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MG MGB Technical - Air Compressor Opinion
|Have also posted in the MGA section.|
I am interested in an air compressor mainly for sand blasting. I have 220 volt line. Any with a reasonable price tag that works well. Saw some fairly expensive ones with one and two year warranties and others about the same size such as Husky that were less expensive with 3 years.
Would appreciate your thoughts.
|If you're going to sandblast you need at least 10 SCFM. Probably 5-7 "real" horsepower, not the compressor HP that Sears advertises. Get a 2 cylinder, around 60 gallon tank. Expect to pay $500- $600 minimum.|
|Motors that use oil are much, much quieter than the standard cheaper models, and tend to last forever. I have a Chaisson 60 gallon that has been very nice.|
|One comment regarding motors....it is the air compressor pump with the piston that uses the oil. The electric motors will wear out..especially if you don't heed the manufacturers recommendations about keeping the unit far enough away from the wall to allow the fan action of the belt driven pulleys to cool the motor and piston pump. I have a friend that had to replace his electric motor after about three years due to having it against the wall without enough space.|
|Shoot for 16cfm. Anything smaller will be frustrating and you will be exceeding the recommended run time of the motor under load. You will do a lot of waiting for the compressor to catch up if you get something under 12cfm. Either that or you will be using a VERY small tip and progress will be very slow - such as 30-60 minutes to do the tranny crossmember or a set of seat slides. If you ever want to do a full car body, nothing under 16cfm will suffice. |
|Ascertain whether if the compressor cylinder block|
is made of 100% aluminum - or a combo of
aluminum block with sleeved clylinders - or
cast iron. Compressors that are made of iron,
or aluminum w/ sleeved cylinders, tend to live
longer than those that are 100% aluminum.
2-stage compressors make life easier on the
electric motor when cycling on & off, than the
1-stage types, but this may be over-kill for
a hobbyist or weekend warrior.
|Stay away from the homeowner type units that have the motor and the pump as a single unit. you have to replace the entire unit if any part goes bad. Cost more than the original whole unit did.|
These units also have a rubber piston that wears out rather quickly with any use.
|You know, unless you're going to go into the abrasive blasting business I don't know how you can justify the cost of the equipment and supplies. I had a guy with a portable unit come here and sandblast my MG bodyshell. Did everything I wanted for around $100. |
For $12.00 I bought a sandblast gun from Lowe's and a $5 bag of sand from the local lumber yard. Does most of the smaller parts I need done.
For less than $100 I bought an abrasive blast cabinet and glass beads from Harbour Freight. Does all the smaller parts just fine.
All this is using a 3 1/2 HP electric motor air compressor I bought from Farm and Fleet. Agreed, I do not have production equipment, but I'm not doing production work. I think I could build a sand blasting cabinet to hold anything I wanted to do for under $150, but once again, if it wasn't a business it would stand idle for long times between jobs. And, if it was a business, I don't know how I could survive without being mobile, which would require a self-contained, gasoline powered air compressor.
|Hi Tom- I invested nearly a grand on a 2 stage, pumping 17 cfm at 90 #'s, 80 gallon storage as a justifiable offset to commercial shop pricing. Previously, at $80/hr, I spent $720 to bare metal blast ( with recycled 30 mesh sand) 4 MGA clips and 1 inside, out and under 1979 mgb roadster and felt it was ok bang/buck. This after my home unit could not keep up. Before that on a single chassis, 2 clip, 4 fender MGA , I pumped 17 @100# bags of 30 mesh over about 4 days with the compressor running constantly. Too much! Pay the piper I said. Your 1 yard cost on blasting is great, around here, in the cities, they're getting $125-200/hr. To date, I've pumped out over 2 tons ( 44 @ 100# bags) of 30 mesh : about six months, and opted twice for commercial service at $720 above, and a before-compressor charge of $854 for 2 MGA chassis, misc parts, wheels, body panels, and 2 clips. It's not been cheap, excluding my time, I've thrown nearly $3k at the master-blaster. Vic|
This thread was discussed between 09/11/2004 and 10/11/2004
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