build my own enclosed +Duplex Receptacle +solid state for router or shop Vac from http://www.mpja.com
1 PART# (special store item) $2.00 120v AC enclosure.
1 PART# Stock No: 31931 RL $5.95 10A, 480VAC Solid State Relay
http://www.mpja.com/10A-480VAC-Solid-State-Relay/productinfo/31931+RL
L
Be careful as you can get into trouble without UL listed.
There is a unit that I bought that works perfect and you do not have to build anything.
Here is the list:
https://www.amazon.com/Iot-Relay-Enclosed-High-power-Raspberry/dp/B00WV7GMA2/ref=sr_1_20?ie=UTF8&qid=1477807797&sr=8-20-spons&keywords=arduino+controlled+switch&psc=1
You can build stuff for low power but when it comes to mains you have to get it UL listed cause if the house catches filre and you have that there you can get into trouble with it. Unless of course where you live they don’t care.
Nice setup. Just run it little while while it’s open to see if any heat you have, make sure. I’m using similar way, but my dust collector is 3 phase runs with 3 mechanical relays. I use this relay to trip them only.
Never said it was required by law.
I just said that if your house burns down it can cost you in court. Tampering with the 120v line without safety checking the device is dangerous and I have heard of many people getting into trouble. Especially if your house is a rental that you are not the owner of it. The UL listed is for products and is all about safety. Safety should be priority when working with house current.
What I said was just a caution.
I do not know what the local laws are there but here it can cost you if something goes wrong.
Btw I am not suggesting that you don’t build stuff. Just that you be careful.
The box could use a bit of better planning as the wires are too close and may cause short if they are pinched.
Open up a power strip and see how they make them and do your wiring similar. This will help you see ways to prevent wires getting shorted crossed or pinched that could fry your machine.
Please do not take my comments as a negative on the part of building your Duplex Receptacle.
I just want to ensure people do not make errors. I have and from experience I just want others to build and be happy.
I have found some insides of power strips:
In this image we see they do use solder. However its not your Radio Shack type. Most of these are slightly different in the ratings. (Sometimes companies will use the same stuff you have in your shop. Its cause they are being cheap)
Also be aware that the solder connections must be good quality and the factory inspects these.
Here is a page that you can read about it in more detail: (I have had to solder to NASA specs! while in the military)
These connections have 120v at max of 10 to 15 amps. You can weld with that current!.
http://computerchristmas.com/tmp/myimages/13-PowerstripInside.jpg
In this one I really like the construction and layout. None of the wires are crossing each other and there is no solder.
http://www.avrev.com/images/stories/equipacpower/cryo/new_cryoparts_power_strip-3.jpg
Now notice one thing in common with the 2nd strip and yours?
No fuse.
Fuses are very helpful from over current that can cause fires if there is a short.
Solid state relays also get very hot. Especially when they have been on a long time. (See image below)
If it gets hot it can melt the plastic and cause it to catch on fire.
This is the reason I mentioned the use of one already build with a UL listed rating. Its safe and made so it will not catch fire and they have a fuse (circuit breaker) in them.
Please be careful. Wood dust is very flammable. More so than most would think.
This is what inventables uses on their solid sate relay. I am sure they did it for a very good reason.
The data sheet on the unit you have: https://cdn.sparkfun.com/datasheets/Components/General/SSR40DA.pdf
Also look at your wiring. The load needs to be switched. It looks like you have it on the Neutral. (Black is usually Load and White is Neutral unless you switched them around.)
Look at these. Check your datasheets on proper hookup.
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSSax0228CdZPi_9YA7rwFBuRYnSAB6MNzRy4tQ04zEYDuzs0C1
Here is a good video on the devices if you do not believe me:
His link I added it for you as well:
In the video this guy explains what I am talking about.
Have fun. 
