Utter Noob Guide to Spray Gun Installation
Discussion
Morning chaps..
I'm after a bit of professional / advanced advice on sorting out a spraying installation in my workshop. I've had a bit of a dig round on the internet and found most of the basics of system layout, but I don't really know where to start when it comes to brands or sourcing the equipment.
The first job is to spray my race car with primer, base and clear, but I will no doubt have more jobs for it in the future! I am very much of the mantra "buy right, buy once" and prefer to pay for quality over buying crap that breaks / wears out / doesn't work properly.
The main things I need help with are:
Choosing the right spray gun - I've heard of DeVilbiss, Iwata and SATA, and my budget is around the £300 mark. I want to use HVLP equipment but I have no idea about nozzle sizes or any of the details!
Installing the air feed - I have a 14cfm compressor with 150l tank, but need to get the solid pipes, connectors and flexi hoses in. Does anyone know a good source?
Filter / regulator - Can anyone recommend a good water filter and regulator for spraying? As above I would prefer to use HVLP equipment. Also need a good source!
Finally.. Paint! - Where is a good source to get decent quality paints? What are the laws on what I can and can't paint with in my workshop?
There's probably a bunch of stuff I have overlooked, so if you have experience with setting up a high quality spraying installation please feel free to add anything you think might be necessary.
I'm after a bit of professional / advanced advice on sorting out a spraying installation in my workshop. I've had a bit of a dig round on the internet and found most of the basics of system layout, but I don't really know where to start when it comes to brands or sourcing the equipment.
The first job is to spray my race car with primer, base and clear, but I will no doubt have more jobs for it in the future! I am very much of the mantra "buy right, buy once" and prefer to pay for quality over buying crap that breaks / wears out / doesn't work properly.
The main things I need help with are:
Choosing the right spray gun - I've heard of DeVilbiss, Iwata and SATA, and my budget is around the £300 mark. I want to use HVLP equipment but I have no idea about nozzle sizes or any of the details!
Installing the air feed - I have a 14cfm compressor with 150l tank, but need to get the solid pipes, connectors and flexi hoses in. Does anyone know a good source?
Filter / regulator - Can anyone recommend a good water filter and regulator for spraying? As above I would prefer to use HVLP equipment. Also need a good source!
Finally.. Paint! - Where is a good source to get decent quality paints? What are the laws on what I can and can't paint with in my workshop?
There's probably a bunch of stuff I have overlooked, so if you have experience with setting up a high quality spraying installation please feel free to add anything you think might be necessary.
Squiggs said:
?????? To supply an air fed whilst doing a respray will push a 150ltr
As I understand it, tank size doesn't really matter.. it's the output of your pump that's important. As the job size is pretty small I think my compressor will be ok. Worst case is I have to wait for it to recover occasionally.
Cheers Steve.
It's just the one car at the moment, and it'll be painted in front & rear clam halves, doors, and frame, so I can break the spraying up in to small chunks. Later on I would like to spray whole cars, but I don't have the space right now. I'm in a small workshop and will just create a temporary dust-free area to paint in, so extraction isn't going to be great.
It's a bit of money to get an air-fed mask, but it beats becoming a respiratory cripple so I don't mind!
It's just the one car at the moment, and it'll be painted in front & rear clam halves, doors, and frame, so I can break the spraying up in to small chunks. Later on I would like to spray whole cars, but I don't have the space right now. I'm in a small workshop and will just create a temporary dust-free area to paint in, so extraction isn't going to be great.
It's a bit of money to get an air-fed mask, but it beats becoming a respiratory cripple so I don't mind!
Byteme said:
If you only have a small workshop where do you propose siting the compressor and how do you intend extracting and safely venting you painting area? Air fed equipment could be the worst method of protecting yourself unless the two areas are kept isolated from each other.
Don't underestimate the amount of over-spray and solvent fumes that will accumulate in a poorly ventilated area.
The compressor is in my workshop, but I'm looking in to extending the inlet so it draws fresh air from outside if I were to use an air-fed mask.Don't underestimate the amount of over-spray and solvent fumes that will accumulate in a poorly ventilated area.
The "booth" will just be a sealed area of the workshop, with some sort of extraction to get the worst of the mist out.
What would you recommend if I couldn't get adequate fume extraction to use an air-fed?
Byteme said:
How much painting do you intend to carry out and using what materials?
You really need to get the compressor out of the workshop well away from any area you intend to use for spraying.
Extraction tends not to work as easily as you may imagine as it will take away fumes and over-spray but it will also draw in dirt. A proper booth maintains a positive pressure using a series of baffles but you could approximate this by using a larger fan to blow filtered air in while using a smaller one to extract. Whatever you choose the fan motors will need to be flame-proof.
If you intend spraying an entire car with a decent gun you'll need a big compressor and 3hp is about as much as you can use from a 240v supply. That won't leave enough of a reserve for an air fed mask. Air-fed masks also require additional filtration.
Good info, thanks. You really need to get the compressor out of the workshop well away from any area you intend to use for spraying.
Extraction tends not to work as easily as you may imagine as it will take away fumes and over-spray but it will also draw in dirt. A proper booth maintains a positive pressure using a series of baffles but you could approximate this by using a larger fan to blow filtered air in while using a smaller one to extract. Whatever you choose the fan motors will need to be flame-proof.
If you intend spraying an entire car with a decent gun you'll need a big compressor and 3hp is about as much as you can use from a 240v supply. That won't leave enough of a reserve for an air fed mask. Air-fed masks also require additional filtration.
I hadn't thought about the negative pressure sucking dust in.. that would be a big problem as my workshop is very dusty! I'm not going for a show car finish by any means, but I do want it to be as good as it possibly can be for my level of experience. (Zero)
I might have to think about a small 240V compressor for supplying the mask in that case. I think if I put one of those outside the unit and used a 20m hose to route it to my mask, that might be a good solution.
It's fixable... said:
Not wishing to sound like an arse but the post about maintaining positive pressure in the spray booth cabin is totally wrong and illegal.
Negative pressure between 0 and -20pasacals must be maintained in the spray booth cabin to avoid ejecting nasties out into the workshop.
Take some time to familiarise yourself with the various health and safety publications and the requirements given therein - there are stacks! Also make sure you are familiar with the requirements of ATEX and have a good grasp of the concept of zoned areas.
Then and only then attempt this project.
Oh, and before the flaming starts, this is what I do for my day job...
Thanks for the input. Negative pressure between 0 and -20pasacals must be maintained in the spray booth cabin to avoid ejecting nasties out into the workshop.
Take some time to familiarise yourself with the various health and safety publications and the requirements given therein - there are stacks! Also make sure you are familiar with the requirements of ATEX and have a good grasp of the concept of zoned areas.
Then and only then attempt this project.
Oh, and before the flaming starts, this is what I do for my day job...
Could you give me some advice on filtering the extracted air? I want to duct it from the extraction fan out the workshop, but I want to make sure I filter it properly as it's a semi-residential area and I don't want to pump isocyanates out everywhere.
I've seen the panel type filters you can get for extraction, but are these enough? They don't look like much to my untrained eye, but they claim to filter out ~99% of particulate. Is it enough to have one of these in front of the extractor vent, or do I need more?
I think I'm getting there with the concept now.. air lines and everything should be done in a couple of weeks, then I'll get round to making the booth. I will DEFINITELY use an air-fed mask, and make sure my inlet & outlet filtration is adequate. I want to do this properly.
It's fixable... said:
First things first.
What is the height x width x depth of your spray area; assuming the width dimension is the same side you'll have your extract filters on. You need to maintain an average of 0.7m/second airflow across the height x width cross sectional area. This will give you an airflow size for the extract fan.
Now you are pulling air out! But how will you get an equal amount of replacement air in? Ideally it will come down through the "roof" and will be filtered so it is clean and doesn't leave a load of contaminants in your spray job.
Post some photos or sketches of your spray area and the surrounding structure.
Also be aware that to be legal your spraying area will need planning permission and approval by the local environmental and petroleum officers. If you have anyone in there spraying for you, you will need a LEV test certificate...
Plus the exhaust stack must be 3m higher than the roof peak - a red rag for any nosey parkers in the neighbourhood...
Dimensions are roughly H 5.0m, W 3.5m, H2.5mWhat is the height x width x depth of your spray area; assuming the width dimension is the same side you'll have your extract filters on. You need to maintain an average of 0.7m/second airflow across the height x width cross sectional area. This will give you an airflow size for the extract fan.
Now you are pulling air out! But how will you get an equal amount of replacement air in? Ideally it will come down through the "roof" and will be filtered so it is clean and doesn't leave a load of contaminants in your spray job.
Post some photos or sketches of your spray area and the surrounding structure.
Also be aware that to be legal your spraying area will need planning permission and approval by the local environmental and petroleum officers. If you have anyone in there spraying for you, you will need a LEV test certificate...
Plus the exhaust stack must be 3m higher than the roof peak - a red rag for any nosey parkers in the neighbourhood...
It'll be a sealed area in my workshop.. only temporary, mind, as I will only be doing the one spray job. I don't think it will be possible to have air drawn in through the top of the booth as the roof is pretty dodgy and leaks in places.. I was planning to have an inlet with some panel filters at one end and the exhaust(s) at the other, then duct out the roof fascia at the front of the workshop.
The workshop is rented on private land which the landlord lives on. He knows about my plans to spray in there and is happy for me to just spray to atmosphere, but I'm not happy to do this. I think planning permission will be going a bit too far for the scope of my work.. probably not what you would like to hear.
As for nosey parkers there is no risk of that.. the unit is right at the back of this guy's land and really out in the sticks.
I just want to make sure I'm not going to take any undue risks to my own health (or my landlord's) and the environment.
It's the 2nd one.
Hmm.. that would be 7 300mm ATEX fans from what I can find on the internet, at a cost of £800 per week. Not going to happen!
I understand you're giving me advice from experience with a permanent spray booth, to be as safe as possible, and compliant, but that is too expensive! I could afford one, realistically, two at a push.
What filter elements should be used ahead of the extraction?
Hmm.. that would be 7 300mm ATEX fans from what I can find on the internet, at a cost of £800 per week. Not going to happen!
I understand you're giving me advice from experience with a permanent spray booth, to be as safe as possible, and compliant, but that is too expensive! I could afford one, realistically, two at a push.
What filter elements should be used ahead of the extraction?
Squiggs said:
One thing I haven't seen mentioned (unless I've missed it) is that the fumes can be flammable and any motors for fans etc should therefore be approved.
I think it was mentioned somewhere that they needed to be flame-proof, but worth reiterating! I still have a couple of unanswered questions:
1 - Are paint arrestor filters like THESE suitable for removing paint & iso particles from the extracted air? They are supposed to remove >95% of paint particles.
2 - Assuming the above filters are fine, are there any other measures that I need to take with the exhausted air, or am I ok to duct it straight out of the workshop?
I'm going to start building the booth this weekend.
It's fixable... said:
I did mention ATEX and zoning - ATEX is the European directive relating to explosive atmospheres and zoning is the process by which areas are identified with respect to their flammability. Electrical equipment working in an area that is zoned as hazardous needs to appropriately rated and or be enclosed or be shrouded with fresh air to avoid the risk of an explosion.
However the OP has dismissed the use of the correct type and quantity of extraction fans as they are "too expensive" and although he realises he has to filter the extracted air he does not appear to realise that he will also need to allow an equivalent amount of fresh filtered air into the booth to replace what he is extracting. The inlet air needs to be filtered otherwise it will bring in contaminants that will affect the quality of the spray job.
A temporary spray facility has to meet exactly the same legal requirements as a permanent one.
I'm out !!!!!!!
I think you've misunderstood.. I understand that I need to use ATEX fans, and am actually going to view an 8000m^3/h unit later today.However the OP has dismissed the use of the correct type and quantity of extraction fans as they are "too expensive" and although he realises he has to filter the extracted air he does not appear to realise that he will also need to allow an equivalent amount of fresh filtered air into the booth to replace what he is extracting. The inlet air needs to be filtered otherwise it will bring in contaminants that will affect the quality of the spray job.
A temporary spray facility has to meet exactly the same legal requirements as a permanent one.
I'm out !!!!!!!
I also realise the intake air needs to be filtered, and will do this. I haven't mentioned that because I am concentrating on the potentially harmful extraction side for the sake of safety - that's my primary concern. If it offends you that I can't spend £800 per week on extraction then I'm sorry to hear that but understand if you no longer want to contribute.
For anyone who is interested:
Those filters I linked are adequate for the extracted air - mounted in the booth, ahead of the extraction fan(s).
I'll construct the spray room out of stud work and clear polythene sheet, so that it can be dismantled when I'm done. I'll have 4 inlet points (2 top, 2 bottom-ish) on one wall with filters and one large outlet point on the opposite wall with filters, then duct the extracted air out the workshop. I can then blank off portions of the inlet openings as necessary to reduce flow and maintain a slight negative pressure vs. the outside.
I'll rent a small compressor to feed my air mask, and run my spray gun off the large workshop compressor. Once it's all built I'll smoke test for leaks & clearance time.
I'll stick details of the build in my project thread, for anyone who wants to follow things from here.
Cheers sausage. I'm going to paint it motorsport white! Some kind of frozen white I think. The frame will be powder coated satin black and have aluminium panels between all the tubes, which should be a pretty nice contrast. Then most components anodised / powder coated black, with a few gold bits here & there for some motorsport bling. 
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