Rust is the Enemy

Susquatch

Well-Known Member
Premium Member
Also got some advice offline from Brent about Scotch-brite and Evapo Rust to clean up the surface rust on mill table and mill, and then protect it with some way oil and Minwax.
Please share!

I have not tackled mine yet. But it's on my to-do list. The normal use of evaporust is dipping. Can't do that with a mill table!
 

Brent H

Ultra Member
@Susquatch :

basically for mild surface rust I clean it off with a green scotch bright pad dipped in evaporust. Comes off great. Next wipe down with a damp rag to end the evaporust and follow that up with some WD40 to remove any water. Wipe that off and then apply some way oil (not like dripping but at least a film). For other cast Iron tables I remove the surface rust and then clean the surface with a rag and some WD40. Apply a coat of flooring paste wax. Let it dry about 15 min, buff off.
Of course for machines that will get oil on the surface the wax will wear off quickly, but it works great as preservative for lesser used metal surfaces and keeps the rust off.
 

Susquatch

Well-Known Member
Premium Member
Sounds great Brent. You might be the only other guy on the planet who uses wd-40 for its intended purpose. Getting rid of water. The WD means Water Displacing.

Quick clarification question. Sounds like you are not putting wax on the mill table, just on other cast iron surfaces. That makes sense because oil dissolves wax.

But what other cast iron surfaces are there that require the wax?
 

Brent H

Ultra Member
@Susquatch : I have a full cabinet shop so table saw, planer table, jointer, bandsaw, shaper etc.
For the mill, once cleaned and oiled there is a set of boards that cover the ways, one on each side of the vice. The bottom of the boards are a bit oiled and serve to keep the table the same. I posted the build in another thread somewhere on here.
 

architect

Well-Known Member
The two tiny units I got for my travel trailer are both like that too.

View attachment 16491

But I hunger for a small hose (tube) drain to the sinks.

I plan to add that but have not been able to find a small bulkhead connector yet. I want something in 1/4" size range. I may have to make one.
I actually returned mine and got a another 35-pint one instead. I realize in my tiny garage I want to hide the compressor in dead space like behind the mill and then just run a hose to a bucket in the front that I can easily dump periodically. This is easier than trying to reach behind my mill to lift the 40lbs unit up to drag the bottom water bucket out. I still think Midea is a great design and would be great for lager space and no drain. But I'm trying to maximize every inch so have to trade quieter, larger condenser with with one that's a smaller footprint but produces more hot air.
 
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Susquatch

Well-Known Member
Premium Member
I actually returned mine and got a another 35-pint one instead. I realize in my tiny garage I want to hide the compressor in dead space like behind the mill and then just run a hose to a bucket in the front that I can easily dump periodically. This is easier than trying to reach behind my mill to lift the 40lbs unit up to drag the bottom water bucket out. I still think Midea is a great design and would be great for lager space and no drain. But I'm trying to maximize every inch so have to trade quieter, larger condenser with with one that's a smaller footprint but produces more hot air.
Sounds good to me. I really like my bucket system. I have a downspout right outside the barn door that drains to my pond. I took the square eaves drop to 4" Big O adapter cap off so I can dump my water into that.

My guess is that your bucket will take a week to fill. The water is basically like distilled so you can dump it anywhere.

As someone earlier posted, don't forget to circulate your air a bit - especially with your Dehumidifier tucked into a corner. I'm not really sure that is required in your space. But you will find out soon enough.

Also don't forget to turn that exhaust fan of yours off as much as possible. There isn't much point in dehumidifying the outdoors. I'd prolly only use it when welding, or painting, or running an engine, and I prolly wouldn't use it all for small jobs of short duration.
 

architect

Well-Known Member
It's been so humid here. I got almost a full bucket since Monday night! This is a temporary setup so my elderly father can easily access and dump the water while I'm away all of next week backcountry portaging.

PXL_20210811_150831194.jpg
 

Susquatch

Well-Known Member
Premium Member
Today is Wed. So that's a pretty darn good machine! It's also a lot of water for a small space. Are you sure you are not moving air in and out of there? Surely it should have slowed down by now.

What does it say the humidity is now?

Mine did that at first too, but they are not producing nearly that much water anymore. The outside humidity here is UGLY, and my space is HUGE!

Being an "elderly" father myself and grandfather, and could be a great grandfather (if my oldest grandson ever figures out how his tools work), I'd be moving that bucket so he doesn't accidentally step in it and have a nasty fall like I did this past spring! My ankle is still badly swollen many months later. Old guys like me seem to lose our peripheral vision far too damn soon.
 

architect

Well-Known Member
There's been heat/humidity alert here over the last couple days so it's been rough. I have 10' ceiling in here that may also be it. I have a ceiling fan moving the air 24/7 as well. I watered the flowers so I'll see what the bucket looks like in the coming next few days. My garage door may have some gaps. Maybe the exhaust fan lets in humidity even when it's off?

I have the unit set to 45% but it holds it as low as 42% so I don't know what the deal is. When I had it set to 50% it would turn off and get to 55% again before turning back on (3min condenser timer) so I decided on 45%. It's a cheap unit so not the best at controlling probably but the price was right and 2-year warranty.

I haven't had time/energy to do the rust cleaning and protection that you and Brent recommended so good thing I didn't hesitate to grab dehumidifier, especially since I'm away all next week!

The bucket is just by the door on the step so he can just open the door and grab it from inside the house without setting foot into the garage :)
 
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Susquatch

Well-Known Member
Premium Member
There's been heat/humidity alert here over the last couple days so it's been rough. I have 10' ceiling in here that may also be it. I have a ceiling fan moving the air 24/7 as well. I watered the flowers so I'll see what the bucket looks like in the coming next few days. My garage door may have some gaps. Maybe the exhaust fan lets in humidity even when it's off?

I have the unit set to 45% but it holds it as low as 42% so I don't know what the deal is. When I had it set to 50% it would turn off and get to 55% again before turning back on (3min condenser timer) so I decided on 45%. It's a cheap unit so not the best at controlling probably but the price was right and 2-year warranty.

I haven't had time/energy to do the rust cleaning and protection that you and Brent recommended so good thing I didn't hesitate to grab dehumidifier, especially since I'm away all next week!

The bucket is just by the door on the step so he can just open the door and grab it from inside the house without setting foot into the garage :)

I'm going to do some research for both of us and others who are following this.

You have a 10ft ceiling, but what size is your garage again?

In the meantime, I doubt that door leaks or an open exhaust fan that is not running would be that bad. If the plants you are watering are in the garage, that would add humidity. Plants use sunlight to break down water into hydrogen and oxygen, the oxygen is released, and the hydrogen is combined with carbon dioxide to make hydrocarbons. But not all the water is used. Actually only a small bit of it. So most of the water you give your plants ends up in the air.

It might be a cheap Dehumidifier, but it's working GREAT! Don't be afraid to set it to 50 or even 55. That will save you a bundle and there is nothing really worrisome about 60% humidity. My only real concern is the accuracy of the humidity reading. My two units seem to differ by about 5%. I also have a humidity gauge that suggests the unit with the higher number is correct.
 
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architect

Well-Known Member
No plants in garage I just meant I emptied the bucket into my outdoor plants :)

I think the last few days have just been -really- humid and recall seeing 80%+ on the weather reports. I've now set the unit to 50-55% and with weather easing up today the bucket has barely filled.

I also caulked the garage door trims a bit just in case :)
 

Susquatch

Well-Known Member
Premium Member
I feel your pain. Essex/Kent is usually over 90% because it is the south-most part of Canada at the same Latitude as the north border of California and surrounded by huge lakes and I live right on the North shore of Lake Erie. But it can get worse - @whydontu has salt in his air!

I promised a little more research. I dug out my psychometric charts again and made the following chart that shows the data in a little more useful format. This is the MAXIMUM water that air can hold at the temperatures listed - ie at 100% humidity.

20210812_112016.jpg

I figured per 1000 ft3 and per 100m3 were pretty reasonable multiples for most shops and garages.

For example, if I assume your garage is 20x20 with 10ft ceilings, that is 4000 ft3. Per the chart, 30°C air can hold 1L of water per 1000ft3. Therefore, the 4000 ft3 of air in your garage can hold 4x that or a maximum of 4L of water.

% Relative Humidity is a term that was developed to describe how much water there is in the air compared to how much water CAN be in the air. For example, if the air in your garage can hold 4L of water, then at 75% humidity, the air is holding 3L of water and at 50% relative humidity it is holding a total of 2L of water.

One look at the maximum water content at temperatures below zero VS temperatures above 20 (winter VS summer) and it becomes easy to see why homes need to add water in the winter and dehumidify in summer. When that low water winter air gets into your house and then gets warmed up, the relative humidity DIVES!!!!

The reason that rust forms in humid air is also evident in the chart. For example, let's say the temperature is 30°C and the relative humidity is 90% inside your 4000ft3 area. Then let's say the temperature overnight drops to 20°C. From the chart 1000 ft3 of 30 degree air CAN hold 1L of water. At 90% relative humidity it is actually holding 90% of 1 L which is 0.9L. However, at 20 degrees, that same air can only hold 0.6L of water. For 4000ft3, it's 4 times that or 3.6L and 2.4L. As a result, 1.2L of water MUST condense out of the air by forming dew on everything in the garage. Rust is inevitable. When people talk about the dew point, they are referring to the temperature at which the relative humidity reaches 100% based on the amount of water in the air before it started cooling.

It's important to recognize that you cannot go by how much water your bucket accumulates in the first week of its use. Wet concrete, absorbant materials, dampness, and other water sources in your garage can add up to a LOT more water than there is in the air. As the air dries out, all that absorbed water starts to dry out too. That's probably why your pail filled so fast at first.

The good news is that the air will dry out those areas once it is dry enough itself to be able to do that. It appears to be doing that already, but you can expect the overall process to take a week or so.

After that, you should actually be able to use the amount of ongoing water removal as a proxy for how much your garage is leaking air. In the process of doing that, don't underestimate how much air gets changed every time you open a door or run that exhaust fan. That said, your Dehumidifier should work much faster and better once the garage itself is dried out. A little internal air circulation will help too.

Although the data is definitely not linear, it is still reasonable to use standard linear interpolation to determine the maximum water contained at other temperatures not listed in the chart.

I hope all that is useful to @combustable herbage and you and others. I'm annoyed with my progress on my Hartford Mill right now, so I really needed a good distraction and this was perfect!
 
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architect

Well-Known Member
Well that's all too smart for me to understand but I'm sure tons of people will find your research useful!

My unit has still been taken out quite a bit of water. But the humidity has his 95%! I'll see what it looks like in a week when I'm back in town but at that point the humidity will have dropped anyway, hopefully.

I'm avoiding any rust cleaner chemical work until the weather changes and I can open up my garage for air circulation.
 

Susquatch

Well-Known Member
Premium Member
That's a good writeup. I always thought Calgary was a cracker comparatively. Everyone has dry skin issues, pay bucks to install humidifiers, people generally don't seem to have the same degree of rust battles, inside at least. But looking at the seasonal charts, maybe not as dry as I thought.
Your charts are very interesting to me. I guess I don't think 85% is all that bad. Especially if I assume those monthly numbers are the highs. Still, they are certainly higher than I expected. And looking at the daily numbers was equally interesting. The high humidity was typically overnight as the air cooled and low during mid afternoon - exactly what you would expect if the actual amount of water didn't change but temperature did.

How often do you get dew on the grass in the morning?

Just thinking, my life would be so wonderful if Ontario could swap climates with Sask/Alta........