compressor

[jtd.75]

can anyone tell me what size compressor would be needed to do small spraying jobs eg wings bonnet boot, and where I could pick a reasonally priced used one. and what does cfm mean
Jimmy

[Willie]

CFM means cubic feet per minute. If you only mean to spray these items
once so that you do not wish to invest in an expensive sprayer, with a
reservoir tank and of course the spray gun itself then there are several
cheap 'all in one' electrical sprayers available. Look in 'Practical Mechanics' etc. The trouble is they are exactly that,' cheap' and
difficult to obtain a good finish with even if you are experienced at
spraying. Then you have to buy the matching paint and suitable
thinners of course.

[jonathon]

Your average spray gun will demand between 3.5 and 5cfm. You should use a compressor with a descent sized reciever to so the motor doesn't need to run all of the time. You can hire compressors and guns but make sure that you have a good water trap and the air line has not been used with air tools that have been oiled, water/oil mix = bad paint job. If buying or renting a spray gun go for the best you can afford as the difference as said previously is massive in terms of achievable quality

[jtd.75]

Hi Johnathon/Willie thanks to you both I have a 25 litr comp wihich I use for tyres / dust gun, I also have a S/gun its just the size of the comp . that I need, I have been told that a 50 litr one would do is this correct as this seem small to me
Jimmy

[brixtonmorris]

air line has not been used with air tools that have been oiled, water/oil mix = bad paint job

johnathon why would oil get in the air line?

dont wast money on expensive air guns. the spray quality is not that much differant, its all in the nozels. annd the mix.
jack sealy no worries, with a selection of nozels

also if you have low pressure you can use a gravity feed guns.

[rayofleamington]

why would oil get in the air line?

A lot of industrial compressors 'consume' oil during their running and it ends up in the air - obviously not good if you want to use the air for paint. I think it varies between types of compressor but i can't remember which ones are oily.

[bigginger]

Plus (I'm guessing) the tool oil will run out of the line to tool connection when the air isn't flowing (trigger isn't pulled).

[Blunt]

I know nothing about this subject...

but I found this...

Single-Acting Reciprocating Air Compressors
This type of compressor is characterized by its "automotive" type piston, driven through a connecting rod from the crankshaft of an engine or motor. Compression takes place only on the top side of the piston. Small, single-acting reciprocating air compressors generally are air cooled. These may be single-stage or two-stage, usually rated at discharge pressures from 125 psig to 175 psig. Exposure of the piston and cylinder walls to lubricating oil often results in some oil carryover into the air stream delivered from the compressor and carbon deposits on valves and pistons. The lubricant should be used and changed regularly as specified by the compressor manufacturer. Oil-free models are also available.

here http://www.energyusernews.com/CDA/Artic ... 11,00.html

[jonathon]

If you are using an air ratchet and the like you need to oil regulary this oil plus the oil that the compressor will generate will contaminate your airline. If you wish to spray with the same airline you will run the chance of wax spots in your paint.I use a Boge screw compressor,ie no piston, runs very much like a supercharger, but on electric. this feeds a 300ltr reciever then a freeze dryer,to ensure that the air is clean and dry. I have a dedicated air feed for the spray booth , seperate from the general system on which I use other mechanical tools such as air ratchets etc. I also do not wish to breath neat compressor air when spraying so I have a good quality air fed mask with the relevant air filters. As for spray guns it really depends on the quality you require, yes the cheap gun will spray paint but theprofessional paint gun will make the job a lot easier and with more competance. There really is a place for buying good kit ,thats why pros use pro equipment. Cheap it aint but then we need to ensure a quality product at the end of the day, day in and day out.

[bigginger]

If you are using an air ratchet and the like you need to oil regulary this oil plus the oil that the compressor will generate will contaminate your airline.

Good grief! I got something right! So did Ray mind - I'll sulk for weeks now...

[jonathon]

LOL!!!!!!!!!

Andrew, I forgot to mention water as well, over to you!!

[bigginger]

Nah, that's physics or something... Oh, all right - when you squash air, the water in it comes out, and ends up either in the air line, or sitting in the bottom of the air resevoir/tank. That's why you have to empty the tank every day, so it doesn't rust through. Is that close enough?

[jonathon]

Excellent!!!, just waiting to see if Ray knows, before you can claim your prize.

[bigginger]

I'd better delete that post then - he'll only cheat...

[jonathon]

Ah!! didn't think of that! We will change the rules then, if he doesn't reply by 11.45 real time ,you win

[bigginger]

Hee hee! Haven't won anything since I was 7!
Mind you, with my kind of luck, he'll win anyway...

[jonathon]

Yeh! but you don't know what the prize is yet

[jonathon]

Blimey talk of the devil!! I see Rays just signed in ,he's only got 1 min though!!!!

[rayofleamington]

shucks - I read all the threads, starting oldest first ;-)
and with those extra posts this was the newest one so the last that I read

[jonathon]

Never mind Ray, a drivers seat is on its way as a booby prize