Primitive Archer

Main Discussion Area => Bows => Topic started by: Sasquatch on December 16, 2015, 09:27:18 am

Title: Mold under skins
Post by: Sasquatch on December 16, 2015, 09:27:18 am
So why would I be getting mold spots under the skins?  I used TB2.  Is there any way to get skins off without waisting them?  Skins had been air dried and then frozen. 
Title: Re: Mold under skins
Post by: BowEd on December 16, 2015, 09:42:42 am
Not sure.Too much membrane under there or what.I usually don't freeze them after drying.Might be it is more character to your bow now because I don't think there is a way of removing those skins without wrecking them short of soaking the heck out of it.Anyway sorry but you might have to live with it.Like those copperheads though.
Title: Re: Mold under skins
Post by: half eye on December 16, 2015, 09:47:50 am
Big foot,
      I have used TBII on all of my skin applications and never saw that before. Just a thought (not sure if it is your case) those spots might be a very small air bubble that let the mold get started. It would not take much air given the wet raw skins. If that is the case (or not) you could try to use a diluted bleach mix and carefully apply with a syringe....might take a few applications  but will definately kill the mold. Unless the bow is no good, my advice would be to try and save the by treating the issue.
     When I apply skins I first soak in warm water, then use a towel to "pat" the excess water off. Then I spread a thin layer of TB II on the bow back AND skin with my finger (so there are no gaps, bubbles or "fish eyes" then apply the skin. Once it's on I use my fingers to smooth and work the two together....this also helps me get an even stretch and align the pattern. You will probably have too much glue (squeeze out ) but clean that with a damp rag....then set it aside. Like I said I never have had any issues with mold.

Dont know if this is the problem but might be a way to save the bow "as is" without ruining the skin or bow.
rich
Title: Re: Mold under skins
Post by: Sasquatch on December 16, 2015, 10:46:11 am
half eye, thanks for the detailed response I think I will V's in skin peal back and treat mold then glue back down.  I  did use a lot of glue but might not have squeezed the excess all out. Thanks guys.
Title: Re: Mold under skins
Post by: PatM on December 16, 2015, 10:58:57 am
How long after you applied the skin did they form?
Title: Re: Mold under skins
Post by: PEARL DRUMS on December 16, 2015, 11:14:43 am
A syringe, needle and ammonia will kill it.
Title: Re: Mold under skins
Post by: bradsmith2010 on December 16, 2015, 12:07:50 pm
I have never seen that,, I am guessing that it had to be some place with high humidity ,,???,,, maybe it had something to do with the finish on the bow,, hmmm,,,,
the ammonia sounds like a good idea
then touch up the spots with paint,,
then refinish,,, you are good to go
dont cut the skins,, I think it will be to hard to get the back
Title: Re: Mold under skins
Post by: Pat B on December 16, 2015, 12:39:15 pm
How much moisture was still in the wood? Did you clean the skin before gluing it down? 
 TB glue will add moisture before it cures and the skin will prevent or at least slow the moisture release.
Title: Re: Mold under skins
Post by: PatM on December 16, 2015, 12:49:21 pm
The spores that cause it must have been present when you glued things up. I've seen people from humid southern climates show sinew backings with those spots showing through the dried sinew.
Title: Re: Mold under skins
Post by: PEARL DRUMS on December 16, 2015, 01:04:12 pm
I have had sinew show those spots, using hide glue.
Title: Re: Mold under skins
Post by: Sasquatch on December 16, 2015, 01:25:55 pm
Thanks guys ill use the syringe with ammonia like PD said.  They formed within 24 hrs of warping skins.  They also showed anywhere the glue was thicker. thanks guys i think i got what i need now. Great ideas! I wonder if the color will go back to normal?
Title: Re: Mold under skins
Post by: PEARL DRUMS on December 16, 2015, 01:29:12 pm
Did you size the back first? That helps immensely.
Title: Re: Mold under skins
Post by: Sasquatch on December 16, 2015, 01:30:32 pm
How much moisture was still in the wood? Did you clean the skin before gluing it down? 
 TB glue will add moisture before it cures and the skin will prevent or at least slow the moisture release.
What do you mean clean skins.  They were scraped and dried and then soaked before applying.  Could there be spores in the glue? Wood was real dry.  But i do live in south.
Title: Re: Mold under skins
Post by: Sasquatch on December 16, 2015, 01:32:27 pm
Did you size the back first? That helps immensely.
yes I applied the glue and let it soak in first. If thats what you mean by "size"  I think thats what it meant.
Title: Re: Mold under skins
Post by: PEARL DRUMS on December 16, 2015, 01:34:36 pm
Yup. Smear glue on the night before so it dries hard and smooth. Then add more glue and a skin the next day.
Title: Re: Mold under skins
Post by: osage outlaw on December 16, 2015, 01:49:27 pm
You said they formed where the glue was thicker.  Did you leave globs glue under the skin?  You need to squeeze the excess glue out.
Title: Re: Mold under skins
Post by: bradsmith2010 on December 16, 2015, 02:29:52 pm
I did have some mold on some hide glue I left out,, maybe your glue cured slow enough in the high humidity to make the spots,,
I think next time put the bow by a fan or something to speed dry time,,, :)
Title: Re: Mold under skins
Post by: Dakota Kid on December 16, 2015, 02:44:35 pm
If you wipe the bow with alcohol or acetone before your next glue up it should sterilize the surface. You could have spores in your glue, but more than likely with just a couple spots it came from the air. Putting your bow in a bright place while drying will also help.

I don't know if ammonia will make the color disappear but a bleach water mix will. I use the same thing on moldy basement walls prior to sealing and algae covered decks before refinishing.  I mix 50/50, but you should probably do less bleach, maybe 70/30.
Title: Re: Mold under skins
Post by: Pat B on December 16, 2015, 04:27:12 pm
I wash skins, sinew and rawhide(and the bow) with Dawn soap and warm water to remove any grease or oil from it before gluing it down.
Title: Re: Mold under skins
Post by: Dakota Kid on December 16, 2015, 04:46:22 pm
I often use soapy water too. It's my most reached for squirt bottles. I usually follow with denatured alcohol. It gets anything the soap may have missed plus helps the remaining water to evaporate faster. Getting rid of the water is only really necessary when using oil/poly based finishes.
Title: Re: Mold under skins
Post by: Sasquatch on December 16, 2015, 04:50:14 pm
Yup. Smear glue on the night before so it dries hard and smooth. Then add more glue and a skin the next day.
Thanks for this I didn't know the night before thing. 
Title: Re: Mold under skins
Post by: missilemaster on December 16, 2015, 05:06:52 pm
I have also had that happen with sinew. I think what happens is that the glue dries/cures before the skin dries completely, not giving the moisture anywhere to go. make sure your skins are pliable but not dripping when you put the glue on. I soak them for 10 minutes or so then squeeze them out with a towel. But think about this, because copperhead skins are thinner, you may just be able to see the mold easier. for all I know, the same thing could be happening under other skins, but you cant see it because they are darker or thicker.
Title: Re: Mold under skins
Post by: PatM on December 16, 2015, 06:10:12 pm
Getting your materials as sterile as possible and putting in a cold dry area initially is the best bet for reducing mold growth.
 I would think that this was the reason old time composite bows had a particular season for each process.
 If you sinew in the colder dry months you'll have better luck.
Title: Re: Mold under skins
Post by: BowEd on December 16, 2015, 06:23:05 pm
Sure hope it works out ok for ya.I think it will.Got a feeling there was a combination of things going on for this to happen,but I agree the winter is the best time for these things.

Title: Re: Mold under skins
Post by: Eric Krewson on December 16, 2015, 06:49:11 pm
I am not an advocate of wrapping skins when you put them on because you are only putting pressure on the sides unless you have a high crown bow.

If you roll your thumbs to the outside of a limb over and over for about 15 minutes you will  get all the excess glue and air bubbles out. I start at the handle and work my way side to side to the tip then start over again. You don't have to worry about your skin coming off after about 20 minutes. You can tell when it stops moving under thumb pressure.

Like this;

(http://img.photobucket.com/albums/v181/ekrewson/bow%20making/snake10.jpg) (http://smg.photobucket.com/user/ekrewson/media/bow%20making/snake10.jpg.html)
Title: Re: Mold under skins
Post by: Dakota Kid on December 16, 2015, 07:03:37 pm
If all of your soaking and pre-moistening of skins/sinew is done with 50% rubbing alcohol you'll never get mold. I use it when I water down my glue as well.
Title: Re: Mold under skins
Post by: PatM on December 16, 2015, 07:39:39 pm
A small wallpaper roller works very well for smoothing the skin/glue bond and squeezing out excess.  Basically designed for the same purpose. Couple of bucks at HD or the like.
Title: Re: Mold under skins
Post by: mullet on December 16, 2015, 08:10:26 pm
Vinegar works better then ammonia or bleach. I have sealed TB airtight with skins before and the glue did not fully dry.