Best material for carpet cleaning tank out of aluminum.

[Portable Welder]

I have a aluminum tank out of a truck mounted carpet cleaning machine that has several holes in it, years ago I built a tank out of 3003 aluminum and within a year it was leaking due to the chemicals in the soap.

The company that makes the machines still uses aluminum tanks and the customer wants another aluminum tank.

So my question is, Should I use a 6061 aluminum instead or is their a better aluminum that is still weldable.

[eecervantes83]

Effects of Composition and Microstructure on Corrosion
1xxx Wrought Alloys. Wrought aluminums of the 1xxx series conform to composition specifications that set maximum individual, combined, and total contents for several elements present as natural impurities in the smelter - grade or refined aluminum used to produce these products.
Corrosion resistance of all 1xxx compositions is very high, but under many conditions, it decreases slightly with increasing alloy content. Iron, silicon and copper are the elements present in the largest percentages. The copper and part of the silicon are in solid solution.
2xxx wrought alloys and 2xxx casting alloys, in which copper is the mayor alloying element, are less resistant to corrosion than alloys of other series, which contain much lower amounts of copper.
Alloys of this type were the first heat-treatable high-strength aluminum base materials and have been used for more than 75 years in structural applications, particularly in aircraft and aerospace applications. Much of the thin sheet made of these alloys is produced as an alclad composite, but thicker sheet and other products in many applications require no protective cladding.
Electrochemical effects on corrosion can be stronger in these alloys than in alloys of many other types because of two factors: greater change in electrode potential with variations in amount of copper in solid solution and, under some conditions, the presence of no uniformities in solid solution concentration. However, that general resistance to corrosion decreases with increasing copper content is not primarily attributable to these solid-solution or second phase solution-potential relationships, but to galvanic cells created by formation of minute copper particles or films deposited on the alloy surface as a result of corrosion.
2xxx Wrought Alloys Containing Lithium. Lithium additions decrease the density and increase the elastic modulus of aluminum alloys, making aluminum-lithium alloys good candidates for replacing the existing high-strength alloys, primarily in aerospace applications.
3xxx Wrought Alloys. Wrought alloys of the 3xxx series (aluminum-manganese and aluminum-manganese-magnesium) have very high resistance to corrosion. The manganese is present in the aluminum solid solution, in submicroscopic particles of precipitate and in larger particles of Al6(Mn,Fe) or Al12(Mn,Fe)3Si phases, both of which have solution potentials almost the same as that of the solid solution matrix.
4xxx Wrought Alloys and 3xx.x and 4xx.x Casting Alloys. Elemental silicon is present as second-phase constituent particles in wrought alloys of the 4xxx series, in brazing and welding alloys, and in casting alloys of 3xx.x and 4xx.x series.
Corrosion resistance of 3xx.x castings alloys is strongly affected by copper content, which can be as high as 5% in some compositions, and by impurity levels. Modifications of certain basics alloys have more restrictive limits on impurities, which benefit corrosion resistance and mechanical properties.
5xxx Wrought Alloys and 5xx.x Casting Alloys. Wrought Alloys of the 5xxx series (aluminum-magnesium-manganese, aluminum-magnesium-chromium, and aluminum-magnesium-manganese-chromium) and casting alloys of the 5xx.x series (aluminum-magnesium) have high resistance to corrosion, and this accounts in part for their use in a wide variety of building products and chemical-processing and food-handling eguipment, as well as applications involving exposure to seawater.
6xxx Wrought Alloys. Moderately high strength and very good resistance to corrosion make the heat-treatable wrought alloys of the 6xxx series (aluminum-magnesium-silicon) highly suitable in various structural, building, marine machinery, and process-equipment applications.
7xxx Wrought Alloys and 7xx.x casting alloys contain major additions of zinc along with magnesium or magnesium plus copper in combinations that develop various levels of strength. Those containing copper have the highest strengths and have been used as constructional materials, primarily in aircraft applications, for more than 40 years.
The copper-free alloys of the series have many desirable characteristics: moderate-to-high strength, excellent toughness, and good workability, formability, and weldability. Use of these copper-free alloys has increased in recent years and now includes automotive applications, structural members and armor plate for military vehicles, and components of other transportation equipment.
The 7xxx wrought and 7xx.x casting alloys, because of their zinc contents, are anodic to 1xxx wrought aluminums and to other aluminum alloys. They are among the aluminum alloys most susceptible to SCC.
Resistance to general corrosion of the copper-free wrought 7xxx alloys is good, approaching that of the wrought 3xxx, 5xxx and 6xxx alloys. The copper-containing alloys of the 7xxx series, such as 7049, 7050, 7075, and 7178 have lower resistance to general corrosion than those of the same series that do not contain copper. All 7xxx alloys are more resistant to general corrosion than 2xxx alloys, but less resistant than wrought alloys of other groups.
Although the copper in both wrought and cast alloys of the aluminum-zinc-magnesium-copper type reduces resistance to general corrosion, it is beneficial from the standpoint of resistance to SCC.

[eecervantes83]

Most aluminum alloys are readily weldable using GTAW or GMAW. However, some are not. Let's take a quick look at the common families of aluminum alloys and their weldability characteristics:

1XXX alloys. Essentially pure aluminum (99 percent pure) and used to carry electrical current or for corrosion resistance in specific environments, these alloys are all readily weldable. The most common filler metal is 1100.

3XXX alloys. This family comprises medium-strength alloys that are very formable. They often are used for heat exchangers and air conditioners. All are readily weldable using either 4043 or 5356 filler metal.

4XXX alloys. These usually are used as welding or brazing filler alloys. However, they are sometimes used as base materials. If that is the case, they are readily welded with 4043 filler metal.

5XXX alloys. This is a family of high-strength sheet and plate alloys. All of them are easily welded using 5356 filler metal, although 5183 or 5556 should be used for the stronger alloys, such as 5083.

6XXX alloys. These are primarily the extrusion alloys, although they are available in sheet and plate as well. They are prone to be crack-sensitive. However, with the proper techniques, they can all be readily welded using 4043 or 5356.

2XXX and 7XXX

2XXX alloys. These are high-strength aerospace alloys in sheet or plate form. Their chemistry makes most of them unweldable using GTAW or GMAW because of hot cracking. The exceptions are 2219 and 2519, which are both readily welded using 2319 or 4043 filler metal. In any case, you should never weld 2024. It is very common and very high in strength, but it is extremely crack-sensitive.

7XXX alloys. This too is a family of high-strength aerospace alloys. Like the 2XXX alloys, most of them are unweldable using GTAW or GMAW because of hot-cracking and stress-corrosion concerns. The exceptions are 7003 and 7005 extrusion alloys and 7039 plate alloy. All three of these are readily weldable using 5356 filler. Never weld 7075.

[dave powelson]

AL carpet cleaning waste tanks

I have a aluminum tank out of a truck mounted carpet cleaning machine that has several holes in it, years ago I built a tank out of 3003 aluminum and within a year it was leaking due to the chemicals in the soap.

The company that makes the machines still uses aluminum tanks and the customer wants another aluminum tank.

So my question is, Should I use a 6061 aluminum instead or is their a better aluminum that is still weldable.

For forming, 5000 series is easier, I think 6063 may be more corrosion resistant,
but the material selection isn't as important as what follows:

I've modified new, used and rebuilt these things. The contaminants from the cleaning--not just the cleaning solution used, make for all kinds of corrosion.
They'll all pinhole out in time, but that time can be extended for years.

1-Operators need to wash out and thoroughly drain tanks at least daily, especially at end of day. This is a biggie. The guys that do this, see tanks lasting for 5-10 years. The guys that don't, have tanks fail fast. The things smell like a cesspool--since they literally are just that...and worse.

2-Set the tank mount tabs up on UHMW blocking, to produce a 1- 1/2" slope to the drain outlet. On tank bottom replacement or sometimes on new....I'll move the drain outlet doWN to create a really, TRULY, low point drain. I started 'tipping' waste tanks 8 years ago and have had a tank bottom blow out.

3-On new and used/rebuilt/re-plated tanks, hot pressure wash the inside, aluminum etch, dry, then brush, swab, spray to coat the lower 12" of the sides, baffles and bottom with 'Submarine Cooler Coating' (a tar-based coating used for swamp coolers).

4-Drain outlet hose-use inside coated 'red stripe' make sure it's got a continuous, lowering drain path. The coated hose doesn't get clogged.
The ball valve for drain is located towards trailer rear, not connected at the tank proper. Assemble all rubber hose connections with silicone grease, pipe threads with teflon pipe dope--for ease of dis-assembly.

When working on any carpet cleaning equipment, use disposable gloves, keep
washing and sanitizing hands during work. Wash tools after. You're in direct contact with all manner of diseases and bacteria. I've seen carpet cleaning guys get critically ill from ingestion of unknown bugs that the hospital couldn't identify. The waste tank is a concentration cesspool of disease borne stuff.

[Portable Welder]

EEcervantes83, Thanks for your input, a little overwhelming I might add, Thanks Dave Powelson, I think we are all leaning towards 6061 for its weld ability and corrosion resistance.
I certainly welcome any additional comments, this is a very complex tank to build due to extremely odd shapes end extensive hidden chambers.

[dave powelson]

build al carpet clean waste tank

EEcervantes83, Thanks for your input, a little overwhelming I might add, Thanks Dave Powelson, I think we are all leaning towards 6061 for its weld ability and corrosion resistance.
I certainly welcome any additional comments, this is a very complex tank to build due to extremely odd shapes end extensive hidden chambers.

By chance is this a Hydramaster tank?
Those sell--if available, for something like $3500++

The tank also functions as a vacuum reservoir. The top tank edge needs to be flat and flush, to seal against the inside of the top, removable cover. Any vacuum leaks severely reduces suction power 100' away at the wand or rotary extraction machine. Adhesive backed, 3/16- 1/4" thick, by 1.25 or 1.5 width closed cell neoprene foam works well and is comparable to OEM. McMaster -Carr has this.
Use rubber u-shaped edge protectors on the inner baffle edges to bring those edges uP to flush (and NOT ABOVE) the outer tank edge.

I forgot to mention in prior post, that the bottom 6-12" of the tank outside and mounting tabs is sanded, etched, then brush coated with Damon Overcoat-a hard one part epoxy that has held up well in service, compared to the poor performance of OEM powdercoating.

[Portable Welder]

I did not ask about the brand, They just brought me the tank, they wanted 5K for a new tank, this tank has 2 tops covering with the neoprene u- edging, I told the customer I would do it for 4,000, thanks for letting me know about the epoxy coating, I will sand blast the inside of the tank and epoxy coat it, it will be hard to get it every where however.

[Tryagn5]

I did not ask about the brand, They just brought me the tank, they wanted 5K for a new tank, this tank has 2 tops covering with the neoprene u- edging, I told the customer I would do it for 4,000, thanks for letting me know about the epoxy coating, I will sand blast the inside of the tank and epoxy coat it, it will be hard to get it every where however.

Why not build the tank out of stainless steel? I would not coat the tank with anything which could peel and destroy the vaccum pump. Unless the tank is strickly waste, which gravity feeds out.
Kevin

[Portable Welder]

This is the waste water tank, the fresh water tanks dont have the chemicals, so they dont go bad from what I understand.

The customer doesnt want to pay the extra for stainless.

I'm building the new tank out of 1/4" 6061 verses the 3/16" that lasted 6 years.

[Tryagn5]

This is the waste water tank, the fresh water tanks dont have the chemicals, so they dont go bad from what I understand.

The customer doesnt want to pay the extra for stainless.

I'm building the new tank out of 1/4" 6061 verses the 3/16" that lasted 6 years.

Well i was wondering how the waste water is drained? Ie pump or gravity. How foolish the customer is to pass on stainless, this is exactly where it shines, also would be easier to bend to elimate welds where possible. 1/8 ss in 304 would outlast the machine.
Kevin

[Portable Welder]

Tryagn5, I cant disagree with you but he had a couple other quotes which were for aluminum, so he wanted to stick with aluminum.

[dave powelson]

waste tank vacuum pump?

Why not build the tank out of stainless steel? I would not coat the tank with anything which could peel and destroy the vaccum pump. Unless the tank is strickly waste, which gravity feeds out.
Kevin

Failed coatings and mis. tank debris, including corrosion chunks of the tank wall can't get thru the baffling and filtration system.

The vacuum pump is a indu$trial, CI, engine driven, lobed, $upercharger. The vacuum inlet at the tank is baffled, etc. It draws thru a series of HD filters. In use, these pumps rarely fail before the engine wears out….unless the auto shutoff for max. tank fill level has failed.

Tanks see all manner of sand, dirt, debris scouring the inlet fittings, etc.--Whatever's in the carpet--ends up in that tank. A good share of tank pitting is metal electrolysis from metal debris being sucked up, then added to an ungodly, hot soup, alkaline cleaners, human, animal and bacterial waste. Take a sniff inside a waste tank-but only on an empty stomach.
Biggest single item in tank life is draining and washing it out very frequently, more than just once a day and especially as the last item of the day. Many to most operators cannot be trained or bothered to do routine maintenance on the equipment arrays in this industry. A decent power unit starts around $25K, a min. of wands, hoses, extraction machine, etc.--sees at least $35K spent; not including the truck/trailer/etc.

A few, but not many, owner operators actually give a ****--since it directly impacts their wallet.

[Tryagn5]

Failed coatings and mis. tank debris, including corrosion chunks of the tank wall can't get thru the baffling and filtration system.

The vacuum pump is a indu$trial, CI, engine driven, lobed, $upercharger. The vacuum inlet at the tank is baffled, etc. It draws thru a series of HD filters. In use, these pumps rarely fail before the engine wears out….unless the auto shutoff for max. tank fill level has failed.

Tanks see all manner of sand, dirt, debris scouring the inlet fittings, etc.--Whatever's in the carpet--ends up in that tank. A good share of tank pitting is metal electrolysis from metal debris being sucked up, then added to an ungodly, hot soup, alkaline cleaners, human, animal and bacterial waste. Take a sniff inside a waste tank-but only on an empty stomach.
Biggest single item in tank life is draining and washing it out very frequently, more than just once a day and especially as the last item of the day. Many to most operators cannot be trained or bothered to do routine maintenance on the equipment arrays in this industry. A decent power unit starts around $25K, a min. of wands, hoses, extraction machine, etc.--sees at least $35K spent; not including the truck/trailer/etc.

A few, but not many, owner operators actually give a ****--since it directly impacts their wallet.

I understand all of that. I also work on vac trucks which dry excavate holes and collect waste bore mud. These trucks can be
Quarther to million dollers machines. Now all vaccum systems have filters for incoming debris, now external debris is different. Espically coating which come off in sheets and really like to clogged intake pipes. Putting any coating espically on aluminum with varying chemicals would make me very nervous.
Kevin

[Portable Welder]

The factory tank was 3/16" wall so I'm rebuilding it with 1/4" since thats what I have in the rack.

The owner who I'm dealing with has approximately 8-10 trucks on the road and has been in the business since 1988 so he is no dummy.

He did not indicate that tanks leaking have been a problem in the past and did not know this was leaking until he started switching it to a new van

The sticker on the tank says Cleanco Compact. They drive the pump off a PTO from the van motor.

The inside of the tank does not appear to ever had a coating and the out side appears to be powder coated.

If I do coat the inside and it fails we will have chemicals trapped between the the bare aluminum and the coating causing excessive corrosion.

should I coat it or leave it bare.

[Tryagn5]

The factory tank was 3/16" wall so I'm rebuilding it with 1/4" since thats what I have in the rack.

The owner who I'm dealing with has approximately 8-10 trucks on the road and has been in the business since 1988 so he is no dummy.

He did not indicate that tanks leaking have been a problem in the past and did not know this was leaking until he started switching it to a new van

The sticker on the tank says Cleanco Compact. They drive the pump off a PTO from the van motor.

The inside of the tank does not appear to ever had a coating and the out side appears to be powder coated.

If I do coat the inside and it fails we will have chemicals trapped between the the bare aluminum and the coating causing excessive corrosion.

should I coat it or leave it bare.

Bare! Chemicals change in cleaning formules, also when they get mixed who knows. Why chance it? Anyhow...seems like you will be good at tank building. Might need the work in say 8 years or so.....