MadModder
The Shop => Metal Stuff => Topic started by: John Stevenson on May 27, 2013, 06:38:30 AM
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As many may know I make a lot of special dividing plates, these are made from laser cut blanks usually out of a material called A36 which is a hot rolled steel plate that has a thick oxide layer on it.
There is an alternative material called HRPO which stands for Hot rolled picked oiled, basically A36 but cleaned up, costs more and not every company uses it of has it in the stock you want. They like A36 because the oxide layer stops reflection and also stops any dross sticking the the top surface.
Problem with A36 is the thick oxide coat destroys the tips on drills in a heartbeat, OK for the odd hole and if you heavily centre punch that also helps but many thousands of holes on a CNC is asking for a broken drill, especially in under 3mm sizes.
So what's special about HRPO ? Basically it's been through a commercial picking process, so if we can replicate this it helps with laser cut frames, angle iron and anything that needs to be finished, paint sticks the HRPO better than A36.
Picture of a plate straight from the laser cutters.
(http://www.stevenson-engineers.co.uk/files/descale1.jpg) Also in the picture is a piece of bronze and a piece of copper to see how these perform. I'll say at this point the process didn't do much for them.
A tub was prepared out of an old plastic 5 gallon suds container by cutting the side out and a 'plate rack' cut on the laser to hold 20 plates which really only applies to me.
(http://www.stevenson-engineers.co.uk/files/descale2.jpg)
The solution used is Cementone Brick and Patio cleaner which is basically a weak hydrochloric acid. Don't buy any cleaner that says GREEN on it, that's just basically soapy water.
I mix this 1:1 with water and in my case it takes 10 litres of solution.
I put these in the tub last night at about 7:00pm and just been out 10:30 am following day and they are all clean and de-scaled, just need a rinse and a wipe with oil.
(http://www.stevenson-engineers.co.uk/files/descale3.jpg)
(http://www.stevenson-engineers.co.uk/files/descale4.jpg)
Even cleans the 'burnt' laser cut edge up.
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John -- A36 is more properly designated ASTM A36 steel. All that means is that this is a steel with between 0.15% and 0.22% carbon content that has a minimum yield strength of 36,000 psi. Without that designator, it is Merchant Stock or Merchant Grade Steel that can have a minimum yield strength as low as 22,000 psi. You can often save some sheckles by using the MS designation in your order if the lower yield strength is acceptable (and it is usually much closer to 36,000 psi).
Muriatic acid (weak hydrochloric acid) works quite well for descaling operations. My local steel yard calls me whenever they have n X 6 inch "drops" lying about. I can pick them up for $0.50/lb rather than the usual $0.90/lb for non-"drops." I set them on pieces of ø1/2 inch plastic (usually ABS or acetal) "tips" left over from longer stock in various sized plastic tubs (I even have an 8 ft long tub scrounged from a siding container at a building site). I cover the pieces to (about) 1/4 inch deep of muriatic acid in such tubs and the scale dissolves within 15 minutes (that after having reused the muriatic acid several times). I rinse them off with a soda-water (call it 1 lb to 5 gallons of water) mixture and dry them. I dress the faces (i.e. 1 inch nominal thick becomes .95 inches thick and .5 inch nominal thick becomes .45 inches thick, etc.), wax them down, and store them in my rack for use in various things I make.
One thing that is really handy if you do this is an all-plastic suction-pump (they go on sale for less than $5 regularly at Harbor Freight) to suck up the muriatic acid when the task is complete. This makes it simple to put the acid back in the bottles. I can usually get 5-7 "reuses" before the acid no longer works effectively.
Doing this en masse means that I have nice clean & bright steel in my rack when a project crops up...
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White vinegar is my choice, fairly safe, flush-able, Cheap to purchase and grand on Chips,
:lol:
Potato type not metal.
:)
Regards to all.
Trev
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I've banged on about this before but here we go again.....
Citric Acid - removes rust, scale and leaves a nice clean surface and is safe enough to put your hands in (cuts sting though!) and it can be disposed of down the drain when finished. Cheap as chips in powder form on eBay
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I've banged on about this before but here we go again.....
So, I bought some. From Ebay.... http://www.ebay.co.uk/itm/270958120373?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
Didn't need it, at that moment. So, I chucked some in the teapot....... Nowt happened! :palm:
So, it's in Mrs. Drillin's kitchen cupboard. Waiting to come in useful, mebbe! :scratch:
David D
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Lew, If you dress them up why do you bother to descale ?
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Didn't need it, at that moment. So, I chucked some in the teapot....... Nowt happened! :palm:
David D
Bio detergent refurtigrates teapots most splendidly.. :thumbup:
Does nowt for silver solder flux though ..
Just a thought ..
Dave BC
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I've banged on about this before but here we go again.....
So, I bought some. From Ebay.... http://www.ebay.co.uk/itm/270958120373?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
Didn't need it, at that moment. So, I chucked some in the teapot....... Nowt happened! :palm:
So, it's in Mrs. Drillin's kitchen cupboard. Waiting to come in useful, mebbe! :scratch:
David D
Presumably it's the tannin you are trying to remove from a tea pot? Dish washer tablets work a treat. If it was a kettle with lime scale then use citric acid. Horses for courses !
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Dave.
A friend of mine advised washing powder, in the kettle. I had to buy a new one! The plastic had absorbed the smell/ taste of the powder. :bang: :bang:
It made a good steam water kettle..... :thumbup:
Andy.
Ah! limescale. Yes! :Doh:
The only dishwasher Mrs. Drillin has, is me........ And I don't use tablets for that job! :)
Thanks for the advice Fellas!
David D
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Ah yes, should have said stainless steel or ceramic teapot.
But then I don't brew much tea in the kettle ... :coffee:
My plastic kettles never seem to need de-scaling ... they snuff it long before then ...
Dave BC
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My plastic kettles never seem to need de-scaling ... they snuff it long before then ...
Dave BC
You have the gas ring set too high then :D
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Lew, If you dress them up why do you bother to descale ?
John -- So I don't ruin cutters on hard scale! Descaling makes my fly-cutter tip last more than 3X what no descaling does.
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My plastic kettles never seem to need de-scaling ... they snuff it long before then ...
Dave BC
You have the gas ring set too high then :D
You don't know how near the truth you are :lol: :lol: :lol:
For 'gas ring' read 'propane torch'. :Doh:
Dave BC
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I've banged on about this before but here we go again.....
So, I bought some. From Ebay.... http://www.ebay.co.uk/itm/270958120373?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
Didn't need it, at that moment. So, I chucked some in the teapot....... Nowt happened! :palm:
So, it's in Mrs. Drillin's kitchen cupboard. Waiting to come in useful, mebbe! :scratch:
David D
David D
If you are talking about an electric tea kettle (plastic), I just throw in a couple of cups of white vinegar and bring it to a boil. That usually cracks off all the lime scale from the elements. Sometimes I just let it cool and boil it a second time if the first go-round didn't get it all. Dump that then boil a couple of kettles full of water and you are good to go. Shiny kettle, heats quicker, jobs done. :D :D
Cheers :beer:
Don
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Don.
It's a very long running saga, ........ :doh:
No.1 Son, started work as an Industrial Chemist/ Quantitative Analyst, (or something).
Brought home some "citric acid" for mum's teapot. Whatever it was, it worked!
It also worked in the kettle. Mum was delighted!
Somehow, over the many years, and kettles, and teapots, we forgot what cleaned what. :palm:
This evening, I've cleaned the stainless teapot. With a good dollop of Persil washing powder, and hot water.
Herself refused to drink the suppertime cuppa. "It tastes of powder". (It did an all!).
Soo..... The sparkling teapot is soaking overnight, in a strong mix of citric acid.......... :thumbup:
I just hope it is tasteless, before breakfast time....... :(
David D
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Gordon friggin' Bennet !!!!!!!!!!!!!!!!!!!!!! What a saga. The Norsemen had nowt on you. :lol:
1 dessert spoon of detergent.
Top up pot with boiling water.
Leave to fester for a couple of hours.
Empty pot.
Stick under running cold tap.
Leave to fester for a couple of hours.
Empty pot.
Brew.
Done it many times.
Does not taste of detergent.
Q.E.D
Dave BC
PS Why not drink Lemon Tea ?? Built in citric acid :thumbup:
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Don.
It's a very long running saga, ........ :doh:
No.1 Son, started work as an Industrial Chemist/ Quantitative Analyst, (or something).
Brought home some "citric acid" for mum's teapot. Whatever it was, it worked!
It also worked in the kettle. Mum was delighted!
Somehow, over the many years, and kettles, and teapots, we forgot what cleaned what. :palm:
This evening, I've cleaned the stainless teapot. With a good dollop of Persil washing powder, and hot water.
Herself refused to drink the suppertime cuppa. "It tastes of powder". (It did an all!).
Soo..... The sparkling teapot is soaking overnight, in a strong mix of citric acid.......... :thumbup:
I just hope it is tasteless, before breakfast time....... :(
David D
David D
OK, now I think I understand. :scratch: :scratch:
Cheers :beer:
Don
PS: I think Bluechip might have the right idea.
Don
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Dave, Don.
Yes, it does taste of detergent. Even after several rinses and boilings....... :bang: :bang:
We'll see what tomorrow brings. :palm:
David D
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Dave, Don.
Yes, it does taste of detergent. Even after several rinses and boilings....... :bang: :bang:
We'll see what tomorrow brings. :palm:
David D
Must be powerful Persil in Chesterfield. ?? I use Sainsbury's el-cheapo ...
Put it under a tap, just running fairly slow. That's all I do, never had it still have detergent taste left in it.
I am willing to loan my pressure washer out for a modest sum .... :)
BC
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My wife uses about a cup of white vinegar, (weak acetic acid) than fills kettle and set it to boil. Couple of rinses and presto, Clean kettle.
Cheers all.
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After a good rinsing out, we've just had a crackin' breakfast cuppa! :thumbup:
The problem, is a build up of tannin, between the body of the pot, and the tapered spout. Below the holes.
I used to take it to work, "annually", and give it a good blast out with the 110psi airline. Been retired for 7yrs now........
I'll invest in a small pack of dishwasher tabs. Guess they don't taste of wash powder! :lol:
David D
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My wife uses about a cup of white vinegar, (weak acetic acid) than fills kettle and set it to boil. Couple of rinses and presto, Clean kettle.
Cheers all.
I've found that leaving 500mls of lemon juice overnight in the kettle leaves it sparkling clean (the bottom anyway), Don't boil it without watching it like a hawk, it has the tendency to froth up and over flow your kitchen worktop. Works very well for thermos flasks too.
Also if it leaves a taste, at least it is not a foul one :thumbup:
Tim
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And guess what lemon juice is primarily - yes you guessed - Citric Acid :beer: