how to paint alloy bars

[ljacko78]

howdy all,

Am looking at painting up the rear alloy sports bar (roll bar) on my D22 just to be different. Have done a web search on the "how to's" and have different opinions on what to which has included:
- wash with detergent
- sanding with 400 wet/dry
- wash again
- prime seal and dry
- colour coat

or as simple as

- just prime and then paint (which doesn't sound right ???? )

If anyone has any tips for me it'd be greatly appreciated. And powdercoat would be nice but as I've got a crap load of primer and paint in the shed already I thought I'd go use it up. Cheers in advance

Lj

 

[KraftyPg]

While relatively easy labour it's still a prick of a job but the etch primer and a super clean surface is a must. Powder coating might be a better, although maybe not cheaper option and will be a bit more robust, even when prepared right paint on alloy chips quite easily.

One of our guys did a black paint job on an alloy bullbar on one of the trucks and it lasted about 2 months before the speckles started to appear, mainly from bugs but also general road grime. Once it started it just got worse and after 6 months it looked like the black bar had dandruff.

 

[Matt76]

Mate go the powdercoat. I reckon it would cost maybe $200 max?

 

[Aido]

Close to home this one.
I have a home based business in metal polishing - predominantly bike related and aluminium.

Anodising - cheaper than you think. Because the extruded material used in forming these bars is a pure aluminium it will respond well to anodising - alloys are a gamble. Unfortunately in this area you are limited to mostly architectural colors as that is the bread and butter of anodisers here in Australia. Anodising is far and above the best way to go to colour aluminium. Grab your yellow pages and speak to a few local plating / anodizing shops. I would be surprised to see quotes over $150. if you do then I'll get mine out of the shed and get it done and posted to you for less than that!
DONT POWDER COAT THEM it wont last. Powder coating is the expensive poor mans option when it comes to aluminium- sorry Matt.

 

[Matt76]

C
DONT POWDER COAT THEM it wont last. Powder coating is the expensive poor mans option when it comes to aluminium- sorry Matt.

Can you explain more mate? I have never had any problems with it. I probably get 3 or 4 jobs a month powdercoated.

 

[Aido]

Well this is science....in simple terms
Powder coating will work but will cost more and not give the same result. Powder coating is an overlaying substrate which can be chipped, scratched, damaged etc. But it is only as strong as the film applied
Anodising is a controlled form of corrosion that is dyed and is has a greater resistance to damage due to the fact that it has a higher Rockwell figure than the parent metal.
Anodising here in Australia limits colour and surface finish though due to the shelf life and cost of the dye. Most anodisers can only produce architectural colors for that reason unless you are willing to pay for the cost of fresh dye - worth it if you have a large batch but for one off's it is exorbitant.

 

[Leprechaun]

And you can't anodize anything welded.

 

[Matt76]

Yeah I agree with the benefits of anodising whole heartedly. Maybe it works on how much volume the customer does, I get powdercoating done much cheaper than anodising. If it were purely for corrosion resistance I would get it anodised too.

I guess it will come down to the look he is after, and the availability in townsville.

I would like to see some anodised stuff on a car, everything s painted or chromed these days, or polished ally that becomes dull after a week.

 

[Matt76]

And you can't anodize anything welded.

Are you sure about that mate? I know you cant weld it after it has been anodised. The strength characteristics are significantly changed too, the surface becomes quite hard.

 

[Aido]

Depends upon the filler material used in the weld.
The more pure aluminium the better - alloyed materials containing zinc, nickle or magnesium are problematic.

 

[stubbsy351]

If you want paint to stick on alloy the best method is to scrub it with an acid called Deoxidine and scotch bright, then apply alodine 1200 to it, then prime and paint. That is the procedure used for painting Defence force aircraft (aluminium ones any way).

 

[ljacko78]

thanks for the info guys -

Looks wise - I'd like it to be mat black finish if possible, but as Krafty noted without the "dandruff" chips so maybe not a DIY job this time. Might call round to the local shops this arvo and see what the costs are for powder or annodising and availability. Will post a pic when it gets done...

Lj

 

[ljacko78]

got a quote of $60 to powdercoat bar but they said if a sandblast is needed it'd be an extra $50. Am getting it done tomorrow

 

[Jason]

Nice, will be interested to see the end product.

 

[Dion]

the extruded material used in forming these bars is a pure aluminium it will respond well to anodising - alloys are a gamble.

I've always been under the impression that about the only application for pure aluminium was alfoil - I'm amazed to hear that those sports bars are pure aluminium also.

 

[Matt76]

I think he might mean a 'clean' aluminium Pro-nav. I'm not sure about alfoil but yeah all aluminium is an alloy of some kind (mixture of metals)

 

[stubbsy351]

Hi mate, where are you getting it coated? am wanting to get my motorbike frame done

 

[ljacko78]

Hi Stubbsy

Powdercoat Select.
25-27 Auscan St, Garbutt
ph: 4725 6009

I should have mine back Monday arvo

 

[ljacko78]

installed the bar yesterday. Nice finish. Had to do a bit of sand blasting. $100 all up.

 

[Matt76]

That looks bloody good mate!