Methods to fuel proof firewall
01-07-2009, 12:30 PM
#28
Senior Member
Join Date: Sep 2008
Location: Covington,
WA
Posts: 505
Likes: 0
Received 0 Likes
on
0 Posts
RE: Methods to fuel proof firewall
Epoxy is exothermic, it generates heat as it starts to cure. The hotter it is, the faster it cures. If you are going to nuke it, do it in a wide container, so the epoxy has a good surface area to volume ratio, i.e., it's not a thick layer of epoxy. That will help keep the thermal reaction from getting into a runaway stage and smoking or melting out a container.
Jack
Jack
01-08-2009, 10:42 AM
#29
Banned
Join Date: Jun 2006
Location: Lacona,
NY
Posts: 1,159
Likes: 0
Received 0 Likes
on
0 Posts
RE: Methods to fuel proof firewall
ORIGINAL: jib
Epoxy is exothermic, it generates heat as it starts to cure. The hotter it is, the faster it cures. If you are going to nuke it, do it in a wide container, so the epoxy has a good surface area to volume ratio, i.e., it's not a thick layer of epoxy. That will help keep the thermal reaction from getting into a runaway stage and smoking or melting out a container.
Jack
Epoxy is exothermic, it generates heat as it starts to cure. The hotter it is, the faster it cures. If you are going to nuke it, do it in a wide container, so the epoxy has a good surface area to volume ratio, i.e., it's not a thick layer of epoxy. That will help keep the thermal reaction from getting into a runaway stage and smoking or melting out a container.
Jack
[sm=lol.gif] "What ya got cooking in the microwave hun... it smells good?" I looked at my wife and said, " We're having Chinese ARF... it's the new fast food that tastes like delivery." [sm=lol.gif]
01-24-2009, 08:10 AM
#31
Member
Join Date: Nov 2004
Location: Buffalo Junction,
VA
Posts: 91
Likes: 0
Received 0 Likes
on
0 Posts
RE: Methods to fuel proof firewall
Re : bucket full of Epoxy The cure is set off by heat generated when the 2 parts get together & a large mass like a bucket full
does not have enough surface to allow enough cooling. A gallon spred out in a thin layer would not have done that .
You can extend the working time somewhat by spreading out on a sheet rather than it beeing in a cup.
does not have enough surface to allow enough cooling. A gallon spred out in a thin layer would not have done that .
You can extend the working time somewhat by spreading out on a sheet rather than it beeing in a cup.
01-26-2009, 01:28 PM
#32
Senior Member
RE: Methods to fuel proof firewall
Thumbs up for the finishing resin. Much thinner than epoxy. It is easily brushed on and being thin the brush marks pretty much disappear without hitting it with the old heat gun.
02-10-2009, 08:52 AM
#33
RE: Methods to fuel proof firewall
Wow... a 7yr old thread comes back... this is a record for me. I've never had a 7yr old thread come back. There was one that was over 5yrs old that surfaced again...that was a few months back.. but 7yrs..? This thread started just a few weeks after this site opened I believe... cool.. keep it going.
Kind of interesting really... reading my post 7yrs ago, and thinking about how I've changed a few techniques from 7yrs ago...(I'd still listen to me though I think...nah..probably not LOL
).
Kind of interesting really... reading my post 7yrs ago, and thinking about how I've changed a few techniques from 7yrs ago...(I'd still listen to me though I think...nah..probably not LOL
).
02-10-2009, 09:18 AM
#34
Senior Member
Join Date: Aug 2008
Location: Burtchville,
MI
Posts: 2,158
Likes: 0
Received 0 Likes
on
0 Posts
RE: Methods to fuel proof firewall
ORIGINAL: SeamusG
Thumbs up for the finishing resin. Much thinner than epoxy. It is easily brushed on and being thin the brush marks pretty much disappear without hitting it with the old heat gun.
Thumbs up for the finishing resin. Much thinner than epoxy. It is easily brushed on and being thin the brush marks pretty much disappear without hitting it with the old heat gun.
Bill
02-10-2009, 11:25 AM
#35
Senior Member
RE: Methods to fuel proof firewall
The following quote is from Tower. It's the description of Zap Adhesives Z-Poxy Finishing Resin ...
"This is Z-Poxy Finishing Resin from Pacer.
FEATURES: Pacer's Finishing Resin system is specially formulated to bond fiberglass to wood and foam. Resistant to shock and solvents and is odorless. This Epoxy is resistant to shock and solvents, is non-brittle, easy to sand and has flow characteristics. The total working time of this Resin is 60 minutes, and fully cures in 3 Hours completely clear.
INCLUDES: One 6oz Bottle of Hardener One 6oz Bottle of Resin
COMMENTS: This product contains Epoxy resin and Polyamide resin, some people are allergic to these compounds."
Other "finishing resins" may have different specifics.
"This is Z-Poxy Finishing Resin from Pacer.
FEATURES: Pacer's Finishing Resin system is specially formulated to bond fiberglass to wood and foam. Resistant to shock and solvents and is odorless. This Epoxy is resistant to shock and solvents, is non-brittle, easy to sand and has flow characteristics. The total working time of this Resin is 60 minutes, and fully cures in 3 Hours completely clear.
INCLUDES: One 6oz Bottle of Hardener One 6oz Bottle of Resin
COMMENTS: This product contains Epoxy resin and Polyamide resin, some people are allergic to these compounds."
Other "finishing resins" may have different specifics.
02-14-2009, 06:38 PM
#37
Senior Member
My Feedback: (24)
Join Date: Dec 2004
Location: Scottsdale,
AZ
Posts: 272
Likes: 0
Received 0 Likes
on
0 Posts
RE: Methods to fuel proof firewall
Folks,
After modeling for 40+ years I have come to the resolution that glow fuel used or unused will contaminate balsa and plywood over time. The best protection I have used to combat the fuel soaking into the wood is very thin 30 minute epoxy. The first coat is critical. You want the thined epoxy to be absorbe by the wood much the same way the wood absorbs the fuel. Once the thin coat is absorbed the fuel proofing is very effective. I have learned that thick coat material like finishing resin, non thinned epoxy, polyurethane, etc. don't work as well for a first coat over the long term. You can apply several thin coats of epoxy and hopefully you have reached all the vulnerable spots. The point is to not let the fuel penetrate, with a thick coat only, there always seems to be a point of failure, and the fuel finds it, and undermines the thick epoxy, etc. coating. Using the very thin coat first will get the protection beneath the surface of the wood ahead of any fuel seepage. Yes, thicker coats over the thin coat/s can't hurt. Try sticking a piece of balsa sheet into a pan of water. Watch how the balsa absorbs the water. The fuel does the same thing. So try sticking the balsa into a solution of very thin epoxy ( like water) it will absorb it also. When it dries, it will not absorb any more water if you place it into the water again. Protection at its best.
Sledge_78
After modeling for 40+ years I have come to the resolution that glow fuel used or unused will contaminate balsa and plywood over time. The best protection I have used to combat the fuel soaking into the wood is very thin 30 minute epoxy. The first coat is critical. You want the thined epoxy to be absorbe by the wood much the same way the wood absorbs the fuel. Once the thin coat is absorbed the fuel proofing is very effective. I have learned that thick coat material like finishing resin, non thinned epoxy, polyurethane, etc. don't work as well for a first coat over the long term. You can apply several thin coats of epoxy and hopefully you have reached all the vulnerable spots. The point is to not let the fuel penetrate, with a thick coat only, there always seems to be a point of failure, and the fuel finds it, and undermines the thick epoxy, etc. coating. Using the very thin coat first will get the protection beneath the surface of the wood ahead of any fuel seepage. Yes, thicker coats over the thin coat/s can't hurt. Try sticking a piece of balsa sheet into a pan of water. Watch how the balsa absorbs the water. The fuel does the same thing. So try sticking the balsa into a solution of very thin epoxy ( like water) it will absorb it also. When it dries, it will not absorb any more water if you place it into the water again. Protection at its best.
Sledge_78
02-15-2009, 04:20 PM
#39
Senior Member
My Feedback: (24)
Join Date: Dec 2004
Location: Scottsdale,
AZ
Posts: 272
Likes: 0
Received 0 Likes
on
0 Posts
RE: Methods to fuel proof firewall
Yes, thinned with alcohol. Drill all the holes in the firewall that you will need then use the thinned epoxy. Make sure to use a small brush and let the epoxy get into the small hole. Besides the firewall, don't forget the fuel tank compartment.
Sledge_78
Sledge_78
12-18-2009, 01:18 AM
#40
Member
Join Date: Sep 2009
Location: Atascadero,
CA
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
RE: Methods to fuel proof firewall
Wow, I learned a lot. I don't know about you guys but I'll be using Sledge's technique. I was wondering also what do you guys make your firewalls out of? How thick? (Sorry for the n00b question.
12-18-2009, 05:06 PM
#41
Senior Member
RE: Methods to fuel proof firewall
I'm planning on painting the inside of a built up wood cowl and then fuel proofing with finishing resin.
Does anyone have a recommendation for the type of paint to use? One that won't interact badly with the finishing resin?
TIA,
Em - where was I in November 2001?
Does anyone have a recommendation for the type of paint to use? One that won't interact badly with the finishing resin?
TIA,
Em - where was I in November 2001?
12-18-2009, 08:23 PM
#43
Senior Member
RE: Methods to fuel proof firewall
ORIGINAL: BuiltNotBought
Wow, I learned a lot. I don't know about you guys but I'll be using Sledge's technique. I was wondering also what do you guys make your firewalls out of? How thick? (Sorry for the n00b question.
Wow, I learned a lot. I don't know about you guys but I'll be using Sledge's technique. I was wondering also what do you guys make your firewalls out of? How thick? (Sorry for the n00b question.
My experiences are limited to 40 / 60 sized glow powered planes. Plywood - 1/4".
07-21-2015, 11:14 AM
#45
Over the past 5 decades I've personally graduated from butyrate dope to thinned epoxy, now I tend to use fibreglass resin mostly. Paints just fine, lasts as long as epoxy (which means "decades").
07-22-2015, 01:46 AM
#46
Join Date: Jan 2015
Posts: 280
Likes: 0
Received 0 Likes
on
0 Posts
07-22-2015, 06:13 AM
#47
Member
I'm sure Skylark-flier does mean polyester resin. I have used it also to fuel proof the insides of flight box drawers. Other than the strong odor it does work well. The cure rate can be adjusted from slow to smoking hot.
07-22-2015, 11:43 AM
#48
Oops, sorry 'bout dat! Yeah, polyester resin - works like a charm. Stu's right too - only smell worse (stronger) is a skunk. My worse habit with it (Stu also mentioned it) is to add enough hardener to make marshmallows like stones.
Love the stuff!
Love the stuff!
07-22-2015, 06:47 PM
#49
I've had really good experience with epoxy and denatured alcohol though.. I think you'll do fine. I've got planes almost as old as this thread that are in great shape.
05-30-2016, 07:09 AM
#50
Junior Member
Join Date: Apr 2011
Location: Portland,
OR
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
I know this is an old thread, but what is good with gas. I have some laminating epoxy that I was going to use but I am concerned with weight. This lead me back to dope. I was thinking of using Sig Nitrate dope. What are your ideas?