[Markus]

I have to do couple of little tanks in near future. Those will be made of 316L 306x2 mm pipe and surface must be polished to mirror, including weld beads.

I did some small testing today and noticed some waviness on surface. Nothing too bad, but I just wondered that is it possible to get those waves flat. Any experience?


Grits used: #40 - #60 - #80 - #120 - #320 (usually I use 240 before 320, but didn't have any today)
After sanding I polished it up with tree stages.


Some pics.

Waviness appears horizontally

IMG_0497.JPG (18.29 KiB) Viewed 1701 times

Not that awfull

IMG_0510.JPG (31.3 KiB) Viewed 1701 times

Mill finish

IMG_0511.JPG (36.27 KiB) Viewed 1701 times

IMG_0514.JPG (33.97 KiB) Viewed 1701 times

IMG_0515.JPG (54.69 KiB) Viewed 1701 times

[jwright650]

That looks pretty good for #320 grit....I would have thought that you would have needed a few more finer grit stages to get it polished down that shiny...like #600, #800, #1000 and #1500

[Markus]

Hmm usually #320 is fine enough, when sisal's are used. However I haven't tested to go finer, maybe it will help a bit. I will give it a go.
I also thought that maybe flap wheel won't deliver equal pressure, which could cause those waves Specially with grit sizes #40 and #60.



From this site I have learned some precious things. http://www.thepolishingshop.co.uk/
Here is their short guide for polishing.

Polishing Steel, Stainless Steel & Iron.
If the metal is in a poor condition then abrasives will be needed. Thats where experience of polishing comes in, looking at then metal and knowing what process you need to start at.
You will need to get the surface to 240/400 grit before you start polishing at process 1.
If the condition of metal is not too bad or you have the surface to 600 grit + then you could start at process 2.

Process 1 (Burnishing) Grey 523LBZ compound with a sisal polishing mop
Process 2 (Prepolishing) Green 439T compound with a white close stitched polishing mop
Process 3 (Polishing) Blue P164 Compound or Rose P126 Compound with a Loose G quality
Process 4 (Finishing) P175 for super finishing with a Loose WDR quality mop

[noddybrian]

I think standard flap wheels inherently cause ripple marks - but the " interleaf " type that has " Scotchbrite " material in between each layer is better - I have had good results not using flap wheels but doing virtually the whole process with mops - we have a compound called " Sateen " - referred to as a greasless gritted compound - it's available in grit sizes 80 thru 320 - it's applied usually to a hard spiral stitched mop & needs time to dry before use - it's great as a first stage on anything except soft metals.

[Markus]

I think standard flap wheels inherently cause ripple marks - but the " interleaf " type that has " Scotchbrite " material in between each layer is better - I have had good results not using flap wheels but doing virtually the whole process with mops - we have a compound called " Sateen " - referred to as a greasless gritted compound - it's available in grit sizes 80 thru 320 - it's applied usually to a hard spiral stitched mop & needs time to dry before use - it's great as a first stage on anything except soft metals.

I tested those Scotchbrite flap wheels, but those don't remove metal fast enough. So in this case those are completely useless. However I have used those with good results in repair jobs where metal have always been in really good condition at the beginning.

I read some topics about that Sateen from different forums. I'll have to test that one day.

[Markus]

Ok fellow welders problem is solved.

I changed those flap wheels to angle grinder and sanding discs. Dropped rpm's down to 2000 and started to work that baby from grits #80-1000. After that polished it up with two soft mops. Results... Near perfect!

Thanks guys!

No more waves in straight line

IMG_0529.JPG (23.05 KiB) Viewed 1589 times

[WerkSpace]

I use tooth paste as a polish. and... it smells minty fresh.
It works great on plastic car headlights, chrome wheels, etc.
You can even use it to fix up those scratched CDs and DVDs.

[Otto Nobedder]

WerkSpace,

I've done that several times. It works great, but it doesn't seem to last. How do you treat them to resist UV?

Steve S

[WerkSpace]

Sun screen?

WerkSpace, I've done that several times. It works great, but it doesn't seem to last. How do you treat them to resist UV? Steve S

[Otto Nobedder]

Sun screen?

WerkSpace, I've done that several times. It works great, but it doesn't seem to last. How do you treat them to resist UV? Steve S

Well, they make UV blocker treatments for eyeglass lenses and safety glasses, so yeah, "kind-of". There should be something available to treat a freshly polished plastic to resist UV.

Steve S

[79jasper]

Clear coat paint spray. Most of it has UV blockers.
Best way is wet sanding.

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[Markus]

Well if we start to discuss about detailing

Headlights->
5sZg9cj2hxI





Aaaaand for coating.. C1 ofc and Exo on top of it. Shines and bead like no other...
U2vOsu-RtUM

[shade-tree]

Hey Otto.
I'm no ace but I have been called something similar. Try this:
http://www.autopia-carcare.com/headligh ... MFtWS6y7KA
I don't know how long it lasts because my truck is only 18 mos old. Time will tell. The sealant is intended to be used each time you wax or seal the vehicle (3 - 6 months). But nothing lasts very long parked in the sun.
Jon

[79jasper]

^ if you use that every time you wash it from new, you won't even have any headlights left after a few years.
In essence, don't do that.
Get something like this, since yours are still fine. http://www.xpel.com/products/headlight_protection.asp



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