aluminum problems

[strickland4701]

not sure this is the same problem as everyone else seems to have with aluminum( haze cloudy). my aluminum will get a mirror reflective finish, but not a bright reflective finish like chrome. my process was as follows

1- grease less 150 up through 400
2- back over with sandpaper 220 - 800 to remove any waviness
3- green compound on sisal, tried black emery but it did not cut as well on this piece as the green
4- Tripoli for final finish

this is s triple tree from a Yamaha roadstar. I am not sure what the composition of the aluminum is. I did the front fork sliders with a similar procedure and they have the bright finish I want, I have attached this photo hopefully it will help out some

looking for any help in shedding some light on how I can get a brighter finish

thanks
charlie

[baz]

Re: aluminum problems

first thing you should know, not all aluminium come out looking the same . some come out as nice or nicer than chrome plating and some other castings will have that hazy looking shine.
now about your polishing steps ,why do you go back to 220 grit when you where done with 400 greaseless . then there is the sisal , i think sisal is way too rough for aluminium .

[strickland4701]

Re: aluminum problems

baz,
that should have read Spiral sewn. not sisal. I actually have a sisal but have not found and good use for it on the aluminum or stainless that I have done. I much prefer(and get better results with grease less and standard compound on a spiral sewn wheel .

as stated in the original post I went back over it with paper to remove the waviness left by the greases less. I would have just used 400 paper but it was not really getting rid of the waviness. it seems to have the potential for a bright shine I just can not seem to get the right combination.

I als see I left out that I used Mother mag polish as a final step and that seemed to add more haze to it. not sure but maybe I need to ty a blue compound or another type of poilsh. I also tried white compound with no luck , it left hazy scratches on the part.

[Rasper]

Re: aluminum problems

I have found that a polish, such as Mothers, will leave a haze if there are scratches in the piece large enough to trap the polish. Obviously there will always be scratches, (polishing is the process of making progressively finer scratches in metal until they are small enough to not interfere with the reflected light); the problem is that if we skip over a step, or don't do it enough, we leave scratches that the finer paper or compound on down the line only polishes; it doesn't cut them away; you have polished scratches. These scratches make a piece look hazy, and they trap and hold polish, which makes it look hazier still. When I go back and really sand as much as I should have the first time, the result is always better.

I believe this is the single biggest problem facing beginners. But not only beginners; I catch myself getting lazy frequently and not sanding as much as I need to. The only solution is to go back and start over.

R

[strickland4701]

Re: aluminum problems

Rasper,
the haze for lack of a more descriptive word is there before I use the mothers. On the other aluminum parts I did, they did not really shine until I used the mothers as a final step. I followed the same on this piece, but the mothers did nothing for it although it did not seem to make it worse. I am going to go back over it from 400 up to 800 or 1000 and see what happens.

seperate question. when do you guy dispose of used wheels ?? I have some that have been used and now the material lays down at the edges and it does not seem to polish as well. I use a rake frequently and only use 1 compound per wheel . how do you tell whn the useful life of a wheel is done ??

charlie

[baz]

Re: aluminum problems

if your other parts did not really shine until you use the mothers then i suspect you are doing somthing wrong in your previous steps.
on most aluminium after the 400 greaseless i go to the buffing with a tripoli then a green bar and that s it , mirror finish


Rasper , yes i also skip some steps to save time and yes sometimes it takes longer because i have to either go back a few steps or i have tu buff for longer time.

[strickland4701]

Re: aluminum problems

baz I should not state they did not shine until the mothers, they just looked nicer after the mother,more luster or at least to me. maybe an optical illusion.

ok I went back to scratch this evening. I started with 240 greaseless and went to 400, then to the tripoli and then green . same result as before
I then went to the orbital sander with 400 , then hit with green then tripoli. same result as before

I have really spent a lot of time sanding. I make sure to go opposite way and to no avail

I get a mirror finish without doubt, it just does not have a chrome luster to it like my other pieces. let me also add that if I hold it on an angle I can read items in it from about 12 - 16 inches away and it looks much brighter and has more definition . Now if I look at it straight on it just does not have the definition still mirror just not as nice

I am about ready to just chrome the damn thing !!!

my last thought is maybe the wheels have went past useful life. I buy the spiral sewn from mcmaster as shipping is free so it makes it a deal . I vaguely remember having a similar issue on my other pieces( stainless and aluminum) till I switch to a new wheel . would a new wheel make that big of a difference ? how do you tell when the wheel is to worn to be useful ?? I am not sure who mcmaster uses but I know they work as I have gotten excellent results with them, just not sure if they have the endurance

[Rasper]

Re: aluminum problems

I use wheels until they get too small from wear. I do like to wash them occasionally, in hot water and detergent, then spin them dry. Gets the dirt out.They seem to do better after a good washing.

R

[Rasper]

Re: aluminum problems

Free shipping from McMaster Carr? Is there a secret code to get that?

I use their wheels. They work fine for me.

R

[strickland4701]

Re: aluminum problems

I have never washed mine but have held a rag with cleaner to the face cleaned it a little . maybe I will try to wash one and see how that works out !!! sorry no code for free shipping. where I work we use mcmaster for a lot of little stuff so I get to tack onto the orders, and get the benifit of free shipping as the company wouilld pay for it anyway .

[strickland4701]

Re: aluminum problems

Baz, question for you . have you ever needed to go with say blue or red rouge to get aluminum to shine ?? I resanded with 1000 this evening and it showed promise, but neither Tripoli, green or white would shine it. I even cleaned the wheels . the one thing I did notice was if I touched it really, really light to a spiral with Tripoli it would shine beautiful, but just a little to hard and haze. the aluminum is not soft but the face seems to retain scratches even from tripoly and a sewn wheel

thanks
charlie

[baz]

Re: aluminum problems

Baz, question for you . have you ever needed to go with say blue or red rouge to get aluminum to shine ?? I resanded with 1000 this evening and it showed promise, but neither Tripoli, green or white would shine it. I even cleaned the wheels . the one thing I did notice was if I touched it really, really light to a spiral with Tripoli it would shine beautiful, but just a little to hard and haze. the aluminum is not soft but the face seems to retain scratches even from tripoly and a sewn wheel

thanks
charlie

i mostly finish parts with green compound ,sometimes with white or blue also .you can also try with some new buffs , a loose buff with a low cutting compound should bring out the shine
i never need to sand with 1000 grit to get to a mirror finish , like i mentoned earlier in this thread some aluminium castings no matter what you try will not come out looking as nice as some other castings .

[strickland4701]

Re: aluminum problems

I am beginning to see what you mean about some castings not polishing as well, out of about 10 - 12 different pieces this is the only one that has given me issues.

I just did the risers from my bike last night. I used a 150 to remove the factory coating, went to 240, then 320 and straight to the green on a sewn wheel. looks like chrome right off. the other parts I did were pretty similar, but this damn part is just driving me crazy. I am going to try a new buff and some red or blue, and if that does not work I think I am going to call it quits on this piece and just gt it chromed,
thanks
charles

[smooth72]

Re: aluminum problems

I agree with what has been said before. I do my sanding with a little da and lube with wd40. One thing that I really do like at the end is to use Mothers Billet polish, cost about double but I think it is worth it. You could use mother polish first because it has more cut, then mothers billet to finish.

[Novacite]

Re: aluminum problems

Charlie, I work for a company called Malvern Minerals, which mines and produces the media that you are using in you blast . If you do not mind me asking , what grade of Tripoli ( Novacite ) you are using . Mabey i can help you with your problem easily with changing the grade of media that you are using.

Thanks, Novacite ( Kim )