Tool for small letters/designs

[adbuch]

Still waiting for tool recommendations j/k

To put my 2 cents in regarding acid baths, I have been using this method for about 6 mos now. What I have learned is it does not have to be a 50:50 ratio and matter of fact it is kind of a waste of acid and money to mix it that strong. I use approx a 1:3, 1:4 ratio using a large plastic tote (for now) I have had the same water in the tub the whole time and when I notice the parts are taking longer to clean I just dump some more acid. I also read it isn't necessary to neutralize the part after an acid bath because once rinsed there is no longer acid, Bill from Steel FX has a great post about this. I am kind of questioning this after reading this thread because after rinsing the steel I have to immediately dry it to keep it from getting a surface rust and a patina look.

Here is the thread with Bill's input
viewtopic.php?f=85&t=29703l

Also I have tried the vinegar bath, it took about 24 hrs to clean a piece that the acid does in 20-30 minutes.

Have a great week
Krystal

Krystal - with your 1:3 or 1:4 acid/water mix - how long do you typically soak your parts for complete removal of dross? By the way, I cleaned some bare metal on a 1932 Ford coupe body last year using muriatic acid/water mix. I rinsed after the cleaning with water and everything looked good. But when I came out the next day to take a look, everything had turned brown with surface rust. If I knew what I know now, I should have used baking soda or equivalent to neutralize the acid. Oh well!

By the way, if you would care to post some photos of the parts with the small letters/designs - I think we could probably give better advise on perhaps what tool or tools might be used for cleaning/deburring.

David

[djreiswig]

I'm not sure the baking soda will keep steel from surface rusting. When you acid wash, you're removing everything from the steel. The moisture in the air causes flash rust. You need to dry the steel and apply primer right away.

[adbuch]

I'm not sure the baking soda will keep steel from surface rusting. When you acid wash, you're removing everything from the steel. The moisture in the air causes flash rust. You need to dry the steel and apply primer right away.

Not necessarily true. I have acid washed bare metal with Dupont Metal Conditioner (acid based conditioner) and it has gone years with no visible surface rust. When I get ready to paint, I again wipe down the entire metal surface with the same metal conditioner right before applying my catalyzed sealer followed by paint. This is for auto body panels, not cnc plasma cut parts - but the same principle applies. But I agree that for the parts we are cutting - the best approach is as you have recommended.

David

The truck in the photo was "acid washed" probably over 10 years ago using the Dupont metal conditioner. It still looks the same now as it did a few years ago when this photo was taken. The acid formulation for the Dupont metal conditioner is much different than muriatic acid, and is not intended to dissolve dross. As I mentioned, I followed the same procedure using muriatic acid and it rusted very quickly.

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[djreiswig]

Found this. 2nd post has a lot of good info.
https://www.yesterdaystractors.com/cgi- ... d&th=62294
It appears the metal conditioner you speak of is phosphoric acid. It actually converts the rust to a phosphate. That's probably why your truck isn't rusting.

[adbuch]

Doug & Tom - I cut two of these this evening.

Nice Cut! your machine is cutting good.
Post up the one that you soak in acid overnight if you get a chance, as well of your impression of both methods.
And which cleanup method you prefer overall/pros/cons

Doug - I did soak my second part in acid "overnight" - it actually ending up being about 15 hours which was maybe too long. It cleaned off all the dross, but left the surface pretty etched with some pitting. I rinsed it with water right after I took it out of the acid and then dunked it in a second pan with the wash soda/water solution. Then dried it. It had sort of a sticky film coating on it which was hard to get off.

If this was to be a painted "yard art" piece, then I think it would have been fine and would save much effort using the wire cup/flap discs, d/a sander. But for a part I wanted to leave in bare metal with a clear coat - I was not all that happy with the result and much preferred to spend the extra time manually cleaning with wire cup/flap disc, d/a sander. I ended up cleaning it with lacquer thinner, then hit it with the d/a with 80 grit and then satin clear coat.

As has been suggested, perhaps I could use a weaker acid solution for a longer soak - and maybe forget the wash soda if I was going to paint it right away. I spent about $75 at Lowes on buckets, lids, tubs, and a 2 gallon pack of the muriatic acid. I have the acid/water in one of the sealed bucket for future use, an the wash soda/water solution in the other bucket.

David

This is what it looked like right after the acid soak.

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5 gallon buckets with sealed lids and pour spouts.

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Cleaning tubs.

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D/A sander and sanding paper.

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[adbuch]

Red letters on acid soaked part. Black letters on manually cleaned part. I used the "poor man's engraver" to label the sizes on these circle templates, then sprayed the stain clear coat over the top.

David

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[acourtjester]

David thanks for posting the results, very good side by side comparison very helpful for those looking at which method to use.
Side note the white buckets are food grade and cost about twice as the other buckets, ( at least that way at Home Depot )

[plasmanewbie]

Both parts look great to me. So what do yo think is better overall for time spent and quality edge and surface of the parts David? The acid or the manual prep?

[tinspark]

Red letters on acid soaked part. Black letters on manually cleaned part. I used the "poor man's engraver" to label the sizes on these circle templates,

Nice log of results. The red letter disc does show the pitting issue.
Thanks for the extra time spent to document the results!
what acid, water ratio will you try next?

LOL on the poor mans engraver comment (aka marking pens)

[adbuch]

David thanks for posting the results, very good side by side comparison very helpful for those looking at which method to use.
Side note the white buckets are food grade and cost about twice as the other buckets, ( at least that way at Home Depot )

Tom - I'm happy to post my results! I don't care for the plastic buckets with the Lowe's name on them, so I was happy to pay a few bucks more for the food grade, which also seem to be higher quality.

David

[adbuch]

Both parts look great to me. So what do yo think is better overall for time spent and quality edge and surface of the parts David? The acid or the manual prep?

Plasmanewbie - I spent more time on the acid cleaned part, with poorer surface quality for my intended purpose of leaving it in bare metal with satin clear coat. Most folks may not care, but in the past I've done quite a bit of "custom automotive painting/finishing" and have gotten sort of "picky" about my finish.

But if this was "yard art" and I was painting like I usually do, the acid would have been fine. I will probably do some tests to find out the optimum soak time to remove the dross but minimize the pitting. I'll keep you informed.

David

[adbuch]

Red letters on acid soaked part. Black letters on manually cleaned part. I used the "poor man's engraver" to label the sizes on these circle templates,

Nice log of results. The red letter disc does show the pitting issue.
Thanks for the extra time spent to document the results!
what acid, water ratio will you try next?

LOL on the poor mans engraver comment (aka marking pens)

Thanks Doug! I was using a 50/50 acid-water mixture. Perhaps I will try 1:2 or 1:3 acid to water ratio for my next batch. Or maybe use the same ratio I have now and reduce the soak time. I'll keep you posted.

David

[plasmanewbie]

Plasmanewbie - I spent more time on the acid cleaned part, with poorer surface quality for my intended purpose of leaving it in bare metal with satin clear coat. Most folks may not care, but in the past I've done quite a bit of "custom automotive painting/finishing" and have gotten sort of "picky" about my finish.

But if this was "yard art" and I was painting like I usually do, the acid would have been fine. I will probably do some tests to find out the optimum soak time to remove the dross but minimize the pitting. I'll keep you informed.

David

Gotcha, thanks David. A lot of what I cut is powdercoated so the surface from the acid bath is a big benefit for adhesion since it saves me from sandblasting them. For bare metal finish or coating I can see how the minor pitting may be undesirable.

[Splinters&Sparx]

Krystal - with your 1:3 or 1:4 acid/water mix - how long do you typically soak your parts for complete removal of dross? By the way, I cleaned some bare metal on a 1932 Ford coupe body last year using muriatic acid/water mix. I rinsed after the cleaning with water and everything looked good. But when I came out the next day to take a look, everything had turned brown with surface rust. If I knew what I know now, I should have used baking soda or equivalent to neutralize the acid. Oh well!

By the way, if you would care to post some photos of the parts with the small letters/designs - I think we could probably give better advise on perhaps what tool or tools might be used for cleaning/deburring.

David

That's a good question, I really don't get too much dross especially heavy dross, I typically soak for about 30-45 min. and the dross just chips right off. I did recently forget about a couple small pieces and left them soaking for about 24 hrs, they did have a couple areas with dross but it was very easy to remove. I will experiment with timing and ratios in the next couple weeks and update.
The pics I attached are examples of the small areas I would like to find a tool to help clean them up, these are signs that didn't work out for multiple reasons, I don't always have this issue but when it happens I would like to try and save the piece. The bottom one is stainless and of course due to using air always looks dirty so I would love to find something to clean that.

[DMoneyAllstar]

Depending on the concentration, 12-24hr will do the trick. Dross/slag will fall off with ease. Temperature swings can change the reaction time, IME. I've even seen some parts take on what looks like copper plating appearance. Also typically takes on a grey/black haze which will rinse off in the neutralizer solution (baking sode & water). If you over-etch it, the steel can get pitted / rough.

Fumes will choke you and will flash rust anything in its vicinity. Take precautions not just for you, but for your kids, dog, neighbor kids stray baseball, birds, etc. I left the lid off my small tote once and next morning two robins were lying in it dead. Prob instantly overcome by the fumes and "kerplunk."

I buy the Costco bags of baking soda. Dissolves faster in hot water. Make sure it's fully neutralized, or else it will drive your painter and customers crazy.

if you overlap parts, the acid will etch a shadow onto the parts. Keep them separated (Hey, man, you disrespecting me? Take him out (you gotta keep 'em separated)...good jam, lol).