Stripping stain from cedar

pob3444

New member
My neighbor's house (and two story garage) is cedar, stained about 15 years ago, she estimates. I'm 90% sure it's oil-based but haven't tested it. Attached are pics.


She wants to go lighter, but stay with semi-transparent. I tried to wiggle out of the prospect, but she offered to pay more for stripping.


I've done some research on the store-bought strippers, and the RAD "injectable" stripper. Looks like NaOH is the central ingredient. I would love to create my own mix, and apply through the downstream detergent pickup on my little pressure washer so I don't have to 1)climb all over the house 2) do any scrubbing.


Is this possible? Can I create a mix that will allow me to skip those steps? If not I need to charge her more. I'm a painter, and I understand the work/steps required to neutralize and stain everything, so I don't have any questions about that aspect.


If it's not possible, I guess I'll just have to say "stripping is going to cost too much, we'll have to go darker"? If I'm way off base here, please tell me what you would recommend overall. Also, she's ok with a two-toned look. So where the old stain looks ok, I can skip stripping. I'm only concerned about the splotchy areas.
IMG_20140819_174740.jpgIMG_20140819_174919.jpg
 
I would love to have this job! There is definitely some type of product on the wood surfaces. I would strip and brighten this and get it back to original color and tone, or as close as possible. This definitely needs a two step process of cleaning with the stripper and then applying a brightener (oxalic acid) to lighten the wood. I do not see any scrubbing other than any cutting in that may be needed it is all a matter of dwell time, don't leave the stripper on too long or it will excessively fuzz up the wood. In my opinion, you should be able to strip and brighten without "splotchy" areas. The answer would be yes to going lighter after this process. These are excellent paying jobs as well. Take plenty of before and after pictures for marketing and your portfolio. If you are on the job and have questions feel free to call my cell if your not sure of something 609-351-6117, if I do not answer for some reason I usually return calls within the hour.
 
Ha, you probably wouldn't love to have this job at what I'm being paid :p

So, it is possible, good to know... As far as stripping I've got the NaOH beads here, how do I apply? What is the proper mixture/suggested dwell time? Do I add soap to increase the dwell time? What type/how much?
 
Initial tests turned out great. The mix of NaOH and detergent (dish soap) did its job in 15-20 minutes, and the oxalic acid mix worked well too, no scrubbing!

A couple more questions:
Do I wash with water before the oxalic acid, or after, or both, or neither?? Is it important to use pressure, or will a rinse do?

Is there a suggested dwell time for the brightener?

What type of detergent do you recommend?

How can I compensate you for sharing your wisdom? Bitcoin or paypal, perhaps?
 
I'M IN TOO DEEP!

Lots of problems. Here is the 'broadside' before pic:IMG_20140819_174740.jpg

Here is after a pump-up spray 16oz/gal NaOH + detergent + 15 minutes dwell time. Wash. DS oxalic acid. Not bad, but kinda splotchy.IMG_20140923_121537.jpgIMG_20140925_114911.jpg

So I DS'd it with bleach at a 20:1 ratio, and oxalic again. Also tried a crazy strong oxalic mix, and think I found my problem. I'm having trouble getting the oxalic to remain dissolved, and I think it's just going on to weak. Thoughts? I've tried boiling water, and it just recrystalizes : (IMG_20140925_135100.jpg


I think the diluted bleach did help, so I did more research and came across a recipe to use sodium hypochlorite at 50%! along with the 16oz/gal NaOH. Lets see what that does to the side of the house!

Before:IMG_20140819_174716.jpg
After:IMG_20140925_114946.jpg
What the heck? Why so splotchy? Why did it seem to work but just in a tiny corner? That's the area that dwelled the least!
 
And what is this? Am I destroying the wood with bleach?
IMG_20140925_115101.jpg
Here, I tried again to strip the area between the two lower windows, increasing dwell time to 25 minutes. Still not working. Is this not enough dwell time? 15 minutes was plenty on the broadside. Is the bleach somehow causing the sodium hydroxide not to work? Not pretty
IMG_20140925_144542.jpgIMG_20140925_144635.jpg

I am at a standstill at this job until I discover the proper technique.
 
Slow down, take a breath, relax. whats good about this is it can be fixed. you are not ruining the wood but slow down on the bleach. you need bleach but only in the right doses.

This is a large job with a TON of work that needs to be done. this is not a three day job. FOR ME this would be a 10k plus job

I never downstream my oxalic. I mix it at 4 ounces to the gallon. sometimes i mix up 200 ounces at a time. hot water should mix it up good do a little at a time.

Dwell time for stripper is critical. one side may take 15 minutes but another side might take 40 minutes thats what you need to find out. when i mix my stripper i start at 4 ounces to the gallon but sometimes you need more. my last strip was 8 ounces with a pint of butyl mixed in.

The last two pictures you put up look like you did not let it dwell long enough. this wood can be fixed and looking good. You may need to talk to Everett on the phone to get you back on track.

Good luck
 
Spoke to James tonight and offered my help and recommendations. He also has my cell phone number so if he needs help on the job I will be available. Unfortunately at this point it has to be re-done but there seems to have been issues with strength of solution as well as dwell time.
 
Your a bit over your head it seems and need more potty training . Keep the diaper on ! Finish one section of the house at a time. Use hot water to mix the acid . Don't use bleach on this house . Adding and using bleach for wood is for when you no what your doing and knowing when , why and how to.
 
Your a bit over your head it seems and need more potty training . Keep the diaper on ! Finish one section of the house at a time. Use hot water to mix the acid . Don't use bleach on this house . Adding and using bleach for wood is for when you no what your doing and knowing when , why and how to.

Amen to that, I saw a finish that completely failed after four years. what should have been a simple re-coat turned into a complete strip and re-stain because the person that did it had no idea about the effects of excessive bleach. That ignorance ( I hate to use that word but i couldn't think of anything else in this situation ) cost the homeowner a good chunk of change.
 
Spoke to Everett, and decided to ditch the bleach idea, and just try the simple strip and oxalic attack again with longer dwell times. No longer DSing anything, so I'm strictly controlling the concentrations of chems.

Here is the broadside of the house after a second attempt with 20 minute dwell time. Hopefully the setting sun doesn't make these pictures too confusing. The splotchiness hasn't changed much, and yes it's fully dry. Is this normal? Will a medium-tint semi-trans stain hide this much?
IMG_20140927_180637.jpgIMG_20140927_180651.jpg

Either way, the broadside of the house is now without stain. But here is the other side after a second strip and a 40 minute dwell time. Doesn't look much better at all. This has now been stripped twice with 16oz/gal NaOH (the first time with sodium hypochlorite added)


IMG_20140927_180544.jpg

And this is what I see close-up.
IMG_20140927_180711.jpg
Is this some old water based semi-solid stain? A test with denatured alcohol indicates that it IS waterbased. Walking around the house, I do more spot tests, and confirm that most of the house is covered in oil-based stain. It looks like I'm not the first person to experiment on this place X-(.

I look at the products recommended for water-based stains and just keep seeing NaOH. Am I missing something? Is there a way to get this all off?
 
This is why you should do a test spot first in the most difficult looking area and get as much background information as possible like old cans or pails of products. Water based products are usually better removed with solvent based strippers and not sodium hydroxide strippers. I have applied both together and had great results with multiple coats of water and oil based products and some of the solvent based strippers work real well on both oil and water based stains and sealers. You look like you have 90% of it off which and obviously some sides are better than others. Depending on the coating you need to get them looking more consistent and you still have issues of some stain as in picture 4 and areas where you can tell it has been bleached more than other areas as in picture 3 top versus bottom of that side. To get this back to natural wood it will get costly from here, as if it isn't already. Solvent based stripper is expensive but effective on water based products and there are some that are sprayable through an airless sprayer. You also may have to re-bleach to get the wood to match up better, in picture 3 the higher part being so dark it will not look consistent with the bottom area where it is so light. There are a lot of factors to consider here moving forward from getting the wood consistent in appearance to what should be the next coating. Also, you may want to familiarize yourself with change orders for the future and include language in your proposal to cover you when occasions like this arise. When a job costs more because of previous work performed you should have some language in your proposal to cover you in these instances. I will try and contact you again this morning.
 
Tried a product recommended by Everett called Stripit by Chemique.

Still not the miracle product I was hoping for. The water based stain lifts a little, but turns to tiny gumballs which are not easily washed off, with water alone or another NaOH application for good measure. I've tried dwell times ranging from 3 hrs to 24+ hrs.

So on this splotchy side there are now places where I've tried NaOH with various strengths and dwell times, bleach, "industrial strength" solvent based Stripit, and their "safer, water based" formula. Not much has changed. Each step gets things only slightly better, but still no magic bullet found.

What's next? Freezing temps are right around the corner!!
 
So I decided to throw in the towel, and find another company to strip the house even if it meant losing half my paycheck. Got one quote from some meth-heads that was way too low, and they were way too sure of the outcome. Got another quote from CertaPro: "We don't want to do it. We can't guarantee results better than you have" They also said they would use SW Deck-Cleaner/Stripper...

Went to talk to my local Behr rep again, and he said "Just sell her on the solid stain. The warranty is better, it will last longer, and you can guarantee consistent results"

So I did (along with a price reduction)! We're sampling colors now, and I'm putting them on as thin as possible to avoid the "painted" look. Going with water-based Behr Waterproofing due to Consumer Reports recommendation.
 
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