Blasting dangers??

[Shakey]

Have done a search and couldn't find an answer to the following particular question: when blast cleaning your engine cases, especially the head and barrels, what provision do I need to take to protect the machined mating surfaces? Presumably you don't want a blasted finish on those...? Any advice?

 

[sreimer]

A little texture doesn't hurt if using glass bead or soda it helps retain the sealant and gaskets

 

[hotrdd]

Tape them and blast at an angle that pushes the tape onto the surface. Use a few layers of duct tape if you are blasting with hard sand otherwise one layer is fine.

Baking soda or glass bead are both fine, otherwise sand at very low pressure.

 

[sreimer]

Do NOT use sand backing soda works the best. It doesn't open the pores on aluminum

 

[XSLeo]

One thing with the soda, it cleans up after blasting much easier than sand or beads. The soda desolves in water, so just hot soapy water washes the parts nice and clean. And if you do miss any it won't hurt the engine like beads or sand.
Leo

 

[Shakey]

Thanks for the replies folks! It looks like soda is the way to go. I guess masking off might still be a good idea with soda?

 

[1Tlew0]

Not trying to thread jack here but do you guys typically do this with the motor on the bike or off?

 

[blackbetty]

I use aluminum oxide for my blasting, it came with the HF blaster. Works really well.

You'll be spot blasting if you don't do it in a cabinet. Spot blasting goes through media very quickly since it's not contained within a blast cabinet.

 

[sreimer]

I don't but that's up to you. I just blast them then run a honing stone over them

 

[Ironsled77]

Not trying to thread jack here but do you guys typically do this with the motor on the bike or off?

When the motor is apart.

Posted via Mobile

 

[sreimer]

Parts not assemblies. That is a motor out of the frame and disassembled to it bare components like a cylinder head with the valves springs etc removed

 

[XSLeo]

Some do it with the engine in parts, others with it assembled and all openings sealed. Always out of the frame, unles you want the frame blasted. In that case engine out is better. You can get to all the frame then.
Leo

 

[Tomterrific]

Blasting engine parts can lead to damaged engines in the future. Soda is okay and walnut shells are okay but when you use something agressive like Black Beauty media the chance of a speck getting stabbed into the soft aluminum to be released when the motor gets hot for the first time is too great for me to recommend. I know blasting seems like a good idea to get parts pretty but there can be horrible downsides.

Tom Graham

 

[KentMoney]

but granted that the blasting is done on the outside of the cases, even if there is some impregnation isn't still ok if it gets released once the engine heads up? How would the media enter the engine if you covered all orifices correctly?

Kent