I recently built 8 horse jump standards for our Grandaughters as well as four more standards for use at our place.
The lady who boards her horses here gave me a bucket full of old jump cups for the standards. This was a nice gift as I have fabricated the cups in the past and it is time consuming.
The jump cups were rusty from being stored in a damp location plus they had peeling paint. The maker had painted over the mill scale that hot rolled steel comes with. I used to do that until an engineer explained that mill scale must be removed or the paint will simply flake off slowly along with the mill scale.
The most common way to remove mill scale is by sand blasting.
Unfortunately I do not have a sand blast cabinet in the shop. I've often considered buying one but would want one that is large enough for complete motorcycle frames. That gets expensive plus a big cabinet would take up a lot of room in the shop, which is pretty full of machinery now.
In the past I have rented time on sandblast units at place called Ublast.
They charge $80 per hour for you to use their sandblast cabinet. It's expensive, but they do have cabinets large enough to take a motorcycle frame. I did three there one day just prior to covid.
It is a very tedious job and expensive at $80 per hour!
The owner encouraged me to buy a time card. Each machine records the time so this way he could go for coffee at a coffee shop nearby and still be making $80 per machine (5 machines) while the customers toil away.
That was how it seemed to work as he said the prepaid time was for our convenience, but it seemed perhaps it was more for his convenience!
Anyway, I recalled that I had about $80 of sandblast time remaining on my prepaid amount and that might just about be enough to get the jump cups done.
I called to make sure of the amount and learned that the business had been sold and the new owner " purged" all of the prepaid time amounts. Stolen might be a better word!
The new owner encouraged me to purchase a new prepaid time amount.
Screw that I'll chip the rust off with my teeth rather than give them any more money.
I did some reading and dipping in diluted muriatic acid seemed worth a try. I had a gallon on hand from some long ago concrete job so that went into a 5 gallon plastic pail along with the jump cups and a couple of gallons of water, just enough to cover.
The article I read on this method suggested leaving the items submerged for 24 to 36 hours.
I did not take before photos but the before condition of the jump cups was about like these-
The muriatic did a great job but quite a bit of mill scale remained, although the muriatic had really loosened it up.
Here are some of the cups after the muriatic bath
The lady who boards her horses here gave me a bucket full of old jump cups for the standards. This was a nice gift as I have fabricated the cups in the past and it is time consuming.
The jump cups were rusty from being stored in a damp location plus they had peeling paint. The maker had painted over the mill scale that hot rolled steel comes with. I used to do that until an engineer explained that mill scale must be removed or the paint will simply flake off slowly along with the mill scale.
The most common way to remove mill scale is by sand blasting.
Unfortunately I do not have a sand blast cabinet in the shop. I've often considered buying one but would want one that is large enough for complete motorcycle frames. That gets expensive plus a big cabinet would take up a lot of room in the shop, which is pretty full of machinery now.
In the past I have rented time on sandblast units at place called Ublast.
They charge $80 per hour for you to use their sandblast cabinet. It's expensive, but they do have cabinets large enough to take a motorcycle frame. I did three there one day just prior to covid.
It is a very tedious job and expensive at $80 per hour!
The owner encouraged me to buy a time card. Each machine records the time so this way he could go for coffee at a coffee shop nearby and still be making $80 per machine (5 machines) while the customers toil away.
That was how it seemed to work as he said the prepaid time was for our convenience, but it seemed perhaps it was more for his convenience!
Anyway, I recalled that I had about $80 of sandblast time remaining on my prepaid amount and that might just about be enough to get the jump cups done.
I called to make sure of the amount and learned that the business had been sold and the new owner " purged" all of the prepaid time amounts. Stolen might be a better word!
The new owner encouraged me to purchase a new prepaid time amount.
Screw that I'll chip the rust off with my teeth rather than give them any more money.
I did some reading and dipping in diluted muriatic acid seemed worth a try. I had a gallon on hand from some long ago concrete job so that went into a 5 gallon plastic pail along with the jump cups and a couple of gallons of water, just enough to cover.
The article I read on this method suggested leaving the items submerged for 24 to 36 hours.
I did not take before photos but the before condition of the jump cups was about like these-
The muriatic did a great job but quite a bit of mill scale remained, although the muriatic had really loosened it up.
Here are some of the cups after the muriatic bath
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