Sand blasting

[Seamus murphy]

I bought an engine that was painted and took it to a shot blasters who assured me that the stuf he was using wouldnt damage or mark the metal its come back with a sand blasted finish (surprise) anyone ever been this thick but has found a way to sort it and get a smooth finish back on casing

[johnnyXS]

oops ! ...

Oh well at least its clean.

Welcome to the forum Seamus ....

For future reference the best method to clean aluminium by far is to Vapour clean but its expensive. Alternatively use a non abrasive media like Soda crystals or Aluminium beads or glass beads or Oxide shot grit or Walnut husks or even plastic beads but never ever sand

Theres only one way you'll get any sort of smooth finish now and that is to use emery cloth or aluminium oxide sanding paper and lots of elbow grease followed by finish with polishing wheels but frankly it would take months and you'd never get to all the awkward parts.
I would just accept the finish and repaint it or maybe highlight the rough finish with an aluminium silver coloured crinkle finish paint

[coaster]

I think Johnny is probably right but it might be worth taking it somewhere else for an opinion, possible bead blasting might smooth the surface out a bit.

[MickYork]

I think there's someone on this forum (or the other one) that polishes alloy to a near chrome finish ........might be worth trawling the threads to see if you can get a contact number and see what they suggest.

[gaz_powell]

How bad is it??

I once did this with a set of vespa casing and the surface finish although marked and visible blasted wasn't too bad. I just give them a coat of clear heat resistant engine lacquer.

There's not much og the block visible when built, side casing you could have polished??

[gaz_powell]

JL polishing - is very good by all accounts and looking at his work - Hinkley area I think

[johnnyXS]

Apologies if my original post seemed a bit negative
There are some good links here for polishing so hopefully it can be recovered but my bet is it would possibly prove too expensive to be viable.
I was quoted £85 +Vat just for a vapour blast of a crankcase recently.
There are some cheap brand new Indian 150cc and 200cc crankcases on Scooter Restorations at the moment . They have slight casting faults etc but it could be a viable alternative

[dickie]

Shaun burns' brother does vapour blasting. I think he trades as 'north east vapour blasting '.

I think I paid him £65 including vat. You'd have to factor P&p in though, unless you live in the north east of course.

[johnnyXS]

Shaun burns' brother does vapour blasting. I think he trades as 'north east vapour blasting '.

I think I paid him £65 including vat. You'd have to factor P&p in though, unless you live in the north east of course.

thats a very fair price.! I think I saw a youtube guide recently that actually recommended doing a media blast first followed by a vapour blast to get the best finish.

[Seamus murphy]

Ive spent the last couple of hours sanding with a multi tool plus rubbing like feck and to be honest a few more hrs and itll be done my initial shock was because my last engine was vapour blasted and it look mint. This sciot is no show pony and its going to be ridden plus ive wont take a pannel off if it dosent break down. Thanks for your replies see you in italy

[Freight10]

Seamus,

Just a thought...

They powder coat "chrome" finish now days, so if it isn't to your liking once you've rubbed it down, this might be worth enquiring about

[xenia1]

Give it a couple of light coats of spray on satin lacquer seamus, this will stop the dirt sticking to it and make it easier to clean, will also keep ali corrosion at bay.

[Seamus murphy]

Once again thanks lads

[steve c]

wire brushes in a drill burnish it back quite well and close the grain of the ally after harsh blasting rub oil over it, more blasting will remove more metal so I would avoid that, brillo pads and a bit of water do the same with more hard work, wash off with clean water, chromer could polish them for you , you could use a polishing kit and 3m fibre discs like nylon and corbundum wool, these are all quite kind and not too aggressive