in a quandary...

[Spence]

Hi folks, sorry for another compressor thread... i just can't get my head round this one!

my current compressor is a direct drive oilfree jobby with a tank capacity of 100ltrs... i think its getting tired because it takes best part of ten minutes to fill the tank to 10bar

it runs a die grinder fine, it runs my 1/2 impact gun fine, but a d.a sander? not a hope! the d.a will drain the tank down to approx 40psi but the compressor will maintain that pressure all day long.

my d.a is a blue point 6cfm item.

i borrowed my friends compressor (12cfm, 100ltr) which was only marginally better than mine.

whats my best solution as ive got a whole car to sand down!!

do i buy a pump only and adapt an electric motor i have here, or do i buy a whole new compressor?
budget is only around £250, so iam very limited i know

all advise appreciated

 

[KTMMICK]

Hi folks, sorry for another compressor thread... i just can't get my head round this one!

my current compressor is a direct drive oilfree jobby with a tank capacity of 100ltrs... i think its getting tired because it takes best part of ten minutes to fill the tank to 10bar

it runs a die grinder fine, it runs my 1/2 impact gun fine, but a d.a sander? not a hope! the d.a will drain the tank down to approx 40psi but the compressor will maintain that pressure all day long.

my d.a is a blue point 6cfm item.

i borrowed my friends compressor (12cfm, 100ltr) which was only marginally better than mine.

whats my best solution as ive got a whole car to sand down!!

do i buy a pump only and adapt an electric motor i have here, or do i buy a whole new compressor?
budget is only around £250, so iam very limited i know

all advise appreciated

Bigger tank may help! Why not make yourself one out of a Gas bottle! Just a thought.

 

[Shox Dr]

A Bigger reservoir will only delay the the pump starting, and then he will be in the same position.

I would buy a new compressor, forget about the tank size and go for the biggest CFM rating you can get hold of, if you want you can then add a larger tank at a later date.

Don't forget CFM means jack, the important value is "Free Air Displaced CFM" and ALL manufacturers like to state CFM. To work out Free Air Delivered CFM take 30% off the advertised CFM and you will be somewhere near, the compressors true power.

It's also worth bearing in mind the Tools manufacturers also Underestimate the CFM required to power the tool as well.


HTH

 

[Spence]

A Bigger reservoir will only delay the the pump starting, and then he will be in the same position.

I would buy a new compressor, forget about the tank size and go for the biggest CFM rating you can get hold of, if you want you can then add a larger tank at a later date.

Don't forget CFM means jack, the important value is "Free Air Displaced CFM" and ALL manufacturers like to state CFM. To work out Free Air Delivered CFM take 30% off the advertised CFM and you will be somewhere near, the compressors true power.

It's also worth bearing in mind the Tools manufacturers also Underestimate the CFM required to power the tool as well.


HTH

now that does make sense

6cfm for a die grinder and the comp copes, 6cfm for d.a and its useless

as iam on single phase, and assuming this motor i aquired is only 3hp (should be fitted to a tesco van running the fridge compressor from mains when van isn't in use) iam limited to a "14 cfm" compressor?

 

[eil]

You should be able to get a good second hand one for that money, you could consider coupling two of them together for more capacity.

 

[Shox Dr]

You should be able to get a good second hand one for that money, you could consider coupling two of them together for more capacity.

Very true, when I said "new" I meant new to Spence

 

[eil]

Oops gotcha.

 

[Spence]

what about 2 12cfm's?

failing that, ive got a twin cylinder, 1080cc (unknown output) water cooled, oil pressure fed truck compressor here, would that work?

(if i can rig a system to supply oil and coolant)

 

[scarecrow]

be careful buying some of them old compressors make sure you see them running as it can be hard and expensive to get the parts

 

[eil]

I remember back in the seventies lads were always on the look out for truck compressors to make their own using calor bottles, but that was because proper ones cost a lot more back then, A water cooled one with external oil pressure would be quite a bit of work though. Rtb made a similar setup http://www.mig-welding.co.uk/forum/showthread.php?t=8692&highlight=westinghouse+compressor
http://www.kingstonemodeleng.com/MachineShop/compressor/compressor.htm

 

[Spence]

thanks for the links eil,

so far i have this compressor, a choice of car power steering pumps, and could run a convection type cooling system?

i cannot find any flow capacities for this comp, its a wabco twin cylinder for an FH12 Volvo truck. will build the truck up to 12bar in 3 minutes (approx 150ltrs)

the clincher here is, would i be better off buying a 14cfm pump, or going to the hassle of adapting this truck one?