bit of bonding info

Kayak Jack · Post by **Kayak Jack** » Thu Apr 03, 2008 6:43 am

Morten, I know that wood will take on and breathe off moisture from the air. the 1/4 guideline is new to me; never heard that before. It helps to explain some of your earlier propositions.

I also understand that excess water isn't good for wood. Leads me to a question: Where builders live in high humidity areas, do you think it would help to warm the wood (sun, artificial heat, etc.) prior to applying epoxy? As the wood cools, it will suck in some extra epoxy. Would that epoxy work to displace some moisture?

Wannabe · Post by **Wannabe** » Thu Apr 03, 2008 6:39 pm

If you thin down the saturation coat of epoxyand apply it to both sides of the wood, will it soak compleatly through the wood? If so there is no question of moisture because as I understand it, the epoxy displaces moisture. Jack is on the money with heating the wood. That will suck more epoxy into the wood. This is my humble opinion.
Bob

Oldsparkey · Post by **Oldsparkey** » Thu Apr 03, 2008 7:34 pm

Guy's ...

In Florida you do not need to heat the wood , it is already hot and the only time to epoxy saturate it is in the evening when the sun is setting and the temperature is starting , or thinking , of receding. Besides that is the best time to work on the boats when doing epoxy and glass work. Early mornings for wood work.

It sure sucks up the saturation coats and I only do one side at a time. Usually it takes three coats to do the job. The Red Wood I used for the stripper pirogue went threw 6 coats on each side. It sucked up the epoxy like a kid at a ice cream shop.

1st 4 coats you could not tell I had put any on it.

Chuck.

LEE SCHNEIDERMANN · Post by **LEE SCHNEIDERMANN** » Tue Sep 23, 2008 1:26 am

Kayak Jack wrote:Morten, I know that wood will take on and breathe off moisture from the air. the 1/4 guideline is new to me; never heard that before. It helps to explain some of your earlier propositions.

I also understand that excess water isn't good for wood. Leads me to a question: Where builders live in high humidity areas, do you think it would help to warm the wood (sun, artificial heat, etc.) prior to applying epoxy? As the wood cools, it will suck in some extra epoxy. Would that epoxy work to displace some moisture?

I always thought warm air has more "potential" to carry a higher humidity content than cold.
Wouldn't that hold true for wood as well?
When we had to dry out documents and records after the recent floods, the paperwork all got put into a freezer(-80 Farenhiet) to dry out.

Lee

john the pom · Post by **john the pom** » Tue Sep 23, 2008 8:10 am

Hmm, fridge/freezer makes sense for drying out stuff as they (fridge/freezers) are also dehumidifiers, hence the evaporation trays or ice build up in older style fridge/freezers.
Curious to know Lee, did they scrape ice off've the documents while frozen, or was all the moisture removed by simply freezing them. ?
Seems we might be spoit for choice now; put our wood in the sun, then the shade, or the freezer.
Going back to the original idea. I believe it would make sense to assume that humidity as low as practicable would optimise the bond outcome.
Regards John.

LEE SCHNEIDERMANN · Post by **LEE SCHNEIDERMANN** » Tue Sep 23, 2008 1:57 pm

I'm sure the humidity is a contributing factor to any adhesive's performance. Anything below 15 or 20 percent is probably acceptable. Anything above 25% is going to start to affect any kind of paint or epoxy application.
In the world of refrigeration, colder means drier.
That was my only point in mentioning the temperature thing.
Lee

In answer to the question about the paperwork. The freezer removed the moisture to under 10% humidity. That's VERY dry. No additional drying was nesecary. (I just re-read your post)

Oldsparkey · Post by **Oldsparkey** » Tue Sep 23, 2008 2:40 pm

I'm not sure about the humidity factor. I have built boats when we have had Hurricanes and the humidity was 100 % and you could see it coming down outside ( Rain ) , not the normal 80% or in that area that you only feel.

Most of the time ( actually all of the time ) all the boats I have built have been in high humidity , I live in the land of heat and humidity , and all the boats came out OK.

My shop is not air conditioned , I wish it was , so the heat & humidity is there with me on every build and I probably don't help matters by running the exhaust fan , dragging the outside air in over me and the boat but it feels good.

Never have had a problem with the epoxy setting (except when I mixed a batch wrong , it started smoking ) on any of the boats. The smoking batch never made it to the boat , can you say .... Hot Fingers from holding the cup. It was a 2 to 1 mix and I used two of the wrong one.

Which brings up an interesting thought , Epoxy cures by chemical reaction (Heat) , does that heat help to remove and humidity that has gotten into the wood ? When you epoxy saturate the boat the epoxy goes into the wood and cures.

Chuck.

Post by **jem** » Tue Sep 23, 2008 3:07 pm

Chuck,

The exothermic reaction you're able to feel is a result of a bunch of epoxy concentrated in one area. You'd have to glob on a WHOLE LOT of epoxy on to get a significant dehumidification. (Is that a word?)

Oldsparkey · Post by **Oldsparkey** » Tue Sep 23, 2008 3:34 pm

Just thinking out loud on those thoughts since I never , ever , even , considered the humidity when building a boat , just made them and paddled away. That was on the real humid days , the rest of the time it was down to the river.

Chuck.

Post by **jem** » Tue Sep 23, 2008 4:48 pm