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Swiss two-become-one 240Z Ground up restauration / JDM mods

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On 19.9.2017 at 10:50 PM, rturbo 930 said:

Looking good. But I can't help but find it a little funny (or a little scary) that a business in Switzerland has an English business name. Talk about foreign influence, lol.

Haha that's quite normal. Little switzerland is going international. :) Also i guess "Chäfig-buäb" would sound a little strange :P

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Glass beads are really just a different shape being round rather than rough like silica sand, less abrasive. It isn't the same as say "shot peening". In my experience, the dull appearance is normal. The beads do remove less material and are less abrasive, giving more of a matte finish almost a dull sheen. The actual sand depending on grit is similar in appearance but much more aggressive and rough in finish texture. Sand will remove more material and leave a rougher finish. Keep in mind as well that the "glass" beads break as they are used in the cabinet and are no longer round as does the sand which depending on the material of choice may become less aggressive or more as they break into smaller pieces. Silica sand loses its sharp edges and bite. Garnet, and other materials behave differently. All of this is assuming it was blasted in a cabinet where the material was used over and over. If done outside with one hit, things will behave more consistent as you only get the original material hitting your part. Usually the cabinet is used as media gets expensive if it's a one shot deal and also messy.

Your photos do look consistent with glass beads. You could roll that media in your fingers to see if some are round or if all of it is rough and jagged.

As a an example, I am building a custom lever action rifle and will use the glass beads in a cabinet to just texture an already clean aluminum receiver. Low air pressure and fine beads to get a light even matte finish without removing material is the goal.

On parts like yours if they have to focus on removing dirt, grease or paint you could end up with material removal in certain areas if part is raw and part painted, the raw part will lose some material while they are trying to get the painted part to let go. Beads are less abrasive but also slower and less aggressive at removing the junk while tending to leave a less rough matte finish. Beads will also tend to close up the surface a little like shot peening rather than open it up to better accept paint. Shot peening is more a of a hardness treatment rather than to clean. I don't know of any media except for maybe shot peening that would leave a part shiny from blasting. Shot peening is like thousands of tiny hammer hits.

I hope that helps and anyone with more extensive experience is more than welcome to clarify anything that I may be missing here. Sorry I got a little wordy there.

Your project is coming along and it's nice to see the progress and quality of work.

Dave

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thanks for the input. makes sense somehow. I contacted the blasting company again and let's see what they come up with.

As far as it goes i got some other replies in other forums, claiming that hydro/vapour/soda blasting is the thing to go when looking for the glossy OEM finish on raw aluminum. sounds promising but let's see what the current blaster replies and what solution i can come up with.

I'm not happy with the current finnish. although it would definitively work. it's just not what i was looking for..

 

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Posted (edited)

That looks normal to me for glass beading. Raw castings are usually shot blasted then machined. I found that putting parts in a vibratory finisher after blasting restores some of the luster. 

 I can fit my DOHC valve cover in my finisher. If you look closely you can see the difference. V3 is in the foreground and it has been shot blasted and then run in my vibratory finisher with burnishing media and liquid. V2 in the middle has only beed shot blasted. You can see a slight luster on V3.

20170810141258-7e818f41-me.jpg

Here are two parts I glass beaded.

20170707041056-f21a38ac-me.jpg

And here they are after vibratory finishing.

20170707041100-01e22bd7-me.jpg

 

There are many types of finishing media. Burnishing media is what gives the parts the luster. 

 

Derek

 

Edited by Derek

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I agree with Derek on what it seems you are after finish wise. Unless you coat the parts a vibratory polish/burnish is going to be the way to do. I would be careful with soda. I haven't used it but I have a good friend that is in high end paint for custom cars and he is adamant against it. Definitely more delicate at removal of rust and paint while not damaging the surface it can leave residue.

Have you considered a really high quality clear coat? The bead blasted parts won't stay that clean color and texture. Aluminum will corrode over the years unless it is somehow coated or anodized. You could also clear anodize which might be a good choice. I'm not sure how much corrosion resistance if any the vibratory media would provide and how much residue is left preventing an anodize or paint. With as much work as you have put into this project I would certainly want it to stay that way.

I am chemically stripping my car then blasting what that misses. Aluminum will be bead blasted for texture then probably clear coated or anodized to prevent corrosion. If I had access (meaning reasonably priced without having to send it out at full shop rate) to the Vibratory finish Derek is showing I would really consider that option. I have two blasters in my shop both a cabinet and pressure pot and a compressor large enough to run either all day long. I just can't justify paying for something I can do here. I don't mind the dull finish as long as it is clean and even and protected from corrosion.

The rifle project I mentioned is going to get a nickel boron plate after engraving trying to get as close to the stainless barrel as possible. That finish is outstanding at corrosion resistance and lubricity but is really expensive to have done. OK on small parts but would be obscene overkill for car part castings, at least for covers and housings.

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In my last post, i wrote about the fact that the transmission looked wrong after the "glass bead blasting". Many readers pointed out it seems to have been just sandblasted. I contacted the blasting company again and asked what happened. He excused himself a hundred times and told me that his guy somhow missunderstoud somthing and that it was only blasted. but not sand blasted as you thought, but blasted with "broken glass". this is softer and won't attack the surface of the Aluminum. It's less corrosive than regular silicat-sand used for blasting. At least that was good news. He promised me to immediately fix that. Today i was able to pick it up again:
P1190241-Kopie.jpg

They glass-bead blasted everything and the surface now looks and feels a lot smoother and got this slight "satin gloss" finish. just as it should be. The sense of Glass bead blasting is to improve the surface density of aluminium. Like that it's much stronger and will keep the appearance for a longer time when used unpainted in a car.
P1190244-Kopie.jpg

While it doesn't have the super-glossy OEM-like finish it's what i was aiming for. I got told for the glossy finish it should be soda/vapour/fluid blasted. But for me it's perfect as it is. it's not going to be a concours build anyway and it seems much fresher again. Also they clearcoated the cast-iron bits as promised, to protect it from corrosion:
P1190245-Kopie.jpg

This is how the gear selector looks after the protective tape was removed. Still needs a bit of cleaning though but looks perfect. just as i wanted it :)
P1190246-Kopie.jpg

Super happy with the result. and while it took me a few extra hours to bring it back again and pick it up. the good thing is they felt so sorry that the extra-work was for free. They only charged me for the first part of the work. which is awesome and came out on a budget :)

 

Edited by jdmjunkies.ch

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On 1.10.2017 at 7:26 PM, jpndave said:

I agree with Derek on what it seems you are after finish wise. Unless you coat the parts a vibratory polish/burnish is going to be the way to do. I would be careful with soda. I haven't used it but I have a good friend that is in high end paint for custom cars and he is adamant against it. Definitely more delicate at removal of rust and paint while not damaging the surface it can leave residue.

Have you considered a really high quality clear coat? The bead blasted parts won't stay that clean color and texture. Aluminum will corrode over the years unless it is somehow coated or anodized. You could also clear anodize which might be a good choice. I'm not sure how much corrosion resistance if any the vibratory media would provide and how much residue is left preventing an anodize or paint. With as much work as you have put into this project I would certainly want it to stay that way.

I am chemically stripping my car then blasting what that misses. Aluminum will be bead blasted for texture then probably clear coated or anodized to prevent corrosion. If I had access (meaning reasonably priced without having to send it out at full shop rate) to the Vibratory finish Derek is showing I would really consider that option. I have two blasters in my shop both a cabinet and pressure pot and a compressor large enough to run either all day long. I just can't justify paying for something I can do here. I don't mind the dull finish as long as it is clean and even and protected from corrosion.

The rifle project I mentioned is going to get a nickel boron plate after engraving trying to get as close to the stainless barrel as possible. That finish is outstanding at corrosion resistance and lubricity but is really expensive to have done. OK on small parts but would be obscene overkill for car part castings, at least for covers and housings.

that clear annodization is maybe a cool idea. have to think about it...

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Nothing big here. just spent two hours cleaning all the transmission parts after the glass bead blasting. Removed some leftovers from the masking tape and blew away all the leftovers from the blasting from all the small corners, etc. Since i forgot my cam at home you only get some crappy mobile-phone shots:
DSC_1696-Kopie.jpg
When done i started going through the small parts and decided i could clean them too. so the trusty green scotch-n-brite came in handy again to clean all the small pieces:
DSC_1697-Kopie.jpg
Then decided to make a little test-assembly with the new PU shifter bushings (red), since the old ones were quite worn-out (black):
DSC_1698-Kopie.jpg
This is how it all goes together:
DSC_1699-Kopie.jpg
And this is the result. quite happy. Will remove it all again, grease the rubber with some bushing-grease from the energy-bushings kit and have the washers and nuts zinc-plated alongside all the other nuts and bolts from the transmission before the final assembly:
DSC_1700-Kopie.jpg
 

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