Prep for bead blasting

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jhajjar

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I am in the process of prepping my cylinder head for bead blasting, never done this before, any tips would be greatly appreciated.

1. What is the best material to use to mask the machined surfaces.
2. Should I mask off completely the internal areas? ( I am assuming at least the area for the rocker spindles)
3. Can the valve seat be blasted or should it be masked.
4. Should I have the valves blasted as well? (They are brand new Black Diamonds) Read somewhere that the blasing process is supposed to help eliminate surface cracking, is it really needed on new valves.

thanks
 
You can bead blast all over, unless you hold the gun on any one part for an excessive amount of time it won't remove any metal. Leave the guides in & might be a good idea to put the rocker shafts in with the rockers on. This will protect the bores & blast the rockers at the same time, though lightly blasting said bores will do no harm.
You can blast the seats & intake & exhaust bores, combustion chamber & gasket face.
Only problem is the machined face on the outside between the rocker shafts. If you use masking tape, it is one hell of a job to remove afterwards.
I use size 13 glass, which is about average.
 
thanks,
will put the shafts and rockers back in. Took them out originally. I am having a machine shop do the blasting as I don't have the equipment to do it myself.
 
If you don't mind I have a couple of questions on this topic.

In particular I would like to know what grit/ size glass bead is recommended. The 60/80 & the 80/100 seem to be available.

Is this medium also safe to use on cleaning up the cases? I assume it will damage any surface needing to be polished.

What is typically used to mask areas that you don't want to blast?
 
T95 said:
If you don't mind I have a couple of questions on this topic.

In particular I would like to know what grit/ size glass bead is recommended. The 60/80 & the 80/100 seem to be available.

Is this medium also safe to use on cleaning up the cases? I assume it will damage any surface needing to be polished.

What is typically used to mask areas that you don't want to blast?
Click to expand...

Do not use glass bead at all! The sharp glass opens up the aluminium surface and leaves residue into the open blasted pore which could ruin your bore and piston rings! No need to say it is also not advisable to use for other aluminium engine parts.
Instead use a ceramic bead that will clean and shot peen the surface (fine will give you a grey surface the more coarse you go it gets more silver coloured) Ceramic bead is more expensive but last longer.
 
nortonspeed said:
T95 said:
If you don't mind I have a couple of questions on this topic.

In particular I would like to know what grit/ size glass bead is recommended. The 60/80 & the 80/100 seem to be available.

Is this medium also safe to use on cleaning up the cases? I assume it will damage any surface needing to be polished.

What is typically used to mask areas that you don't want to blast?
Click to expand...

Do not use glass bead at all! The sharp glass opens up the aluminium surface and leaves residue into the open blasted pore which could ruin your bore and piston rings!
Instead use a ceramic bead that will clean and shot peen the surface (fine will give you a grey surface the more coarse you go it gets more silver coloured) Ceramic bead is more expensive but last longer.
Click to expand...
Edit:
jhajjar,
Sorry for the hijack, I thought I had did PM to this response. I hope you find the info valuable.

Thanks for the advice! I picked up a small cabinet thinking I would do some of the clean up myself. I found the choices in media confusing at best, the materials are not so easy to source and if shipping is required it easily doubles the coast. I had thought glass was preferred over other media due to the lack of residue left behind. So if the residue is a problem in the heads I am sure the same applies for the interior of the cases? Can you please define fine in either a grit or screen size?
Gary
 
I found that a great masking material was the foil tape that heating guys use for duct work.
 
IMHO anyone who bead blasts aluminum cases and heads or buy a bead blasted head off ebay deserves what they get....

My friend had Ron's Cycle (leominster Mass) do a BIG bux rebuild. It sat for many years...then when he finally installed the motor...he ran it for about 200 mile and then felt a need to swap the cam. When we split the cases, in the bore we found a HUGE mess.... scored bores etc. The damage was from grit .....an absolute shame. What an expensive lesson!!!
The evidence of blasting was unmistakable.
 
dynodave said:
IMHO anyone who bead blasts aluminum cases and heads or buy a bead blasted head off ebay deserves what they get....

My friend had Ron's Cycle (leominster Mass) do a BIG bux rebuild. It sat for many years...then when he finally installed the motor...he ran it for about 200 mile and then felt a need to swap the cam. When we split the cases, in the bore we found a HUGE mess.... scored bores etc. The damage was from grit .....an absolute shame. What an expensive lesson!!!
The evidence of blasting was unmistakable.
Click to expand...

OK? I am that guy who thought media blasting was the preferred way to clean up the cases and possibly the exterior of the heads and jugs. Those that sell the products claim that glass beads were not prone to embedding themselves into the material like some of the other media. It makes perfect sense that if residual media is left behind damage will occur. I guess the million dollar question is how did the media get into the motor, was it embedded and later free up or were deposits left behind? I can see if you don't use the process you eliminate that type of contamination.

So if one is looking to clean up the cases, head and jugs and media is not the way to go, what is?
 
Bead blasting is OK if you mask/plug orifices and clean the heck out of it afterward. You must then follow it with shot peening to close the "pores" that the glass beads create. Shot peening is the trick; for bright and shiny exteriors on your aluminum heads and cases, it also seals the surface of the aluminum against later oil penetration.
 
swooshdave said:
No one has mentioned vapor blasting].

Really nice results! Interesting process, just water, glass beads & detergent. Once again claims that glass beads are a safe medium with no residue left behind. Apparently everything is flushed clean with a little fresh water and carb cleaner down the journals.

Bikesalot looks like they are priced fairly, even when shipping is required.

So any first hand experiences out there?
Click to expand...
 
T95 said:
swooshdave said:
No one has mentioned vapor blasting].

Really nice results! Interesting process, just water, glass beads & detergent. Once again claims that glass beads are a safe medium with no residue left behind. Apparently everything is flushed clean with a little fresh water and carb cleaner down the journals.

Bikesalot looks like they are priced fairly, even when shipping is required.

So any first hand experiences out there?
Click to expand...
Click to expand...

Met the guy at the bike show a couple weeks ago. You watched my video, right? No first hand experience yet. But I will.
 
I guess it is time to start shopping for an ultrasonic cleaner.
 
vapor blasting seems to be the way to go, but before that i'd always thought ground up walnut shells was the media of choice. won't mess anything up when the aluminum heats up and any media that's left behind from the post clean cant hurt bearing surfaces/cylinder bores etc. Cj
 
I am curious as to why glass media in water isn't going to pose the same potential problem as glass media in a blast of air?

Just askin'

Russ
 
rvich said:
I am curious as to why glass media in water isn't going to pose the same potential problem as glass media in a blast of air?

Just askin'

Russ
Click to expand...
I'll second that request!
 
Vapor bead blasting is the method advocated by most of the classic bike type magazines over here, I had my head done my a local company last year, I haven't had & don't anticipate any problems. We have a very expensive vapor blaster at work loaded with aluminium oxide, which I'm in the process of changing to beads, for a finer finish. All the sites I have just googled mention "no material removed" some refere to it as a peening process. heres just one quote -

"The key to wet blasting is that the finish is produced through flow of water borne abrasive giving a finer finish due to the flushing action of the water. No media is impregnated into the component, nor is there any dust created by the break up of media, unlike dry blasting where the finish is produced by sheer force of media impact."
I'm halfway through a Rudge restoration & I intend doing all the engine & gearbox casings. I don't think I would advocate any kind of dry blasting on engine/box casings.
Terry
 
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