How rough a surface for powder?

AgentX

AgentX

Over 1,000 Posts
I really, really thought Google would take care of this question, but nothing seems to have quite what I'm looking for...

Is a rough wire-wheel finish too rough to get an even powdercoat on top? (New tank looks too rough to me, and obviously a high-build primer is out of the question for powdercoat.)

If so, what's the best remedy? Media blasting of some sort? Hand-sanding? Scotchbrite?

I have local metal polishers who can do work nearly free by US standards. Should I just have them get it to a fine satin finish?
 
Bead or sandblast is perfect. Check with your powder shop. A lot of them will have a sandblast and powder option, usually a minor up charge.
 
Bead blasting is NOT recommended at all. It peens and seals the surface and does not leave the correct profile for coating. Fine sand blasting is the preferred method for powder coating. Your wire wheel finish is probably not too rough, but blasting is more effective method to actually remove all the old finish.
 
01marc is right. Bead blasting is too smooth of a surface for powdercoat. Sandblast is the way to go, and all powdercoaters can do it for you before coating. Sandblasting is usually included in the price. There can be an upcharge if the sandblasting is particularly time consuming due to a previous finish. Basically, don't do anything to the surface, let the powdercoater take care of it, that way, the metal gets coated immediately after blasting so that there will be no surface rust.
 
There can be a lot of finger prints on the freshly blasted surface by the time the customer brings it to me. I won't know they are there until it fails up the road and I get blamed for doing crappy work. So no discounts for parts already blasted because I am going to blast it again even if you did it 30 minutes ago. The only way I will warranty my work is if i do the whole process. Just do your coater a favor and clean the parts well before dropping them off. I will charge extra to clean grease and grime off your parts.
 
I also have some parts that I want to get powder coated. They are the hubs from my RD350. The aluminum is very oxidized so I thought I would sand the surfaces before I take them in. How fine a sandpaper should I go to? Do I need to heat the parts to rid them of oil? Do I just leave this up to the powder coat place?

Brian
 
o1marc said:
There can be a lot of finger prints on the freshly blasted surface by the time the customer brings it to me. I won't know they are there until it fails up the road and I get blamed for doing crappy work. So no discounts for parts already blasted because I am going to blast it again even if you did it 30 minutes ago. The only way I will warranty my work is if i do the whole process. Just do your coater a favor and clean the parts well before dropping them off. I will charge extra to clean grease and grime off your parts.
Click to expand...

In my case, I just wasn't sure if the coater's prep (including media blasting) would be able to make this surface ready for powder, or if there was going to be some kind of additional smoothing that needed to be done before blasting, at US shop rates.

I'd have asked the powdercoater instead of the Internet, but I'm currently in India and planning for my return to the US, so it seemed good to know before I left a country where I can get someone to polish a tank's worth of metal to a mirror sheen for about $4.

Appreciate the advice.
 
AgentX said:
In my case, I just wasn't sure if the coater's prep (including media blasting) would be able to make this surface ready for powder, or if there was going to be some kind of additional smoothing that needed to be done before blasting, at US shop rates.

I'd have asked the powdercoater instead of the Internet, but I'm currently in India and planning for my return to the US, so it seemed good to know before I left a country where I can get someone to polish a tank's worth of metal to a mirror sheen for about $4.

Appreciate the advice.
Click to expand...

If you don't think your coaters prep would be sufficient to coat I would start looking for a more qualified coater. When you talk about additional smoothing are you referring to the rough cast texture of some parts? Powder will not smooth this out without first sanding them to the smoothness you want. You can do that or leave it up to the coater who will, of course, charge extra for this service.
 
o1marc said:
If you don't think your coaters prep would be sufficient to coat I would start looking for a more qualified coater. When you talk about additional smoothing are you referring to the rough cast texture of some parts? Powder will not smooth this out without first sanding them to the smoothness you want. You can do that or leave it up to the coater who will, of course, charge extra for this service.
Click to expand...

As you said, I'm not worried that the coater can't prep the part; I'm worried about a charge to do it. The tank is constructed in India to Indian standards and has a very rough texture from a heavy wire brush.

I'm not experienced with media blasting over a rough surface, so just thought I'd ask if that'd be sufficient. Glad to hear it will be, and appreciate the assist.
 
If you ever stripped a brand new Harley tank you would be surprised how much bondo is in them and wavy they are from the manufacturer before prepping for paint. Some people go berserk when you tell them what it might cost to coat one after stripping it. We have to use special fillers for coating toi smooth it out again. They think you can just sand the paint off and coat it, not so.
 
unless it's really rusted in bits, which I kinda doubt. Always Soda blast sheetmetal. The reason why is that, while you might not know or notice it, alll sheetmetal that came from the factory actually has a galvanizing to it. get something soda blasted and you can leave it in your shop in bare metal for years and it won't rust. Sand blasting ruins your car (or tank in this case) as it rips through this coating and causes you grief. But yeah, if there's rust talk to your blaster dude about what course of action to take, but me personally, i'd never sandblast something unless it was like a ducati engine case and i wanted to get the rough sandcast finish back.
 
shoom said:
alll sheetmetal that came from the factory actually has a galvanizing to it.
Click to expand...

Don't know where you heard that, but it is not true.

Soda blasting does not leave enough tooth for best adhesion of powdercoat. Neither does bead blasting. Sandblasted surface is mandatory.
 
I have powdered after soda with great success (so far)
BUT at the same time I painted some stuff with 2 part urethane paint, and the soda blasted parts are now flaking because there wasn't enough tooth, whereas the sandblasted parts are bombproof.

So I'll agree 100% with ADC here.
 
you should stay away from beadblasting and soda for powder... no shells and bull shit... i like black sand and/or alum oxide
 
You must log in or register to reply here.

DTT Light or Dark

  • DTT Light
    • www.jadusmotorcycleparts.com
    www.lostapostle.ca/
    www.sparckmoto.com

    Spread the Love

    Back
    Top Bottom