Polishing ali castings?

[iconic558]

Never owned anything that's needed things like cases and forks etc polishing.

What's the form on getting a good finish, send them off to a pro, buy an Ebay polishing kit for my bench grinder or hours spent with Solvol Autosol?

 

.....or easy clean ali' coloured powder coating...my local powder coaters do a very good fake ali finish.

[feetupfun]

Polishing using power tools is probably not as hard as you think. I use a combination of bench grinder buff and buffs that go in hand held tools. There are stages before the polishing starts that make the polishing bit quite fast. Google is your friend

Alternatively a suitable and longer-lasting finish for those items is hydrablasting. It's not as shiny, but is very attractive and much more long lasting before a repeat is needed.

[iconic558]

Cheers

[sirdabalot]

Polishing. The act of reducing size and amount of scratches. On line kits are good value but it's a dirty tedious job. 

[iconic558]

Hmm.....I can see a unique paint job ' powder coated cases and forks....I don't think I can't be asked with the regular polishing

[olaf the lofty]

Wire wool and "Brasso" used to work a treat on my Triton if you just want a working bike look and no show pony.

[feetupfun]

Powder coating will look sub-standard or odd from the beginning. If you polish or hydrablast at least it will look great for a while.

Where I live it doesn't rain much and I spray them with WD40 after a wash, so my polished Spanish trials bike engine covers look great for years without any repolishing. I imagine if someone rode where was acidic mud, or didn't wash their bike properly then they would lose shine pretty fast. Many "truck wash" detergents are quite alkaline which takes the shine off aluminium pretty fast, but you can use neutral pH cleaners instead.

Edited May 26, 2017 by feetupfun
better grammar

[spen]

We experimented with a polished and a rough finished engine on an old Suzuki race bike and found the polished engine ran warmer due to the lack of small peaks on the surface.

It wasn't a lot but the temperature increase lost us  half a horsepower after 15 minutes. (which was enough on a 26 hp two stroke tiddler), on the 'rough' finished motor it went for another 5 minutes before it reached the temperature where the power dropped off. We found the roughness acted like mini fins and dissipated the heat..... and we didn't have to keep polishing it..... ;>)

[floydbassman]

When I restored my Greeves TFS back in 2015 I machine polished the hubs and rims and assembled using stainless spokes. went over the engine cases and frame alloy beam with polishing wheel but still has the casting "orange peel look, " and the top end bead blasted. I got a tin of Simichrome polish from ebay. Cost a bloody fortune due to our dear government screwing me for import charges from the states, but its brilliant polish. other alloy bits of the bike are polished, mainly to give an easy to clean finish after muddy trials. 

[iconic558]

Cheers guys

[pmk]

I did the polishing on my MAR.  In the past, I have polished other aluminum items and even plastic aircraft windsheilds.

Depending upon how bad the surface is kind of determines the action to take.

My OSSA had been stored outdoors for many years.  The surfaces of the engine side covers was corroded, and there were scrapes also.  Same for the rims, hubs, forks and more.

I was able to glass bead all the parts except the rim.  Glass beading removed the corrosion for the most part, but leaves a blasted textured finish.  Next I used a Dual Action sander, same as for automotive bodywork.  I started with 120 grit and finished with 600 grit.

For polishing, I secured the item by either clamping or using screws into the wooden makeshift plywood polishing table.

I then used an electric polisher, with a large knitted wheel.  Foam wheels would work also until the final finish.  Using the knitted wheel, I used Mother brand aluminum wheel polish.  Going from 600 to near mirror finish is pretty easy.

On aircraft parts I have used other polishes.  Most work well.  Flitz is good.  Simichrome is good.  Met All.  And no doubt others will all give good results.  Often it is simply how much time and effort are you willing to endure.  It is very dirty work.  Once done though, often a simple touchup restores the finish.

For those doing the tadk by hand, yes it can be done.  To obtain a good result with less effort a low cost polishing pad or wheel in the electric drill can work also.

If you do use a knitted or fabric pad, use an old screwdriver and clean the wheel often.

Remember, do not use papertowels, they can scratch the finish, I was using old towels, not the best but they do work.  Microfibre cloths work well also.  Just ensure if you wash the rags, do so outside with soap and water before the washing machine.

 

 

[pmk]

On 5/26/2017 at 5:09 PM, feetupfun said:

Powder coating will look sub-standard or odd from the beginning. If you polish or hydrablast at least it will look great for a while.

Where I live it doesn't rain much and I spray them with WD40 after a wash, so my polished Spanish trials bike engine covers look great for years without any repolishing. I imagine if someone rode where was acidic mud, or didn't wash their bike properly then they would lose shine pretty fast. Many "truck wash" detergents are quite alkaline which takes the shine off aluminium pretty fast, but you can use neutral pH cleaners instead.

I will probably need to do the WD trick to the center cases.  They came pretty clean but still had a few spots that concerned me enough to avoid painting them until a later time.  My center cases are not polished, so for them it will be Scotchbrite and WD.

[iconic558]

8 hours ago, pmk said:

I did the polishing on my MAR.  In the past, I have polished other aluminum items and even plastic aircraft windsheilds.

Depending upon how bad the surface is kind of determines the action to take.

My OSSA had been stored outdoors for many years.  The surfaces of the engine side covers was corroded, and there were scrapes also.  Same for the rims, hubs, forks and more.

I was able to glass bead all the parts except the rim.  Glass beading removed the corrosion for the most part, but leaves a blasted textured finish.  Next I used a Dual Action sander, same as for automotive bodywork.  I started with 120 grit and finished with 600 grit.

For polishing, I secured the item by either clamping or using screws into the wooden makeshift plywood polishing table.

I then used an electric polisher, with a large knitted wheel.  Foam wheels would work also until the final finish.  Using the knitted wheel, I used Mother brand aluminum wheel polish.  Going from 600 to near mirror finish is pretty easy.

On aircraft parts I have used other polishes.  Most work well.  Flitz is good.  Simichrome is good.  Met All.  And no doubt others will all give good results.  Often it is simply how much time and effort are you willing to endure.  It is very dirty work.  Once done though, often a simple touchup restores the finish.

For those doing the tadk by hand, yes it can be done.  To obtain a good result with less effort a low cost polishing pad or wheel in the electric drill can work also.

If you do use a knitted or fabric pad, use an old screwdriver and clean the wheel often.

Remember, do not use papertowels, they can scratch the finish, I was using old towels, not the best but they do work.  Microfibre cloths work well also.  Just ensure if you wash the rags, do so outside with soap and water before the washing machine.

 

 

Wow....if Carlsberg did answers to polishing case's thanks for that

Edited May 31, 2017 by iconic558

[pmk]

FWIW, you can see how it came to me, the one photo is after blasting (with skidplate also shown), next is sanded, then after polished.  Consider the polished photo is after handling and install onto the motor.  A couple of minutes touch up and it will be no handling marks from fingers and grease.

 

Edited May 31, 2017 by pmk

[lowbrow]

That's a great job; the carb has been transformed!  What is it?