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Good Patching Epoxy--other stuff as good?

PostPosted: Tue Sep 26, 2006 8:57 am
by kayakrguy
Hi Everyone,

I am going to need a good epoxy for filling holes, blemishes etc on outer walls. I have already sealde the walls overall with laminating epoxy, but now will have to fill drill holes etc after mounting walls, spars, roof etc...

Thanks,

Jim

PostPosted: Tue Sep 26, 2006 9:17 am
by doug hodder
Jim, if you are already working with an epoxy system...you are going to want a low density fairing filler, most of the systems have one designed for their formulas...it's designed to fill, won't shrink and it is going to be easier to sand...it's a seperate filler that you dump into the epoxy mix...Doug

PostPosted: Tue Sep 26, 2006 1:30 pm
by asianflava
Yup, make shure you use the right stuff (low density filler). If you use the wrong stuff (microfibers) you'll be sanding it forever. It won't hurt the final result but it will take you a lot longer to get there.

PostPosted: Tue Sep 26, 2006 5:16 pm
by angib
asianflava wrote:Yup, make shure you use the right stuff (low density filler). If you use the wrong stuff (microfibers) you'll be sanding it forever.

Let's complete the list of fillers: there is also silica - this makes the resin/filler mix stiffer during application so you can give it the shape you want. It also makes the cured filler much, much harder than microfibres - only a sanding disc in an angle grinder will deal with it.

So stick with the low density filler! For ease of sanding, wait at least an extra day after the resin has cured before trying to sand - you get less clogging and easier sanding.

Andrew

PostPosted: Tue Sep 26, 2006 5:18 pm
by kayakrguy
Hi Guys,

Since this whole epoxy thing is new to me, let me see if I understand exactly what you're saying. I used CFI's laminating epoxy resin and hardener to seal my outside walls and edges.

What I understand is that I should use something called low density filler with resin and hardener in order to get a patching epoxy.

First, I understand you to be saying I better get that from CFI

Second, what I am not clear about is using the low density filler with
laminating epoxy...I doubt that the epoxy would ever get truly thick enough to make it behave like patching material...in its natural state, it is fairly viscous. Mind you the only epoxy I ever used before was in High School when I worked in a MFG Boat plant putting potted, hot epoxy on the bows of fiberglass hulls and sanding them smooth...

Jim

PostPosted: Tue Sep 26, 2006 8:22 pm
by doug hodder
Jim...I'd check to see if the epoxy brand you are using has a variety of fillers for different applications...if not...you could always experiment with some low density filler from West, Epoxy III, Raka etc...can't hurt on a test piece...you can mix it up as thick as peanut butter, won't run and trowel it into the holes with a bondo spatula...lots more working time over a bondo also...but I don't know if the brand you're using is compatible with other fillers...best to check and see...Doug

PostPosted: Sat Sep 30, 2006 3:07 am
by Artificer
What everyone is talking about is a material that you add to your expoxy to thicken it. The lowest density filler is micro-balloons. You can mix up a batch that has the consistancy of wall spackle. Its almost perfectly ridgid, weighs almost nothing, but has little strength when its that thick.

One of the most popular epoxy systems is the West System. Take a look at thier filler here. There should not be a problem with using it with your epoxy. If your epoxy manufacture has something similar, use that.

Here is a list of the West System fillers. A great resource to learn about epoxy is the West Systems web site.

PostPosted: Sat Sep 30, 2006 8:14 am
by Juneaudave
You can also tint the thickened epoxy filler using fine sanding dust from your sander. I keep small containers of dust from various different colored woods, and use a pinch from this one and a pinch from that. You can get pretty close to matching most any wood that you are filling.

PostPosted: Sat Sep 30, 2006 1:15 pm
by gasmanptb
HEy kayaker go to this site for a little tutorial, Yes it is a boat but it could help some. Also you can use flour and a littlet trick I picked up is to use some chalk dust from a chalk line to color the thickened goo so if you sand to far you will see the wood this could be good or bad depending on the situation. most of the replies so far have been great and keep asking so you don't messed up. Here is the link http://bateau2.com/content/view/46/28/

PostPosted: Mon Oct 16, 2006 6:33 pm
by kayakrguy
Hi Folks,

Been busy running around to family, NE Teardroppers Fall Foliage camp in, getting Bendy Birch, yadda, yadda, yadda...

But, I want to say :shake hands: thank you for the good advice. I feel prepared, when it comes time to do my fill stuff and will check each of the suggestions you made. Right now I am dealing with the mysteries of bending plywood :)

Jim

PostPosted: Mon Oct 16, 2006 6:38 pm
by kayakrguy
Oh, one more thing. When in HS, I worked part time in a MFG boat factory.
We put epoxy on the bow of the fiberglass hulls to reinforce them and then belt sanded the stuff off. No masks etc...

The epoxy was hot...out of a pot...mostly cured and you really had to work fast...terrible job, really. But my point really is that that was completely different than what we discuss here--and didn't prepare one to use other stuff...

Jim

PostPosted: Mon Oct 16, 2006 7:52 pm
by K-1
The most basic and effective of fillers is Wood Flour .. I am not talking about the stuff that you can get from your sander ... it is much much finer than that ... and is actually the stuff used in adding "fiber" to your bread that you buy at the store.

A proper wood flour is from hardwood and is so fine that it is like a talcum powder. It is also relatively cheap to buy and easy to add to epoxy ... just mix in enough so that you have a peanut butter consistency.

You can find wood flour at ... www.bateau.com ... -Wayne-