Sunday, April 10, 2011

Cement Mixer Update

The cement mixer is finally breathing! I met the short term team that brought the pulleys over at the airport at 2:30 the other morning, and after a bit of adapting, we've got things going! The big main pulley fit just right - thanks to the $25 micrometer that was sent over in the last container! We did need to do a bit of work to make the key stock that keeps the pulley from slipping on the shaft, but half an hour on the bench grinder turned a chunk of rebar into a pretty well fitted section of square key stock!


Sometimes you just have to do what you can...


A near perfect fit!

The motor we're using was donated and sent over in the container a couple of years ago. It was crated, and didn't want to start when I opened it up. After taking apart and cleaning the carb, it seems to be running pretty well. The pulley we bought for the motor is the wrong size because the supplier I found at the last minute didn't have metric sized pulleys like the motor's shaft is. So, we did a little careful bending of a piece of sheet metal and it did a great job of filling in the gap between the 20mm shaft and the 7/8" pulley opening!

video
Not bad!

We found and cleaned up the nameplate on it, it's an Italian machine (Dieci) from 1989. It looks pretty good for its age - and it's getting ready to start its second life, for us.

All we need to do now is patch a couple of rusted spots of sheet metal and find/adapt some wheels for it!

Tuesday, April 5, 2011

Prepping the pillars

Now that the holes are dug, we're moving on to the next step. I've never been around commercial/concrete construction in the States, so I'm not sure how we'd do this part there, but the last couple of days the workers have been cutting, bending, and tieing rebar together by hand to make the steel skeletons that will be poured around to make the pillars.


This is how the skeletons end up

They cut all of the chunks of rebar apart with a hacksaw and vice, then bend the chunks using a steel bar with a notched head at the end that grabs the rebar, and finally use wire to tie all of the pieces together.


The next step will be to build wooden forms, stand the skeletons up in the holes and fill the footings in with rocks and concrete. After that, to make the pillars, they'll nail the wooden cement forms around the skeletons, and then start filling the form with bucket after bucket of cement dumped into the top of the form, until it's full. Hopefully the cement mixer will be ready to roll by the time we get to that point!

Cement Mixer

Once the decision was made that we couldn't get material strong enough to make the two story solar support structure out of steel, we had to revert to the way things are usually done here - reinforced concrete. The normal way of doing small concrete jobs here is to mix the gravel, sand, water, and cement together on the ground with shovels. That works fine if you have time and don't mind the concrete being incompletely mixed and thus weaker. Given that these pillars need to hold up the weight of a pair of cars, that's not going to cut it here even if we had forever to work that way. So, given that we already had a donated motor just waiting for a cement mixer to be used in, and that it costs $80 a day to rent a small mixer or $3000 to buy a new one, we started looking for one we could rehabilitate for this and the many other foundations we'll need to pour for the block maker's various projects in the future.

Fortunately, after several weeks of asking around, our main construction guy, Nilton, got a line on one out on the islands that had been stripped and was sitting unused. He made a deal with the owner of the shell, and for $190 we had ourselves a pretty decent sized mixer that needed some TLC, brought in on a canoe from the islands!


There's a good amount of rust on it, and it's missing the pulleys and motor needed to drive it, but fortunately all of the important parts like the mixing drum, gears, and bearings, seem to be in pretty decent shape!

After sanding it all down, the workers hit it with a coat of primer and some good enamel, and now it's looking pretty good!

The last big piece of the puzzle was to find the proper pulleys to reduce the speed of the generator motor we have to make work with the mixer. After searching around in the used parts market here (which is mostly parts taken off of cars) we realized that finding a pair of pulleys with the correct diameter to gear up the motor to be able to spin the mixer drum and with the correct shaft diameter was like looking for a pair of matching needles in a haystack. I thought about heading down to the local Grainger or McMaster-Carr to pick them up, but... alas, there are none. :) We didn't have time to wait for the mail, and UPS could've gotten the $50 parts here for about $400, which also didn't seem like a good option.

Fortunately, we heard about a short term team coming over, and they very graciously agreed to surrender 20 lbs of their luggage allowance to bring the parts over this week! We'll be ready to hit cement production hard next week, so hopefully we'll get the parts and get the mixer fixed before we even miss it!

Friday, April 1, 2011

Solar Project Begins

In preparation for the solar system, we're starting to build the structure where we'll mount all of the panels! We looked in every corner of the youth center to find the best spot for the panels, but since they're going to occupy either 30x42' or 30x72' depending on how we lay them out, it's not like you can shove them just anywhere! We needed just the right spot, where they'd be high enough to be safe from mischief, far enough away from the edge of the youth center to be safe from thieves, and never in any shade. We're also trying to balance the desire for the perfect spot against the cost savings of using an existing roof or building that isn't as ideal.

We had planned (and budgeted) to put the system on the roof of our house all along, but when we arrived and talked to the mason that built the house, we found out the foundation wasn't strong enough to support all of the weight, so we beg
an our hunt for a new location. In the end, we came up with just about the only spot in the center that fulfills all of our requirements.

The back section of the youth center is the guesthouse, and the yard in front of the guesthouse is going to be our spot. The yard is beautiful and green in a city with lots of dirt and dust, so we're doing everything we can to minimize the appearance that the solar system is taking over the yard. We'll be building a cement support structure of pillars to hold the system up, which will connect to the front of the guesthouse, and give us a place to mount the panels at the same height as the roof of the guesthouse, but out over the yard in front of it.

Here's the guesthouse before we got started.

This is the basic idea, but now that we decided to use cement instead of steel we'll also have to put connecting horizontal beams all the way around at the half height altitude as well as the ones on top that are in the diagram. We would've preferred steel, but there isn't anything tough enough available here.

The decision about whether to occupy 30x42' or 30x75' depends on how much there is to be gained by building the system to rotate to follow the sun througout the day. After lots of searching online, I haven't found a clear answer, so we're keeping our options open. We're going to build to the smaller size with the option of expanding. When the panels arrive, we'll do a test for a few days to compare the amount of energy collected by a couple of fixed panels compared to a couple next to them that follow the sun. Once we know how much improvement we're talking about gaining by following the sun, we'll be able to evaluate if it's worth the extra expense and complication to do so or not. If it's 2%, we'll be sticking with the much simpler and cheaper fixed method. If the number were closer to 30% extra energy, we'd have to think hard about if we want to leave that much generating capacity on the table, given how expensive the panels are in the first place.

So, in the first phase we'll be building four of those six rows of columns. If we need to add on later, we'll go back and build the other two to get our full 75'. The first step is digging some deep footings, to make sure the system has a solid foundation. The workers dug eight holes that are five feet deep and a bit over three feet across!





Sunday, October 10, 2010

Craigslist and Ebay - Fueling the Shop!

It's been a while since I've taken the time to sit down and blog, but I thought I'd catch up on some of my projects while we're home. We're going to be sending another shipping container over to Bissau in January, for a big solar project at the center (more on that later). The container going over means there will be some extra space for other things, and we've set aside some money to round out the shop's equipment roster. For anyone not familiar with the project, we started documenting it (including a floor plan) on our website here.

I've been scouring ebay and craigslist in an attempt to make the money we've got go the furthest it can, and I've gotten some great deals! Some of the things I got were ready to go, some needed fixing, some just needed supplies bought, and many will require the motor being removed and replaced with one compatible with our power over there, and rewiring. For anyone interested, here are the main things so far:

Jet HVBS-7MW Horizontal Metal Cutting Bandsaw
A nice 7x12 metal cutting bandsaw! I got it used on eBay. We have an abrasive chop saw like this one already, but it's pretty obvious as we use it that it wasn't meant for the kind of abuse and level of use we're going to need in Bissau. Our current one will become part of our mobile setup, and will do a great job at that. Meanwhile, this new (old) bandsaw will give us a quieter (though slightly slower) way to cut steel in the shop. Since the center is a school as well, the decreased noise level will be appreciated by all. The saw is working great after some adjusting, but will need a new motor, pulley, and rewiring to make it compatible with our 50Hz generator power.

100 or 120 Gallon two-stage Champion R15 16cfm@175psi compressor
A sweet air compressor. We have a little portable compressor that I sent over last time, but it already wasn't in great shape, and doesn't have enough snort to keep up with several of our tools. It's making some funny noises since it wasn't meant for the power over there, so it will live longer if we can move it into our mobile setup which uses American power. This new one is about 2x as big, and is a step above in terms of durability, being industrial. It retailed around $2000 when it was new 15 years ago, but I got it for $275 without a motor, which I would've had to replace anyway! I found a replacement motor on eBay and lucked out, winning it for less than the cost of shipping it to me! There's some flaking paint on it, so I'm going to sandblast it and give it a new coat of paint, but other than cleaning it up, installing the new motor, and putting it back together, it should be ready to roll! It's big enough to be able to run all of the air tools we have over there, and the sandblaster I'm hoping to take over this time too!

Miller SR-300 DC Stick welder
A monster DC stick welder. We have a very nice gas driven Lincoln welder that was sent over last time, but with fuel being so expensive, it's a little stressful to work knowing how much every minute is costing! That Lincoln welder will transition to being the heart of our mobile setup. I paid $42 for this stick welder from the 80's. It will run from the youth center's power, so we can take our time and be more careful. It needs sheet metal repair, sandblasting, painting, and new welding leads, but then should be ready to rock! It's an 800 lb monster, and should be way more than we ever need - but for $42, who can complain, right?

Delta Industrial floorstanding 1HP drill press
This old drill press was a great find on eBay. I brought a used benchtop drill press over with us last time, and it's gotten a ton of use already. Unfortunately, it has a wobble which makes it hard to drill accurately and has snapped several smaller bits because of it. This one should be hardier and is supposed to spin nice and true. I haven't seen it in person yet, but we got a great deal on it - and as an added bonus it looks like it's motor is already dual rated for U.S. and European power, so the motor won't even need to be changed out! Unfortunately the seller lost the top belt cover, so I'll have to make and paint a new one of those, but other than that it should be ready to go!

Hobart Handler 180 Mig welder
A small wire fed welder. Much of the fabrication work we do uses thin metal tube stock, which is what's mainly available in Bissau. It's difficult to stick weld since it's so thin (19 gauge), so we're going to use this machine to make those welds stronger and work more quickly. Other than buying more supplies for it and changing the power plug once we're over there, it's all set and works great!


The last big tool is still in the planning stages. Like I said before, the chop saw we have wasn't meant for the workout it's getting in our application. The bandsaw will be great, for quieter, gradual cuts, but there will still be some times when we need a rotating blade for cuts. I did some research on industrial versions of the abrasive cut off type saw we have, and found out about saws like the Kalamazoo K10B. They cost a pretty penny, but have a nice powerful motor that won't wear out. I then did some more reading and found that there's a newer style of steel cutting saw called a dry cut saw, which works the same way, but uses a carbide tipped saw blade to do the cutting. This dry cut style is actually cutting chunks away instead of grinding fragments - so it cuts clean lines and cuts more quickly, doesn't heat up (and warp) the thing you're cutting. The blades are supposed to last about 10x as long as the abrasive disc kind. Sounds great, but since we'll have to send the blades back to the U.S. to be sharpened, we kind of need the best of both worlds. So, I'm going to build a saw from scratch that can do either - we'll use blades when we have them available, and then switch a pulley to be able to use abrasive discs when we can't. And, by building it, it's going to end up being a lot cheaper than buying either. Good plan, hopefully!

I've got big plans for the shop once we get back, and the new tools are going to put us in a good position to really be able to get stuff done. I'll try to post some updated photos as all of these various conversion and restoration projects have some progress.

It's been really fun being home and having the opportunity to find tough, well-engineered machines at used prices, instead of having to pay 2x for Chinese junk over in Bissau!

Thursday, October 22, 2009

Njita

Sometimes in the process of learning another language you get an interesting peek into the culture of the people who speak the language. For example, in Creole there is a verb, “neni”, meaning “to run, greet someone, and hug them”. The fact that we don't have a word like that shows something about the way we greet each other compared to the way Guineans greet each other.

We recently ran across an interesting word. I have always known that the following mindset existed in Guinea-Bissau, but never found a word for it. We see things cobbled together all the time. Half of the taxis in Bissau are push started each morning by neighborhood kids because their starters don't work, it's routine to see auto repairs done with zip ties, I saw someone last week using cardboard as a replacement turbo gasket on an engine, etc. Doing things in an excellent way is not valued by this culture as it is in ours. This characteristic of Guinean culture comes largely from how hard it is to survive, I'm convinced. People spend so much energy on daily life (cooking, eating, getting water, caring for their health, etc) that there isn't enough energy to be worried about doing things better than they need to be done. If a zip tie makes your car work again, then it's a sufficient repair. Why spend the time and money finding someone to weld and repaint the broken area if the zip tie make the car work just as well?

So when Emily was glancing through the dictionary and found the word “njita”, we had an “Ah hah!” moment. Here is the dictionary entry:

Njita (v): To fix something temporarily

And some visual definitions I've been collecting over the last couple of months as examples of the way we're not going to do things:

I think this is a flagpole. Not that bad, but since they didn't bother to paint it, in 10 years that truck bed will have a giant hole rusted into it.


Our bike seat, worked on by a local mechanic while we were gone. Check out that craftsmanship.


The welder at the local building supply store.

I have been dreaming about the machine shop: how to set it up, lay it out, and how to impart a mindset of excellence; both in what we produce and in how we operate. Tools here are shared among many people because there aren't many of them, which is good as it promotes a culture of sharing, but also has the unfortunate side effect of meaning there are no complete sets of anything anymore because of tools that have been borrowed and either broken or never returned. Then, since someone only has part of the set, they use the wrong tool to do the next job and end up ruining the tools that are left over because they weren't designed for what they're now being used for. So, setting the shop up in a way that fits into the culture but also protects our equipment is a little difficult; we want to be good neighbors but don't want to lose 20% of our tools each year!

I am anticipating that a good dose of patience and perseverance will be necessary to change the mindset of the people that will eventually run the shop that it is worth the extra energy to build things stronger than necessary, spend the time to rustproof them well, and organize the shop in a way that it stays well supplied and won't allow tools to walk off. But, if it were as simple as just building a building instead of changing mindsets, we wouldn't need to be over here! :)

Monday, June 22, 2009

My Sweet Shirt

It's always funny when stuff from the States pops up over here and reminds us of home. There's a section of the market here that sells used clothes, most of them donated, from all over the place. Last week our teammates were in the "fooka" and bought a shirt for me.


It's pretty awesome, because everyone over here assumes I had the shirt made in the States and brought it over. When they find out it came from the market here, they all laugh. The story got funnier, however, when I looked for the website. The website isn't there anymore, but a google search lead to this "sweet" campaign video for Emily Hutchins for student body president from 2008. Awesome. :)