We used to have a category for posts like this but I couldn’t find it so I’ll ask it here.
I want to change mufflers on my Wisconsin engine generator that has a one inch pipe nipple threaded into the block. I believe the block is cast iron not aluminum. That nipple looks like it won;t be easy to remove so I am asking for anyone who has experience with this to share ideas please. Thanks.
Sounds like what you are saying the threads are rusted too block. I think if it was me i would weld my other muffler too the nipple that is off the old muffler. Or weld something too the nipple then use some high tech liquid wrence type lube and try removing just after weldeing.you may have too remove parts too have it machined out and or hili coil . Thats my only way of removing plans plans.Good luck with it .hope some body has newer ideas than the old weld it heat trick.
There are a lot of good ole tricks for getting rusted stuff loose, but none of them work all the time.
Remembering that cast iron is brittle, I would avoid heating and quenching for fear of cracking the block.
A couple sharp raps with a hammer will sometimes break the bond.
I like to heat the outer metal and oil it as it cools to draw the oil into the void.
Often with pipe threads, it will break off right at the end of the threads, then you are left trying to peel the threads out of the hole. Maybe I’ll think of more tricks later. Keep us posted on your efforts.
Annual antique engine show here this past weekend. One of my friends talked about using muriatic acid to break loose bolts on old rusted engines. Now wish I paid closer attention
If ya have time mix up some acetone and automatic transmission fluid to use like WD40. Some raps and taps with a hammer from time to time. Can run it in order to heat things up.
I forgot to consult You Tube before posting this but I found this there later. It is one way to do it.
A less invasive way would be to use PB Blaster (penetrating oil), and just saturate the joint with it. I’ve worked in the oilfield on components that were torqued together with thousands of ft/lbs, and PB Blaster worked almost every time. Sometimes, to make the oil penetrate the joint a little better, you can hammer the stuck part to shock the metals and allow the oil to dig in just a bit more. In certain situations when the metals bond severely tight, a few hours to a day may be needed for the oil to penetrate the joint deep enough for you to break the joint and unthread the part. The method in the video looks way funner IMO, but if you cut too deep, you can damage the threads in the block and possibly require a larger drill size and tap which weakens the block or head.
Thanks Mike, That’s what I did and it worked! Here is a pic with the car muffler in place. I don’t expect to run it on gasoline because the carb is gummed up from non use and it starts so much better on wood gas anyway. I had it running for 30 seconds or so by squirting carb cleaner in the mixer tee and I would have to say it sounds about 4 times quieter and with a much lower tone.
Nice Don , is that a 1800 rpm unit? Did you get it ? Or leave the sleeping dog lay? That a liquid cooled unit on right? My motorcycle exuaste is 3/4" and I used a bicycle seat post and used the height adjusting clamp for an exuaste clamp.
It is 3600 rpm and 1 inch exhaust. I used PB Blaster to get the threaded muffler off but left the nipple in the block.
That is a HF 2 HP compressor.
Here is something that might work really nice for the rearward visually impaired.
That’s pretty sweet, but it would almost double the value of my truck. 
Hi Doug
Put one on my wife’s car and it has a 7’’ monitor on the dash, she still backed into a light post in a parking lot.
Hope she don’t see this----me tilling on her she might run over me.
Well Jim, that’s a female thing. When I first married, my wife would rarely drive my 1968 F250 with a stock manual choke. She would start out cold and proceed to drive every where with that choke still activated. She doesn’t get to drive my 1982 AMC Eagle with it’s manual choke now a days. Hmmmm… Dakota, noooooooooooooooo.
Doug, if you build a auto mixer and installed it on the Dakota she could drive your truck and make it her daily driving vehicle. And no I do not drive like a girl. LOL
Bob
I recently hinted that I’ve been working on a micro WK-inspired gasifier through a haze of depression.
Before starting to weld on the actual ammo-can and lower housing 5-gal steel bucket (which I was rightly anxious about, having never welded on anything that thin), I tried practicing on the scraps that I’d cut out of the bucket/ammo-can. Even on minimum settings on my little Hobart AutoArc 120v MIG welder, it was frequently burning-through almost instantly.
I have chunks of 3/16ths aluminium plate, or 1/4 inch steel plate, for heatsink backers, but it didn’t seem to make much difference. 
Any suggestions/tips/tricks on how to actually weld up this thing so it’s air-tight without burn-through?
Thanks, Brian H in WA
One method I have used on thin metal is to move really fast with the tip and try to thicken the edge to be welded with a thin layer or two, then weld normally on the thickened metal.
What Don said and you need the small wire in that small Holbart, I think it’s .024. That small wire makes a world of difference with thin material. Herb
You just beat me Herb. Also go with short sperts. Don’t try to weld constant. Come back after filling in with short sperts and do a more constant weld. TomC
