What's the best way to apply epoxy or fiberglass resin?
03-12-2003, 08:05 PM
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What's the best way to apply epoxy or fiberglass resin?
Hi all,
Here is the problem:
Anytime I need to apply epoxy to a large area, such as joining layers of the firewall together or using thinned epoxy to fuelproof an area, I have been using the cheap Hobby brushes. You know, the kind with the metal handles and black plastic bristles that come in pack of about 6-8 for a buck or two...
Well, the problem is, when I go to spread the epoxy, even the thinned epoxy, the bristles pull out of the brush and make quite a mess. Obviously, I don't want the bristles stuck to my airframe, so I frantically try to clean them up, usually making more of a mess all over my fingers, the table, etc.
Now, I do heat the epoxy on an index card over a small candle flame, just to "soften" it a bit and make it more spreadable. I am needing to fiberglass the inside of a cowl in a plane I am working on, and having never fiberglassed before, don't want a repeat of my problems that I have with the epoxy...
So, can anyone help?!
Thanks!
John
Here is the problem:
Anytime I need to apply epoxy to a large area, such as joining layers of the firewall together or using thinned epoxy to fuelproof an area, I have been using the cheap Hobby brushes. You know, the kind with the metal handles and black plastic bristles that come in pack of about 6-8 for a buck or two...
Well, the problem is, when I go to spread the epoxy, even the thinned epoxy, the bristles pull out of the brush and make quite a mess. Obviously, I don't want the bristles stuck to my airframe, so I frantically try to clean them up, usually making more of a mess all over my fingers, the table, etc.
Now, I do heat the epoxy on an index card over a small candle flame, just to "soften" it a bit and make it more spreadable. I am needing to fiberglass the inside of a cowl in a plane I am working on, and having never fiberglassed before, don't want a repeat of my problems that I have with the epoxy...
So, can anyone help?!
Thanks!
John
03-12-2003, 11:08 PM
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What's the best way to apply epoxy or fiberglass resin?
I use the cheapest 3/4" (or so) brushes you can get in the paint department at Home Depot. They used to be about 50 cents, but they've gone up a bit. I don't remember a problem with hairs coming out, although maybe one or two. Usually the epoxy is in a place that doesn't show (like the firewall), so a hair here or there doesn't matter anyway. I've also used the really cheap foam brushes, which don't shed, but I don't like them as much.
03-13-2003, 02:18 AM
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What's the best way to apply epoxy or fiberglass resin?
I do not know squat about RC epoxy!
I have worked with WestSystem epoxy on boats for last 15 years. You name it I probably did something similar.
You post has me suspect of just what you are using and just how fast (timing/ hot ) the stuff is.
My experience with with a fresh batch of West is that you normally have about 15+ minutes of a very liquid state before it starts to kick and thicken a bit. Plenty of time to wet out a surface, apply some glass or carbon, wet it out totally again. Then set back and let it kick off,
While still green you can knife cut, course sand, and dress up your work before it really gets hard and becomes a much more difficult job.
Unless you are working in very low temps, the warming to thin is the wrong way to go. you are speeding up the cure process with heat. We have refrigerated West and hardener to slow the process down in very hot weather.
find a store that sells epoxy product for real size products, maybe like a West Marine Store, buy some of there foam brushes and cut them to the sizes you may need to poke around inside a cowling or fuse, some popsickle type sticks and some string can make some weird little brushes for special purposes. I mentioned an true epoxy store cause some of the same grey foam brushes just swell up you just toss'em. My experience is that the hairs do not start pulling out untill the exopy is thickening.
The quicker the kicktime the weaker the end product is my experience. It all depends on the application and how strong you really want it and the time your willing to spend.
mikenlapaz
I have worked with WestSystem epoxy on boats for last 15 years. You name it I probably did something similar.
You post has me suspect of just what you are using and just how fast (timing/ hot ) the stuff is.
My experience with with a fresh batch of West is that you normally have about 15+ minutes of a very liquid state before it starts to kick and thicken a bit. Plenty of time to wet out a surface, apply some glass or carbon, wet it out totally again. Then set back and let it kick off,
While still green you can knife cut, course sand, and dress up your work before it really gets hard and becomes a much more difficult job.
Unless you are working in very low temps, the warming to thin is the wrong way to go. you are speeding up the cure process with heat. We have refrigerated West and hardener to slow the process down in very hot weather.
find a store that sells epoxy product for real size products, maybe like a West Marine Store, buy some of there foam brushes and cut them to the sizes you may need to poke around inside a cowling or fuse, some popsickle type sticks and some string can make some weird little brushes for special purposes. I mentioned an true epoxy store cause some of the same grey foam brushes just swell up you just toss'em. My experience is that the hairs do not start pulling out untill the exopy is thickening.
The quicker the kicktime the weaker the end product is my experience. It all depends on the application and how strong you really want it and the time your willing to spend.
mikenlapaz
03-13-2003, 04:39 AM
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What's the best way to apply epoxy or fiberglass resin?
I use the same brushes. It seems like 2 or 3 bristles will come out of every one. So before I use one I give it a little twist and flex with a finger & thumb. The loose ones will come out and it's fine after that.
03-13-2003, 05:27 AM
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FluX Brushes
Been there done that. I pick up flux brushes at my local hardware store (plumbing department.) The look a lot like the el-cheap-o brushes, but they hold together better, at least they have for me. I trim the brush down to about 1/2" or so before I use it.
Never thought of using a 3/4" paint brush, but I bet that would work real well for large areas.
West Systems is very good epoxy in my opinion. If you can find it, I recommend it's use as well as their fillers, like micro-fibers.
Never thought of using a 3/4" paint brush, but I bet that would work real well for large areas.
West Systems is very good epoxy in my opinion. If you can find it, I recommend it's use as well as their fillers, like micro-fibers.
03-13-2003, 07:16 PM
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epoxy
cut it with alcohol,work fast!.also i pinch my brushes,at the brisle
end of course with my needle nose plyers.i first give them a little
squeeze, top to bottom,then i pinch them really hard at the seam.
rarely do i loose even one hair anymore.
end of course with my needle nose plyers.i first give them a little
squeeze, top to bottom,then i pinch them really hard at the seam.
rarely do i loose even one hair anymore.
03-13-2003, 07:17 PM
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epoxy
cut it with alcohol,work fast!.also i pinch my brushes,at the brisle
end of course with my needle nose plyers.i first give them a little
squeeze, top to bottom,then i pinch them really hard at the seam.
rarely do i loose even one hair anymore.
end of course with my needle nose plyers.i first give them a little
squeeze, top to bottom,then i pinch them really hard at the seam.
rarely do i loose even one hair anymore.
03-13-2003, 07:26 PM
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What's the best way to apply epoxy or fiberglass resin?
NO NO NO NO NO NO NO!!!!!!!!!!!! Do not thin epoxy ever for any reason whatsoever!!!!!!!!!
If you need it to be thinner, then either use laminating resin or put the container in warm water.
If you thin epoxy you risk solvent trapping which will result in rubbery and weak epoxy. After a while (who knows how long) it will harden and then it will be brittle.
Thinning epoxy is risky and ALWAYS unnecessary.
If you need it to be thinner, then either use laminating resin or put the container in warm water.
If you thin epoxy you risk solvent trapping which will result in rubbery and weak epoxy. After a while (who knows how long) it will harden and then it will be brittle.
Thinning epoxy is risky and ALWAYS unnecessary.
03-13-2003, 10:38 PM
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Thinning Epoxy
Hey Cafeen Man,
We've been thinning epoxy for years with denatured alcohol. This gives it a nice viscosity for brush spreading. The alcohol must evaporate out of it because it sets up very nicely. I should mention that we use the 30-minute epoxy to give time to work with it.
Roger
We've been thinning epoxy for years with denatured alcohol. This gives it a nice viscosity for brush spreading. The alcohol must evaporate out of it because it sets up very nicely. I should mention that we use the 30-minute epoxy to give time to work with it.
Roger
03-14-2003, 01:03 AM
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water and epoxy??
The site listed explains a number of alternatives on how to thin out your epoxy.
YOU ARE ALL CORRECT BUT EACH METHOD HAS ITS DRAWBACKS. DO YOU KNOW WHAT THEY ARE AND WHAT THE ALTERNATIVES ARE FOR REDUCING VISCOSITY?
Who knows the manufacture of the stuff you buy for RC but the data presented is from a well-known manufacture, who is not afraid to put their name on a container when they offer it to the public!
http://www.seqair.com/skunkworks/Glu.../Thinning.html
YOU ARE ALL CORRECT BUT EACH METHOD HAS ITS DRAWBACKS. DO YOU KNOW WHAT THEY ARE AND WHAT THE ALTERNATIVES ARE FOR REDUCING VISCOSITY?
Who knows the manufacture of the stuff you buy for RC but the data presented is from a well-known manufacture, who is not afraid to put their name on a container when they offer it to the public!
http://www.seqair.com/skunkworks/Glu.../Thinning.html
