LumberJocks

Observations on ammonia fuming

  • Advertise with us

« back to Finishing forum

Forum topic by RipFence posted 09-17-2017 08:39 PM 984 views 0 times favorited 10 replies Add to Favorites Watch
View RipFence's profile

RipFence

77 posts in 2891 days


09-17-2017 08:39 PM

Topic tags/keywords: oak finishing arts and crafts tip

Hello All:
I am currently ammonia fuming all the (QS white oak) parts for a pair of Morris chairs and thought I would share a few observations.
First, I had read from a variety of sources that fuming required ~28% ammonia. That strength is available for about $30/gallon plus hazardous shipping fee of about $20. Pretty pricey. Being frugal (cheap) I decided to try the 10% “industrial strength” ammonia sold at ACE for $5/gallon. It is working great! Parts are darkened to my liking in as little as a few hours or as long as a couple of days depending on the content of the wood and the temperature.
Second, in reading up on fuming I generally saw folks using some sort of custom built tent and fuming the finished project. I’ve done that in the past but in this project I’ve been using plastic storage bins with great results. I put on a few clamps or place a bit of plywood on the top to help the seal. If I sniff around the top I can only detect the faintest scent of ammonia so I’m confident I’m getting a good seal. Using these containers allows me to place them in the sun to heat things up and speed up the process. One of my boxes is clear and I can see the vapor condensing on the inside when its sunny.
Third, if you fume the finished piece the color will likely vary from board to board based on tannin content. By fuming individual parts I can let parts go longer or shorter till I get the color I want. Of course I still get some variation but less than if I fumed them all for the same time.
Of course I wear a respirator with ammonia cartridges, swim googles, and chemical protective gloves whenever I open the box or the ammonia containers but that’s common practice. Anyway, lots of what I read on this topic seemed to make the process fairly complicated. My experience fuming individual parts in storage bins is that its really simple.
EDIT to add two observations and have them all in one place. 1) Yes, googles are needed for the 10% janitorial strength from Ace. 2) The solution looses its strength over time. I guess the ammonia part of the solution evaporates more readily than the water leaving the solution weaker. Keep this in mind because sometimes your piece won’t darken but if you use fresh ammonia it will darken up readily.
Best wishes,
Jim


10 replies so far

View StumpyNubs's profile

StumpyNubs

7681 posts in 2998 days


#1 posted 09-18-2017 12:30 AM

Thank you for the great suggestions!

-- Subscribe to "Stumpy Nubs Woodworking Journal"- One of the crafts' most unique publications: http://www.stumpynubs.com/

View splintergroup's profile

splintergroup

2422 posts in 1420 days


#2 posted 09-18-2017 03:04 PM

I love fuming!

I also swear by the 10% Ace brand, cheap enough and does the job. Typically I’ll use a tent made from a PVC pipe frame and some painters drop cloth. Clear plastic lets me monitor the progress.

For small parts (like boxes), I use a simple 5-gallon bucket. I have a plastic screen that sits up about an inch from the bottom. Pour in the ammonia, add the screen, add the wood, cap and wait. usually I’ll do these until the fuming is as dark as the wood will allow (overnight).

I like your storage bin idea, I’ve been needing an “in-between” enclosure and the bin idea eliminates the setup time involved with a tent. Just need to think up a useful shelf arrangement.

View RipFence's profile

RipFence

77 posts in 2891 days


#3 posted 09-18-2017 03:59 PM

The bucket is a great idea! Where did you find the screen? I have a tall trash can that could handle longer parts. Just put a plywood top on it and clamp it down.
Thanks,
Jim

For small parts (like boxes), I use a simple 5-gallon bucket. I have a plastic screen that sits up about an inch from the bottom. Pour in the ammonia, add the screen, add the wood, cap and wait. usually I ll do these until the fuming is as dark as the wood will allow (overnight).

View splintergroup's profile

splintergroup

2422 posts in 1420 days


#4 posted 09-18-2017 07:56 PM

Jim, the screen was from an old refrigerator. Plenty of plastic contraptions (colanders, etc) in the kitchen cabinets that work to keep the wood out of the ammonia pool (just don’t tell the wife 8^)

For the bucket, I don’t use the snap-on lid since I want to avoid any sloshing/splashing so I use a piece of plywood with some thin foam from packing material as a gasket. The top is weighted closed with a rock….

View RipFence's profile

RipFence

77 posts in 2891 days


#5 posted 09-25-2017 03:16 PM

One new observation: I wondered if goggles and respirator were really necessary with the 10%. Well, yesterday I forgot to pull my goggles down before I opened the lid. I felt an immediate irritation in my eyes. It was mild but enough to get my attention. So the answer is yes, goggles with 10%.

View RipFence's profile

RipFence

77 posts in 2891 days


#6 posted 02-20-2018 02:39 AM

One more observation that may be helpful. A couple of boards had stunning figure but would not darken up with fuming. This led me on a long journey of reading and trying various concentrations of tannic acid and pyrogallic acid. I would try a concentration of one or the other and then fume but could never get the color I was after in these particular boards. Then it occurred to me to try brushing on wet ammonia. Google searches found a number of discussions on this topic so I gave it a try.
Here is the combination that finally gave me just the color I was looking for and looked just like some of the other fumed parts:
1. Wet thoroughly with tannic acid mixed 1 teaspoon of tannic acid powder to 1/4 cup of water.
2. Let the tannic acid solution had soak in and dry.
3. Wet the surface thoroughly with 10% ammonia from Ace.
4. When the ammonia is dry the color was ugly but light sanding / scraping revealed just the right nice brown color. Yippee!
The pyrogallic acid (in various combinations) gave me a color that was too tan rather than brown.
Cheers,
Jim

View splintergroup's profile

splintergroup

2422 posts in 1420 days


#7 posted 02-20-2018 06:58 PM

Interesting.
So you are saying that the tannic acid “infusion” basically made the oak more susceptible to the ammonia?

I’ve had light colored WO boards that obviously had low tannins (low “T”)? and I’d usually leave them for a long while to get them as dark as they seemed able to go. If that wasn’t enough, I’d wipe them down with straight ammonia
which usually did the trick, but the depth was minimal.

I’ll have to try the tannic acid in the schedule and see if I can “fix” problem parts that seem to not darken enough.

Glad you are experimenting Jim!

View RipFence's profile

RipFence

77 posts in 2891 days


#8 posted 02-20-2018 08:13 PM

HA! Tannic acid as hormone replacement therapy for wimpy oak!

low tannins (low “T”)?

View asavet's profile

asavet

1 post in 308 days


#9 posted 02-20-2018 08:15 PM

I’ve used strong tea to increase the tannic acid. This was on a piece of locust with lighter sapwood on one edge and it blended right in.

-- Roger

View RipFence's profile

RipFence

77 posts in 2891 days


#10 posted 02-21-2018 03:10 AM

I had mixed results using tea. The first time I tried it, it worked beautifully. But the next time it didn’t give me hardly any color at all. Pretty sure I did it the same way both times.
How did you make your “strong” tea? I’d love it if I could make that work every time.
Cheers,
Jim


I ve used strong tea to increase the tannic acid. This was on a piece of locust with lighter sapwood on one edge and it blended right in.

- asavet


Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com