Author Topic: Early Sandcast Found......  (Read 88986 times)

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Offline RAFster122s

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Re: Early Sandcast Found......
« Reply #925 on: May 01, 2023, 10:09:24 am »
If it were not a K0 I would say leave as is, but since they are on a K0, I would agree, polish them. It did a great job bringing them to a consistent tone of finish erasing all oxidation.
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Offline BenelliSEI

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Re: Early Sandcast Found......
« Reply #926 on: May 01, 2023, 10:14:13 am »
Polish gets my vote. Would look totally wrong as-is imho.

Thanks James, value the feedback.

Offline BenelliSEI

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Re: Early Sandcast Found......
« Reply #927 on: May 01, 2023, 10:14:36 am »
If it were not a K0 I would say leave as is, but since they are on a K0, I would agree, polish them. It did a great job bringing them to a consistent tone of finish erasing all oxidation.

I probably will......

Online denward17

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Re: Early Sandcast Found......
« Reply #928 on: May 01, 2023, 10:34:26 am »
I responded in the other thread to keep them as they are, but on 2nd thought, I bet they would polish up to a nice mirror finish.

I think I would polish them, since most of the work is done now.

Offline PeWe

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Re: Early Sandcast Found......
« Reply #929 on: May 01, 2023, 11:05:59 am »
Close to stock look.
That includes clear coat as Honda did?

Some parts had a brushed look and clear on top.

It look otherwise really good on a not back to 100%  stock bike.

What future buyers would expect how a Sandcast should look is one fat factor too.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline BenelliSEI

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Re: Early Sandcast Found......
« Reply #930 on: May 01, 2023, 01:16:12 pm »
I’m thinking these would stain easily if I just leave them. Whenever I’ve tried any clearcoat, it ultimately yellows and peels..... I wonder what clear powdercoat would look like?

Offline RAFster122s

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Re: Early Sandcast Found......
« Reply #931 on: May 01, 2023, 01:44:25 pm »
Generally the finish is very durable, unless you get a corrosive fluid on the cases that you don't clean off...
The finish is peened and holds up very well, unlike a sand or glass bead blasted finish that would oxidize. You would be safe leaving it bare.
The vapor blasted finish really is good at not picking up stains.
« Last Edit: May 01, 2023, 01:48:03 pm by RAFster122s »
David- back in the desert SW!

Offline Stev-o

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Re: Early Sandcast Found......
« Reply #932 on: May 01, 2023, 02:16:10 pm »
I’m thinking these would stain easily if I just leave them.

What would stain them?  On my Kawasaki, I did polish the side covers but the heads, cylinders and carbs look as good as they did when I received them from from being vapor'd.
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Offline Terry in Australia

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Re: Early Sandcast Found......
« Reply #933 on: May 01, 2023, 11:44:26 pm »
Yep, don't worry about stains John, I've been riding my K0 since 2020 with no staining on any other vapor blasted parts, and the Suzuki T500 (which dribbles two stroke over everything) is stain free as well. ;D
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Offline BenelliSEI

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Re: Early Sandcast Found......
« Reply #934 on: May 02, 2023, 09:44:51 am »
Yep, don't worry about stains John, I've been riding my K0 since 2020 with no staining on any other vapor blasted parts, and the Suzuki T500 (which dribbles two stroke over everything) is stain free as well. ;D

Good to know, thanks all!

Online MauiK3

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Re: Early Sandcast Found......
« Reply #935 on: May 02, 2023, 02:46:26 pm »
I didn’t know there was such a thing as clear powder coat. I wonder how well it works.
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Offline RAFster122s

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Re: Early Sandcast Found......
« Reply #936 on: May 02, 2023, 03:42:05 pm »
Clear powder coat has improved greatly in past few years but it dulls a high gloss powder coat a little like the near chrome powdercoat finishes. The later do not hold up well without top coat, last I read.

Some will use the clear powdercoat over polished aluminum rather than tackle the periodic polishing that polished aluminum requires.
It reduces the luster a little.
 A bare polished aluminum part can have higher reflectivity than the bulk of chrome plated finishes.
David- back in the desert SW!

Offline BenelliSEI

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Re: Early Sandcast Found......
« Reply #937 on: May 02, 2023, 06:46:42 pm »
I didn’t know there was such a thing as clear powder coat. I wonder how well it works.

The local shop (they do very nice work) use it over some very high gloss finishes (chrome and pewter). It prevents yellowing and looks great. My only criticism is it can make small parts look a little “over coated”, but the guys are getting better at doing very light, even applications. They do a lot of tubular, fabricated hot rod parts this way. They look almost identical to the bright nickel finish on my Rickman CR frame. I am considering it as an option......
« Last Edit: May 02, 2023, 06:48:43 pm by BenelliSEI »

Offline HondaMan

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Re: Early Sandcast Found......
« Reply #938 on: May 02, 2023, 07:30:20 pm »
About polishing the cases: there is one product (not cheap) called Simichrome that I've used for decades that also seals the surface as you polish it, and it never needs to be revisited again (at least, not since 1973...). I polished the front forks and side covers of my engine in the winter of 1972-73 and aside from some scratches from wear & tear since then, they still look like I just did it. All the other aluminum polishes I've tried (including "Mother's", which doesn't work very well despite its hype) have disappointed me with loss of gloss and/or surface smoothness over time.

One thing, though: wear sacrificial gloves and maybe pants while using it: it doesn't come off the skin easily, nor the clothes.
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Offline BenelliSEI

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Re: Early Sandcast Found......
« Reply #939 on: May 02, 2023, 07:38:30 pm »
About polishing the cases: there is one product (not cheap) called Simichrome that I've used for decades that also seals the surface as you polish it, and it never needs to be revisited again (at least, not since 1973...). I polished the front forks and side covers of my engine in the winter of 1972-73 and aside from some scratches from wear & tear since then, they still look like I just did it. All the other aluminum polishes I've tried (including "Mother's", which doesn't work very well despite its hype) have disappointed me with loss of gloss and/or surface smoothness over time.

One thing, though: wear sacrificial gloves and maybe pants while using it: it doesn't come off the skin easily, nor the clothes.

Thanks, I’ll look for some and give it a try....

Offline PeWe

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Re: Early Sandcast Found......
« Reply #940 on: May 02, 2023, 07:59:52 pm »
John, check on the Sandcast forum how the oppinion is about which procedure so the bike will keep it's best value. Those covers are not easy to find.

The covers are otherwise really beautiful as they are!
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline newday777

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Re: Early Sandcast Found......
« Reply #941 on: May 03, 2023, 01:42:00 am »
My K5 covers were polished with Semichrome years ago. I had instructed my friend that had it before me to polish the covers with Semichrome when he got the bike in the early 80s from the original owner. He did it all by hand. Lots of work but winters are long in NH. He kept it in his warm basement in the winter months, where it was when he passed. It still looks good. I polished my K6 that way back in the day.
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1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
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Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
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Offline PeWe

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Re: Early Sandcast Found......
« Reply #942 on: May 03, 2023, 11:28:39 am »
Look good! I have never heard about Semichrome.

I removed the oxidized covers and hubs, put them into a bucket with water + caustic soda. One by one.
The alu oxide became black within a minute or 2. Heavy reaction. Long sleeved gloves and eye protection.

Dishwashing brush and a few minutes brushing in the bucket. Rinsed with water.
Used steel wool to grind off the black oxide. The aluminium got an old look.

Grind off scratches and polish further from here.
« Last Edit: May 03, 2023, 12:54:20 pm by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline BenelliSEI

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Re: Early Sandcast Found......
« Reply #943 on: May 03, 2023, 12:42:33 pm »
All good ideas. Thanks!

Retorqued the head today and then a neighbour walked in with a crusty carb off his HONDA generator. He’s all fixed up. He has a back hoe I like to borrow occasionally, so worth the time.

Offline Stev-o

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Re: Early Sandcast Found......
« Reply #944 on: May 04, 2023, 06:41:42 am »
My K5 covers were polished with Semichrome years ago....polish the covers with Semichrome ...

It's Simichrome, I have a tube on the shelf.  Great stuff, invented in Germany back in the 60's.



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Offline BenelliSEI

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Re: Early Sandcast Found......
« Reply #945 on: May 04, 2023, 08:42:41 am »
My favourite is “Autosol”. Also a German product! 

Offline Don R

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Re: Early Sandcast Found......
« Reply #946 on: May 04, 2023, 08:52:47 am »
 I had some green dragon polish, it's pretty good, when I tried to find more I learned that's also the name of an Everclear and Marijuana drink.
No matter how many times you paint over a shadow, it's still there.
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Offline Slow2

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Re: Early Sandcast Found......
« Reply #947 on: May 29, 2023, 06:23:13 am »
I’m with the Semichrome crowd. Have hand polished many covers and they stay looking nice for a long time. The stuff is impossible to find locally and I’m almost out. Guess I’ll just order some. Oh yeah, not cheap but a little goes a very long way!!!

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Offline RAFster122s

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Re: Early Sandcast Found......
« Reply #948 on: May 29, 2023, 07:55:27 am »
Simichrome is often carried at Ace Hardware...worth a phone call if you have them in your area... Sometimes Amazon is more expensive than local suppliers.
« Last Edit: June 01, 2023, 01:10:01 pm by RAFster122s »
David- back in the desert SW!

Online denward17

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Re: Early Sandcast Found......
« Reply #949 on: June 01, 2023, 11:13:34 am »
Was going to ride some this afternoon, but started raining, so broke out the simichrome and touched up a bit.