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Forum topic by mahdee posted 08-05-2015 12:37 PM 751 views 0 times favorited 9 replies Add to Favorites Watch
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mahdee

3553 posts in 1232 days


08-05-2015 12:37 PM

Topic tags/keywords: question finishing

Hi,
I am trying to permanently waterproof a piece of wood. The water will be sitting/travelling through this wood. As I was diggin the channels in the wood, I noticed some large rotted area which I cleaned up with a router and inserted new wood using gorilla glue. I will still have some irregular areas that need to be filled-in. I am wondering what is the best way to fill this void (about 10”long and 2” deep). Would bondo do the job? And if so, should I use fiberglass resin on the wood prior to filling the void with bondo? Do I need to do anything special to ensure epoxy will adhere to the bondo like roughing it up or making sure it is smooth?
I am using Total Boat as a waterproofing agent and the direction says to use filler where needed but does not make any suggestion as to what type of filler to use.
Thanks

-- earthartandfoods.com


9 replies so far

View AZWoody's profile

AZWoody

697 posts in 689 days


#1 posted 08-05-2015 02:35 PM

You can seal it with just epoxy to make it waterproof.

Even to fill the void, you can use epoxy as well.

People make plywood aquariums all the time and use epoxy to seal the interior.

View mahdee's profile

mahdee

3553 posts in 1232 days


#2 posted 08-05-2015 03:03 PM

Thanks AZ,
The issue is that this epoxy is too expensive for filling void and I was hoping to know what “filler” is appropriate for this project.

-- earthartandfoods.com

View Rick M's profile

Rick M

7923 posts in 1845 days


#3 posted 08-05-2015 03:08 PM

I wouldn’t use Bondo, I would plug it with wood and glass over it.

-- http://thewoodknack.blogspot.com/

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shipwright

7173 posts in 2263 days


#4 posted 08-05-2015 03:15 PM

First of all I wouldn’t use bondo or “fibreglassing resin” (polyester). It doesn’t stick well to wood. Polyester really only sticks well to other polyester as in laying up a fibreglass boat. For many years it was used to glass wooden boats, even by commercial builders but eventually it will fail.
Another thing to keep in mind is that epoxy will cure over polyester but polyester won’t cure over epoxy.

For simple waterproofing I would recommend S1sealer from System Three. It is as thin as diesel and will actually penetrate before it cross-links unlike other epoxies. I have even used it to make fresh water tanks.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees. http://thecanadianschooloffrenchmarquetry.com/

View Dabcan's profile

Dabcan

252 posts in 2136 days


#5 posted 08-05-2015 04:34 PM

I’d fill the void with an epoxy/saw dust mix. Basically mix up some epoxy and add sawdust to increase the volume. It’ll become a bit like a paste and you can stick that in the void, as long as you’re covering it with epoxy in the end you could even put in some bits of wood to fill the void, the epoxy will seal it all in.

-- @craftcollectif , http://www.craftcollective.ca, https://www.etsy.com/shop/craftcollective?

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mahdee

3553 posts in 1232 days


#6 posted 08-05-2015 04:51 PM

Thanks guys. Good information and suggestions. Floating wood and sawdust sounds like the way to ago. I am assuming that is what the direction was saying by applying the filler.

-- earthartandfoods.com

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mahdee

3553 posts in 1232 days


#7 posted 08-05-2015 04:55 PM

Paul, this wood is spongy enough for the epoxy to soak right into it. After the 3rd coat it gets shiney.

-- earthartandfoods.com

View MrUnix's profile

MrUnix

4230 posts in 1664 days


#8 posted 08-05-2015 05:10 PM

Another thing to keep in mind is that epoxy will cure over polyester but polyester won t cure over epoxy.

Not really relevant to the original question, but polyester over epoxy is not a problem at alll… I’ve done it many times – particularly with putting gelcoat (polyester) over epoxy repairs.

See this: http://www.westsystem.com/ss/polyester-over-epoxy/

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

View shipwright's profile

shipwright

7173 posts in 2263 days


#9 posted 08-05-2015 07:04 PM

New one on me. I’ve had failures of bondo over epoxy /cloth – no cure. When I asked my supplier he told me the above. I never tried it again. May have to do with the particular residues on the surface of the epoxy. In the case of filling cloth the areas getting filled haven’t been sanded.

Thanks for the correction.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees. http://thecanadianschooloffrenchmarquetry.com/

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