OP
tmassey
Contributor
Just thought I’d update this thread with additional results. I’ve learned new lessons and wanted to share.
I cleaned four different tanks after hydro. I used the flash rust mixture: 1/3 cup filled to 1 gallon total. This volume of fluid filled a single tank up to near the opening when they were on their side. This was true for both LP75’s and HP120’s: even the larger tanks were mostly filled. I mixed up two gallons and did two tanks at a time.
I simply placed the tanks on their side and rotated them 1/8 of a turn every 2 minutes. I then followed the rinse and dry procedure outlined above.
Looking at them after pouring the solution out showed dark grey steel with a little sheen of orange. The solution was barely grey. After drying them, the steel was light grey, with a bit more orange. I’m not sure if the orange was more noticeable after drying, or if they rusted a bit during the dry process. I suspect the former: I’ve used this rinse and drying process before with less resulting orange.
I suspect that the issue might be the strength of the solution or the amount of dwell time. This is the first time I’ve used the “flash rust” solution. I think it’s too weak for great/fast results. As a comparison, I reused the solution for the second set of tanks and got a similar result (improved but not pristine), so I don’t think the acid was exhausted, just maybe not done yet.
Looking back over my previous notes, I did more like 30 minutes of dwell instead of the 16 I did today. And the original source of this process suggests 30-60 minutes of tumbling. Plus my previous attempt used a stronger mixture. So it’s probably not reasonable to expect the same results!
These are my personal tanks and they look better than any tank I’ve ever had straight from hydro, so I will use them as they are. In the future, though, I think I’ll step up to the mildly-rusty mix. I don’t have a tumbler, and babysitting these to rotate them every few minutes is annoying. I’d rather use a touch more acid and (hopefully) get better results without taking more time. But next time I’ll check them after 15 minutes and if I see a bit of orange I’ll know they’ll need more time. Patience is a virtue.
Also, some specifics on the drying process: I didn’t time it, but I found that it took 300 PSI of drying air (from an LP72) to go from warm, moist air to cool air. The tank was still warm at that point. I kept drying until the tank was not actively warm, which was another 100 PSI. My wild guess is that the air drying took between 2 and 3 minutes total.
I cleaned four different tanks after hydro. I used the flash rust mixture: 1/3 cup filled to 1 gallon total. This volume of fluid filled a single tank up to near the opening when they were on their side. This was true for both LP75’s and HP120’s: even the larger tanks were mostly filled. I mixed up two gallons and did two tanks at a time.
I simply placed the tanks on their side and rotated them 1/8 of a turn every 2 minutes. I then followed the rinse and dry procedure outlined above.
Looking at them after pouring the solution out showed dark grey steel with a little sheen of orange. The solution was barely grey. After drying them, the steel was light grey, with a bit more orange. I’m not sure if the orange was more noticeable after drying, or if they rusted a bit during the dry process. I suspect the former: I’ve used this rinse and drying process before with less resulting orange.
I suspect that the issue might be the strength of the solution or the amount of dwell time. This is the first time I’ve used the “flash rust” solution. I think it’s too weak for great/fast results. As a comparison, I reused the solution for the second set of tanks and got a similar result (improved but not pristine), so I don’t think the acid was exhausted, just maybe not done yet.
Looking back over my previous notes, I did more like 30 minutes of dwell instead of the 16 I did today. And the original source of this process suggests 30-60 minutes of tumbling. Plus my previous attempt used a stronger mixture. So it’s probably not reasonable to expect the same results!
These are my personal tanks and they look better than any tank I’ve ever had straight from hydro, so I will use them as they are. In the future, though, I think I’ll step up to the mildly-rusty mix. I don’t have a tumbler, and babysitting these to rotate them every few minutes is annoying. I’d rather use a touch more acid and (hopefully) get better results without taking more time. But next time I’ll check them after 15 minutes and if I see a bit of orange I’ll know they’ll need more time. Patience is a virtue.
Also, some specifics on the drying process: I didn’t time it, but I found that it took 300 PSI of drying air (from an LP72) to go from warm, moist air to cool air. The tank was still warm at that point. I kept drying until the tank was not actively warm, which was another 100 PSI. My wild guess is that the air drying took between 2 and 3 minutes total.
