My Other (short) Winter Project

[Gary in NJ]

You can't have too many projects...all at the same time no less. But this one might benefit or inspire some of you.

I have brought a lot of motorcycles back from the dead over the years. Without a doubt, the most labor intensive part of these restorations is the cleaning & restoration of metal parts. I hate it, and it probably keeps me from doing more projects. With my current CB900 project - that needs a lot of metal restoration - I'm gonna get serious about restoration equipment. The first piece of equipment I purchased is a Ultrasonic cleaner. I got a large 10 litter unit so I can submerge fairly large items (the basket is 11 x 8 x 4). The trick to using these units is to put the item to be cleaned in a plastic jar (like a big peanut butter jar) or ziplock baggie. This way you don't have to constantly empty the cleaning fluid from the unit. The dirty cleaning solution is limited and contained in the smaller container. The ultrasonic cleaner will be perfect for nuts and bolts, and washing parts like carburetors and master cylinders. But bigger parts will require some force.

The next piece of equipment is the DIY project. I've been planning this one for weeks, and today I made all of my purchases. I'm going to build a vapor blasting (aka wet media or vapor honing) cabinet. This is not my own design, but my interpretation of what I have seen on youtube. This cabinet should reduce the labor involved to clean dirty and oxidized parts (like an engine case cover) from 2-4 hours to about 15-20 minutes - with better results. Here's the parts list and prices:

Harbor Freight Blasting Cabinet (it's gonna be converted/modified) @$179 (on sale this week)
1.5hp Sewage Pump/4300 gph @$90 eBay
Sandblasting Nozzle @$35 eBay
6 gallon bucket @$15 Amazon
3/8 Check Valve @$20 Amazon
Dragway Tools Pneumatic Foot Pedal Switch @$65 Amazon
Assorted hoses & fittings @$40 Lowes

Total investment about $450.

Not included is the cost of an air compressor - which I already have. I have a 3.25hp 60 gallon Cambell Hausfeld unit that has a max out put of 135psi, with flows of 11.5cfm@40psi and 10.2cfm@90psi. We will come back to this because I have a question for those of you that know air compressors.

The media used in these systems is 175-325 grit glass beads, shot at 60 psi. The system is closed loop so I don't need a fresh water supply at the cabinet. Here is the basic theory of operation:

The sewage pump will be placed in the 6 gallon bucket along with 4 gallons of water and about a pound of media. The output from the pump will be split; with 1/2 of the output used in the cabinet as a blasting media and the other 1/2 will remain in the bucket to agitate/mix the media with the water (the "slurry"). The slurry will be mixed at the nozzle with air from the compressor. The used slurry will fall to the bottom of the media cabinet that has a 4x4 opening at the bottom, and then fall into the bucket (with the motor) sitting below the opening. The slurry will be recycled back into the bucket and back through the pump.

Pretty simple, right?

I'll get photos of the parts as they come in and as they go together with details on any modifications.

OK, here's my question that I can't seem to get my head around. My compressor is plumbed with 3/8 hosing and 3/8 NPT quick connects. The ID of 3/8 hosing is usually a bit less than .375", around .340". OK. The quick disconnects I use have an ID of .190". These are the typical QD found...everywhere. Are there quick disconnects for 3/8 hosing that have a larger opening? I could direct plumb the air lines right to the nozzle using barbs - but QD do make life easier. Also, I notice a lot of people building these cabinets use 1/2 line to get the maximum CFM @ 60psi, but the foot switch is 3/8 NPT - so what's the point of converting to 1/2 lines? The foot switch will always be the restriction. What am I missing here?

 

[trepetti]

Where's the KABOOM? There was supposed to be an earth-shattering KABOOM!

Sounds cool. What's your labor rate for fellow forum members?

 

[TownsendsFJR1300]

Couple things,

I've been using a sonic cleaner for several years now, not as large as yours for mostly carberator cleaning.. I've found water with some Palmolive dish soap works best..

I'm not storing old cleaning fluid and put parts directly into the basket, much easier.

I tried some Simple Green but found it too aggressive leaving aluminum carbs looking dull






Re the quick disconnects, I too use 3/8 hose with quick disconnects. As you stated, I think their pretty much standard. I just measured the ID of a blow nozzle and got a measurement of .22".

I don't know of any larger hoses and what I have is a commercial, heavy duty, rubber hose but my max PSI is 150 slightly higher than yours..

 

[Gary in NJ]

I think I have it figured out. 3/8 hose uses 1/4-18 NPT fittings. Seems to be an oddity to me.

So I’m going to pipe this system with 1/2 hose using 3/8 NPT fittings to 1/2” barbs. That will keep the entire line at 1/2”, including the foot switch. There will be no disconnects in the system. I will keep my current supply lines as is, installing a Tee and the compressor outlet that is all 3/8 NPT with a reducer for the existing 1/4 NPT line. That should do it.

Nice results with the ultrasonic. I’ve decided to use a cleaner called Master Stages 2020/1G. It is deluded at 1-3% (strong stuff). It is highly rated and is aluminum safe…as long as you don’t exceed 3%.

 

[gnyce]

Sounds cool. What's your labor rate for fellow forum members?

This is my question as well!

 

[Gary in NJ]

My goal is to INSPIRE you to make one too. I've got lots of parts today. If I find time to get into the shop tonight I'll start taking photos. I also figured out a way to keep the air line at 1/2" from the compressor to the nozzle....this thing is gonna kick some ass.

 

[Gary in NJ]

I got a lot done today. I built the blasting cabinet today, so that’s probably 75% of the job. I made some modifications to the cabinet along the way. First, I wanted to use the inlet port as the exhaust. The port itself is mounted high on the cabinet, which is awful for vapor blasting, but it has a chimney that starts right at the work level. By closing up the top of the chimney I turned this into a vent with a low point, which will keep the water vapor from fogging the cabinet.









I also had to convert the open port into a 2-1/2 shop vacuum port. A little cutting and JB Weld was all it took.

With the modifications, putting the cabinet together took all of the daylight hours. I also sealed every seam with clear caulking along the way.

The next photo shows (from left to right) the slurry pump, the foot switch and the vapor blasting nozzle. The foot switch also took some modification to keep the air line at 1/2-inch NPT. The manufacturer of the switch sells it as a 3/8 NPT switch, but I could see from the detailed photos what appeared to be a 1/2 to 3/8 reducer. I received the switch today and opened the box to find exactly what the photos showed. The only problem was there was no easy access to the reducer. So I took it apart, modified for my needs and reassembled it. I don’t know why they don’t make this available in a 1/2 inch size. I do note that the valve itself is stamped “145 psi Max”, which isn't a problem for me because my compressor has a max output of 135psi, and I’m running the switch after the regulator, which will be limited to 60psi. The photo of the foot switch shows it after I removed the reducer (the reducer and 3/8 fitting are just resting on the flange).





Now that I confirmed that I can run the system at 1/2, the only thing left to do is to order the pipe fitting.

 

[trepetti]

My goal is to INSPIRE you to make one too. I've got lots of parts today. If I find time to get into the shop tonight I'll start taking photos. I also figured out a way to keep the air line at 1/2" from the compressor to the nozzle....this thing is gonna kick some ass.

Maybe if I got to use someone elses' a few times I would be more inspired

 

[Gary in NJ]

It’s alive, it’s alive!

I finished the air supply side of the cabinet over the weekend. I also made a switched outlet and attached it to the side nearest to the outlet so I could easily turn off the slurry pump.



I finished the vacuum attachment as well and made a fresh air port out of PVC



Today I worked on the slurry supply side. I fitted the circulation hose and the supply hose to the pump and fitted it inside the slurry bucket.





I attached some bulkhead fitting to the cabinet for both air and slurry lines and then attached the vapor blasting nozzle.





With everything in place I decided to give the unit a dry run…well actually a wet run. I didn’t add any glass beads to the slurry bucket and kept it just water. This way if there is a leak I wouldn’t have to worry about cleaning up the cabinet to seal it.

I hit the switch and water began flowing from the nozzle. And then I hit the air pedal - and damn that water comes out with some force. The vacuum kept the work area visible. It all worked just as I hoped.



I think I’ll dry it out and give it another round of silicone caulking - just to be safe/sure. But I’m ready to start blasting.

I got the parts for my CB900 engine rebuild from the UK today (talk about good timing) so I’m going to spend the next few nights getting the bottom end of the engine assembled. Next week I’ll start blasting parts as I need them for the full rebuild. I think I’ll learn to blast on the oil pan; it’s ugly and it’s a part no one will ever see. It’s also the first part I’ll need to get the engine back on my build stand.

Stay tuned for result photos.

 

[Gary in NJ]

Success. Well, sort of.

The system works exactly how I’d hoped. But I chose the wrong blasting media. There are some typical grits used in vapor blasting;

Medium Grade (#7) 60-80g
Cleaning - Excellent
Finish - Rough

Fine Grade (#10) 100-170g
Cleaning - Good
Finish - Satin

Extra Fine (#13) 170-325g
Cleaning - Poor
Finish - Gloss

I bought/used fine grade and I thought I’d be happy with a satin finish, but I’m not. Here are some before and after photos.





The after photo doesn’t do the part justice. It’s a fairly consistent finish, but the lighting makes it look blotchy. But it’s not the finish I want…it’s…satin. So I’ve ordered a second 6-gallon bucket and a box of 170-325g glass media. I will have two buckets, one for cleaning and one for polishing. It seems that a typical slurry for cleaning is a mix of fine glass and aluminum oxide. So I will mix some AL-OX in with my fine media.

Other discoveries:

My air compressor can’t keep up. It barely has enough CFM to run the 6mm nozzle, but it will run itself down to 60psi in about 8 or so minutes, at which point I have to stop blasting and allow the compressor to recover. I’ve ordered a 5mm nozzle which I’m hoping will be better suited to the capabilities of my compressor.

My air vent/vacuum works great. As soon as I release the air pressure the cabinet immediately clears. But while I’m blasting, it’s hard to see. I have to think about a windshield wiper.

I’ve got too much flow going into agitation, and I could use a bit more to the gun. Easy fix; I’ll add a 5/8” barb to barb fitting to the end of the agitation loop, and this will restrict the output to 3/8” and drive more flow to the gun.

The cabinet leaks a tiny amount at the door. Not enough where I have to do something about it…but enough that I’ll do something about it. I’ll add a second piece of rubber coving to the piece I’ve already added to the door.

But overall I’m very happy with the design and functionality of the unit. The slurry pump is whisper-quiet. The shop vac and compressor are not. The two Harbor Freight 2000 lumen LED light fixtures really light up the work area.

It’s a very clean and relaxing way to clean and polish parts. It’s the type of tool that I’ll probably find a lot of other uses for.

 

[Motogiro]

It’s a very clean and relaxing way to clean and polish parts. It’s the type of tool that I’ll probably find a lot of other uses for.

So will your family, friends and neighbors!

 

[Gary in NJ]

So will your family, friends and neighbors!

Indeed

 

[Gary in NJ]

I got this thing figured out.

The 170-325 mesh is easier to work with and gives a perfect finish. I discovered that I can control the amount of shine by varying the distance of the nozzle from the part being cleaned. Close is duller and far (8-12 inches) produces a shine. I did increase the slurry flow by going to a larger nozzle (8mm) and I decreased the air pressure to 50psi.

The result speaks for itself. This was 5 minutes worth of work.

 

[Gary in NJ]

 

[TownsendsFJR1300]

Wow, extremely impressive!

 

[gnyce]

Lovely stuff there....