sillyness

My Feedback: (25)

I am looking to reinforce the firewall on a new 35% Panzl (DA-100). Wondering what resin and cloth is best.

I am thinking of using Aeropoxy... not the BVM stuff, the stuff below:
http://www.aircraftspruce.com/catalo...s/aeropoxy.php

Is this necessary or will regular H9 30 min epoxy or NHP 3 hour epoxy do the trick?

Also, for the cloth, pondering Carbon Weave vs. Kevlar Weave vs. a blend of the two. What weight?

Thanks,
Jason

seanreit

My Feedback: (60)

If money is an issue, for such a small project I would use 20 minute finishing resin.

Let it setup for two days though before you touch it. It's got most of it's strength after about 48 hours.

If you want an epoxy resin, I always recommend west systems above everything.

Ed Smith

First of all use epoxy resin. The fast drying glues are not that strong.

I am assuming your reinforcing will be on inside corners rather than wrapping cloth around the outside of a structure.

If so, Carbon or Kevlar will do nothing here that ordinary glass cloth will not. Not too many cloths tuck right into a corner tightly. chop up some cloth and make up a mix of resin, short fibres and cabo-sil (Filler) for a fairly thick mix. Use this mix to make a fillet in the inside corners of the firewall and fuselage. Then lay on some 6oz cloth along the fuselage across the firewall and back along the fuselage, ensuring it bonds with the fillet. This can be done either side of the firewall, top or bottom, along the sides and front or back.

Ed S

seanreit

My Feedback: (60)

Ed, your input on this subject I have always been a fan of, and consider a lot of it the final word.

Just didn't know if you knew about the 20 minute finishing resins. They are a product idential in sale to the five 15 and 30 minute epoxy's, but much thinner, same consistancy as west systems, but same size bottles as the other products.

My limited use of the product is such that it comes out the same as west or any other epoxy resin system. It is epoxy. I couldn't tell if you knew that from your last post and wanted to make sure you knew there was a cheaper "in the door" alternative to buying an expensive resin system for a small job.

Boy I'm long in the tongue today........Whew.

Sean

rcapmd

Depending on how the firewall is structured, you may also consider pinning it with small dowels.

sillyness

My Feedback: (25)

Actually I am using the cloth on the outside of the motor box... the inside just doesn't make sense... there's no tensile load in there. Inside will get some hardwood tri-stock and T-88 Epoxy.

So what weight cloth?

Ed Smith

Sean,

Thank you.

I was not intending to be critical of finishing resin. I rarely use finishing resin as I always have the lay up resin around. I use it for everything that requires resin. I use so much of it that it is easy to forget that there are those that do not have a half gallon of epoxy kicking around all the time.

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From Sillyness???

Realy? You are on this Forum asking for advice and when you get it you say it does not make sense! Try wrapping cloth round the outside of sharp corners and you will very quickly find out what does not make sense.

Ed S

seanreit

My Feedback: (60)

Ed, no kidding, since I bought my first gallon of West Sytems, it's hard to remember when $100.00 a gallon for getting into it was "expensive" Now if I don't have a gallon sitting in reserve, I get it in here.


Silly, I don't do any "firewall" work, I'm strictly into turbines, so I can't recommend weight cloth for the firewall box, but if no one else chimes in, I'd recommend at least 6 ounce and maybe two layers of it if someone else here recommends two layers.

sillyness

My Feedback: (25)

I'm thinking of using Kevlar. I don't want to go buy a resperator just to reinforce a friggen firewall.

Ed,

It doesn't make sense because I care very much about weight for a 3D ship. I already need to fuel proof the outside of the motor box, so I already need the resin on the outside. I don't want to go smearing the inside with cups full of the goop too. This makes Kevlar a more attractive option... I it should bend easier... though I can't find much info on it... unnerving. Also, FWIW, I just found a guy that carbons the outside of his motor boxes. He says when he crashed one the motor box was the only thing that survived.

Sean,
Thanks for your help.

seanreit

My Feedback: (60)

Silly, if you'd be so kind as to reconsider your response to Ed. He is one of the very few true talents in this realm of the hobby. Most everything I know about working with this stuff started with reading these forums. The man has 1800 posts and a bunch of them are in this particular forum.

Anyway, good luck with your project.

Sean

sillyness

My Feedback: (25)

I changed my response to be kinder and gentler.

Though, I could have been more politely educated on the cons of wrapping carbon around a sharp corner... never thought of it.

Most people on these forums are "less than intelligent". I had no way to know that Ed was some sort of mythic carbon guru. Sorry.

Panzlflyer

My Feedback: (15)

Its easy, West Systems for me and wrap with Surround wrap and then I use 4 ply pieces clamped to hold it all tight.