Topic: Blasting the head

[afkrejci90]

My head is covered in a good layer of carbon in the chambers.  I just picked up a harbor freight blasting cabinet, but no media yet.  What is the best material to blast the aluminum with that won't damage it?  I was thinking of using soda ash, and using that on all the other pieces too.  Is there any tips on blasting the head, especially with the mating surface?

[tlbranth]

I used glass beads. But if you use them, close off all bolt holes, channels etc. The bastards get in there and won't come out - not 'til you drill for helicoils. Ax me how I know this. The glass beads won't hurt the aluminum.

[Reganator]

Wasn't some dude on here just a couple weeks ago freaking out about how the glass beads messed with his mating surface?  Seems that the consensus was he should go ahead and run the head, but it left sort of a texture behind he was very concerned about....

Lemme see if I can find that...

Here we go...  http://forums.sohc4.net/index.php?topic=120298.0

[percolate]

I had my head and jugs blasted when I rebuilt my top end but I only had the outside blasted. The shop I used suggested glass bead since I was going to paint it. The glass is more aggressive than soda and provides a good tooth for the paint to stick to. If I had not painted it I would have gone with soda blasting per their recommendation. So for you I would think soda would be the way to go.

Maybe this doesn't apply to your situation but Gorilla tape is awesome for masking. Fresh utility knife blades are a must for trimming and some laqueur thinner was needed to remove some stubborn adhesive before painting prep. Good luck!

[70CB750]

I had only chambers blasted to get valve guides safely out.    The rest I cleaned by scotch bright, much more tender process than blasting.

[MRieck]

Soda blasting isn't as effective as glass bead. Neither are walnut sheels or plastic bead. As somebody said....put bolts or screws in the threaded holes. I have also vapor blasted parts and that leaves a very nice finish.

[Lostboy Steve]

I had it all glass beaded. Then a full rebuild was done with some port work. After of course a good powdercoating.

[afkrejci90]

So here's the media I picked up, I think this should be good enough?
http://www.harborfreight.com/25-lbs-80-grit-glass-bead-blast-media-46426.html

[Jasondo]

fine glass beads. do not worry about mating surfaces.

[afkrejci90]

Everythin so far is taped up top and bottom, the only remaining holes are the spark plugs.  Will I be good enough to just place some rags through the holes, or will I need to get some spark plugs (if I can even find any) and plug the holes?

[Powderman]

There are a lot of misconceptions when it comes to glass media. There is glass bead that is actually little balls (beads) that don't actually remove any material, it peens the surface instead, leaving a nice semi gloss finish. Crushed glass on the other hand is much more aggressive and will remove material and leave a very textured finish that any oil or debris that gets on it will just migrate through the piece. Sometimes both of them will embed themselves into the walls of the substrate and need to be cleaned out thoroughly or they will do so themselves when the motor gets to temp and expands releasing this debris and it will quickly destroy your engine.
Vapor Blasting is the way to go on any motor parts you would be concerned with getting into the motor. It is a glass bead that is mixed into a soapy water slurry and shot wet. This peens, hardens and seals the surface and leaves a beautiful semi gloss finish. You can right on the part with a Sharpie and it wipes right off with alcohol. I use Jeff Gibson at (http://www.vaporblasting.biz), he is very reasonably priced . He is in Ore. and shipping is not too bad to get them to him. Vapor blasting is done wet so there is no heat build up and concern of warping parts. You can vapor blast bearing races, valve guides, etc. because it doesn't actually remove any material. Just a thorough cleaning afterwards is all that is necessary. Check out Jeff's website for more info. I had my whole Harley XR 1327 motor done with this but sadly he shipped the parts back to my motor builder and I have yet to see them.

[phil71]

Before you assemble that cabinet, silicon caulk all the joints.. It's not built all that great, and this helps a LOT. Consider getting a better gun too, the one it ships with falls apart pretty fast.

[afkrejci90]

Before you assemble that cabinet, silicon caulk all the joints.. It's not built all that great, and this helps a LOT. Consider getting a better gun too, the one it ships with falls apart pretty fast.

I wish I knew this before I assembled it    After my first blasting I found a nice pile of glass beads in every corner as well as a bigger pile on the floor underneath the chute.  I've already caulked the corners but this stuff still seems to find gaps all over the place, guess all of it is getting caulked.  So far those hose on the gun popped off and the trigger sticks, but its still working for now.

[Powderman]

I never did get my small cabinet to stop spewing media even after caulking everywhere I thought it could leak.