Electro cleaning stainless tig welds
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- Опубликовано: 9 фев 2025
- When stainless is welded, it often discolours at the weld. Not only is it good to remove this 'scale', or discolouration, for cosmetic reasons; it also may help to prevent corrosion.
For years the only ways I knew of to clean the welds was with abrasives, or by applying a strong pickling acid.... normally in the form of a paste. This paste would typically sit on the weld for half an hour, then you'd use water and a scouring pad or stainless wire brush to remove it.
The traditional pickling paste is a relatively dangerous substance, and the disposal of the rinse water and waste acid is a problem.
Chemicals used as the electrolyte for electro-cleaning can be relatively benign. The liquid featured in this video is a commercial product designed to inhibit rust. I understand that it contains phosphoric acid and another organic chemical which is not essential to the cleaning process (and may even hinder it). So while the results I'm currently getting are good enough for now, I intend experimenting with other chemicals. There are commercially produced weld-cleaning electrolytes that appear to work very well.
I have seen references to citric acid and phosphoric acid as major ingredients for this process. Pure forms of both these substances are sometimes used in food products.
In this video I'm using a 12 volt battery charger as a DC power source. I've also used my TIG welder set on low amps to do the job, and I think it works faster...although sometimes small arcs from the brush will mark the stainless. I've made an adapter for the brush which clamps on to the TIG electrode. I tried using some old, small DC chargers that I had laying around but I burned them out. The battery charger shown in the video 'grunts' a bit when the brush is applied to the metal, but it is still working after quite a few test runs.
With what I know of electroplating and electrolysis, I have assumed that this electro-cleaning will only work with a DC current. However I have read that a low voltage AC source will also work. I am yet to try this. As far as I know, it appears that the voltage to use for the job can typically be anywhere between five and thirty volts. If I were to choose an ideal power source, I'd like one that could happily provide 20 amps, although less will still give results. It may be a good idea to include some sort of resistance like a light bulb wired in series to the circuit to help restrict the current in some circumstances.
The brush is made from carbon fibre. I purchased a small amount of carbon fibre cloth for just a few dollars through AliExpress. The fibres are bound to a bit of 4mm stainless steel rod... the same way that old brooms were made. I used thin polyester thread for the binding on this particular brush, but I've also had success with monofilament fishing nylon.
I've also made a 'brush' by binding strips of scouring pad to the end of a metal bar. This certainly works, but I found that it is easy to get an arc travelling through the pad, and the pad melts or falls to bits easily.
Sturdy rubber gloves and safety glasses should be worn when doing this kind of work.
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Thanks for showing this!
Hi please can you make video how to made a brush and which chemical exately you have been used...
Sorry... haven't got the time to make a video. I bought some carbon fibre cloth from Aliexpress. It looks a bit like fibreglass cloth... but it is black and conducts electricity. I just wound some of the cloth around the end of a stainless rod and bound it in place with cord. I am not a chemist and there will be people who know a lot more than me about chemicals used for cleaning stainless welds. Phosphoric acid, I believe, is the chemical which does the work. There may be other, even better ingredients. I used a commercially made 'rust-kill' product containing phosphoric acid which I bought from an industrial paint shop. If you make enquiries in your part of the world and read the ingredients statement on anti-rust products, you are likely to find something. I would personally select a product that contained as few ingredients as possible beside the phosphoric acid. Unfortunately I don't even recall the name of the product I used. You may be able to buy straight phosphoric acid. There are commercially made electro- passivating machines and chemical products are specifically made for this process. If you have a commercial business and have to be efficient and comply with safety rules, it may be prudent to look at commercially available systems. Best wishes.
Hi! thanks for the video. Where do you recommend getting the brush? Is that just carbon fiber bristles?
Hi Eric. I bought a strip of carbon fiber cloth from either AliExpress or Ebay (can't recall). I then bound some of those fibers on to the stainless rod 'handle'. The carbon cloth was relatively cheap. Best wishes.
Eric, click on SHOW MORE in the description...
The brush is made from carbon fibre. I purchased a small amount of carbon fibre cloth for just a few dollars through AliExpress. The fibres are bound to a bit of 4mm stainless steel rod... the same way that old brooms were made. I used thin polyester thread for the binding on this particular brush, but I've also had success with monofilament fishing nylon.
that the material is from the brush?
I'm not sure that I understand what you are asking Alex. The brush is made from carbon fibre. I purchased a small amount of carbon fibre cloth for just a few dollars through AliExpress. The fibres are bound to a bit of 4mm stainless steel rod... the same way that old brooms were made. I used thin polyester thread for the binding on this particular brush, but I've also had success with monofilament fishing nylon. I hope this helps... best wishes.
@@StephenCooteNZ The brush is made from carbon fibre.
give me a link
or write the exact material
@@StephenCooteNZ
or write the exact material
@@alexman8528 Here is a link: www.aliexpress.com/item/4000640621315.html?spm=a2g0o.productlist.0.0.1dee179836fwmL&algo_pvid=f9c11b89-c616-4cba-9f0d-985fc5b173e9&algo_expid=f9c11b89-c616-4cba-9f0d-985fc5b173e9-14&btsid=0ab6fa7b15944163072565030e6e60&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_ If the link doesn't work, go to Aliexpress.com and in the search box type 'carbon fiber cloth'
In this process, is hexavalent chromium particles leached off from that surface? (i have no occupational experience with this and am a random civilian)
Sorry, I don't know the answer to that.
Which chemical using for cleaning welding
Mild phosphoric acid. Best wishes.
@@StephenCooteNZ after welding cleaning will it remove acid toxic?
@@abdulmatinabdulkhalique985 I don't think phosphoric acid is particularly toxic, but I always wear rubber gloves when using it. After applying the acid to the welds I wash my welds, my brush and my gloves in cold water. I'm not an expert, but I think that the chromium in the stainless steel alloy is probably the most toxic substance.... and I think that it is the chromium which sometimes makes the acid wash a green colour. I was using this electro method for cleaning my welds when I thought that store-bought pickling paste was going to be hard to find. But I did find some and I am using that now. I use baking soda to neutralise the acid before washing it off the weld. No matter what acid I use for cleaning welds, I often use a stainless wire brush and/or abrasive paper to clean the finished work completely.
@@StephenCooteNZ thanks for sharing your experience sir
@@abdulmatinabdulkhalique985 you are welcome !! I did a lot of TIG welding on stainless steel when I was a maintenance engineer in a fish processing factory. Now most of my stainless welding is done to create bases and frames for the glass artwork that my wife makes.
Como hago el liquido q usa
El líquido contiene ácido fosfórico. Compré una lata de líquido inhibidor de óxido en una tienda de suministros para automóviles. Use guantes y gafas de seguridad cuando manipule este ácido. Los mejores deseos...