Compressor Sizing-3

This is the third of three pages - compressor sizing 3 - providing information on sizing the air compressor correctly, and this is the forum page to which you can add a comment or a question.

Page one on compressor sizing is right here.

Forum On Compressor Sizing

On this forum page you can review the postings of others found below the form, and post your own questions, comments or advice about compressor sizing.

All new postings will be live on this forum for about a week to allow the original poster and others to comment. After that, if the content is relevant, I will move the post to the appropriate page. The posts are all numbered. If you then wish to add a comment or question to one of the existing posts below, do use the form, but also please identify the entry number shown in the original so I can match the new with the old. I am told that adding posts in this way will help improve the SEO for this site.

Thanks,

Bill

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Comments and questions about compressor sizing

See other sizing questions and answers below.

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Entry #005 - Size of compressor to sandblast house?

Question: I live in cedar sided house it needs clean up had a guy sandblast with glass 2 years ago did one side of house great job but cost an arm and a leg. Would like to know what size air would i need to sandblast siding.

Response: You have the process backwards, a bit. If you want to operate any air tool with compressed air, and you want to buy a compressor for that project, you need first to determine the flow and pressure requirements of the air tool. That, and knowing that you will get about 4 CFM of compressed air flow at 90 PSI for each HP of motor size will guide you. I actually have an el-cheapo blaster (a world famous brand) in my garage. I use a dinky little el-cheapo compressor (another world famous brand)to run it. The little compressor can supply the pressure OK, but not the flow. So, I blast what... 1 square inch, and then wait for the compressor to rebuild air, then blast another square inch. Didn't cost me an arm and a leg, but pretty much could have used up all my life if I had continued. Find the right sand/glass/media blaster for the job, and ask the supplier (or read the documents) to see what air flow it needs to perform properly. Get an air compressor that will provide that, and you are golden!! Cheers and happy blasting...

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Entry #004 - What type of air compressor do i need?

Question: I need to run a DA at 135psi continuously for on average about 15 to 20 min, meanwhile i dont mind it kicking on to rebuild preesue, but i would like that 125psi to be there constantly. Also i need one that will run an ingersol rand half inch inpact up to 225 + possibley, at times to do things such as automotive work like motor mounts, tie rods, ball joints, ect. you get the picture! would also like to no of one that has multiple outputs. The HVLP is about 65 to 70 in and it cuts it back to about 10psi at the nozzle. I found one that had 1 or 2? 400psi outputs and 2 125psi outputs. i believe it was a rotary type, but im not sure i need to step up that big. although I could end up running 30 40 feet of air hose and may need more than one going at at time in a shop type setting. Thanx for the help, any information is really appreciated.

Response: The simple answer is you need an air compressor big enough and reliable enough for all the air flow you expect to use, and also within your budget. For these reasons I can't tell you what to buy. If you haven't the time to go through the process of figuring out the total air use yourself, as outlined on the Compressor Sizing pages, then your best bet is to contact some compressor manufacturers and ask them to do an air-use audit for you, towards you possibly buying a compressor from them. Then they will ensure that whatever type of unit you buy, it will suit your needs. You won't get that service from a store, you need to go to the compressor manufacturer's reps. like some of those noted on the Repairs page.

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Entry #003 - How big an air compressors for spray painting?

Question: I am doing a philco refrigerator restoration and i am planing on buying an air compressor to run a paint gun on there, i need a paint gun that can shoot the paint used on cars, is a 120 vlt 1.7 hp 3.8 scfm @ 90 psi 26 gallon tank going to be enough juice to plug a paint gun? What kind of paint gun do you suggest i use. Do i need any additional equipment.

Response: Hi Andrew. I think you're going about it the wrong way. First, find the right spray apparatus, and in so doing, that will tell you the flow and pressure (the compressor size) needed to run that spray painting equipment properly. I don't know much about spray painting guns for automotive type paints. I do have some background on spray painting for buildings and homes. What you need to know is:

• the type of paint (by manufacturer) that you are planning to use
• that will tell you what the viscosity of the paint that you are planning to spray is
• that will tell you the type of gun you want to get - the paint supplier will help here
• and that will tell you the compressed air demand of the gun that is recommended
• and that will tell you the size of compressor you will need to get

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Entry #002 - How much air compresor - If i want build motorcycle service station?

Question: Hi, Bill If i want build motorcycle service station. 8 pit area, each need 1 air gun with air consum 0.42m3/min, 1 air screw driver with 0.5m3/min, 1 air impact wrench with 0.5m3/min, and bike lift with 275 l/min all need 90 psi how big air compressor must i have. My compressor and service station with distance 40 meters. distribution pipe with 1/2 inch. Must i change my distribution pipe with 3 inch or more big. how big storage must i need, how big air compressor,how much FAD, please help me to rebuild my works shop.

Response: Herry, glad to help, but sorry, I am not going to retype all the information that is already on the pages of this site for you to read and use. See the pages on COMPRESSOR SIZING, COMPRESSED AIR PLUMBING, PRESSURE DROP and all of the other pages on this site that relate to your question. All the info you asked for is already here. Once you figure out how much air you will need, then you can decide on the right air compressor that suits your needs. Or, contact your local compressor suppliers and ask them. Most will be pleased to visit to determine your needs so they can bid on your air compressor.

Entry #001 - Reducing eletrical consumption but at the same time
       supplying the demand of the plant

Question: i work in a daimler group owned foundry,we manufacture engine blocks for trucks,now there is a lot of melting that uses a lot of eletricity. my job as the engineer is to see opportuities to reduce our eletricity consumption without impacting negatively on production.

now one of the areas i am working in is compressed air,where we have 3 ingersoll 530kw compessors,the system that was working prior to our troubles that affected production because the supply was not enough to the plant,as there are many important users that use air for example jolter that squezez the mould to keep shape before molten metal is poured. we had 2 compressors supplying the plant,with one full load and the other minimum load and the third one as back up,on standby. they supply to a ringmain inside the plant where the others users tap off from.if one user taps off exorbitant amounts,the correct pressure to supply the others drops or is disturbed and you have equipment not working optimumly. but for the moment all 3 are put on, 1 full load and the others minimum load.this solves the problem about insuffient supply as lines are added continously.this means we have 530kw compresors using eletricity. to save eletricity,and cut down on the bill how do you get back to using 2 compressors,with increase in demand. the demand i have quantified only 30% of what is sent to the plant is unaccounted for. but still how do we go back to the old system?

Response: Simon, based on what you have written, if the demand exceeds the two compressors, then you need the three. In your shoes, I would certainly access an ultrasonic leak detector to find and clear up all the leaks that will inevitably be in a good plant. That could save a ton of air. But really, you need to have a full air audit performed, and some recommendations, in situ, for compressor efficiency. Sorry, but that's pretty hard to do that from here.