Longer Cracks

[DryStar]

Screenman;

My self-contained oilless compressor (which also can be used in vacuum mode) is rated at 100 psi and 1.7 cfm. These are the nominal specs at the compressor outlet at full power without attachments like a hose or nozzle. I use a needle tip nozzle the orifice of which is about the size of a mechanical pencil lead (smaller than a wood pencil lead) which increases the psi but probably slightly impedes the cfm.
I was made aware of the potential for contaminated air by the instructor that taught me long crack repair techniques more than twenty years ago and that potential was confirmed by more than one fleet/truck/bus service manager. You probably won't ever see a mist of either water vapor or lube oil spewing from the air nozzle but this doesn't necessarily mean that contamination isn't present. In fact, even a brand new oil-lubed compressor will pass enough lubricant around the piston ring(s) to significantly (for the purposes of WSR) contaminate the air flow. So if you use shop air chances are the air is contaminated by either moisture or oil. As I've found through experience that effective long crack repair is excessively dependent on environmental factors my strategy has always been to be safe rather than sorry. A question for you: if you use shop air exclusively, how do you dry out long cracks on site prior to repair? Or do you not repair long cracks on site?

puka pau,

Would you mind sharing the manufacture name or contact that sellls these?. So far I've never found one that includes a 12v compressor and vacuum pump that delivers 1.7cfm. The best I've found so far in 12v was 0.5 cfm with no vacuum abilities, which wouldn't help much with blowing out cracks. Thanks

Cheers;

Puka Pau

[puka pau]

Screenman;

Yours is an interesting perspective on servicing fleet accounts. Close to 65-70% of my fleet vehicles have no easy or immediate access to a service facility and if they do a service bay is rarely available when I require access and the 30 or so percent of vehicles that I service that have convenient shop facilities are those that I usually service on the weekends so normally the shop is closed. In addition, in the last ten or so years many shops here are becomiong more reluctant to allow outside vendors to work inside the premises due to potential liability situations so being that my approach to WSR has historically been conservative as well as expedient, I find it crucial to be as self-contained as possible; time is money and I just really depise leaving money on the table or stepping over dollars to pick up pennies. Thanks for the insight.

Drystar;

Being that my compressor is more than 20 years old, the model has been discontinued. However, the manufacturer is still in business: www.Gastmfg.com will get you to the site. They very well may have an updated design that will satisfy your requirements. I have a diaphragm-type compressor that can be used in vacuum mode by switching the supply hose from the outlet side to the inlet side. I attached quick disconnect fittings on both ends to facilitate switching between modes. I must say, however, that I have not used the compressor in vacuum mode for about 19 years because I found vacuum to be an ineffective technique to remove moisture. The moisture evaporator tool is the only technique that I've used that reliably removes moisture from star breaks and although compressed air works reasonably well on bullseyes, I always use the moisture evaporator in addition just to make sure. In my experience, compressed air remains by far the best technique to dry long cracks.

Cheers;

Puka Pau

[screenman]

My fleets run 24/7 and they have been trained to get anything with a long crack in inside for me, any other repairs I can choose. I am at an age where I like things easy for me, no wind, no rain, no cold, but I would like a little sun.

[puka pau]

Screenman;

Roger that. Aruba? Vanuatu? Costa del Sol?

Cheers

Puka pau

[DryStar]

Thanks for providing the company and link info puka pau, interesting 12v air pumps but somewhat costly.

I think for now I'll stick with my 20 gallon air tank which I fill using a oil-less garage compressor daily. A little bulky to haul around but works fine for the limited number of long cracks I do.