This has me baffled me and no one seems to as yet have a answer to why.. Basically stripped my Ducati engine and building it back up.. Stripping the engine casings and sump etc down to the metal, via blasting and vapour blasting, under the paint I found some areas have this lovely patterned texture finish to it.. But how is it formed? The metal seems to hard for blasting to effect it.. So it must be there from manufacture, is it in the casting process? And can it be replicated on the areas where there is none.. I have tons of patience but need the expertise from someone to tell me how please..
Being an ex toolmaker I would say that the pattern came from the original casting block, it was not a completely smooth surface so when the casings were casted it picked up all the small imperfections in the original cast hence the nice dimpled pattern, I have seen this many times on all sorts of metals that have been cast.
Have a look at Snap-on tools they have that same sort of stippled look on them and where they write Snap-On on the spanner is normally milled then polished to give a smooth shiny finish.
+1 for above. If you really wanted to replicate it, ask Santa for a BB gun and some metal ball bearings for Crimbo
Wow you guys amaze me with your knowledge 10 out 10 for all so far... Better go check my 1970 s snap ons then... N@@DS
Don't ask me to use a lathe these days I wouldn't even know how to switch one on they are all bloody computerised now
Do you think small lead eg 1 or 2 mm lead shot fishing tackle weights through my sand blaster would get the desired effect.. ?
You will never match it like for like that's for sure . You may get a similar effect but will depend on how hard the metal is, don't use SSG, if the metal is soft enough maybe No 6 or 4's might do the trick.
I'm inclined to agree, but it doesn't look quite rough enough compared with the 80's Guzzi sand cast engine cases. It could be that your own actions in cleaning it have smoothed it off a bit because it looks remarkably like the rocker box covers on my Guzzis where they were the easiest things to get cleaned each time. But whatever it is, I would leave it unpainted............Guzzi engines were so easy to keep clean with that finish. To replicate it (or as near as possible) I reckon if bead blasting doesn't do it, you should sand blast it and then maybe use walnut shell blasting to smooth it off a bit.
The cases on my 916sp are like that never had paint on them and don't suffer with the effects of corrosion. Then again the side cases do but they are easy to keep tiptop
