Car wash foam cannons - yay or nay?

Yes they work really well, also hand for washing a house and windows..

do you use a regular car wash or do they use a specific car wash for them?

Most detail places sell soap specifically for foam canons. Try detailersdomain.com.

However any soap should work ok.

Absolutely. I have my tundra ceramic coated and with the foam cannon makes hand washing much easier. Spray it with water wide nozzle to wet it and knock off mud. Then a quality foam soap will stick to the vehicle and basically allow you to hand wash at least half at a time before restarting pressure washer and without having to use buckets, etc.
I’ve also used the foam cannon for cleaning the house, patio furniture, etc. cheap and effective.

If you are looking at foam cannons at that price range get the MTM Hydro. I have the MTM pro, I have had it for years. Some companies have knocked off the MTM pro and have some pretty good reviews but you would have to dig around to find the good cheap ones. Some have some $15-$20 cannons highly rated.

I'd love a Kranzle that was mentioned earlier but I have a Karcher 1700, all MTM hoses, gun and wand that I can switch over when I pluck down the cash for a kranzle one day. The biggest hold back for me is I need to run electrical somewhere to support it, my old house just doesn't have a good outlet for it.

Thanks for the replies all.

I have an older Troy-built Pressure washer, 2550 max psi and 2.3 max GPM.

My intent would be to foam the vehicle and most likely follow with a handwash at least 1/2 the time.

I just started using a foam cannon a few months back when I bought a black truck. Using foam and a pressure washer as a prewash makes the rest of the wash a breeze. I am very picky about preventing swirl marks so the foam and two bucket wash method has done great. Btw - I bought a cheap $26 armor all cannon from Orielly’s and it is sufficient. You can watch the dirt fall down.