How to trash 4 pistons

Tomtall · 04-24-2006

I saw these pistons up for sale on E-Bay. The seller Glass beaded all for piston.

I am no expert on beading but I was always told never, never glass bead the skirts of a piston because you can never get the glass bead thats inpregnated into the aluminume removed enough to not scratch the H** out of the cylinder walls. Is this true? Or just myth? Sure look pritty.

**Ron Hill** · 04-24-2006

Nine out of ten times when I glass bead something, the glass beads break and become dust. One arguement for glassbeading parts has always been that gals beading doesn't remove metal...Hell, a little glass could make thme smoother.....

OK, you MOTOR HEADS......Let's hear the TRUTH....Somebody like Ted Zahorski or Jim Nerstrom, or Freddy Hauenstein will probably post something...of which none of us will understand...I ask those guys "What time is it and they tell me how the clock works...." Anyway....I would fear SAND BLASTING more than glassbeading...Because one piece of sand could rais hell..That I know...

**will350** · 04-25-2006

I would be sort of worried about the effect on the ring lands and the wrist pin holes because those have to "fit".
The "dust" from glass beading is incredibly fine and unbeleivably abrasive. It is also very difficult to get it all off (or out) without going to extremes (like washing with hot water and soap a half dozen times).
In the early 70s a customer decided he wanted a custom paint job on his brand new 350 triple Kawasaki. It was a beautifully and tastefully done peice of work. Yellow all over as I remember. It also ate crankshafts for breakfast, lunch and dinner. I put 3 factory shafts in it in less than 2000 miles. When we got to #4, I put a whole new motor in it because of the abnormal amount of wear. 2 months later, the crank was gone again. All on warranty. Turned out that the paint shop had glass beaded everything to strip it. Since it had a snap on gas cap,that came off during the beading as well as the shut off and filter.. The filler hole did get taped but the outlet did not. Probably wasn't a 1/8 teaspoon total. The last time it left,it had a new tank on it(red with blue stripes and the customer whined heavily about it) but it never came back for anything other than normal maintenance after that.
Personally,I would never use glass beading on internal engine parts.
Will

Originally Posted by RonHill

Nine out of ten times when I glass bead something, the glass beads break and become dust. One arguement for glassbeading parts has always been that gals beading doesn't remove metal...Hell, a little glass could make thme smoother.....

OK, you MOTOR HEADS......Let's hear the TRUTH....Somebody like Ted Zahorski or Jim Nerstrom, or Freddy Hauenstein will probably post something...of which none of us will understand...I ask those guys "What time is it and they tell me how the clock works...." Anyway....I would fear SAND BLASTING more than glassbeading...Because one piece of sand could rais hell..That I know...

**Joe Silvestri 36-S** · 04-25-2006

From experience, glass beading the internal engine parts will devistate the engine once put back together and ran. Glass does get into the pores of the aluminum and once the engine and the engine parts get hot the pores open up and out comes the glass. Its a quick way to wear out an engine. This happened twice to two different engines of mine. No more glass beading is ever done on an engine of mine.

John (Taylor) Gabrowski · 04-25-2006

Fine blasting can be done with either baking soda or walnut shell if you want a bit more abrasive. Neither of them once the part is cleaned, stay. Anyone wanting to buy those "A" pistons would only be safe to leave them in a not to be run saw horse queen.

**Fast Fred** · 04-25-2006

well i know that Pistons Are glassed off, 8yrs ago started glassin the combustion chamber on heads, thay are still out thare, kickin bum.

Tomtall · 04-25-2006

Had a coversation with one of the hydraulic pump engineers at my place of employment today (Parker Aerospace) about beed blasting. We do quit a bit of it when aircraft hydraulic pumps are rebuilt in one of the departments. He informed me that glass beeding and and sand blasting are not used on any wear surfaces due to the inpregnation into the part being blasted. This he said is not possible to remove from the metal once it's done. He said this is detectable by using an electron microscope to see what is left behind in the porse of the metal. What he says they do use is plastic medium to blast surfaces to clean them. I asked him about alum. oxide medium which is also used by some people to etch parts and blast them. He showed be a part that failed many years ago in a pump that had a brass ring riding on a steel ring. Know we all know brass is softer than steel , however the steel ring had a deep groove cut into it from the brass ring, with no sighns of wear to the brass. I ask how this was possible? He said the brass ring had been beed blasted with Alum. Oxide medium and then cleaned. The oxide had been inpregnated into the brass and acted as an abrassive, cutting the steel ring. Lesson learned, don't beed blast parts with abrassive medium if it's a wearing surface.

**smittythewelder** · 06-11-2006

Yo, Tomtall, Maybe you saw an old post of mine. Somewhere it have a factory service bulliten from one of the automotive piston or ring manufacturers (I forget) that said do not glassbead pistons. And a sure way to frustrate a welder is to bring him a broken aluminum casting that has been "prepared" by glassbeading. If you want to clean pistons with your home blaster, buy a bag of salt from a wholesaler.

But all is not lost. After you have made all the suggested efforts to get the residual glass out of the "pores" of those nice clean pistons, you can cover up what's left by molycoating the skirts. I learned about this from a Boeing lubrication expert in the '60s, Zak was coating pistons and bearing retainers in the '70s, and coatings specialists like Swain-Tech are doing it now, but you can do an acceptable job yourself. In the heyday of 2-stroke motorcycle racing in the '70s, a company called Kal-Gard was selling do-it-yourself molycoating supplies to all the gung-ho bike tuners, and if you look through 25 year old copies of Cycle you can read their ads. Sales declined with the coming of all those wretched 4-strokes and Kal-Gard was sold, but if you Google "KG Industries" you'll get to the original owner. He still sells the coatings, mostly to his first customer base, the gun-nuts (no, I'm not dissing them).

Get the pistons extremely clean, maybe including a final acid-etch with mag wheel cleaner. Heat the pistons enough to boil out the moisture, but let 'em cool to just over room temperature. Spray on the molycoat with an airbrush; have the piston rotating on an old, cheap phonograph turntable. Don't go over .002 to .003'', probably (get some no-good pistons to practice on). Bake at 300F for an hour. Zak swore by molycoating, which enables you to re-use pistons indefinately . . . ''til you stick 'em!

**Ron Saxvik** · 06-11-2006

Hey Smitty.....will walnut shells work ? Just got some at Harbor
Freight to use in a vibratory tumbler and was thinking bout using
them in my bead blaster for cleaning up pistons etc. Am retired
from the Timken OverBearing company and used to clean up all my
pieces/parts in a vapor blast cabinet that we used for cleaning up
stamps after heat treat. Thinking that it used a soda/water combo
and that did an excellent job with no problems. Would like to have
that here but think they are still using it.....with all the tool room
activity being shut down doubt it they will be needing any more.
Most of tooling is now being made in India, Poland or China but they
still may use it for post heat treat on the masters that are still being
made here.

**Dr. Thunder** · 06-11-2006

... how about powder coating parts. What is the maximum temperature that powder coating will tolerate? Can you powder coat, blocks, cases expansion chambers ... or, will they get too hot and blister, peel, crack, disintegrate, or what???