glass bead blasting

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sean

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anyone had any parts blasted lately ?
Just wondering what the approximate cost would be to do heads barrels and a frame
thanks
 
I was surprised how glass bead got lodged in a fork slider,it only takes a small amount to ruin bearing surfaces...so when a head is blasted ,spend Lot's of time cleaning the glass out, it will fill up any corner ,hole etc. the head drain is a cross drilled affair ,and this is a likly area to hold the stuff..so tap in some small taper plug's to stop it from the start!
De-grease well before . after wash,wash.wash....then wash again!
Frames require fine grit ,alloy Oxide ..just hope its not been powder coated :!:
Cost? Green backs or beers?...take a few of each...just in case :D
 
Glass bead is famous for embedding and not being washed out - until well heated running - for a while. Check out baking soda and walnut husks and don't expect head to brighten like the almost pure Al cases and covers, as its a better alloy.
 
Don't do it. As Hobot said, use other abrasive media. Be sure to plug every orifice, including blind screw holes.
 
For the frame, they will probably use sand. I talked to one place and they just charge by the hour. If you're powdercoating the frame most powdercoaters will sandblast or have someone do it.

Vaporblasting is another option for the engine, although they use glass (I think) it's suspended in a water vapor. I'm still not convinced that's not enough to prevent later contamination.
 
http://www.vaporblasting.biz

glass bead blasting
 
I found blast media in the flats of my rocker spindles that had been there 25 years since my last rebuild. I thought I had made a pretty good job of cleaning it all out, obviously not. A friends Rocket three race bike ran the big ends after the cases were blast cleaned and a bloke at a campsite in Shropshire last year told me of his T140 with a trashed engine after the "oil in frame" frame had been grit blasted and powder coated.
Soda blasting is the way ahead and you can rig something up using a cheap compressor with good results. My article on this has just been printed in May Roadholder.
 
Commando frames aren't oil-in-frame, so sandblasting is perfectly safe here.
Mask off the streering head bearing area though, keeps sand out of the frametubes too.
And I use taper wooden plugs (bits of old tree !) in all frame bolt holes, so they don't get enlarged.
You can judge how aggressive and careful the blasting was by how blasted the wooden bits are.
 
I agree with the no glass bead blasting on the motor and gear box vote. Glass will erode the alloy .
Baking soda is easy and safe.
High pressure water can be OK too.
 
I've used bead blasting for 30 years without any of the reported problems, but I have had a lot of stick over the years from the women in my life for 'inappropriate' use of kitchen facilities to wash things down afterwards.
As JRB stated - clean is everything, and if you haven't got a compressor to get into all the crevices, you need to get friendly with someone who has, or buy one (never lost once bought).
I'd have to take issue with the statement that bead blasting erodes the alloy; it certainly erodes the corrosion, but that's all, IME.
I get my frames sandblasted, and expect to pay £30 for the frame, swinging arm and cradles. The small bits fit in the bead blaster, so I do those myself.

I had a T14o frame blasted and powdercoated 20 or so years ago, and it took me half a day to clean the grit out - there was a lot of it. Been using the bike for many years since and the engine still hasn't exploded.

I have sandblasted my own stuff in the past, which is why I'm more than happy to pay others to do it!

I'll be researching soda blasting though... pity I didn't renew my NOC menbership this year :roll:
 
sean said:
anyone had any parts blasted lately ?
Click to expand...

Yes, but the guy I went to uses soda as a medium for engine parts. It's slightly less abrasive than glass and the blasting media is water soluble which means cleaning afterwards is a lot safer. Dry ice pellets or snow are good alternatives for engine parts which are often crusted with material that is much softer than the metal. The frozen ice hits the dirt and instantly evaporates which gives an extra cleaning effect.

Soda is not very good though for parts which are to be painted as the soda leaves a slightly alkaline trace on the surface and etch primers therefor are partially neutralised and thus stick less to the substrate. Walnut shells have a similar problem as the blasting hammers essential oils into the substrate which e.g. disturbs anodising of aluminium parts.

For frame parts I usually use glass or well used corundum.



Tim
 
Aren't there modern ceramic beads that would be good for blasting? And yes, lots of air and solvent to get the crap out of the nooks and crannies. That said, I had my barrels sand blasted and there was sand all in the thing. I used a power washer on it to get the stuff out, but of course it flash rusted immediately. I used a can of WD40 on it with a steel brush and scotchbrite to clean the rust off, it didn't seem to suffer from it. I'm not sure I would do that again, but not sure what I would do. A power washer with solvent like varsol or similar would be nice.

Dave
69S
 
There are also plastic beads too that will not embed and just flush off but baking soda just dissolves with water like table salt too.
 
Paint stripper and a wire brush. then wipe over with Cure Rust, brush Bonda primer, under coat and three coats of brush enamel , that's how it was done back in my day... :lol:
 
When I used to design and build plastic injection tooling we would sometimes be required to produce a finish that would give the product a textured surface similar to the one on your monitor case, mouse or cell phone. A kind of matt surface for tactility.
We cut the tool out of stavex or EN 34 which was then hardened to ROC 38.
Glass bead blasting would erode that very hard surface. It will erode alloy. Steel and cast iron are able to withstand some types of media blasting such as wall nut shell's quite well.
Tomb stones are made by masking out the rock with masking tape and cutting out the letters of art work. The blast medium erodes the rock and just bounces off the masking tape.
If you really need to media blast your motor you may want to mask critical areas first. You can also mask out security code marking on cases so you can ID your shit if it gets stolen. Just do it subtlety and somewhere unobtrusive. keep a photo record of the job too.
What ever you do, find someone who is experiences and has a good reputation at doing this.
Good luck to you.
 
Don't forget a plain old brass wire brush and a good scrub with hot soapy (car wash) water.
A coat of silicone spray and wipe down for done.

glass bead blasting


glass bead blasting
 
Tintin said:
sean said:
anyone had any parts blasted lately ?
Click to expand...

Yes, but the guy I went to uses soda as a medium for engine parts. It's slightly less abrasive than glass and the blasting media is water soluble which means cleaning afterwards is a lot safer. Dry ice pellets or snow are good alternatives for engine parts which are often crusted with material that is much softer than the metal. The frozen ice hits the dirt and instantly evaporates which gives an extra cleaning effect.

Soda is not very good though for parts which are to be painted as the soda leaves a slightly alkaline trace on the surface and etch primers therefor are partially neutralised and thus stick less to the substrate. Walnut shells have a similar problem as the blasting hammers essential oils into the substrate which e.g. disturbs anodising of aluminium parts.

For frame parts I usually use glass or well used corundum.

Tim
Click to expand...

Excellent post.

The secret to a great looking set of cases is to follow bead blasting with shot peening - this is sometimes called vapor blasting, its actually a two step. The steel shot closes the pores of the metal that was torn up by the glass beads and then it polishes the new clean surface; the closing of the pores, pre-existing and new, is important because it locks out oil that would otherwise take up residence in those pores.

Still, the contamination issue is a huge liability and absolutely every screw hole and passage and bearing seat and even the mating surfaces must be protected and then cleaned fanatically.
 
My brother and I always use an engine builder to clean our alloy bits. His company is Hydroblast in Sandringham, Victoria. The process is waterbased with microbeads and chemicals. He uses water blast to remove the residue, and the result is excellent.
 
shot peening - this is sometimes called vapor blasting, .
Click to expand...

Careful - shot peening and vapor blasting are 2 very different processes.
Shot peening is shot peening.
Vapor blasting is using water, usually with plastic microbeads. Also called aqua blasting, waterblasting, etc.
A lot of gearbox rebuilding places (cars) have vapor blasters, its all the rage for cleaning gearboxes with no ill effects.
 
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