paint spraying compressor

[chrisgriffiths]

Hi everyone
I'm after a bit of advice please
I'm thinking of investing in a small air compressor to enable me to spray initially the rear wings on my saloon. The advice I'm after is what size compressor do I need. They seem to come in all sorts of sizes but I was wondering if I could do a reasonable spray job with a 24 litre compressor. They seem to be the most common available
Cheers

[blues2rock]

If you intend to do serious spraying with a professional gun then you will need a powerful compressor - 8cfm and 50 litre tank is about the minimum. If you go that route check that the cfm figure quoted is the 'free air delivered' not the theoretical output which is often quoted in cheaper ranges.

You would also need to obtain an accurate regulator and water separator, together with a suitable connecting hose (to the gun) which is certified for paint spray use (the cheap ones often leech contaminants). By the time you have purchased all that and the paint and thinners the cost will be surprisingly high.

If it's only a couple of wings it would be considerably cheaper to use aerosols - not the 'touch up ones as per Halfords etcetera, but there are several suppliers who will mix the colour and put it into good, high pressure cans with a trigger and decent fan spray pattern. These are also easier to get the hang of than a professional gun and won't spatter like the touch-up sort.

No doubt someone will tell you how they achieved a mirror like finish on a complete respray in a damp dusty wooden shack using a plastic gun they purchased from Woolworths.

As always you pay your money and take your choice.

[chrisgriffiths]

OK cheers. Sounds logical what you said. The large aerosols you mention are they from paint specialist s

[blues2rock]

Yes if you google "auto refinish aerosols" you will find several that can do the job, there is also one that advertises on ebay (sorry can't remember the name).

Only other thing to say is if you did go the compressor/gun route avoid 2K paint as it is very harmful unless you are protected by an air fed mask.

[bmcecosse]

The paint cans from Bull Motif are excellent - shake very well, and warm them up in a bucket of hot water, Only spray light coats. There is easily enough in one can to spray the two wings - but probably best to get two in case of mistakes. If you do go the compressor route - the Aldi one I have is perfectly satisfactory for spraying one panel at a time -again light coats to avoid runs or sags. I only spray outdoors - in warm/still weather. And of course - DO NOT attempt to use 2K paint.

[bigjim]

most decent motor factor refinishers will do the aerosols , you could use a 25 litre compressor but use a piggy back tank to up the air available but the compressor will still need some recovery time to refill the larger capacity, if your local to me i could help show you what you need /how to use it , 1k coach paint is easy to use but cellulose should be available as yours is a classic, 2k not a problem you just need a good respirator, i use an air fed full face mask that i have for confined space /low air atmosphere use

[chrisgriffiths]

Cheers big Jim I appreciate the offer. I'm situated just outside Chester don't know if that's local to you
Thanks yo all for your help
Cheers
Chris

[kennatt]

Theres a lot of talk about 2k being deadly,due to the isocyanate in the activator,but if you do a bit of research on the net,re paint health hazzards,it looks as though its reputation in unfounded,and a bit of a myth,apparently the only hazzard is that because its a 2 pack,if you get it into your lungs,it will then go off inside you and harden,The cyanide bit has been oxidised and is non poisonous.The problems with long term use are a high likelyhood of developing serious asthma,so with a high quality mask,not so much of a problem as I originally believed. I was directed to this info by my paint supplier who said that I was being a bit over cautious re 2k,he said he could supply me with a dust mask that would give total protection,he says its no more dangerous than using celly without a mask.His reasoning was if you put the mask on and can't smell the paint ,whatever it is,then its not doing you any harm .

I'm Still sitting on the fence,just don't know if the benifits of using 2k outweigh the risks,

[blues2rock]

The post mortem report stated: This man died because his lungs were Trafalger Blue!!!

A useful link: http://www.hse.gov.uk/mvr/bodyshop/myths/myth3.htm

[tysonn]

Well yes maybe his lungs were blue but thats to be expected if he had been spraying blue paint.Any job you do on an old car in a dusty garage will create coloured dust that without breathing precautions will end up on your lungs.You only have to spend a couple of hours welding and grinding and your nostrils are full of black.I made a point on here a long time ago about the "if you can't smell it its not doing harm" and mentioned the type of non airfed mask that are sold as being safe with 2K.I know its impossible to give assurances about these sort of dangers but there are plenty of people,myself included, that have been spraying all paint types for decades using standard precautions.I won't begin to mention the people I know that don't use ANYTHING.

[kennatt]

yes,my paint supplier assures me that the dust mask he sells is ok for 2k.and he did explain,forgotten the full details,that the cyanide bit oxidises as soon as it is sprayed ,into another compound,which is in itself non toxic,other than breathing it in,It can't get into your system via your skin etc.He did advise that an Air feed was the way to go if you are employed in regular use ,of any paint method,but for the once or twice in your life time a good dust mask will do

still on the fence.

[tysonn]

Funny thing I noticed on these American car restoration programmes is that I have yet to see anyone spraying paint using anything other than a standard mask?

[tysonn]

http://www.ebay.co.uk/itm/Gerson-2K-Pai ... 23368e4047

[bmcecosse]

Absolutely DO NOT rely on a 'dust mask' is spraying 2k.Or for celly either for that matter!! This is NOT good advice! 2k IS horrible stuff, and yes can coat the lungs short term - but it's main risk is the asthma - which could seriously ruin your health and shorten your life. In any case - 2k gives a horrible 'false sheen' to paintwork - you can spot cars sprayed with 2k a mile away!

[tysonn]

Its not "advice" its a comment about a personal long term experience using these materials.I aren't "advising" anyone to do anything.Another opinion might be that spending nearly £14 on an aerosol can of paint is a waste of good money that would be better being put to one side until there's enough money to buy a cheap compressor to do the job properly.We've been here before about paint finish.I challenge you to be able to visually tell whether two pack or celly were used to paint a car if both types had been wet flatted and machined to a gloss afterwards.Unless of course you then left it a while when you would be able to tell because the celly had gone flat and sunk as it always does.

[moggydriver62]

There has been some very bad advise on this site.
2 stage paint is very dangerouse. All urethane paints
are lethal,and can kill very quickly.Most of the tv
shows you see in the U S.are done for money.
It costs too much money to have all the proper
equipment,paint stuff jack stands etc.

[chickenjohn]

Its not "advice" its a comment about a personal long term experience using these materials.I aren't "advising" anyone to do anything.Another opinion might be that spending nearly £14 on an aerosol can of paint is a waste of good money that would be better being put to one side until there's enough money to buy a cheap compressor to do the job properly.We've been here before about paint finish.I challenge you to be able to visually tell whether two pack or celly were used to paint a car if both types had been wet flatted and machined to a gloss afterwards.Unless of course you then left it a while when you would be able to tell because the celly had gone flat and sunk as it always does.

Celly often goes flat because the sprayer used celly primer. I've found much better results, no sinkage and a lasting shine by using Branth Korrux Nitrofest primer. A German anti rust primer suitable for cellulose and other finishes. Oh and 2K will go flat as well if badly applied or neglected.

[tysonn]

True.I have used 2k primer with celly too when the owner insisted(for whatever reason)on celly top coat.There are non isocyanate hardeners available although I've never tried it.

[Matt]

Off topic - that HSE link has some interesting reading in it!

I work in an environment where RPE (respitory protective equipment) is critical - and its not automotive related.

Any negative pressure breathing apperatus (masks/respirators etc) need to be "face fitted" to ensure they achieve the necessairy protection factor. This involve undertaking a number of tasks (talking, walking up and down steps etc) whilst a "contaminant" is pumped in to the air within the room, and the levels of contaminant within the mask assessed via computer. Posative pressure equipment (like air fed masks) do not need to be face fitted. You also need to be clean shaven to get the seal.

If it fits correctly your chosen RPE will have a protection factor. If the protection factor is 20 (standard for most masks) then it will allow no more than 1/20th of the contaminant in the atmosphere in to the mask. If its a Protection factor of 40 it will allow 1/40th in etc.

I am currently out of face fit for a mask, but the last one I did showed a protection factor of over 10,000 at fit test - on a mask thats nominally got a protection factor of 40. But thats because the mask suited the shape of my face... it can be significantly less!

Remember you also get at least 2 filter types - one soley for particulate (normally P2 or P3) and one for organics/vapours. When painting you would want an organic vapour one which is significantly larger than a particulate filter.

Those of you who have worn masks/respirators etc, how many of you have had a face fit to check it fits correctly, and how many have used them whilst stubbly?

My preference (if the choice is available) is an air fed mask, its easier to breathe, it doens't mist up, its cooler and provided there is air flow you know its doing its job. (remember the pressure inside only wants to be 1-2psi higher than outside). This would, however not work very well with a small compressor.

I will leave the debate about whether a negative pressure mask is suitable for 2k up to everyone else.

With regards to the compressor...

I used to use a 2hp 25L SIP compressor to paint celly, with a machine mart gun (about £50) and got very good results. I now use that compressor to run an airfed mask, and a much bigger one to run the paint gun.

[tysonn]

Before I bought my 3hp,150l comp i had a sealey 2hp with 50l tank and sprayed a fair few cars with no problem at all.It kept up with the gun most of the time.The cheapest guns are usually the most air hungry so check the requirements before buying.I'm assuming the comp you use for feeding your mask is oilless?Or are you filtering the oil out on the way to your mask.If not you're probably risking your lungs more with the compressor oil than the paint!