[Vwdiesel] 3M bristle disc use? Re: prepping block for head gasket tips

[James Hansen]

No worries on how you hold it really.  If you get it perfectly flat to 
the surface, it's too hard to hold straight and want to walk all over. 
It really cuts so slowly that holding the disc at an angle has no issues 
at all.  Electric drill will be fine Will, just use till shiny... it 
will LOOK prepped when it is. :-)
There is just no better thing for cleaning up any gasket mating surface 
that I have seen or used in my days as a gearhead, period. You'll like it.
-james

Will Taygan wrote:
> On those bristle discs, how much pressure do you use?  I'm also assuming
> you use it so the bristles are all touching the block at the same time,
> and not on an edge.
> 
> P.S. I've got an angle grinder, a dremel, and a drill, but no die
> grinder.  Probably have to use the drill, hmmm...
> 
> 
> Thanks,
> 
> Will.
> 
> 
> On Sun, 2009-01-18 at 00:01 -0600, James Hansen wrote:
>> Will, I use these on every gasket surface, especially when using MLM or 
>> steel shim head gaskets on my race car motors.
>>
>> http://www.sjdiscounttools.com/3m7528.html
>>
>> I just googled 3M roloc bristle disc, so you could see  a picture, no 
>> recommendation whatsoever for these guys, but the price seems good.
>> You'll prep maybe 5 blocks with one disc, so try to find one from a 
>> supplier such as acklands that breaks up cases and sells them individually.
>> They are EXTREMELY good surface prep, use with a die grinder (best is a 
>> 90 degree one) and a roloc backing pad to match.
>> You want the white (v.fine) pad, it makes a very good gasket mating 
>> surface for most aanything, is very slow to cut on steel, mostly 
>> polishes, and is designed to surface prep aluminum, so it cuts very slow 
>> on steel.
>>
>> Turn the crank so all the pistons are down a bit, stuff an oil saturated 
>> rag in each hole to catch cooties, and keep them from going past the 
>> piston crown to the top ring.  After polishing, clean clean clean.
>> run a tap down the head bolt holes, vacuum the holes out, blow them out, 
>> such them out with a soda straw, ANYTHING to get them completely 
>> perfectly clean or you can crack the block when the bolt encounters some 
>> foreign material.  Ounce of prevention saves a pound of "Oh shit!"
>> -james
> -snip-
> 
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