Media blasting protocol?

[avenue]

What's the protocol on preparing an engine for media blasting?

My engine is torn down, sitting on the bench, everything is out except the trans shifter, and a few starter gear shafts. It's awaiting a light rebuild and I want to remove the crappy, worn out black paint before going back together.

I'd like to blast the whole thing but I'm new to this and worry about gasket surfaces and important parts being compromised.

thanks for your help and time,
avenue.

 

[tadd442]

Depends on the media used. If you use sodium bicarbonate, (baking soda) it will have virtually no issues, but will take longer than silica sand. Silica sand on the other hand, is about as aggressive of a media as you will find, and will most likely leave a texture after blasting. Generally speaking, tear it COMPLETELY down. That way you are POSITIVE nothing will cause unwanted results. If you are going for an overall "clean up" and want to polish the (motor) side covers, I would use glass beads for all of it. Bead blasting works well, is reasonably quick and the differences, (if any) in the mating surfaces will be taken care of by your new gaskets.

 

[jamesgs4]

the baking soda blasting is awesome on aluminum, and the easy cleanup is worth it.

 

[sherwin]

Soda blasting really is the way to go to get everything cleaned up.

 

[avenue]

thanks for replies.

however, I was not asking what type of media to shoot but rather, what do I need to do in order to prepare gasket surfaces, bearing races, and other critical machined areas of the case and top end before I start blasting? or, do I simply stay away from these areas while in the booth?

and, thank you tadd

avenue.

 

[sherwin]

I suggested soda blasting because it won't damage the gasket surfaces, so you don't have to worry about this as part of your preparation. Sorry I didn't specify my reasoning for suggesting it. Hope this helps.

 

[avenue]

awesome. this is what I needed to hear.

thank you.

 

[Shakey]

+1 on soda blasting. I broke my engine down into its constituent Parts. The soda cleaned off grime, old gaskets, some rust on chromed parts, carbon from exhaust ports (result!), but didn't get deep enough to affect the deeper corrosion/ discoloration on the alu cases. Hosed it all off after. Would go down this route again

 

[TwoJugs]

I used glass bead. My local supplier has different grit glass so you can get as easy as you want on parts. Stay away from any sand on aluminum when possible. I use sand on the frame and other steel parts that I plan on painting. I am going to try some soda on the current project, looking for that frosted aluminum finish.

 

[54inches]

Where in texas; I have a decent cabinet and I am in houston if you need help.

 

[5twins]

I block off and cover any surfaces and holes I don't want the media to get at. This is particularly important with glass beads. They imbed themselves into aluminum. You can rinse and wash all you want, you still won't get them all cleaned off. THEY COME OUT WHEN YOU RUN THE ENGINE AND IT GETS HOT. Sorry to shout but if you glass bead internal parts and surfaces, basically you've screwed yourself.

A guy on another list glass beaded his pistons. I told him that wasn't a good idea. He's an aircraft mechanic so he thought he knew better. His motor didn't even make it through the summer. Now he's rebuilding it again. I hate to say "I told you so", but I did. This is the internet. You have to take the advice you get with a grain of salt and consider it carefully, I realize that. It's just that this glass beading advice is really true. Go ahead, glass bead your internal engine parts and see what happens. Personally, I don't give a shit if you fuck your motor up. All I can do is give a warning and hope you take it to heart.

 

[cra-z1]

I use glass bead myself for the outside of the cases only. I do make sure I cover all bearing surfaces and plug all holes and oil passages. I use a combination of aluminum tape to protect surfaces and plumbers putty to protect oil passages. Just make sure you stay away from all interior surfaces and you will be ok. Make sure you cover the two small holes that spray oil on the rods from the main oil passage. I triple clean everything with hot water and Dawn. I also use #0000 steal wool with the Dawn which polish the outside of the cases very well. Just use a little common sense and you will be fine with Med Glass beads. I run my pressure at about 80-90 Lbs.

 

[Irish750]

So am I right in assuming soda blasting is good for cleaning up the inside of an engine?

 

[XSLeo]

Yes Soda is safe. When done wash with hot water and soap. The soda disolves in water. Easy to get it all out.
Leo

 

[twinrider]

One last tip would be to run your engine 5 minutes and flush oil, two times at least, to be certain no dust or remaining debris are stuck in there.

Got this one off an old Yamaha mecanic, been there for 30 years, he says he always flushed 3 times after any rebuild.

 

[avenue]

So, after much deliberation, sounds like it's okay to blast away with soda on everything, Glass only on the outside, and flush the newly rebuilt motor a few times after initial startup?

Thanks for the help and tips. And, 54inches, I'm in San Antonio. Thanks for the offer but it's a bit of a drive for an engine clean-up. I do make it to Galvez and Dickenson once or twice a year, though.