DIY Smoke/Fog Test to find leaks?

Once I've lowered my fuel tank off my truck, if I wanted to smoke or fog test the tank to find some tiny holes (and plug them with epoxy), what's the best way to test it? Is anyone smoke/fog testing and what are you using? Can I make something or buy it cheaply?

 

Get an old 20-30W soldering iron, put in the lid of a pickle jar, along with a low pressure air pump fitting. For example a simple tire inflator pump will work. JB weld everything sealed. Fill the jar with baby oil plug the soldering iron in, turn on the pump, and you have a smoke machine. Hard to explain. I'll take a picture of mine tomorrow if you want.
Maybe this video will help: https://www.youtube.com/watch?v=GAqHqKq09CA
I've been to shops that were so low-rent that they admitted that they don't have the money for a smoke machine. Not everyone has one. Better to call if you're planning on getting it done professionally.

 

Awesome thank you! I guess I don't have to worry about igniting fumes as long as I have a back pressure of air. Do you think it's ok to blow that into the gas tank? This might be obvious to you but just want to make sure it's not going to effect the gas or running the car later right?

 

Nah the smoking baby oil is barely above room temperature by time it comes out of the plastic tubing. I'm not legally liable if something goes wrong though lol

 

I just smoked my 1st engine the other day. I've been chasing a leak for.... 3 years. Smoked and found 2 leaks in about 5 minutes.

Jump,on cragslist, hit ebay, find a Halloween smoke machine. It forces the smoke out under pressure, no need for an air compressor. I picked mine up for halloween, it was maybe $20 new. Combine it with a piece of pvc and a rubber hose and you're in business. I can't remember what kind of oil they use, but it doesn't bother anything.

 

Take it to your local high school auto shop and ask for a smoke test. It will get thoroughly smoked for sure.

 

https://www.ebay.com/itm/Fog-Machin...2ac8a4111c:g:jeEAAOSw-K1cn~VF&redirect=mobile


One of these. And you have a smoke machine to use for parties when you're done.

 

Perfect The fog machines use a mix of distilled water and 10-30% vegetable glycerine. I appreciate all the advice!