#1171
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Magnet stuck to Stainless?
Jack,
You have a magnet stuck to your Stainless bumper. I assume it is stuck to a bracket behind the bumper.
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Rick in Washington, USA Here to quietly observe and learn. |
#1172
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Quote:
Best, Kelly
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Kelly Coffield www.inlinecarb.com - My Old Carburetor Habit http://www.alloyavenue.com/vb/showth...nace-Build-Log - My Home Foundry Furnace Build |
#1173
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Right. Somewhere in the text I had mistakenly said that the sheet was 304. It isn't, it's 430 which is common for automotive trim parts. It's also magnetic. I remembered as soon as I set the magnetic base on the bumper and it stuck.
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Jack Set a Goal So Big That You Can't Achieve It Until You Grow Into The Person That Can. Last edited by Jack 1957; 03-19-2019 at 11:22 PM. |
#1174
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Amazing work Jack. I'm filing this away in case I decide to have bumpers on the roadster.
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Kerry Pinkerton |
#1175
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Hi Jack
stainless steel is usually very hard to work with But I must say you have done a splendid job on the rear bar Well done! Peter
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P.Tommasini Metalshaping tools and dvds www.handbuilt.net.au Metalshaping clip on youtube http://www.youtube.com/watch?v=WEAh91hodPg Making Monaro Quarter panel: http://www.youtube.com/watch?v=KIpOhz0uGRM |
#1176
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Quote:
When we weld 430, we always see a color difference at the weld. Hopefully, that's not the case here. |
#1177
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430
430 thermal expansion is only 60% of 304. Should have helped a lot with the weld distortion. Not that you would ever drive this through the salt of a Minnesota winter, but I had 400 series Stainless (Can't recall exact alloy) gas tank in a year round driver. It showed surface rust after several years. Especially on the welds.
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Bill Funk |
#1178
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Quote:
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John |
#1179
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Well said John B
Steve
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Steve Hamilton Hamilton Classics Auto Restoration & Metalshaping |
#1180
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Time to start the polishing process but we're way far from picking up a buffer. 90% of this can be done quicker by prepping with a sander. I use this electric DA (dual action sander) that can also be locked to function as a single action sander. I use the electric one so I don't have to listen to the compressor all day.
This process takes some time but it will get the best results. Stainless is tough stuff stuff. I have a twine buffing wheel that cuts like crazy but it's still a lot of work. Stainless fights back. It doesn't just lay down like aluminum. The best way to get a smooth finish is progressively finer grits of sandpaper. After I ground the welds with a stone wheel, I smoothed them out some with a grinder and 40 grit discs. From there it's all done with the DA. First round was 80 grit to smooth out the rough lines left by grinding. The process I use is what I've found to work best for me. It isn't written on stone tablets, I just do it this way and always get good results. After each round with a coarser grit, the next round will be a little finer grit and so on. If I start off with 80 grit, then follow with 150 grit, I need to make sure that every trace of scratches from the 80 grit is gone before moving on to 320 grit. The reason this is important is that if I move on to 320 and find that there are still some 80 scratches, it will be very difficult to knock those scratches down with 320. So, the key to doing each round only once is to be absolutely sure that each round erases the scratches left from the previous round. If you were to use a SA (single action) sander on all the grits it will be nearly impossible to tell if you have erased all traces of the previous round. It's really difficult to see the difference between the two sanding marks left behind. To eliminate this problem, I alternate between rounds. I'll do 80 grit in SA then 150 grit in DA (dual action, orbital) then 320 in SA, etc.. It is very easy to see the difference between the two sanding patterns. If I'm using SA with 150, I am going to eliminate every single DA mark on the part. Then I would follow that with a round of 320 with DA and eliminate evry SA mark. Continue to 1,000 grit. If you use this simple method it will be easier to finish the part and not have to backtrack and remove scratches that you missed. In the picture below, I am working from left to right using 320 DA to knock down the previous round of 150 SA. You can see how easy it is to tell what has been sanded with the 320 and what hasn't. In the picture below, I'm working from right to left using 600 SA to knock down the previous round of 320 DA. There's no way to miss a spot when sanding. The sanded and unsanded areas are obvious. Sometime during the process above I was starting to get burned out with the sanding so I took a break and made the foam patterns for the side view mirror stands and the backup sensor grommets for the rear bumper. I sent them to Kelly to pour them in aluminum.
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Jack Set a Goal So Big That You Can't Achieve It Until You Grow Into The Person That Can. Last edited by Jack 1957; 04-02-2020 at 09:48 AM. |
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