- Thread starter Trelawny
- Start date
- Messages
- 13,538
- Location
- England
How long is a piece of string.
Theres loads of methods, depending on the state when starting, the finished product uses, the level of finish required, decorative or practical....
Generally, it will be an adbrasive disc or wheel, or an acid wash, known as pickling.
Give us an example or two of what you have in mind?
Theres loads of methods, depending on the state when starting, the finished product uses, the level of finish required, decorative or practical....
Generally, it will be an adbrasive disc or wheel, or an acid wash, known as pickling.
Give us an example or two of what you have in mind?
- Messages
- 13,538
- Location
- England
It will mainly be polished stuff then. If its grained or bright finish stuff, and you make a tidy job of welding it, a lick over with a strip and clean disc will smooth slightly and remove any colour/oxidisation. The downside, is that won't get into tight spaces, so an acid wash may be a useful addition
If you want to totally polish welds out you would be onto flap pads and/or flap wheels, then onto a scotchbrite surface conditioning disc, then onto a wheel to get the polish in the correct direction.
For a brighter satin polished finish, you would need to follow up with perhaps a fine scotchbrite wheel, and then onto a cotton wheel and soap for a bright to mirror finish.
One of the hardest parts is usually getting the polished bits to match the factory polish on the material.
If you want to totally polish welds out you would be onto flap pads and/or flap wheels, then onto a scotchbrite surface conditioning disc, then onto a wheel to get the polish in the correct direction.
For a brighter satin polished finish, you would need to follow up with perhaps a fine scotchbrite wheel, and then onto a cotton wheel and soap for a bright to mirror finish.
One of the hardest parts is usually getting the polished bits to match the factory polish on the material.
norlander
Member
- Messages
- 3,389
- Location
- Europe, mocycling paradise
I wipe it over with acetone before welding and scrub the weld with a stainless steel wire brush immediately after welding as according to Mr TIG (on t'internet) its easier then- if you leave the welds and clean them later on its harder work-seems to work for me.
KemppiFrog
Member
- Messages
- 4,298
- Location
- Aquitaine
Not heard of the acetone wash before. I will give it a try, but I usually pickle it for an hour with an acid mix.That leaves a light matt finish, then some compound on a cotton wheel. I prefere the brush look as it is less trouble. (=lazy)
Tiggy_dorset
It looks just like a bought one!
- Messages
- 1,970
- Location
- Weymouth, Dorset, UK
What is the mix that you use?
KemppiFrog
Member
- Messages
- 4,298
- Location
- Aquitaine
Just looked at the flask: 4% Hydroflourique, 20% nitric acid. Not sure about the rest, there is a thickening agent so it doesn't flow off so easily.
Wurth sell a good one too.
backpurge
Member
- Messages
- 2,397
There seems to be a bit of a tendency for people to go completely over the top with regard pre cleaning stainless steel material before welding it, never did it myself when I was on the tools and am struggling to remember ever seeing anyone else do it either.
So long as the material has been correctly stored and hasn't been allowed to become contaminated with any foreign matter I cannot see any benefit, post weld treatment to remove surface metallic oxides is another matter of course
So long as the material has been correctly stored and hasn't been allowed to become contaminated with any foreign matter I cannot see any benefit, post weld treatment to remove surface metallic oxides is another matter of course
been told to use baby oil to remove handling marks,over the years using this material i become more confused at the name ,thinking STAINMORE is more appropriate as its so vulnerable to knocks,abrasions etc unlike m/steel which seems more resilient.Architects -don't they just love specifying it.
waldershelf
Member
- Messages
- 547
When I used to work in the steel industry we made stainless steel plates, big ones, an inch thick and 15 feet wide. The machines we used to polish the sheets used "scotchbrite" pads.
KemppiFrog
Member
- Messages
- 4,298
- Location
- Aquitaine
Come in 60mm diam X 60 long.
norlander
Member
- Messages
- 3,389
- Location
- Europe, mocycling paradise
should have mentioned Sometimes use a scotchbright to shift any coatings (I only use small amounts of stainless so I source it from a diy shed and its usually protected by a plastic film) but I then wipe over with acetone to shift any possible residue from the scotty.
I don't get too anorak over it-just that I noticed a difference when prepping like that.
Kemppi -I noticed my supermarché sells small packs of citric acid powder, and larger packs are sold in my local Leroy Merlin-not sure if your locals will do the same.
Not really done anything with citric acid myself but saw chunkolini uses it quite a lot- so mentioned for info in case its of use to you.
I don't get too anorak over it-just that I noticed a difference when prepping like that.
Kemppi -I noticed my supermarché sells small packs of citric acid powder, and larger packs are sold in my local Leroy Merlin-not sure if your locals will do the same.
Not really done anything with citric acid myself but saw chunkolini uses it quite a lot- so mentioned for info in case its of use to you.
Lawnmowerboy
Member
- Messages
- 2,165
The only time we'll ever pre clean on new stainless is where the laser cut edged s have melted the glue on around the perimeter of where the laser has cut.
KemppiFrog
Member
- Messages
- 4,298
- Location
- Aquitaine
Thanks, we have a Leroy Merlin near La Rochelle. I haven't tried citric acid, I do quite a lot 'rusting' of steel for one client, so dump it in HydroChloric for the night, then leave it outside without rinsing.
Waiting on a SS railing job for the middle of the month. Balustrade for a balcony with a probable pool railing as well. Might get some citric and give it a go.
KF
Jan
Member
- Messages
- 884
- Location
- Rotherham, South Yorks
As a long time and bulk user of citric acid I'm surprised to see it being used in this context. For the best price on larger quantities it can be found in almost any home brew shop where it's used for a variety of purposes in brewing wines, beers & ciders. In packets of a kilo or so it comes in useful for other things in life:
- 250-500 grams added to the cooling system of a car can dissolve most blockages overnight and more if left in for a day or three while you drive around in it before flushing and replacing the old coolant with fresh (keep an eye on the coolant level as it can drop drastically if it opens up previously blocked waterways).
- A heaped teaspoon in a kettle will remove all the limescale that's built up inside it. Rinse 2 or 3 times afterwards to remove the residue.
- Old copper or brass ornaments can be brought back to 'as new' if soaked in a boiling solution for a while.
- Stains inside a toilet bowl will succumb to its tender embraces if you 'plunge' out all the water, drop in a heaped tablespoon and follow up with a kettle of freshly boiled water. Leave as log as possible and just flush as normal.
- Add to drinks or foodstuffs according to taste to add an extra tartness to them. Why not? It's on the list of ingredients on many of them already eg. crisps.
Citric is an alternative to nitric for passivating stainless. A lot of the small widgets and brackets i make for one of my customers i just hang in a bath of warm citric for an hour or so while i get on with something else. As long as the welds weren't dull grey/'burnt' they come out uniformly bright with no traces of heat tint and no scratches from brushing the colour off. Should be more corrosion resistant too
http://www.bssa.org.uk/topics.php?article=68
http://www.c3p.org/Workshop 2009/Pr...ky_Alternative to Nitric Acid Passivation.pdf
Proper pickling paste (typically nitric + hydrofluoric) is a lot faster and will eat heavy scale and any other nasties to leave the surface rich in chromium but needs handling with LOTS of respect.
There are also electrochemical passivation methods that that work very quickly and use more benign acid blends (phosphoric based or citric/acetic) but traditionally struggle with getting into nooks and crannies although there are switching from solid 'wands' to carbon filament brushes which has helped with the that. The machines aren't cheap but typically output around 4 - 500W at 20 - 30V with many using AC for cleaning and some DC...
What brackish water can do to stainless (don't know the grade but you'd hope it was 316L) that wasn't made properly... http://www.mig-welding.co.uk/forum/threads/crevice-corrosion.15360/
http://www.bssa.org.uk/topics.php?article=68
http://www.c3p.org/Workshop 2009/Pr...ky_Alternative to Nitric Acid Passivation.pdf
Proper pickling paste (typically nitric + hydrofluoric) is a lot faster and will eat heavy scale and any other nasties to leave the surface rich in chromium but needs handling with LOTS of respect.
There are also electrochemical passivation methods that that work very quickly and use more benign acid blends (phosphoric based or citric/acetic) but traditionally struggle with getting into nooks and crannies although there are switching from solid 'wands' to carbon filament brushes which has helped with the that. The machines aren't cheap but typically output around 4 - 500W at 20 - 30V with many using AC for cleaning and some DC...
What brackish water can do to stainless (don't know the grade but you'd hope it was 316L) that wasn't made properly... http://www.mig-welding.co.uk/forum/threads/crevice-corrosion.15360/
