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Author Topic: I know this is backwards but is there a good way to dull aluminum (carb bowls)?  (Read 2134 times)
markb
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« on: August 02, 2015, 03:37:00 PM »

My carb bowls came out shinier than I think they should be.  Does anyone know of a way (like a chemical dip or wipe) that would turn polished aluminum to a dull grey finish?
« Last Edit: August 04, 2015, 04:59:18 PM by markb » Logged

Mark B
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bowswell
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« Reply #1 on: August 02, 2015, 04:59:44 PM »

Sandblast with bicarbonate de soute....cow brand

« Last Edit: August 02, 2015, 05:03:27 PM by bowswell » Logged

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Steve Swan
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« Reply #2 on: August 02, 2015, 08:38:29 PM »

were your bowls polished by someone or unmolested ?

reason i ask, some unmolested bowls i've seen are astonishingly bright.
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« Reply #2 on: August 02, 2015, 08:38:29 PM »

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DW69K0
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« Reply #3 on: August 03, 2015, 05:29:46 AM »

I agree with Steve, I have seen unmolested carb bowls that are very polished. IMHO, I think the earlier Sandy's had a might brighten surface finish on engine cases and other polished areas, as production picked up less time was spend on the polishing.
DW
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4pots1969
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« Reply #4 on: August 03, 2015, 06:32:35 AM »

Mark, here are pictures of a ramp of Carburetors K0 new never installed on a motorcycle...
I think that it can guide you to determine good appearance... Wink
I agree also that the bowls have a different appearance compared to the top..
« Last Edit: August 03, 2015, 06:50:27 AM by 4pots1969 » Logged
markb
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« Reply #5 on: August 03, 2015, 12:40:09 PM »

were your bowls polished by someone or unmolested ?
They were polished by the guy who rebuilt them, a well renowned expert who knew exactly what he was working on.  I had them rebuilt in an effort to expedite the assembly and since I'm not much of a carb expert.

Mark, here are pictures of a ramp of Carburetors K0 new never installed on a motorcycle...
Thanks for the great pictures.  Maybe mine are OK then.  I will post a pic of mine.

Thanks all for the comments.
Mark
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Mark B
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markb
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« Reply #6 on: August 03, 2015, 07:12:32 PM »

Here’s my carbs.  Opinions?





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Mark B
1969 CB750 sandcast #97 current project Restoration thread link
1969 CB750 sandcaxt #576 next project
1969 CB750 sandcast #1553 next project after that
1969 CB750 sandcast #1990 next project after that
1969 CB750 sandcast #5383 Sold Restoration thread link
1970 CB750 K0 restored
2010 H-D Tri Glide Ultra Classic (Huh?)
Ujeni
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« Reply #7 on: August 03, 2015, 10:30:14 PM »

My vote is to keep them like they are. Looks correct to me.
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Ujeni Motors
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DW69K0
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« Reply #8 on: August 04, 2015, 04:41:37 AM »

I agree with Ujeni, leave them as they are, there should have enough shine on them to reflect distorted images but not be mirror like. They look correct and will oxidize with time.
DW
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4pots1969
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« Reply #9 on: August 04, 2015, 06:03:18 AM »

Mark, time normal ca might be correct... But given the level of quality that you bring this restoration... for me, sincerely I think that this is not good...
I see that the carbs are reassembled... Are they finished?
Gerard
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Steve Swan
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« Reply #10 on: August 04, 2015, 08:32:28 AM »

how were carb bodies cleaned ?  the photos make them look overly flat.  the #4 from backside appears to have a bit of a sheen.  the #1 from side looks overly flat.

in my ultrasonic, i use Branson us cleaning solution which suspends debris in solution.  generally, the carb bodies come out with at least a bit of a iridescent sheen (as usually seen on unmolested carbs.)  the last set i recently did (76F1) came out flat, but not as flat looking as what your set looks, Mark.  after they come out of u.s. unit, i wash them with a plastic bristle brush and hot soapy water.

ps - why do the nuts fixing your choke arms not look bzp ?  the rest of your small parts attached to bodies look fresh bzp.  and what i can see, 2 bowl drain screws appears raw brass ?  gosh.  sure don't want to sound like i'm nitpicking.... Angry  surely not my intent.....
« Last Edit: August 04, 2015, 08:42:07 AM by Steve Swan » Logged

markb
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« Reply #11 on: August 04, 2015, 12:37:08 PM »

Gerard,
What does "time normal ca" mean?  Are you asking if I'm done with them?  I don't know yet.

Steve,
These carbs were in terrible shape, worst I've seen.  I had to try to save them because of the horizontal vents.  I believe the bodies were ultrasonically cleaned but I don't know what in.  I will check into it.  The difference in the sheen isn't as noticeable in person.  What would "brighten" them up?

The reason the nuts don't look zinc is they are covered with a soft coating presumably to keep them from loosening.  I intend to remove it.  I think I will replace the drain screws too.  I also have new adjusting nuts (5mm to match the cable) for the tops.

Don't worry about nitpicking.  The reason I posted was to get honest feedback.  So thank you all.

« Last Edit: August 04, 2015, 12:40:22 PM by markb » Logged

Mark B
1969 CB750 sandcast #97 current project Restoration thread link
1969 CB750 sandcaxt #576 next project
1969 CB750 sandcast #1553 next project after that
1969 CB750 sandcast #1990 next project after that
1969 CB750 sandcast #5383 Sold Restoration thread link
1970 CB750 K0 restored
2010 H-D Tri Glide Ultra Classic (Huh?)
4pots1969
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« Reply #12 on: August 04, 2015, 04:32:04 PM »

The translated translator of the times a bit a side "in normal times" it mean: for motorcycle in its own juice not restored... Here is a picture of the restored carbs of Big Boss... But perhaps are new ones?
« Last Edit: August 04, 2015, 04:38:04 PM by 4pots1969 » Logged
markb
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« Reply #13 on: August 04, 2015, 04:58:28 PM »

Those look nice but I wonder if they are too bright.  The more I look at mine I think they are a least a bit dark/dull but I might let them go for now.  I sure would like to have this project together and do a test run yet this season.
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Mark B
1969 CB750 sandcast #97 current project Restoration thread link
1969 CB750 sandcaxt #576 next project
1969 CB750 sandcast #1553 next project after that
1969 CB750 sandcast #1990 next project after that
1969 CB750 sandcast #5383 Sold Restoration thread link
1970 CB750 K0 restored
2010 H-D Tri Glide Ultra Classic (Huh?)
Steve Swan
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« Reply #14 on: August 04, 2015, 10:37:12 PM »

Mark, i wish i knew what would brighten carb bodies.  i have no experience with soda blasting as someone previously mentioned trying it.  would be nice to have a darkened body to try soda blasting on, then run through ultrasonic.  i am goingto guess the heat in u;trasonic sol'n helps bring out the iridescent surface sheen. 
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