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My steam box for bending has mold

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Forum topic by Trevilo posted 07-23-2021 02:27 PM 418 views 0 times favorited 16 replies Add to Favorites Watch
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Trevilo

3 posts in 60 days


07-23-2021 02:27 PM

Topic tags/keywords: steam bending mold box clean

Hi Jocks,

I bend wood using a steam box. After I use it the moisture causes mold to have a fertile ground to grow.

Does anyone have suggestions for how to kill and clean the mold out? It is a 1ft by 1ft by 8 ft box. The opening is only on one end so I can not reach the majority of the box to clean it out.

Thank you for your advice.


16 replies so far

View ChefHDAN's profile

ChefHDAN

1816 posts in 4062 days


#1 posted 07-23-2021 02:44 PM

Bleach 10:1 is always effective, but for me I’d go with an ammonium quaternary sanitizer just because it’s a bit safe and I have good sources from my trade. Best bang for your buck would be these Am-Quat tabs, ver commonly used in hand ware washing applications.

Biggest key would be to leave the box open and if possible have a fan run into it until completely dry.

-- I've decided 1 mistake is really 2 opportunities to learn.. learn how to fix it... and learn how to not repeat it

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SMP

4715 posts in 1118 days


#2 posted 07-23-2021 02:51 PM

is it plastic? or wood? or ?

View wichman3's profile

wichman3

105 posts in 1834 days


#3 posted 07-23-2021 03:08 PM

A copper based fungicide is your best bet. I have used pennies for decades as a fungal inhibitor in 5 gallon buckets of water and in evaporative coolers. I don’t think the penny idea would work for your situation but the copper is what works for fungus.

View Lazyman's profile

Lazyman

7801 posts in 2600 days


#4 posted 07-23-2021 04:07 PM

I think that I would make it out of another material beside wood. Unless you can get it dry quickly afterwards, the mold will be a continual problem. Pressure treated wood might not mold as badly I suppose (copper is one of the substances use to PT wood). I use a section of metal duct for my steam box. I simply block the ends with towels and wrap towels around it to retain the heat better. I keep saying that I am going to find or make some plugs for the ends but I never seem to get around to it. You could use a double walled chimney pipe and wrap some sort of insulation around it to make more efficient. I made a couple of feet to sort of cradle it while in use so it doesn’t roll and I just stand it up in the corner when not in use.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View therealSteveN's profile

therealSteveN

8640 posts in 1787 days


#5 posted 07-23-2021 05:09 PM

Start at the beginning. You have mold growth because you have a water problem. Stop water from laying in the chamber, and your mold problem will stop as well. This is why a steam chamber needs to have at least a hinged top, so it can be open, and allow the wet to dry when not in use.

Bleach seems to kill mold, but doesn’t really, you still have plenty of spores after bleach, that to say you killed it is incorrect.

Vinegar will kill most forms of mold, BUT not all forms of mold, but is cheap enough you can spray some on the wetted wood, and it likely will kill, at least better than bleach.

The Copper mentioned above works great, Just know it can trap the water underneath it, and on the woods surface, so you swap mold for rot. Either you need to completely cover the entire interior, or my suggestion is to use strips of it low, and on the sides of the chamber, but not the bottom, and what is behind it will drip down, and be allowed to dry if you have a chamber with an open top.

The other fix, it to swap wood for a large enough diameter PVC pipe, rot isn’t an issue there, and Vinegar will take care of the mold.

-- Think safe, be safe

View Lazyman's profile

Lazyman

7801 posts in 2600 days


#6 posted 07-23-2021 05:51 PM

How does the PVC hold up the the heat? I went with the metal duct because I read that PVC max temp is around 140°F and I didn’t want to worry about it sagging over time since the temperature of steam is whatever your local boiling point is.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View ibewjon's profile

ibewjon

2592 posts in 4006 days


#7 posted 07-23-2021 06:54 PM

Go with metal duct as stated above. Light weight and easy to handle. Turn it on end to drain and store. Caps are available where duct is sold. Probably cheaper than PVC, and easy to handle.

View splintergroup's profile

splintergroup

5732 posts in 2435 days


#8 posted 07-23-2021 07:19 PM

This brings up a great point. I’ve been contemplating a steamer for strips, thinking about the usual plywood box build.
I do have some leftover wood stove pipe which is stainless steel on the inside with insulation between the inside pipe and the outer (galvanized) pipe.

View Lazyman's profile

Lazyman

7801 posts in 2600 days


#9 posted 07-23-2021 09:00 PM

That stove pipe would be perfect and at current plywood prices a fraction of the cost, especially since you already have some on hand.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Jeff's profile

Jeff

553 posts in 4407 days


#10 posted 07-23-2021 09:43 PM

Is the pipe galvanized? Zinc will kill the mold.

View therealSteveN's profile

therealSteveN

8640 posts in 1787 days


#11 posted 07-23-2021 11:08 PM

Steam is 212* Most folks use a wallpaper removing steam generator from Rockler to build a unit. Those using PVC usually use PVC end caps to cap the ends, and place any attachment for the steam tube. In doing that if they were left without some holes along the PVC you would have a small explosion from trapped expanding steam. Those holes decrease pressure, and also allow the PVC to work fine as a chamber. It’s normal to use the holes to both decrease pressure, but to also support your bend wood on dowels inserted through the holes. They keep the bend wood out of the puddle you would have otherwise, at least until it blew up. PVC is probably used in at least 1/3 of new build chambers, Still wood is used the most. Pipe for a chimney is pretty light to support much weight inside it, not to mention a lot of folks can’t seal it worth snot.

-- Think safe, be safe

View Trevilo's profile

Trevilo

3 posts in 60 days


#12 posted 07-24-2021 12:32 PM

Hi all, Thank you for the many suggestions.

It seems for the existing box a vinegar solution is a good idea. Would residual vinegar have possibility of staining the white oak that I steam? I think vinegar causes white oak to grey/blacken.

The longer term solution is to make a steam box from metal.

Did I follow that correctly?

View Lazyman's profile

Lazyman

7801 posts in 2600 days


#13 posted 07-24-2021 12:41 PM

I don’t think that the vinegar will cause a problem. You may be thinking of the vinegar and steel wool solution used to ebonize wood. It is the iron in the solution that causes white oak to change color.

BTW, most white vinegar is only 10%. If you look for horticultural vinegar in a nursery that sells organic pest control, you may be able to find the stronger 20% stuff. It is used as a weed control. I think that pickling vinegar may also be stronger.

Anyone ever tried denatured alcohol on mold?

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View therealSteveN's profile

therealSteveN

8640 posts in 1787 days


#14 posted 07-24-2021 01:50 PM


Anyone ever tried denatured alcohol on mold?
- Lazyman

I think it would just get it fabulously drunk

-- Think safe, be safe

View John Smith's profile

John Smith

2995 posts in 1375 days


#15 posted 07-24-2021 07:44 PM

how often do you steam long boards ?
there are some videos on YT about boat builders using a long plastic bag for steaming boat parts.
which could be a one time thing if you don’t use your steamer that often.

-- I am a painter: that's what I do, I like to paint things. --

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