Joe_Friday Posted April 22, 2014 Share Posted April 22, 2014 Hello all, Was hoping someone could help me with this. New to blacksmithing , been around it most my life as my grandfather was a farm smith but I am just getting into it myself. Anyways I recently had my blower I bought stolen and now not having the money to get another one I am looking to convert a leaf blower attachment I had setting around to a manual crank blower. My question is for a small coal forge how many CFM are needed ? This attachment says in its specs 380 CFM / 150 mph on a 26cc trimmer head. When tested with a hand drill it has decent static pressure it seems just trying to figure out what the minimum CFM needed is. I do not have electric available with in distance where I smith at so making this hand powered is my biggest concern. I assume it will need a 14 - 16" handle to get it turning at the right speed. Any info, suggestions, advice etc are appreciated. Also I did attach a pic below. J.W Quote Link to comment Share on other sites More sharing options...
Eddie Mullins Posted April 22, 2014 Share Posted April 22, 2014 I don't know what a typical hand crank is raited at, but I am using an exhaust fan that was either 50 or 70 cfm and its more than enough for my forge. The flow needed will vary depending on your forge and use. As far as your out put hand cranking the blower, I'll have to leave suggestions on that to others. You might want to considers a bellows of some type, or there is a thread here somewhere of a squirrel cage fan with a hand crank added for a blower. Quote Link to comment Share on other sites More sharing options...
Joe_Friday Posted April 22, 2014 Author Share Posted April 22, 2014 Thanks for the response. I know just now I was messing with it and hooked a hand twist drill to it. And it was blowing as much as a small electric exhaust fan I have that is rated at 40 CFM. This blower is a paddle type centrifugal fan which seems to work as good as a squirrel cage, so I assumed for free it would work. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted April 22, 2014 Share Posted April 22, 2014 A bellows would be a much better deal; I've built them for under a US dollar before (plywood from a junked printer enclosure, naugahyde from a junked couch, etc) Much easier motion than having to crank a drill by hand between work sets. Quote Link to comment Share on other sites More sharing options...
Joe_Friday Posted April 22, 2014 Author Share Posted April 22, 2014 A bellows would be a much better deal; I've built them for under a US dollar before (plywood from a junked printer enclosure, naugahyde from a junked couch, etc) Much easier motion than having to crank a drill by hand between work sets. I actually didnt plan on using a crank drill to turn it. Was going to put a handle on it like my buffalo blower had. I was only using the hand crank drill since it was able to clamp onto the square end piece. I considered bellows but I do not have a lot of room to the side of my forge. Maybe a box bellow could fit in there if this fails. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted April 22, 2014 Share Posted April 22, 2014 Output, (both volumn and pressure), of such fans depend greatly on speed; I think you would be happier with a box bellows in the long run; but try it and see. Quote Link to comment Share on other sites More sharing options...
Frosty Posted April 22, 2014 Share Posted April 22, 2014 I vote bellows too, easy to build, easy to use. However if you want to use the blower you want to gear the drive up or you'll look like a 3 stooges movie trying to turn it by hand, the longer the handle the sillier it'll get. Keep your eye open for an old bicycle, do a little creative repurposing and you'll have a blower with decent rpm and coast. Heck, it might even have a coaster brake for those special occasions. Making forge blowers out of old bicycles is a paying profession in many 3rd. world countries. Somewhere I had a series of pics from Viet Nam about a man and son who made a good living making ans selling blowers made from old bicycles. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Joe_Friday Posted April 22, 2014 Author Share Posted April 22, 2014 Yes that was what I was thinking too. Doing a gear drive like what was on my buffalo before some meth head smashed it with a sledge and loaded it for scrap. They at least left me the handle. I seen the bicycle wheel ones from Africa and another one that I found on google. My main thing is I guess I am nervous to spend much more money till I get moved to the location next year because of thieves so looking to use what I have on hand. Quote Link to comment Share on other sites More sharing options...
rockstar.esq Posted June 27, 2014 Share Posted June 27, 2014 Maybe a water bellows? Could be built out of a bucket and a plastic trash can. Quote Link to comment Share on other sites More sharing options...
rcbuilder1 Posted August 24, 2014 Share Posted August 24, 2014 how do u make a water bellows Quote Link to comment Share on other sites More sharing options...
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