Conversion Mufflers
 

Okay, checked the Finch book at Lowes on lunch break. It's the newest (1997) edition. On page 120-121 in the TIG section, it mentioned that shielding gas may improve the weld appearance on the back side but it doesn't add any more to the weld integrity. It goes on to say that Al does not pick up contaminates in the air as much as Titanium or Steel do, and that molten Al cools in the presence of oxygen with only minor surface oxidation. Therefore, the use of shielding gas is a waste of money and resources.

My Finch book is an earlier edition (1985?), but I remember it said pretty much the same thing. When I first bought the book I was only interested in MIG and MAW, so I didn't read the TIG section much. I had read in product manuals and spec sheets that Argon is required for welding Al, but I guess it doesn't necessarily apply to TIG?

Needless to say, I'm thoroughly confused.

Conversion Mufflers
 

I believe he is talking about shielding on the back side of the weld. For example if you are welding something that is sensitive to exposure to oxygen when it is molten like titanium or stainless then you not only need shield gas from the torch but you need shield gas on the back side of the weld also. Regular steel or aluminum doesnt require that.



Ill double check my book when I get home tonight but im pretty sure that is what he is refering to.

Adam

Conversion Mufflers
 

Aneat is right, the Al will burn away without shielding gas. Full penetration butt welds in steel will require a purge gas on the back side (usually inside of pipe) to meet some reqirements. Usually only in the nuclear field.
MIG uses a flux cored wire and does not require gas. Think of SMAW (stick welding) turned inside-out.

Conversion Mufflers
 

Maybe I'm just cheap, but has anyone tried these so called "Welding Sticks" that you use with a propane torch? Or is it just hype? Wish I had the talent and equipment that these boat hardtop/tower guys have. Seen some really nice work from them (mainly Pipe Welders in South Jersey).

Conversion Mufflers
 

Try techno-weld welding sticks,I have used them on exhaust
pipes and got exelent results,also price is very low.


ww.techno-weld.com

WALDO
HI8W/HI8WPC ;)

Conversion Mufflers
 

Thanks for the info mangolo.

I will post some pics of my current "Conversion Muffler" on my big Tecumseh. Used a 3/4" conduit junction box. Has a removable cover an gasket and can be had with outlet in various places. Price is right too. Really nothing more the an exhaust diverter, but for now it's the ticket. As soon as the ignition comes in, I'll fire it up and see what the neighbors think!

Conversion Mufflers
 

They work OK, but the process is very finicky. Good temp control is must, just a bit too cool and the stick never melts and just a bit too hot and the molten stick just flows off the parts without sticking. Parts must be very clean too, or the joint is very weak.

check out local electrical supplies
 

It is not fancy, but filled a need for the Ryobis. An electrical conduit connection box, cut out port on side opposite cover, plugged the end holes, put in some alum U chan with partially open ends and holes for deflection, drilled holes for mounting bolts. Installed a single alum tube ( part of a second hand crutch ) in one of the outlets of the box.

The boxes come in various sizes and configerations.

A pic at yahoo :
http://photos.yahoo.com/bc/bnbnlapaz...iew=t&.hires=t

Conversion Mufflers
 

I posted a pic of my conduit junction box muffler in my gallery. I have since added a tractor muffler to hopefully keep the neighbors happy during trial runs! Of course it comes off after that!

Conversion Mufflers
 

I now have pics of a couple mufflers on my site ryobi and poulan the ryobi shows a 1" pipe but i also make them with 2 pipes will have a pic of that later the ryobi is 35.00




Kenneth

Conversion Mufflers
 

ANeat,

Your muffler parts look great!

What is the wall thickness of the tubing you used to make your muffler?

What are the hole diameters in the baffles?

Thank you,

Brian

Conversion Mufflers
 

Thanks Brian; The holes are 3/8 dia. The tubing is .049 6061 aluminum.
Adam

Any tips on keeping mufflers tight?
 

bdtsr
Very nice pics and planes. The plug(s) in the end of the conduit box are they metal? They have plastic plugs locally. Had alum plugs made welded in ends.

I'm having trouble keeping exhaust bolts tight. Any suggestions will be appreciated.

The bolts on my Ryobi are all those slightly tapered trianglular (sp) type. What is the purpose for that stlye? Can they be replaced with round standard bolts? I figured they may be for use in alum so have not messed with them.

As yet have only tightened without Locktite. Is there a problem using locktite repeatedly in alum holes?

Conversion Mufflers
 

Mike the triangular bolts are a type of thread cutting/forming bolt that they can screw into a hole without it being tapped and it will cut its own threads. It makes the weedeaters cheaper to manufacture. Going to a standard bolt may help keep them from loosening up but you can also get Locktite blue that is made for bolts to be removed and re-installed.

Adam

Conversion Mufflers
 

Mike, Thanks! Yes the plugs are aluminum and were available separately. I did smear JB Weld over them to seal them in permanently.

Conversion Mufflers
 

Test running and most of the bolts are loose. mount bolts loosened and until I found them could not get it to start. Started right up once they were tightned.

Conversion Mufflers
 

Think I'll stay with the original bolts for now. Have not checked but I bet the pitch is odd-ball.

Canister muffler
 

ANeat,

How are the canister mufflers holding up and how is the sound level/engine performance with them?

Brian

Conversion Mufflers
 

Hi Brian; The gentleman who designed the first ones has them in a Lanier Staudacer, BME 105 powered. He has been flying IMAC with his setup most of the summer. There is a pic of his instalation in my gallery. So far they have been holding up very well, Only flying time will tell.
The sound level on my 46cc Poulan is in the mid to high 80db range with a 200 to 500 rpm drop from an open header. I keep playing around modifying things. I regret to say I have yet to get a flying combo together for the Poulan :( due to to many other projects going on this summer so I have had to rely on other guys flying for any muffler testing.
Adam