CAL FIRE Model 34 Engines' tanks are failing

[firemechanic]

Go2- Not vendor specific. Many of the Smeals my agency purchased had to be retrofit with pucks on the body mounts because of build-up cracking due to direct mounting of the bodies to the frames. This is especially important with aluminum due to it's characteristic of catostrophic failure rather than bending.

And NC- NOOooooooo!

ive been seeing alot of problems with aluminum bodys latley , cracked welds, improper welding process ive done acceptance inspections on several new apparatus , and there seems to be a trend with welds on alum coming cracked from the factory . it apperes to be due to aluminum being a super picky metal to weld and sensitive to how hot you get it and how fast it cools , welds tend to crack down the middle or right along side the weld

the other problem we are seeing alot of is pump corrosion and erosion, due to poly tanks , and stainless plumbing that the nfpa requires now, anode placement and replacement is paramount to protect the pump

[ht]

Aluminum is not hard to weld if you know what you are doing and do it properly. Requires shield gas in the right amount, no wind blowing over your torch etc. Takes a lot of care but can be made strong. Welding at the right speed to maintain the proper heat etc. Not for learning when you are building an apparatus.

As far as corrosion, the problem is that likely there are too many different metals involved, and they are not all tied together. Sitting idle and wet, a current gets set up between the different metals. If all were tied together electrically there would not be such a big problem. All the hoses (flex couplings) in the system isolates the metals and sets up the currents through the water and outside over the dirt build up. Keep the anodes up and the outside clean; should help. Depending on the tank level indicator set up that could run some current through there also. (As well as other electrical stuff.)

No single perfect solution. The builders will get better at it but it will take time; and be sure to document any issues you find to your Equipment folks.

Every little clue helps the corrosion people learn more what is going on. Corrosion can be very frustrating to deal with. And a clue from boats, make sure the battery charger, if you use one, is properly grounded.

[firemechanic]

Aluminum is not hard to weld if you know what you are doing and do it properly. Requires shield gas in the right amount, no wind blowing over your torch etc. Takes a lot of care but can be made strong. Welding at the right speed to maintain the proper heat etc. Not for learning when you are building an apparatus.

As far as corrosion, the problem is that likely there are too many different metals involved, and they are not all tied together. Sitting idle and wet, a current gets set up between the different metals. If all were tied together electrically there would not be such a big problem. All the hoses (flex couplings) in the system isolates the metals and sets up the currents through the water and outside over the dirt build up. Keep the anodes up and the outside clean; should help. Depending on the tank level indicator set up that could run some current through there also. (As well as other electrical stuff.)

No single perfect solution. The builders will get better at it but it will take time; and be sure to document any issues you find to your Equipment folks.

Every little clue helps the corrosion people learn more what is going on. Corrosion can be very frustrating to deal with. And a clue from boats, make sure the battery charger, if you use one, is properly grounded.

aluminum is not hard to weld i agree , it must be very clean . but we know tig is the best set up and provides the best control of heat . but tig is one of the slowest processes . so most builders utilize a wire feed set up which is fast , but there are times that a welder in a builders shop is too lazy to change settings for different thickness's of matrials .


as far as bonding all plumbing around flex hoses and parts of the sort we have tried it on several apparatus and it seems to have little effect . the biggest problem is in fire apparatus you WILL have electrolsys , galvanic issues . and now with a poly tank and stainless plumbing , (which i really like ) and brass valves the weak link is the cast iron of the pump . which both of the major players , hale and waterous have beefed up the weak areas of there pumps which is the area of the tank inlet flange of the pump . both pump manufactures offer bornze bodied pumps , i guess we could go that route

[ht]

hale and waterous have beefed up the weak areas of there pumps which is the area of the tank inlet flange of the pump . both pump manufactures offer bornze bodied pumps , i guess we could go that route

That would be good, but still have to get things bonded. Bronze/stainless is a good combination with a poly tank as long as the metals are bonded. Would need stainless, copper or rubber plumbing; not iron. If someone were to throw an aluminum tank in there that should rot first. An Aluminum anode (bonded to pump) in a poly tank would be fine.

And you are right, some people get sloppy when welding. MIG is a good welding process (and what I was talking about) for the Aluminum but you have to use a good gas for shielding; Argon-Helium is the best for it but keep that Aluminum stuff for the body, not the tank.

The Navy had some fire pumps (salt water) built from Titanium, some years ago. Really pricey. They ran 24/7 to provide cooling and flushing water also. The Bronze ones would not last. I do not think the fire service will ever go there.

Good luck with your equipment.