Heat Patina Issue after new Oxy/Acetylene bottles

[njschaben]

I am having issues with my new oxygen and Acetylene bottles. Ever since I got full bottles last week I have not been getting the colors I am used to getting. Instead of getting the blues and purples, I get gray and brown. It is only on the front side, the colors on the back are normal. The front side is the side that I heat up with the torch. I have attached 2 pictures showing the front and back colors. I am using a glossy clear powdercoat. The colors seem to change when the clear powdercoat is baked on. Anyone ever had this issue??? All I did was change the bottles to full ones. I did not change anything else. I have had great results for the past year with my old bottles, probably did 50 or more small projects and never had one issue. Any thoughts???

[abmetal]

Just a thought...

When your tanks were transported, were they laid down? If so, the acetylene tank should be standing at least 30 minutes before use because of "fullers earth" inside. This explanation was taken from a tractor forum. [The acetylene tank contains an inert substance like fullers earth or lime silica, which absorbs acetone. The acetone absorbs the acetylene and kind of keeps it in suspension preventing accumulating pockets of high-pressure gas thus stabilizing the explosive tendencies of the gas. Be careful not to lay the tanks on their side as this will permit some of the acetone to enter the valves, lines, and gauges and contaminate the system. A purplish flame color at the torch is an indication of this contamination.]

Allen

[njschaben]

Yeah I did transport them laying down for a 30 min ride home. When I got home I set them upright and they sat there for 2 days before I used them for the first time. I have tried the last 8 days in a row to figure out what's wrong but no luck yet. Tried different metal, new muraitic acid, new denatured alcohol, and new cleaning rags. Every time comes out the same, what ever side the torch is used on it comes out gray instead of blue. Maybe this bottle of acetylene has a different filler in it than the last bottle??? Not sure. What pressure setting is everyone using for your oxy/acetylene setup with a rosebud?

[steelfx]

I may be a little prejudiced...but, chemical patinas are much easier.

Have you changed materials, i.e. HR to CR or vice-versa? Metallurgical differences do exist from one mill to the next and from one production run to the next. If you saw how they made A36 steel, you'd wonder how it even cuts!
All kinds of scrap, including plastic barrels, bricks, pallets & even dirt go into the kiln. A lot of that crap burns away, but still...it's shocking to see what goes in the mix.

You could ask your supplier for a MTR (Mill Test Report) and check the percentages of the batch content. It does vary.
There's no charge for a MTR, so it's not hard to get, even if they don't have one on file for each shipment of plate that they receive. Your supplier can have the mill fax a copy to him or you. I only ask for 'em when I'm buying corten or AR plate...just to keep 'em honest, actually. Don't want to get AR-400 when I'm paying for AR-500.

If you've changed suppliers or even made any thickness changes, that could affect heat-coloring. Ambient lighting is a factor, too. When I've done heat-treating/coloring to mimic case-hardened steel, I found that working in dim light enabled me to see what color changes were occurring way better than if all the shop lights were on. Just my 2 bits..

Some day, try some liquid patinas...I think you'll like 'em!

Bill

[steelfx]

btw...both photos are beautiful! Very Nice work! And trust me, if I didn't mean that, I wouldn't say it.

Bill

[tnbndr]

I would just heat the back side of where you want the blue colors. I have had different color reactions with different projects, both with flame and FX Patinas. That's the beauty of metal.

[njschaben]

Thanks Bill, I have all you spray patinas and the dyes and love them. I have had great results with the patinas using a rattle can clear or an automotive two part clear, but I don't have a spray booth so I went the route of a 4x4x8 powdercoat oven and I love it. I am using the Super durable crystal clear powdercoat from PBTP. The picture of the daisy petals is copper fx and flame fx with the clear powdercoat baked on. Before the clear was baked on the pedals had all the copper and reds and blues and purples, but the clear destroyed all of the color. I need to order some low temp clear powdercoat and try that, I think it cures at 320 instead of 400 so I am hopeful that will allow the colors to remain. The basketball cross memorial I did with the purple dye and clear powdercoat turned out awesome. It is my first dye project and It was so simple just airbrushed the dye and clear powdercoated. I will have to order some of the new gels to try out, just never have enough time...lol. I also wish I had a wash bay in my shop cause it's a little cold and windy outside where I do the fx patinas.

I am using the same batch of metal I have used for the last year. It is all 14 and 16 gauge HR. I cut it, put in muraitic acid tank to remove mill scale and dross, Polish steel with 80 grit flap disk, clean with denatured alcohol, torch it, let it cool down to room temp, clear powdercoat and bake. The blues and purples appear normal on both sides but when the clear is baked on it reacts with the gas residue on the front side and turned the colors gray.

[njschaben]

Dennis, I did try to heat the back side on a few test pieces which allows the colors to look normal on the front but it also shows some little gray splotches that show up in the blue and purple areas that are heated more. The picture shows the spots I am talking about. These spots might be caused by the gas as well. This weekend I'll have to try and heat the front and the back half and half and see if both sides go gray or if that will work. I think I will also try and clean the metal a second time with denatured alcohol after I torch and before I powdercoat. I have never cleaned it twice but at this point I'll try anything. Thanks.