqueen (won't tear as easily) and put the piece I was blasting in the middle. When the hopper got low I gathered the visqueen from the corners and collected the sand. The hopper had a screen through which to sift the media and was more than enough for the whole job. On the LTD I had removed the side cases as they were getting polished so it required a little more attention to detail when sealing up openings and shaft penetrations. The engine itself looked new afterwards.

You'll be happy with the results.
 

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Discussion Starter #5
I used to have an '82 Kawasaki 750 LTD which I completely restored. Having had the frame powder coated and the chrome work rechromed I couldn't leave the engine looking like it was. I sandblasted it using sand that was mild, for lack of a better word. The place you buy media from will be able to suggest the right type. Be very careful though to seal, seal, and reseal every possible opening into the engine. Triple check it to be sure you haven't missed anything. Sand under pressure is as intrusive as water and you don't want any of it getting into the engine. I will say though that it came out beautifully. I actually used it to blast the wheels as well and they came out nicely. I borrowed a little portable hopper with the hose and gun already attached. Next I spread out some relatively thick visqueen (won't tear as easily) and put the piece I was blasting in the middle. When the hopper got low I gathered the visqueen from the corners and collected the sand. The hopper had a screen through which to sift the media and was more than enough for the whole job. On the LTD I had removed the side cases as they were getting polished so it required a little more attention to detail when sealing up openings and shaft penetrations. The engine itself looked new afterwards.

You'll be happy with the results.

Thats what i was looking for lol, someone that had done it and not ruined the soft aluminum blocks and heads by marring the metal beyond repair. When i do this im not going to be to super worried about the dirt getting into the engine because i will be tearing it down and having it professionally cleaned and checked for cracks and warppage, but thanks for the tip on keeping it all covered. What did you use to cover the holes? Mainly the coolant passages and the intake/exhaust ports?
 

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You could also use walnut shells to do the same job as sand but not as abrasive. Any place that you get sand blasting media should have this. It is for softer metals and delicate work but it will do the job. Any open port should be covered. You can use masking tape a couple layers should be plenty and stuff a rag in the hole as well.
 

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On "American Restoration" with the Pawn Stars buddy who owns a restoration shop, the owner Rick, says to never use sand on aluminum because aluminum is soft compared to steel. He says to use walnuts so that's what I would try first. You can always work your way up to something more abrasive. Before sand blasting the aluminum, I would get a junk peice somewhere and see what sand does to it.
 

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On "American Restoration" with the Pawn Stars buddy who owns a restoration shop, the owner Rick, says to never use sand on aluminum because aluminum is soft compared to steel. He says to use walnuts so that's what I would try first. You can always work your way up to something more abrasive. Before sand blasting the aluminum, I would get a junk peice somewhere and see what sand does to it.
Ha ha I beat ya to it LP. lol
 

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Anyone ever use baking soda on the engine? I've seen pics here of carbs cleaned with it, and it did a good job.
 

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I was going to say baking soda also but it might not be quite as good as the walnut shells. Baking soda is good for carbs and stuff with a lot of moving parts where it is a finer grain and chunks can't get stuck in the moving parts.

I used to do a lot of bead blasting and learned about all the different media for certain applications.
 

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I suppose I have to agree on the sand vs aluminum debate. I got lucky with mine and as I said I really only did the coarse part of the engine with great results. With an inline 4 though it was a lot of surface area. The cooling fins is where I saw the most dramatic improvement. Testing a junk piece (or hidden area) is a great suggestion. Of course Gunking the engine and taking a toothbrush to all the nooks and crannies first is time well spent. Eastwood Restoration has a cool gizmo that mixes baking soda with other media...one of these days. They have an awesome array of tools, paints, etc. albeit on the pricey side sometimes.

I used handy dandy duct tape everywhere I thought sand might intrude. Despite the velocity of air & media the duct tape was surprisingly resilient. Check out a site like this for an idea of what's out there. In my town I'm lucky enough to have a place that carries it all. I wish I could remember what they sold me as it didn't harm any piece I could see. Erring on the side of caution is a good idea though - you can unblast it.

http://www.kramerindustriesonline.com/blasting-media.htm
 

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Walnut shells will work the best for blasting aluminum. I used a blaster in a paint shop for 5 years, and sand should only be used for metal, not aluminum.
Walnut is softer, won't mar or pit the aluminum unless you stay on one spot too long.
Like they said in an earlier post, get a scrap piece, and practice. Blast at an angle and not too close. I found it easiest for me to move in a slow circular motion, but a side to side motion will work too.
I will be blasting my engine this spring, and I will post some pics for ya'all.
 

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Discussion Starter #13
I wont be doing the engine removal until next winter (unless something goes before then and i have no choice but to pull it, knock on wood). Just trying to get my ducks in a row and figure out how and what im going to do when the time rolls around.
 

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ok what about fine crushed glass.. then polish it with baking soda.. i have used the fine glass on body panels and it is fairly gentle if it is fine and about 90lbs pressure.....if you used only baking soda you wouldnt have to worry so much about it getting into where it shouldnt as it is kinda inert... that is what i am gonna use and i shall post before and after pics....provideing it turns out good... if not i will delete this post and hope everyone forgets i made any suggestions.......
 

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I took my engine apart, did not split the case, cleaned it real well and then painted it with silver engine paint. I am very happy with how it turned out. No blasting at all.

Jon



 

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Looks good 93.
 

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Thanks!

It looked really awful before, too bad I didn't take before/after pics, night and day.

Jon
 

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