The Pros & Cons of Powder Coating

[Fatguyz]

possibly a tech discussion but whats the deal then.

good

bad

either or :eek:

FG:cool:

[langysrodshop]

My powder coater advises against doing a complete frame, I reckon he should know best.

[farncombe pop]

My powder coater advises against doing a complete frame, I reckon he should know best.
Perhaps it's the heating and possable warpage

[langysrodshop]

No Paul, at a educated guess i would think that under powder there is nothing to stop corrosion but when painting if you start with a good epoxy primer which is anticorrosive you have something to guard against rust getting a hold. I've had many chips on my frames over the years but none have ever gone through the epoxy.



Perhaps it's the heating and possable warpage

[mopar_mark]

No Paul, at a educated guess i would think that under powder there is nothing to stop corrosion but when painting if you start with a good epoxy primer which is anticorrosive you have something to guard against rust getting a hold. I've had many chips on my frames over the years but none have ever gone through the epoxy.

Yep, powder coating will lift when chipped allowing moisture to get under & trapped. As Steve says, when paint chips you still have the primer to protect the metal

[Blackjack]

I think it has it's place but I've been disappointed by it when used on anything that gets road rash or serious amounts of weather - probably for the reasons Steve mentions. I think it is best for smaller components in the engine bay or inside the car. I really don't like the way corrosion "hides" under it and pops up again in advanced stages.

The hardest wearing finish I've seen is plasma arc sprayed aluminium - this bonds to the steel (which is first given a light blasting). It is overcoated with 2 pack. I had my trike chassis done in this over 10 years ago. Not a trace of corrosion anywhere - even where the paint is chipped. The look is an acquired taste - looks a bit like 600 grit wet & dry paper. They did the Ducati Monster in it a while back - very industrial....

[Ford34/2]

At work our supplier that does powder for us does not recommend powder coating for exterior use, fascia panels, trims etc.basically anything outside.

Had a set of Mk 5 golf wheels blasted and powdered at a "wheel specialist"brilliant when they were done , now crap for the money, very disappointed.
so maybe for decorative internal stuff, but def not chassis, and defiantly not for Golf wheels.

Stan

[Tiki Des]

i had a few parts that were powder coated during the build of my old pop and they didn't do too well by time it went on the road. one was the front number plate bracket and the powder coat was lifted by rust underneath. i ended up cleaning it off and painting it. other parts faired nearly as badly. i assumed at the time that i'd had rust on it before it was coated.

reading other replies makes me think that it's not a good idea and so it wasn't just me being unlucky.

[martin]

I used to have a drop tube, hairpins etc powder coated, got a few chips but thats It, no rust or anything coming through whatsoever, & that was on for over a year.

Martin

[Flathead Elmo]

I work with industrial roller shutters and we use powder coating all the time on the slats and cassings but we have everything made from galvanised steel so no rust. the finish is crap, mottled and looks like orange peel you cant buff out... I would stay away from powder coating imoa.

[Morris460]

It is not as durable as it is made out to be. As has been said, once rust gets under it it spreads until the first thing you know is it's coming off in sheets.

[Paul B]

I've used it on a few parts, and like Paul said, it is nowhere near as bullet proof as people say. A light tap with a spanner will put a mark in it as easy as if it were regular paint.

It looks good and glossy when it is fresh, very pretty, but I noticed a few tiny holes and gaps in the parts I'd had done, near welds, or where they had hung it up, straight through to bare metal underneath.

[Humpback]

The guy I use, uses a galvanised primer straight after blasting and then powder coats. I've had no problems with various parts over the years. The biggest problem with a chassis is that you've got to be absolutely sure that every bracket and holes etc. are where you want them, as it's more difficult to 'touch up' afterwards. Plus, if you want a smooth finish you have to grind everything out first as it can't be filled, as with painting.

[chaley]

I have only ever had wheels coated and have to say I'd not bother again.
They looked really good until I picked at scabby bit and it started to come off in sheets.

Chaley

[Fatguyz]

cheers for all your life experinces chaps.........my own experience apart from the wheels on the A which are fine, was a few years back for a project at work and i used a company in Banbury (who also did loads of other specialist paint systems) and the finish and durability was superb. This was on a massive aluminium frame covered in fibreglass panels.....like in the OT pic (its one of the first 900 mhz superconducting magnets ever built) :p

http://i406.photobucket.com/albums/pp142/Fatguyz1/900.jpg

now its all flowery and fancy but the thing would have loads of wires and other stuff all round it and people pouring over it etc and it lasted very well...including quite a few knocks and bangs along the way.........anyhow. Its gonna be back to good old fashioned primer and paint methings cos i aint dragging the chassis to Banbury :p

cheers

FG:cool:

p.s. could always get it Xylan coated....that stuff is like 5hit stuck on a blacket :D

[hershambob]

ive seen powdercoating being done and it goes over primer

[rem]

ive seen powdercoating being done and it goes over primer

Our local powder coaters did some wheels for me: I had them blasted and red-oxide primed, and asked the painters for a light grey. When I picked them up they said they had powder-coated them over the primer. The finish looked as good as any powder coating, but the adhesion was no better than any other paint over red oxide.

[Morris460]

Jas, how often does that go down the M1 in winter after they have just dumped a load of salt on it?:D

[Fatguyz]

Jas, how often does that go down the M1 in winter after they have just dumped a load of salt on it?:D

It went once down the A34 :o but subsequent "kits" went to America and Japan............and inside it all is 3000 or so litres of liquid Helium.....which every now and then turns into....well lots of cold gas :eek:

Take your point though BUT it was very duarable and earlier this evening while taking some rubbish down i did kick my powder coated rims and it didnt chip :D

FG:cool:

[langysrodshop]

Thinking logically wheels don't see a lot of stones so i guess would be ok, although after saying that i still prefer paint.

One thing that seems to work well with powder coat is leaf & coil springs.




It went once down the A34 :o but subsequent "kits" went to America and Japan............and inside it all is 3000 or so litres of liquid Helium.....which every now and then turns into....well lots of cold gas :eek:

Take your point though BUT it was very duarable and earlier this evening while taking some rubbish down i did kick my powder coated rims and it didnt chip :D

FG:cool:

[Blackjack]

Superconductive magnets, aluminium frame, bell shaped housing, supercooled gases.....

You've been working on Die Glocke

http://i406.photobucket.com/albums/pp142/Fatguyz1/900.jpg

[40Stude]

I've known a few people that have had steel rims powder coated and regretted it. The same problem each time. Where the rim meets the centre the powder cracks, water gets in and the rust spreads under the powder until it comes off big time.

[langysrodshop]

I remember Steve Young about 15 years ago getting his steels powder coated and i wondered how long it would last, Its still on them and looking very tidy !!!




I've known a few people that have had steel rims powder coated and regretted it. The same problem each time. Where the rim meets the centre the powder cracks, water gets in and the rust spreads under the powder until it comes off big time.

[Tudor Simon]

FOR MASH GET SMASH !

http://i406.photobucket.com/albums/pp142/Fatguyz1/900.jpg

[toddy]

I own a powder coating company. I plan to do a good honest tech article on it when i get time.
Basically the majority of coaters that you guys have bad experience with either don't have the equipment, time or knowledge to do the job right. A good powder coat job is 50% preparation and 50%process. if the product chips it is either because the surface was not prepped correctly or the powder was not stoved correctly.
To get the extreme durability qualities of a correctly powder coated finish the product must be fully degreased and correctly keyed. The powder must then be applied to the correct thickness usually 60 micron. The stove process must be correct temperature normally 200 deg for a accurately determined time (product material thickness determines this). I will not plug my company as it is an architectural coaters with volume orientated automated plant that does not suit one off's but i don't like seeing misconceptions due to poor workmanship.

Ask what there process is, ask to see there setup. Send them an extra piece of material so that you can test the adherence for yourself (score the coat through to the metal with a craft knife to create a cross hatch with approx 1/4" intervals then apply strong adhesive tape and tare off - No powder should be stuck to the tape).

Helpful info:
Pretreatment: mild steel - best option grit blasted, degreased and coated within 2 hr of blasting,
2nd best option degreased high temperature epoxy primed and coated
If any product can be galvanised this is ideal as the process is then degrease, chemical etch, de-gas (very important to fully stove a bare galv product before coating as galvanise has trapped gas in the coat that escapes at high temperature, will leave small pin holes if not de-gassed) and coat

For aluminium the process is degrease, phosphate (chemical reaction that leaves a key finish on the surface) dry, coat

Powder melts from the outside inwards and for the surface bonding to occur the powder must have not only fully melted to the surface but also the product itself must have reached that temperature.
Min time is approx 10mins at 200deg maintained this is good for products upto 1mm thick, we add 2.5min per additional mm i.e. A set of steel wheels 3mm thick steel will need 15mins at maintained 200deg, a 5mm thick steel plate will need 20 mins.

A quality powder coated product should not only look good, it should last a life time. My company has salt spay tests to enable 25year garantees. I powder coated the radiator cover on my car and have used it as a tool tray for the last 4 years, (it still looks like new with no scratches or chips). I recently bought a tube chassis that was made and coated in 1992, it has no chips and looks like new. I spoke to the original fabricator and he confirmed that it was blasted and dip degreased before coating.

Good luck hope this helps

[toddy]

I've known a few people that have had steel rims powder coated and regretted it. The same problem each time. Where the rim meets the centre the powder cracks, water gets in and the rust spreads under the powder until it comes off big time.

This is a problem with steel rims, where the rim meets the centre is an fine joint. There is a effect called the farad-ah where the static charge rejects powder as opposed to attracts i.e. the surfaces inside the joint are not coated. To overcome this problem a coater should either apply the powder when the rim has been pre-heated to stoving temp or apply a spray on high temp epoxy to this area prior to coating.

Hope this helps,

[Fatguyz]

:)

[40Stude]

toddy, thanks for your reply based on your experience. A very useful insight into the benefits and possible problem areas in one off jobs.






...by the way, I have a set of wheels that need coating....











...;)

[langysrodshop]

I still prefer paint especially on a fenderless car where its all seen

[Paul B]

Where I had my bits done they did about a dozen items for £60 (2 pulleys, fender brackets, tranny crossmember, engine mounts, etc) which I thought was too good to be true. If they had correctly blasted and prepared each item, as Toddy points out is so imperative, just the time involved would have lost them money at that price.

But still, they look good. :D

[Blackjack]

I've just ordered enough zinc phosphate primer, undercoat and coach enamel from Craftmaster Paints to paint my Modified twice over. Also ordered a set of Purdy brushes. It all came to £170.

I've seen commercial vehicles and vintage cars painted with this stuff and it's difficult to believe it's not sprayed or powder coated.

It'll allow me to paint the car as and when suits me and put as much or as little prep work in as I feel appropriate. Then I'll have no one to blame but myself. Going to start with the fuel tank next week and see how that goes. If it turns out rubbish with the brush I can just buy some of the special thinners and spray it on.

http://www.craftmasterpaints.co.uk/products.htm

[kapri]

I'm also planning on coachpainting one of mine. :D

[jonwebb69]

I have just had my wheels done at Maldon Shotblasting and Powder Coating. They guarantee them for five years. Phone Trevor on 01621841100. Time will tell if it lasts.:confused: