Jump to content
I Forge Iron

homemade blower


Recommended Posts

Most turbos output a lot of air so you will need some way to control the flow. The idea way would be to use a variable speed electric motor  but the most common way to do this is with a simple spill valve. However, if the turbo is from a big engine then depending on what RPM is used you might end up with a gale coming out of the spill valve so some form of speed control will be needed.

 

The attached graph gives you an idea of engine CFM requirements versus RPM at different engine displacements (in cubic inches) - this is not exactly the same as turbo outputs but it gives you an idea of engine requirements. 

 

For example a 350 cin engine draws about 300 cfm at 3000 rpm while a 100 cin needs about 90 cfm.

 

My guess is you will need less than 100 cfm to run a forge so if you do decide on a turbo then one for a small engine (~100 cc or less) would be all that you would need.

 

Whatever you use It seems like a very expensive way to go.

 

post-39957-0-48823300-1370567934_thumb.j

Link to comment
Share on other sites

You sure can, it's being done every day in third world countries. Probably the most useful component in Asian countries seems to be bicycles, a little artistic thinking and tinkering and you can get them to gear the drive wheel way up, then use a belt off the tire to drive the blower and you have one screaming fast drive. Fill the tire with sand and water and it's heavy enough to keep turning for quite a while after you let go of the crank.

 

All you need then is a simple impeller. Think balanced disk and bearing on a shaft in a circular housing. The center of the housing needs to be open for the air intake and a small section on the rim has the outlet. A tin can and duct tape will make a dandy outlet and if you tip it in the direction the impeller is turning you're golden.

 

All that's left are impeller blades and these are silly easy to make. If the housing your impeller disk is in is say 2" wide so there's  say 1 1/2" between the disk and the housing on the same side of the housing as the air intake. Now simply start cutting tin cans into small semi circular sections maybe 2-3" long and narrow enough they fit inside the housing without rubbing, go ahead bend them to fit, they won't mind. you DO want them all the same size and weight for balance! Use a couple wood screws each and affix them to the disk near the outer edge. It doesn't make sense intuitively but it isn't as important to have the cup side facing the direction of rotation as intuition makes it seem. That said, have them all facing the direction of rotation and it will blow harder for less effort.

 

Now with a little tinkering make a stand, find something for an air line to the forge and you're almost ready to go. The impeller still needs a little balancing and this is the trickiest part of the whole seebang. If you've used a solid enough axle and bearings a little vibration shouldn't be a big thing. Just make the unit heavy enough and solidly mounted enough it doesn't matter.

 

If it is wobbling badly enough to matter get a lumber crayon and take the outlet can off. Crank it till it wobbles and carefully insert the lumber crayon into the housing till it just kisses the disk. What you're trying to do is find the heavy side of the disk so you only want the crayon to kiss it at the point it's farthest from center. THEN put another wood screw into the opposite side of the disk. Repeat till it's balanced enough to work for you.

 

That's it, easy greasy home made blower, any tinkerer can do it and have fun making it too cool for school. you may wonder why the wood disk impeller. that's because making an impeller with a frame is just so much harder to make and balance. a 1/4" 3/8" plywood disk is just too easy peasy and plenty skookum.

 

Frosty The Lucky.

Link to comment
Share on other sites

thanks for all the input every one

 

i understand where you are getting at Bobl with the cfm stuff i was looking at what frosty said and i think i may do that because here in Alberta it is hard to find any smithing stuff at a decent price

 

thanks again

 

tristan

Link to comment
Share on other sites

That's the one by an IFI member I was thinking of!

 

Thank you Bryan.

 

How's warm feel buddy? I'm basking in 70f but I don't know about this smelly water oozing out of my skin. <grin>

 

Frosty The Lucky.

Link to comment
Share on other sites

How's warm feel buddy? I'm basking in 70f but I don't know about this smelly water oozing out of my skin. <grin>

 

Frosty The Lucky.

 

Now I understand the name.

 

I just had a look at the average highs for Anchorage and the only month in the year where the average high is higher than Perth is July (66 versus 65) - don't forget that's mid-winter for us. I like winter's here - there's a bit of rain every now and then otherwise it's nice and sunny and as we call it "cool".

Link to comment
Share on other sites

IF you are going to have motorized blower go to a resale shop and just spend $3 for used hair drier and disconnect heating element.... IF you want mechanical blower some like of squirrel cage (car heater fan)  with 4:1 or 5:1 dear ration will do fine.... Auto turbos rely on really high rpm to create air pressure.... Its more work and bulk than its worth, but if that is what you want ..Go go it...

 

Dale

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...