[Warby Posts: 1041 Status: Offline]

Ring Mains are generally 30 amps , TOTAL. mine have 32 amp Breaker

[fastd Posts: 46 Status: Offline]

Just watch out you dont overload your domestic power supply ...a  cooker supply is usually at 40 amps...the house ring main is 13 amps. Be carefull at what you plug in at the same time as things may trip. Many modern electric cookers you can plug them in to the ringmain...but if you have 17th edition electrics this should be a simple wiring job. the house should pull 100 amps so if you dont have a cooker socket use a feed from the shower..
 

[Al Posts: 875 Status: Offline WWW]

Thanks for that.  My brain has started clicking    Not sure if that's a good or bad thing 


I feel a project coming on 

[fastd Posts: 46 Status: Offline]

Hi Al, I have been installing painting plant for 30 years and have quite a bit off experience in the subject. As you say it needs 180 deg up to 220 deg. If you know the max size of the item you are wanting to coat a very simple solution would be to take off the door off a convential fan oven and build a housing on the front to put your item in. This could be gas or electric but go for a fan assist to avoid hot spots and circulate the air.


Powder coating is solvent free so there is no need to worry about extraction and harmful gasses. You need a temp gauge mounted top and bottom. It takes around 10-12 mins to powder coat something. I think a fan oven with a 1 bar electric fire underneath to get things started and speed the warm up. Once up to temp turn off the 1 bar and rely on the oven to keep the temp up and circulate the air.


One final thing is the problem in getting an even coating in tight corners ( ie a bike frame) Its called the farraday effect and can  lead to low paint thickness in tight corners. The answer is to turn down the gun voltage a bit. Now I have seen this I recon I could build a powder oven and get change out off 100 quid. Remember that the earthing is critical on any product so make sure you clean your hooks and use dry air.


Our current oven is fired by red diesel as we dont have 3ph on the farm and it works just fine. 

I'm thinking of building a powder coat oven for my own use.  It needs to be approx 5' high & 3' square.


Temperature needs to be controllable with 220*c being max & 180*c the normal temp needed.


I can build the cabinet myself, but I'm looking for advice on the electrics.


For small stuff I can use a small electric oven, but I need something big enough to do motorbike frames.


Would an electric oven heating element & thermostat do the job?


If not what would I need and how much hassle would it be to wire in?


My main priority is that its safe and not going to catch fire or give me a shock.


Link below to the sort of thing I want to make:  They are around to £2000 mark to buy, but I should be able to build one for less than a third of that price



(137) Powder Coating Oven NordicPulver Model XL / 230V 2,8kW 160x85x60cm / Paint Curing Oven - YouTube

[fastd Posts: 46 Status: Offline]

I did an installation at the cummins engine plant in Darlington ...put my hands and sprayed wd all over a 800 HP marine diesel ...they would not scrap it . Maybe the 180k price tag had something to do with that.


I may have found the answer to your coating problem. I have found a can of aerosol wheel paint that claims to be petrol resistant. Done a spray trial on some scrap steel and will dunk it in some petrol and see how it goes. I suspect that this is a moisture cured PU paint. If it is once the atmospheric moisture gets to it , it sets and nothing should bring it off except pure acetone unlike a cellulose which is usually found in spray cans. Will see how this goes as you could spray the filter...rub it down and top coat it with same material at minimum cost.

[Nick Flint Posts: 4853 Status: Offline]

Wow thats serious stuff!
"Fastd" has kindly been in touch and will look over my offending article in the near future.

[Warby Posts: 1041 Status: Offline]

I went on a tour of the Land Rover factory Halewood, Liverpool, some years ago.
We weren't allowed anywhere near the "Paint Shop" as contamination can come from deodorants, hand creams and many other sources. I've heard of complete car bodies being scrapped as a result of bad silicone contamination (That is the bare shell at a cost of nearly £2,000 )

[Nick Flint Posts: 4853 Status: Offline]

Wow, Mr Fastd,,,,, that is very kind of you.
You were correct in assuming, my relaxed attitude to the very poor finish was indeed not a correct representation. I was in fact "well fed up" to quote modern parlance. I will send a PM directly to you ref your kind offer. KRs,
Sorry Al for hyjacking your thread. Back to you!
Nick

[fastd Posts: 46 Status: Offline]

Well said ...also these things transfer by fingerprints. Even a QC guy in an office metres away from the plant can cause problems. You ship a part to a coater ...but the wife has just been polishing the table where you ate your dinner. This will affect the finish particularly with powder coating. 30 years as a painting inspector has taught me a few things.
 

[Al Posts: 875 Status: Offline WWW]

When I was in the body work trade,  WD40 was a big no no in the workshop.  Only silicon free polishes were allowed anywhere near.  Silicon would cause major headaches when it came to painting

[fastd Posts: 46 Status: Offline]

Hi ...the orange peel effect is caused by contamination off the surface . Often by something as simple as furniture polish picked up from a desk and transferred to the finished article surface . Polish and wd40 should never be allowed in a powder finish shop. They cause major problems even with a 13 stage pre treat. I would comment that this is probably cause by contamination at the coaters plant and you  have not done anything wrong...you may have picked the items up just after the cleaner has been in . The only other thing that could cause this is too thin a coat and once again thats not your fault...the operator needs to turn up the volts a bit or replace his feed line ( which can cause reverse polarity and reduce applied voltage).


Would be happy to do it for you if you can ship it to Durham. I know sod all about Hovercraft ...but coating application ...my specialized subject.

[Nick Flint Posts: 4853 Status: Offline]

Sadly - I used to have 1 Cubic metre of oven insulation, which I now believe I must have thrown away as didnt use it on KFer1.
Real shame as could have passed over to you on LF, but will have another rummage in case. 

[Al Posts: 875 Status: Offline WWW]

I have a pressurised grit and soda blaster.  I do have lots to do.  I'm currently rebuilding a Honda XBR 500 and I have a Bantam trials to do next.  I won't say how many bikes I currently have other than Becky thinks I have too many 


With reference to  the problems you had Nick.  If there is likely to have been an ingress of oil/chemical then it can leach out when being baked in an oven.  The recommended solution to that is to soak part in acetone or other solvent cleaner, wipe clean, bake at 200*c then degrease again prior to powder coating.  Also the parts should ideally be soda blasted or similar to give the powder something to key to, like you would if conventional spraying.  To me it sounds like the guy you used didn't care what his workmanship was like.  You get people like that in all trades.


The problem I have is that the nearest powder coating place to me that has a large enough oven to do a bike frame is 70 miles away, but someone told me the other day that they are no longer in business.


There is a place in inverness that can do wheels, but not mc frames.  There is a place in Aberdeen, but that's 180 miles from me + 720 miles driving by the time parts have been taken down to them, then home, then back to collect the bits, so easier just to do the bits myself.

[Nick Flint Posts: 4853 Status: Offline]

Ive had some parts (carburettor and intake silencer) for an old car powder coated and they were a devil.

I blasted them with air compressor driven ALI powder! (no relation!) and took them to the powder coater in the city.
Cost was £50 but they came back poorly finished, some areas were dimpled (orange peel effect +++) other areas were still bare!!!
He was abusive until I took them back for him to see- and he redid the missed bits, (kind of him) but the rippled effect HE said
was due to my poor preparation! (bare matt metal air intake silencer!!!). HE said- Its just possible there was some residual chemical leaching thro from the inside, but there was non to be seen. He redid THIS also but the effect was as he prophesied- the same)
He said that the oven (about 200 deg C? ) was allowing contamination.
I chose powder coating as its fuel safe, and the aerosols of black "fuel proof paint" took one second to dissolve the fuel proof paint, indeed I simply used petrol to remove the "fuel proof paint" prior to getting them powder coated!
Due to the aggressive reaction of "The nasty big man" i spent an interesting hour YOUTUBE researching what can go wrong, including
"The faraday cage effect" where by the particles of powder (precooked) as attracted to close charged metal surfaces, looking like the shadow effect when spraying cellulose. The electric charge connected to the work and air pressure all need to be adjusted. Non of this seemed difficult but as it says at the top "advice needed" i tend to agree with Ron, ie unless youve got a lot of smallish pieces to coat OR sell your developed expertise in your neck of the woods - perhaps - dont?
My coated carb now looks good and the air intake looks like a black orange with acne. This is not too disastrous as the car IS old anyway.
Short of
-dont!
I suggest an hour on Youtube to learn the ins and outs when youre bound to pick up whats essential in the oven department, as many simply use the family oven and you can invest in a gucci pair of ear plugs for a couple of days to block out unwanted female voices! 

[Ronnie L Posts: 507 Status: Offline]

Cheap seems a strange word if you are going to spend quite a lot of cash.
Unless you are going to do a lot. Would it not be cheaper to get it done by a specialist.
You usually find companies that do blasting also do powder coating.
Is blasted metal a good substrate as it is very free of contaminants?