Did a few searches and in conclusion it seems that either will probably work. The question is do I need to treat the entire wall with oxalic? Treat the whole wall with F9? Or can I spot treat with F9?
I’ve done a few on concrete with oxalic but never on brick. I always treat the whole section of concrete to get a uniform appearance. Can I get away with spot treating with either f9 or oxalic on this off white brick?
I’d just do a small test in an inconspicuous area. That brick just has a baked on face that’s super thin. I wouldn’t think the acid would hurt but which knows what they use to make it. Then again, since it is a baked on face you might not have to do the whole wall or try to blend since it might not lighten it up. Start weak with oxalic and pull out F9 if need be.
I’d bet $5 that OA will do the trick. Let’s not forget though like @CaCO3Girl suggested, you can also try a toilet bowl cleaner. I’d actually pay you $5 to do it just so I can see the results. Experimentation, if you will.
Shouldn’t I be getting the $5? Gesh, lol!!! Tough crowd 
Send me the address and I’ll send you a $20 prepaid card so you can have lunch on us. You’ve earned it 
Lol, no but thank you. I like to help
Well, we certainly do appreciate it!
Aye, your info is very much appreciated. Wish we could clone you and bring you to Canada to help us pressure washers.
You back off. You really want to start a border war with the US? Cause that’s how you start a border war with the US.
She backed out of the rust removal for a different add on. So from what I gathered from the thread is there is no definitive way to know if you will need to treat the whole wall or not with a test spot. I was just trying to avoid a blotchy appearance. Test spot it is. Next time
I really doubt you would’ve had to do the whole wall. I laid similar brick at our old house after ripping out some red colored. I brushed muratic to clean up the mortar and it didn’t cause any issues. It was a pretty diluted mix though. Even with oxalic I just don’t think the face would lighten up like it does with concrete. I know it still doesn’t answer your question. Sneak over there late one night and try it. Let us know the results.
I know it’s not very profitable but sometimes you have to do things for free for the first customer so that you know the results you can achieve and are better prepared to sell the next customer on it. I’d do it for free. The likelihood of you doing any irreparable damage is almost nil and you could gain a lot of experience from it. I almost never recommend experimenting on a customer’s house but minor rust stains like that shouldn’t be a big deal at all.
Haha 
now that’s an idea.
Ph please try the toilet bowl cleaner it worked on the patches I tried around the station got a few coming up on Friday with rust one is my uncle I let him read the thread he has agreed to let me try it on the rust stain. It’s in a inconspicuous spot
You can just treat that area and then hit with light mist coat surrounding area to blend it in. Shouldn’t be a big deal on the brick
I’m glad I saw this thread. it reminded me to order some f9. @Racerdid you survive the fence today? Lol
Hey now, you and I may be able to work something out! I’ve been working on Canadian labels at work today and my head is about to explode! Send me a private message and let’s talk. I need the inside scoop on some Canadian things
Yeah, it was partly cloudy and didn’t get super hot so that helped a ton. Actually got finished about 2:30. Nastiest fence ever- had to hit twice with roof mix and then wand it with my 8gpm. Tedious. Big clumps of lichen everywhere and those roots aren’t coming off anytime soon. Check out the last pic and notice section of left - that’s after sitting for 10 min after being hit with a 3.5 - 4% mix
Should have took pics of that really bad section behind the barn.
That’ll be some good before and after pictures. I did a fence like that back in June. it was miserable. I feel your pain. The rest of the week I’m making commercial sales calls so I’ll have some time to recuperate before this weekend. I’ve got to bid 2 more apartment complexes next week. if I get them I’ll be ordering a mini mondo. from what I understand there will be a lot of Sidewalks
