Q. re fire resistance

H

heinz wittenbecher

New member
Mar 1, 1998
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I'm currently redoing my old hatch, basically coating it with a layer of
fibreglass.

I've got my top, including the raised portion done and ultimately will line
the bottom with ceramic fibre paper but I don't think I'll be able to get it
before my next trip so I have to decide on whether to leave the bottom wood
(original) or to go ahead and apply a layer of fiberglass and leave it as
fibreglassed wood for the time being.

My question: what burns easier, i.e. would the layer of fibreglass increase
combustibility of the hatch? Am I better off to leave it just as wood, i.e.
that's how it was/is, but of course the wood is quite dry from the years and
miles, hence the desire to "improve/extend" it's longevity with a layer of
'glass'.

Or... does anyone have any ideas/recommendations of a product I might be
able to obtain locally, perhaps at a racing shop.

What I'm hoping though is that someone can confirm that applying the
fibreglass will not increase combustability so that I can get that far and
then do the ceramic at another time.

Thanks in advance for your comments.

Heinz
 
>
> Or... does anyone have any ideas/recommendations of a product I might be
> able to obtain locally, perhaps at a racing shop.

Heinz, try a boat shop - use the WEST epoxy system(www.westsystem.com).
Much easier to work with than vinylester or polyester resins with little
odor. It's widely used in homebuilt boat and aircraft construction.

> What I'm hoping though is that someone can confirm that applying the
> fibreglass will not increase combustability so that I can get that far and
> then do the ceramic at another time.

AFAIK, all the plastic resins will burn. I've heard that there's a WEST
additive that increases the epoxy's fire resistance, but I've never seen
it listed for sale. Non-expanded(i.e. not foam) plastics ignite and
burn at temperatures similar to wood, but typically give off noxious
gases when they burn. The result of adding "plastic" to your hatch
won't make it any more combustible, but the products of combustion will
be much nastier than burning wood.

I'd be inclined to leave the bottom until I could cover it with ceramic
paper and I definitely wouldn't use vinylester or polyester resin.

My $.02,
Patrick
- --
Patrick Flowers
Mailto:patrick

The GMC Motorhome Page
http://www.gmcmotorhome.com
 
Thanks everybody.

You've helped me decide to leave it as is until I get the Ceramic Paper.

Will contact Eaton tomorrow and maybe by eating UPS overnight I'll get it on
yet before leaving Wednesday.

Thanks again

Heinz

> Heinz, try a boat shop - use the WEST epoxy system(www.westsystem.com).
> Much easier to work with than vinylester or polyester resins with little
> odor. It's widely used in homebuilt boat and aircraft construction.

Thanks Patrick, I'll try and remember for next time and head to a marine
store instead of automotive.
Used the smelly stuff for the top area. Hopefully the smell will diminish by
Wednesday :-)
 
Good idea, but not for me. Not enough room plus that I have a raised portion
in the middle of the hatch so air is going to be swirling anyways.

Thanks for the thought.

Heinz

> Just a few other thoughts on alternatives... Heinz,
>
> I'd give some thought to an aluminum sandwich with an air scoop
> arrangement, if we have decent air flow from front to back that high up
> in the engine compartment.
>
>
>
> XXXXXXXXXXXXXXXXXXXXXXXXXXXXX Plywood
> ____________________________ Aluminum top sheet
> ....................... Interstitial spacer material (forming Channels)
> ________________________ Aluminum bottom sheet
> \
> ooooooooooooooooooo \ \
>
> Ceramic paper = o
>
>
> Thickness of sandwich.... somewhat dependent on lenght of channel, I
> would guess.
>
> --
> Regards,
> John 74 Glacier
>
>
 
> Will contact Eaton tomorrow and maybe by eating UPS overnight I'll get it
on
> yet before leaving Wednesday.
> >>
> Heinz
>
> Please dont take this the wrong way. It is meant to be helpful. Your lady
has
> survived for 20 some years with out this "paper". Do you not think that
she
> might make it another week or two. This comes from a week on the road
> away from my lady thinking while I drive. It also comes from knowing I
have
> two
>

I won't take it the wrong way. I appreciate all input.
I know what you mean, it's survived thus far ;-)

It's more of the "bee in the bonnet" syndrome :-)
plus too many times when I should'a and didn't and the end cost was much
higher [g].

Decisions, desisions.... :-)

Heinz
 
> What I'm hoping though is that someone can confirm that applying the
> fibreglass will not increase combustability so that I can get that far
> and then do the ceramic at another time.

I can't confirm as in UL underwriting, but first I assume you mean
putting a layer of glass wool, as in Dow Cornings insulation product? I
would venture a guess that it might pick up some possibly flamable gunk
(but no where near as much flamable gunk) as your average used car has
accumulated on its "fiberglass" mat that lines the underside of many
cars' hoods.

Thoughts on the positive side (i.e. go ahead an insulate it now)...

Just thinking about it, I would guess that you would use just the batts
of pure insulation without any aluminized paper, and just staple it to
the plywood. Maybe use some none combustible "holder-uppers" if needed.
I first thought about hardware cloth, but since you are going to be
adding ceramic paper as soon as possible, I would hold off on the
hardware cloth till you get the ceramic. ( or maybe just tack the
hardward cloth up temporarily). I'm sure the ceramic paper will have
some fasteners/instructions and don't know if the hardware cloth would be
compatible (as in, would the ceramic paper be too friable to fasten over
hardware cloth).

Thoughts on the negative side (i.e. hold off with that glass fiber for
now)...

I guess the glass wool could greatly reduce the air flow on the
lowere surface of plywood and darn near eliminate any heat removal due to
the air flow in the compartment. Remember it would *slow* but not stop
the transfer of heat from the engine to the bottom surface of the
plywood. Caught in a traffic jam on a LA freeway, after pulling a long
hill with a toad... I might want some airflow to cool the bottom surface
of that plywood.

I know you were hoping to catch a GMCer who did his PhD thesis on
fiberglass over plywood with no additional boundry material... but maybe
some of these comments may spark a few absolute facts from the wealth of
info on this net.

Does your fan clutch work properly Heinz... thinking you once mentioned
confirming the "keep it up if you want it to work properly theory".

If it were me, I'd be leaning on the side of leave it the way GMC did for
now, until you get the ceramic paper. And before you buy the paper,
I would press the vendor on the thermodynamics of traping heat under the
plywood floor with little or no airflow to remove the heat.

Regards,
John 74 Glacier
 
> Heinz
>
> Hate this laptop sometimes. Touch that silly touch pad and the letter is
gone.

Teehee. Tricky little devils, ain't they :-)

Smetimes when doing lost of stuff on laptop I use a regular mouse instead of
the pad.
A USB mouse you can plug in/unplug at will. (Assuming your laptop has a USB
port :-)

> Anyway-----Knowing I have 2 more weeks on the road that I cant work on my
> lady.

So much to do... so little time.

> Hot air fest not looking good. Trying to figure out what I can do without.
I
> did
> not mean to sound harsh--------just been doing some reality searching
here.
> Probably more my problem than yours

I think we all have similar problems, just different titles/topics.

Heinz

>
> Take Care
> Arch
>
>
 
> What I'm hoping though is that someone can confirm that applying the
> fibreglass will not increase combustability so that I can get that far
> and then do the ceramic at another time.

I can't confirm as in UL underwriting, but first I assume you mean
putting a layer of glass wool, as in Dow Cornings insulation product? I
would venture a guess that it might pick up some possibly flamable gunk
(but no where near as much flamable gunk) as your average used car has
accumulated on its "fiberglass" mat that lines the underside of many
cars' hoods.

Thoughts on the positive side (i.e. go ahead an insulate it now)...

Just thinking about it, I would guess that you would use just the batts
of pure insulation without any aluminized paper, and just staple it to
the plywood. Maybe use some none combustible "holder-uppers" if needed.
I first thought about hardware cloth, but since you are going to be
adding ceramic paper as soon as possible, I would hold off on the
hardware cloth till you get the ceramic. ( or maybe just tack the
hardward cloth up temporarily). I'm sure the ceramic paper will have
some fasteners/instructions and don't know if the hardware cloth would be
compatible (as in, would the ceramic paper be too friable to fasten over
hardware cloth).

Thoughts on the negative side (i.e. hold off with that glass fiber for
now)...

I guess the glass wool could greatly reduce the air flow on the
bottom surface of plywood and darn near eliminate any heat removal due to
the air flow in the compartment. Remember it would *slow* but not stop
the transfer of heat from the engine to the bottom surface of the
plywood. Caught in a traffic jam on a LA freeway, after pulling a long
hill with a toad... I might want some airflow to cool the bottom surface
of that plywood.

I know you were hoping to catch a GMCer who did his PhD thesis on
fiberglass over plywood with no additional boundry material... but maybe
some of these comments may spark a few absolute facts from the wealth of
info on this net.

Does your fan clutch work properly Heinz... thinking you once mentioned
confirming the "keep it up if you want it to work properly theory".

If it were me, I'd be leaning on the side of... leave it the way GMC did
for now, until you get the ceramic paper. And before you buy the paper,
I would press the vendor on the thermodynamics of traping heat under the
plywood floor with little or no airflow to remove the heat. I just read
Arch's comments on the space between the cementboard and the plywood...

We may need some ducting or funneling to keep airflow in the equation.
This sounds like a non-trivial final exam question in Thermodynamics

- --
Regards,
John 74 Glacier
 
Just a few other thoughts on alternatives... Heinz,

I'd give some thought to an aluminum sandwich with an air scoop
arrangement, if we have decent air flow from front to back that high up
in the engine compartment.

XXXXXXXXXXXXXXXXXXXXXXXXXXXXX Plywood
____________________________ Aluminum top sheet
....................... Interstitial spacer material (forming Channels)
________________________ Aluminum bottom sheet
\
ooooooooooooooooooo \
 
Heinz said:
> What I'm hoping though is that someone can confirm that applying the
> fibreglass will not increase combustability so that I can get that far
> and then do the ceramic at another time.

John said:
>>I can't confirm as in UL underwriting, but first I assume you mean
>>putting a layer of glass wool, as in Dow Cornings insulation product?

I had forgotten your opening sentence by the time I quoted your above
statement. Sorry.

I was just thinking... somebody must make that kind of aluminum
channelized sandwich.

- --
Regards,
John 74 Glacier
 
Hi Heinz, Was going to insulate the bottom hatch and surrounding area to
reduce heat from engine. Guess the ceramic fibre paper is good for that.
Would you give me ideas, where to get paper? Thanks for any Info.

Ron&Gina
73 Pumpkin-Rose
Ft. Mohave, AZ.

- ----- Original Message -----
From: Heinz Wittenbecher
To: gmcnet
Sent: Sunday, August 01, 1999 6:34 PM
Subject: GMC: Q. re fire resistance

> I'm currently redoing my old hatch, basically coating it with a layer of
> fibreglass.
>
> I've got my top, including the raised portion done and ultimately will
line
> the bottom with ceramic fibre paper but I don't think I'll be able to get
it
> before my next trip so I have to decide on whether to leave the bottom
wood
> (original) or to go ahead and apply a layer of fiberglass and leave it as
> fibreglassed wood for the time being.
>
> My question: what burns easier, i.e. would the layer of fibreglass
increase
> combustibility of the hatch? Am I better off to leave it just as wood,
i.e.
> that's how it was/is, but of course the wood is quite dry from the years
and
> miles, hence the desire to "improve/extend" it's longevity with a layer of
> 'glass'.
>
> Or... does anyone have any ideas/recommendations of a product I might be
> able to obtain locally, perhaps at a racing shop.
>
> What I'm hoping though is that someone can confirm that applying the
> fibreglass will not increase combustability so that I can get that far and
> then do the ceramic at another time.
>
> Thanks in advance for your comments.
>
> Heinz
>
>
 
Here's what I ended up doing/am doing (before wednesday's departure ;-)

I ordered from the roll, from Eaton Distributing (970-454-3673) at $5
sq/foot.

I didn't get the engine kit, just enough to do the hatch x 2 (in case I
screw up).

I'm going to put a layer of fiberclass cloth on the hatch to help the aging
wood and while the resin is still soft I'm going to apply the ceramic paper.
Then I'll 'roll' the edges into the raised area. Some exposed areas/corners
I may cover with non-flammable spray insulation.

And at some point in time I'm still going to install a fire suppression
system in the engine compartment as I believe if you can't get 'it' out in
the first few seconds it'll be game over anyways and the extra fuel the
fibreglass may provide will be of little consequence as my plan is to "get
out" and not even to open the hatch to add draft.

Heinz

> Hi Heinz, Was going to insulate the bottom hatch and surrounding area to
> reduce heat from engine. Guess the ceramic fibre paper is good for that.
> Would you give me ideas, where to get paper? Thanks for any Info.
>
> Ron&Gina
> 73 Pumpkin-Rose
> Ft. Mohave, AZ.
>
> ----- Original Message -----
> From: Heinz Wittenbecher
> To: gmcnet
> Sent: Sunday, August 01, 1999 6:34 PM
> Subject: GMC: Q. re fire resistance
>
>
> > I'm currently redoing my old hatch, basically coating it with a layer of
> > fibreglass.
> >
> > I've got my top, including the raised portion done and ultimately will
> line
> > the bottom with ceramic fibre paper but I don't think I'll be able to
get
> it
> > before my next trip so I have to decide on whether to leave the bottom
> wood
> > (original) or to go ahead and apply a layer of fiberglass and leave it
as
> > fibreglassed wood for the time being.
> >
> > My question: what burns easier, i.e. would the layer of fibreglass
> increase
> > combustibility of the hatch? Am I better off to leave it just as wood,
> i.e.
> > that's how it was/is, but of course the wood is quite dry from the years
> and
> > miles, hence the desire to "improve/extend" it's longevity with a layer
of
> > 'glass'.
> >
> > Or... does anyone have any ideas/recommendations of a product I might be
> > able to obtain locally, perhaps at a racing shop.
> >
> > What I'm hoping though is that someone can confirm that applying the
> > fibreglass will not increase combustability so that I can get that far
and
> > then do the ceramic at another time.
> >
> > Thanks in advance for your comments.
> >
> > Heinz
> >
> >
>
>
>
 
Emery,
That sounds like it might be a good idea to run the vent for the
engine. I do wonder if that would help when you need help
the most, while stuck in slow moving traffic on a hot day.
Do you think you could get enough ram air while moving at
2-3 MPH or slower? I'm wondering about this because I don't
want to go to the trouble if it doesn't have a benefit.

I have a duct now to feed the carburetor with air from the grill
that the PO installed, but do not have the side vents that
you recommend. Those I know would help in slow traffic.
Richard Waters '76 PB, Troy, MI
- ----

> Another thing I plan to do is to run a couple lengths of aluminum dryer hose
> from the grill area to each side of the engine with the thought that a "ram
> air" effect will move more cooler air through the engine compartment.
> Someone must have done that already and any suggestions will be appreciated.
>
> Emery Stora
> 77 Kingsley
> Santa Fe, NM
 
I've been thinking about an in-line fan that's used to vent engine
compartments on boats.
They're available in 3 and 4 inches and perhaps larger.

I thought aboy mounting them so that they evacuate via the side vents, i.e.
one each side.

But sofar it's just thought :-)

Heinz

> That sounds like it might be a good idea to run the vent for the
> engine. I do wonder if that would help when you need help
> the most, while stuck in slow moving traffic on a hot day.
> Do you think you could get enough ram air while moving at
> 2-3 MPH or slower? I'm wondering about this because I don't
> want to go to the trouble if it doesn't have a benefit.
> >>
>
> Probably wouldn't do any good at 2-3 mph unless you install a fan in the
> vents. However, at highway speeds I would think that it would do a good
job
> because right now almost all the air goes through the radiator and doesn't
> cool very well.
>
> Emery Stora
> 77 Kingsley
> Santa Fe, NM
>
>
 
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