bead blasting pistons

just got a new blaster and wanted to know:

What is the best media to do the job without damaging the pistons and what grit ?

Do you blast the ring lands as well or cover them?:o

Thanks in advance

David

When I do pistons I use a Ceramic grade glass media it does no more than polish and clean. I got it a couple of years ago and its green. I change media for several jobs I do .. I have them in 5 gallon pales and when I get ready to use an aggressive grit I just dump the whole blaster and add the grit I choose for the job. I use NO other abrasives other than glass , but 3 different grades of glass... Hope that helped.. Jay

Get the finest grade of glass beads. That will clean the pistons without damaging ring grooves. Ya need to clean the ring grooves if the pistons have much time on them at all.

some people use soda aka soda blasting. its very gentle and its safe to use with out dreading glass particles getting in your engine from stray particles after thorough cleaning. worst case you start baking bread in your crank case :D

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Originally Posted by RichS

Get the finest grade of glass beads. That will clean the pistons without damaging ring grooves. Ya need to clean the ring grooves if the pistons have much time on them at all.

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Worst part of the whole job. If not done properlly your new rings will not seat.

There are a couple of other benefits to bead blasting. 1) it releaves stress risers that are either made into the part or form due to corrosion (corrosion stress cracking). 2) It improves surface finish to better control oil and lubrication. OK, that's it. I've spent my three brain cells on this subject.

Thanks a lot everyone for your feedback:cheers:

I will try it on a few bad pistons first to see how it works out.

David

In aircraft engine rebuilding glass bead shot media is verbotten because of the possibility of broken glass embedding in the skirt or ring land causing bore scratches or ring seal loss.

Now everyone will say they have done it a hundred times and had no problems but the possibility is there. The only shot procedure that is recommended by Pratt & Whitney is walnut shells for the skirts and sisal twine in the ring grooves:rolleyes:, I imagine any of the plastic shot would be acceptable as well.

I have not tried ceramic, to be honest I have had the best results from simply soaking the pistons in Chem Dip style caustic soda cleaner such as used in carb rebuilding. It gets the varnish off without damaging anything and washes off with water and stiff bristle brush.

I like to lap the rings on my personal motors but the quality of todays rings and pistons means its not really all that necessary.

With the extensive chemical and water blast cleaning my parts go through after bead blasting I'm confident my parts at assembly time are clean..

Chemical cleaning of pistons and 4000 lbs HOT soapy water blasting of front halves after bead blasting ...

IMO if you search the internet "SOMEBODY" has issues with "EVERY" method of "EVERY" conceivable method to do "ANY" task on the planet.. I use what has been successful for ME and report MY methods others can do and use what they feel like is correct..

Jay ;)

I think Jay is correct about the differant responses you will get on this subject,I blast the crowns and ring land with the skirts taped off ,after cleaning I stickk them in a ultra sonic cleaning tank,I'm always amazed what comes out of that tank afterwards:D

Couple of well made points made by Jay and Superbender, regardless of the media used, CLEANING is absolutely CRITICAL. Most 'home-builders' so not have access to professional cleaning equipment and maybe should think seriously about that BEFORE bead blasting pistons. Chemical cleaning (without a particle blaster) may have some benefits for those individuals.

I'm sure those with bead blasters will all agree that grit size, regulated air psi, nozzle size, angle of attack, 'sweep' pattern, speed of movement, all can have great effect on the finish appearance AND can actually vary metal thickness if too aggressive.

Experience - ain't NO substitute for it.

Moral of this story, start with EXTERNAL PARTS, develop the 'feel', til you build LOTS of confidence (EXPERIENCE) before attacking pistons.

Quote:

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Originally Posted by 4JawChuck

In aircraft engine rebuilding glass bead shot media is verbotten because of the possibility of broken glass embedding in the skirt or ring land causing bore scratches or ring seal loss.

Now everyone will say they have done it a hundred times and had no problems but the possibility is there. The only shot procedure that is recommended by Pratt & Whitney is walnut shells for the skirts and sisal twine in the ring grooves:rolleyes:, I imagine any of the plastic shot would be acceptable as well.

I have not tried ceramic, to be honest I have had the best results from simply soaking the pistons in Chem Dip style caustic soda cleaner such as used in carb rebuilding. It gets the varnish off without damaging anything and washes off with water and stiff bristle brush.

I like to lap the rings on my personal motors but the quality of todays rings and pistons means its not really all that necessary.

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Not many folks from piston shops anymore, SAE by any chance?