Cleaning Cast Aluminum

[greevous]

Any suggestions on good methods for cleaning up the cast aluminum i-beam on a Challenger?

I want to clean it, but i'm not looking for a shiny, polished finish - this is a bike for riding, not for show so it doesn't need an immaculate finish, but it'd be nice to get the years of gunk off of it.

I'm not against handwork, but I do also have access to a glass bead blaster - which is certainly faster.

Anyone have any suggestions on what has worked well for them?

[dave higgins]

hi, There is only one way to get an even matt finish & that is either shot or vapour blasting?, that said if its not to bad a wire wheel on a drill will clean it.
But this will polish it as well! so dull it back down with 400 wet & dry paper & then buff it with wire wool after.
I have done this with good results & there are a good range of wire wheel shapes ( i can`t spell attachments?) that will gain access to the tight bits, but i`ve had a few blast cleaned & you can`t beat it hope this helps, dave.

[Brian Thompson]

Blasting and Cleaning Media for Cast Alloy Components.

Thanks Dave, great input as always.

As Dave says, and others I have asked also recommend, bead blasting is the way to go for the best finish. I have also been told that some very early Greeves frames (i.e. with cast engine plates) may have been sand blasted, but as this is a very aggressive finish on alloy it must be used with extreme caution I'd have thought!!! Certainly, some of the very early bikes I've seen restored to amazing condition by Dave Bradley and Tim Griffin seem to have an unusually 'rough' finish on the beams, but check with the experts first OK, PLEASE!!!!!!!! I'd hate to see a super rare early frame blasted into a plie of aluminium dust if this information is innacurate!!!

Funnily enough, I was chatting with Dave Pink about this at the AGM this year, whilst admiring his stunning Triumph Greeves Roadster. Dave has his beams bead blasted then finishes them with a thin coat of lacquer. This 'seals' the pores of the alloy and stops it picking up the dirt so easily, as can happen with dry bead blasting on some types of casting/alloy. The finish on Dave's beam was really nice (as you could expect from one of Dave's bikes), as the lacquer coat was all but invisible, leaving that lovely 'as cast' finish, but still easy to keep clean.

Vapour blasting is perhaps a little kinder in this respect, as the water 'cushions' the beads and is a bit less aggressive as a blast media, leaving a smoother finish. Again, a light coat of lacquer may be beneficial. Another even more gentle approach is soda blasting, although it would depends on the condition of the component as to how effective this would be I would have thought.

If you decide to farm the work out I would recommend seeking the advice of a good reputable company who are used to dealing with motorcycle components, as the operator's skill and use of the equipment is often just as important as the use of an appropriate blast media for the desired finish and material.

Here's a link to an interesting site with lots of info and pics about the various process available; http://www.icmhome.org.uk/index.shtml

I've heard that you can get 'soft' type Scotchbrite wheels to attach to a drill that work really well, and clean up alloy castings a treat without 'polishing', the problem Dave H mentioned in his post with this technique. I can't say which ones are suitable, but I know they are available in different grades and for various applications etc. However, I would certainly get some advice before 'attacking' a treasured component with these products, but there are some interesting solutions out there for the home restorer to experiment with these days. Just do it on a scrap casting FIRST!!! Have a look at this link for examples of these kind of products; http://www.gesswein.com/catalog/inde...TOKEN=38042353

Hope this helps, and let's be careful out there, ok?!

Brian.

[dave higgins]

alloy beam clean.

hi, I can only add one thing to that in depth detail brian!.
I`ll get me coat? lol, dave.

[Brian Thompson]

Blasht!

I know.....sad isn't it!!!

Once my fingers get near a keyboard they just seem to take over and I can't stop them..... It's even worse if someone places a guitar in my hands.....!

Anyway, I'm used to getting 'blasted' on 'ere by now.....!

Brian, off for a bit of a lie down....

PS You did spell attachment right by the way, but don't woory aboot shpeeling mayte...nune of us do as you kan tel!

[Peter Rotherham]

Alloy Cleaning.

Over the years, I've seen many Alloy Beams that have been 'cleaned'.....Aqua/Vapour blasting seems to be the best, sand is very efficient, but does leave an 'open' finish. On NO account consider metal based blast mediums, this really takes metal off if used harshly.
Wire brushes are similarly difficult to control. The 175cc Greeves 'XYE 177', which I had back in the dark ages, had had it's frame & forks cleaned up on an industrial wire wheel which left deep striations in the alloy and steel. It didn't bother me, but to a purist???
I had an MDS frame expoxy coated in the early days of this process, and instructed the firm to leave the 'beam' clear of paint. They did this, but, like Dave Pink, I had to overspray the raw alloy with a silver paint to protect it and return it to how it would have looked 'out of the mould'.
In the workshop, in the 70's & 80's, we used to find that thorough degreasing, then washing bought English alloy up to almost clean. As a finishing process we used 'Jenolite' a mild acid based product, (Can you still get this?) to clean up Carbs, etc., Japanese Alloy, being finer grained was almost always laquered over after blasting/polishing.

Other alternatives were Paint Thinners and CocaCola!

I'd have thought that the Classic Car world must know of a suitable cast alloy liquid cleaner...Is it worth researching with them?

[Brian Thompson]

Cleaning/Finishing Alloy Castings etc.

I had an MDS frame expoxy coated in the early days of this process, and instructed the firm to leave the 'beam' clear of paint. They did this, but, like Dave Pink, I had to overspray the raw alloy with a silver paint to protect it and return it to how it would have looked 'out of the mould'.


I'd have thought that the Classic Car world must know of a suitable cast alloy liquid cleaner...Is it worth researching with them?

Thanks for that Peter, great info as always, especially for the warning regarding NOT TO USE shot/iron oxide media on alloy beams!!!

To clarify a point I made in my previous post, Dave Pink actually uses a clear lacquer to protect the beams following bead blasting. I should have made that clearer....! groan...! (What is it with me and bad puns recently....?! Like DH says, I'd better get me coat too!)

Good point on finding cleaning products/materials in the classic car world too Peter. A good source is Frost Automotive (might be worth a look) and I put a link on here a while back; http://www.greeves-riders.org.uk/for...ead.php?t=2000

On a final point, I've noticed that when Steve Gollings of Villiers Services restores an engine to concourse spec, he insists on an 'as cast' finish on the cases as they were originally, and not polished like a mirror! I would have thought this could also aid in heat disipation to due the greater surface area over a smooth polished finish, and I must admit I do prefer the 'rough' finish myself somehow-it just looks 'right' you know? Still, each to their own of course. I've attached a pic to give an example of one of Villiers Services engine restorations.

Brian.

[John Wakefield]

Engine finish

I have seen Villiers Services finish (bead blasting I think) but it is nothing like the original Villiers as cast finish. Very dull, where as Villiers orginally produced a bright finish.

[biggeoff]

soda blasting

Alot of people in the restoration industry use baking soda all you need is compressed air ,blow gun and a length of pipe plus the soda google vw soda blaster for instructins .

[greevous]

Excellent tips all around. Thanks! I'll be sure to post before and afters when we get to that.

Connal