Thursday, August 13, 2015

Patti update and a blower for the forge.


Patti’s update:

Patti is doing well although the last couple of days she has been a bit depressed. She was having a lot of nausea and constipation and has had no appetite lately. We decided to take her off all the narcotic pain killers on Tuesday. Today she says she is feeling a bit better but still has some nausea but I think her appetite is improving. She had a piece of toast and a peach for breakfast.

A blower for the forge:

Many years ago I built a small propane powered forge so I could make hand forged knives and other small items.


The burner is just a couple of small brass plugs that are drilled to the proper size for propane and screwed into the square tubing that goes across the top of the tubes that feed into the forge. The gas is connected to the square tubing and feeds through the jets.
Air is drawn in around the tubing and into the forge through venturi action. The fire in the forge draws air down the tube.

The problem:

The system works pretty well except when the forge gets very hot. When that happens, there isn’t enough air flowing into the tubes and the flame burns inside the pipe instead of in the forge. I have found that if I blow down the pipe the flame goes back into the forge for a short time. But after a bit the flame is pushed back up the pipe to the jet by the heat in the forge. If I leave the door on the forge open it works better but the forge runs cooler with the door open.

The solution:

For a long time I have thought about putting a blower on the forge but I stopped smithing a few years ago so never got around to doing it.

This week I decided that I needed to put a blower on the forge as I will need it to get hot enough to forge weld the basket twist handles for Dave’s wine barrel cooler. 

I decided to use plumbing parts to build an air manifold. I wanted to use Black iron pipe parts but couldn’t find enough black iron pipe in the size I needed so I compromised and used galvanized pipe in stead. The only reason I didn’t want to use galvanized parts is because it is hard to weld to as the steel is low quality and the zinc coating will give you a headache when it is burned off. When I weld on galvanized metal I always grind the zinc coating off first. I also make sure that I have a fan blowing the smoke away from me.

Okay here is the forge with the gas bar and the jets removed.


I had to weld some ears on the side of the 1-1/4” “T’s” to connect them to the venturi pipes.


As you can see in the above picture I used two 1-1/4 “T’s” instead of using one “T” and one elbow. The reason for this it that I didn’t know if the blower would be too strong and maybe blow the flame out so I wanted a way to depressurize the system when the blower is on. Also I was concerned that the forge would not have enough air to start with the blower off so I used a “T” with a damper type valve on it.


To make the damper, I drilled a 10-32 tap hole in the lip of the “T”.


Then I tapped the hole for a 10-32 screw.


Next I had to make the damper plate.

I cut out the shape that I wanted for the damper plate.IMGP5791

Here is how it looks on the manifold.


Mounting the blower and the plumbing:

I had to make a plate to connect the pipes from the blower to the manifold.
I cut a square piece of sheet metal the size of the blower output. Next I drilled four mounting holes in the sheet; after that I used a hole saw to make a hole in the center to attach a piece of pipe to.


Here is the pipe inserted into the hole prior to welding to the plate.


The pipe was cut off the gas cylinder lying on the table; It turned out to be the right size  to connect a piece of flex pipe to.

Here is the whole thing put together and working. I still need to clean up the wiring for the blower and clamp down the gas feed pipe.


Here you can see the blower mounted to the cart with the flex pipe connecting to an old “Direct TV” antenna mast and then to the manifold. I originally had a light dimmer control weird into the system but the motor wouldn’t start with the dimmer in the system.
I’m not sure why as it turned out the speed control isn’t necessary.

The damper doesn’t appear to have much effect on the system ether.

Time will tell if air injection will actually solve the back-burning problem.

Stay tuned.

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