Painting stainless steel

Mark A

Mark A

Mark A

Soldato
Joined
19 May 2005
Posts
18,140
Location
Lancashire
Hi,

I'm going to paint a hiper PSU, just wondered if ill need etch primer or something else so the paint will stick to the steel. I used some grey Hycote acrylic primer and Simoniz cellulose paint on the inside surface, it looked good but flaked really easily. I was thinking of getting some etch primer would this do the job?. Im not 100% sure if its stainless or not but it certainly looks like it.


Will this stuff be ok, i dont want to spend loads really.

Edit, i think its chromed acctually as ive sanded a bit away and its copper colour underneith. Can chrome be painted :confused: .

Thanks

Mark
 
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Right apparently the finish used on the PSU is chrome not stainless steel. Its a very thin layer of chrome though and some light sanding with 600 grit w&d has gone through to the copper? layer beneath. OK so what do i do now, sand all the chrome and copper away to the bare steel?, or just use etch primer on top of the copper/ chrome sanded finish?.

img1269cb2.jpg


This is the finish at the moment.
 
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ive tried and it just chips off with the slightest knock :( . Ive ordered the etch primer as id like to get this done soon but could do with some advice on what to do with the existing finish.
 
painting

If you have chrome or stainless this will need a very high etch to get your first key. The primer that you are looking at on bay only specs good etch to aluminium but if you have chrome or stainless you will need a more 'agressive' etch and you need to be looking for a acid etch primer really. However these primers do not really have any great build to them so will not hide any scratches.

How quick do you need to get this done?
 
Soupyuk said:
If you have chrome or stainless this will need a very high etch to get your first key. The primer that you are looking at on bay only specs good etch to aluminium but if you have chrome or stainless you will need a more 'agressive' etch and you need to be looking for a acid etch primer really. However these primers do not really have any great build to them so will not hide any scratches.

How quick do you need to get this done?
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Thanks for the reply. I dont really have a time limit as such im just itching to get it done to see what itll look like :D . Damit ive already ordered the stuff from ebay as well :( , i emailed the guy to ask if itll be ok for stainless steel and he said "yes perfectly fine", i suppose he just wanted the sale. TBH i dont even know if itll be stainless steel under the chrome, id imagine itll be mild steel?. But thatll mean removing all the chrome and copper layers to get down to the steel. Would etch primer adhere to the copper layer?.

If you know of a place i could get some proper acid etch cheap that would be great. I didnt really want to spend loads but ive already put a lot of work into it so cant stop now.

Cheers
 
I suppose you can try this stuff now that you have bought it but stainless and chromes usually requires an acid etch as they are generally harder surface than say ali and I cannot see what is wrtien on the tin. That aside I own my company and we specialize in amongst other things paints (myself been in the trade for like 20yrs+) so I could sort you some stuff but then you would need proper equipment like guns etc, or let me know what you want and I will do it for you :D . What is it that you are trying to do exactly? Whole case or what and in what colours and using what aerosols? Let me know and we might be able to sort something.
 
Thanks for the advice Soupyuk, I'm hoping this stuff will work, should at least be better than the other primer i was using. Its just a PSU case I'm spraying satin black, it was red but was scratched all over the place so thought id tart it up a bit with some paint i had knocking about.

The chrome is very thin and i have sanded almost all of it off with 600g wet & dry to reveal a copper layer underneath which I'm assuming is a sort of base coat for the chrome plating?. Would etch primer adhere to the copper layer or should i sand back to the steel beneath?.
 
Chrome sticks to most metals (& plastics) it's put over copper because copper doesn't rust. Chrome doesn't rust it's what under it that does.
 
mauron said:
Chrome sticks to most metals (& plastics) it's put over copper because copper doesn't rust. Chrome doesn't rust it's what under it that does.
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Ahh so itll be mild steel under the copper then?. I nthink ill sand all the chrome off and then test to see if the paint will stick to the copper, if not ill sand the copper away to the steel.

Thanks for all the help, ill report back with the results when i recieve the etch primer.
 
If your etch is an acid etch and it is strong enough acid then it will key into most metals that I have come across. (Stainless steel being the toughest). The key to the bond is the strength of your etch same as when spraying plastics it is all about the strength of you solvent . WOnt bore you with a 40 page essay on it :eek:

You will be helping the key by scotching(rubbing down) as it now has a rough surface to bind into. Thats why when you decorate you have to scotch things like the radiators as paint doesnt key very well to an unscotched gloss surface. Try your primer and see how you get on with it like I said I cannot read the tin so I dont know how strong the etch is. Other potential problem that you might have is in that single pac paints do not generally adhere to high etch primers, you would normally put a 2 pac etch onto the acid etch to form a base for your topcoat.

If you get stuck at all or have any questions just ask m8 I am only to glad to help. Will be painted up some cases in some outrageous colour shifting paints shortly so will post some pics. Not quite airbrushing like to chap on here but still very very nice effects.
 
Thanks :) , what grade wet & dry would you recommend to provide the best key for the paint?, Ive used 600 grade so far to get rid of the chrome.

Ive painted a few things before but Ive always just rubbed the existing paint to get a key and painted over the top so Ive never had these problems before. Well once i painted a Alu silencer and had to use etch primer, that worked OK but like you say Alu is soft.



Will be painted up some cases in some outrageous colour shifting paints shortly so will post some pics. Not quite airbrushing like to chap on here but still very very nice effects.
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Thats sounds great, i'll keep my eye out for that.
 
Paper grade depends on what you are doing really. To scotch up ali and other metals inc stainless steel I use a 3M P240 grit on an orbital sander or by hand if it is circular object. To flat a high build etch primer for top coat I would use 3M p1200 wet/dry. This is mainly to give a key and to flat a little but I do not have to sand my primers to get flat finish unless I am using a particular very high build filler primer.

What you have used (i.e the 600) is good enough but you do not have to get rid of all the chrome as long as there is not a distinct line/joint between the surfaces. A rule of thumb that I use is that if you run your nail lightly over it and you cannot feel anything then 98% of time you wont see it, if you pick up the joint with your nail then it is not good enough and need to sand it more.

How much prep work you put in also depends on how good the substrate is. If it is good nick and fairly flat then generally a good scotch will suffice. :D

When you have used your primer elt it dry for a good couple of hours and then try to scratch it off this is a very basic test to see how well it has keyed but make sure it is dry. If you can scrtch off after a couple of hours chances are iy has not and will not key.

If you need anything more just post up m8 and let me know how the primer goes.
 
Mark A said:
If you know of a place i could get some proper acid etch cheap that would be great. I didnt really want to spend loads but ive already put a lot of work into it so cant stop now.

Cheers
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Hey mark.

Bare metal is tricky to paint, and generaly the kind of etch primers tom dick and harry can buy are no good.

"proper" etch primer is compiled of 2 parts, and is Very thin ( as soupy said it has very little "build" )

if it was stainless your painting its still a complete nightmare, so some times you need to use something called t wash before you even etch it.

this is the kind of thing you could drop off at your local car body shop and ask them to prime it for you when they have a little left in their guns ( usualy a lot of paint is wasted in body shops)

Soupy is right though. it is a proffesional job. ans one does need a lot of equipment for soemthign that seems a reletively small job. :( shame really
 
Thanks for your input R B CUSTOMS :) , it certainly is a lot more difficult than id of hoped painting directly to metal :( . The primer hasn't arrived yet but ill give it a go when it does and just hope for the best.

The title is wrong for this thread now as its not stainless but was chrome with a clear red laqure over the chrome. I thought it was stainless but then after sanding to key the surface some areas of copper showed up so then i realised it was chrome. So the paint will either be applied to the copper or if that doesnt work the steel. Most of the chrome has been removed now after a few mins sanding with a sanding block and 600g.

Thanks again and i'll post some pics if it works out :D .
 
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