Re: Materials compatibility

[Royce Woodbury]

Uncle Geoff.  Your suggestion of using 1000 grit and bon ami is a good 
one, but the admonition to "wash intensively" is the key, it would seem. 
I've heard of vehicle engines going bad after having parts bead blasted 
to clean as a result of embedded abrasives that weren't easily washed 
out.  The paper trick Mike Chaney suggested may help in this regard 
where "fluid" cleaning can't grab the particles of abrasive.  Thanks for 
your help.

royce in SB

Geoff Spenceley wrote:

Royce,

The valve block  surface and the valves should be finally finished with
1000 grit on a properly  precision machined steel plate , then  on a piece
of  "real" plate glass using a very light lapping compound such as bon-ami,
to the extent where a high polish 


Intensive washing of the parts to remove all the abrasive
materials and metal is essential when all is done. Before all this make
sure the ports are clear of burrs and wash thoroughly--you don't want chips
of metal to be around as you start the  lapping procedure.
Geoff.

Hi Phil.  Thanks for responding to my dilemma.  On initial installation,
 

I think I hit the valve face and port face with 600 grit wet or dry &
oil before the first run.   But I didn't break the sharp edge on the
bottom of the valve.  On the first run, it may be that the assembly oil
( read that turbine oil) may have run "dry" (although I would be
surprised if that happened within 5 minutes of running).  However,the
scratches (which I am assuming are the result of galling) reappeared
after  removal of the inital scratches by re- honing.  The plans call
for both parts to me made of brass, so I am beginning to think that
there is a problem with the "bronze" that I used to make the valves.
Some impurities may be causing the problem.
royce in SB

Phil Paskos wrote:

   

Hmm.
If the materials are finished well, no sharp edges etc and you're using
steam oil that is getting to the ports, I'm surprised that is happening.
Phil P