Light fiberglass

Light fiberglass

Post by -Wiersbe,R. » Wed, 31 Jul 1996 04:00:00



Quote:


>>Date:   30 Jul 1996 08:44:01 GMT

>>Newsgroups:     rec.models.rockets
>>Subject:        Light fiberglass

>>In most "hardware" stores you can buy self-adhesive fiberglass "drywall tap
>>e",
>>which has a very open and lighweight weave (sort of like window screen.)
>>Is this of use in reinforcing rockets?  The self-adhesive properties seem
>>like a big win...

>>BillW

>    Slick idea!...I'm gonna folowup on this one, and let you know!
>Jack Wiker

Missed this the first time thru...

I've used this several times, and it _does_ work. I've used it to hold the
fins on models that were going to fly with G40 motors. The fins were glued
on as usual, then I put the tape in the valley between the fins, laying
it partway up the fin and covering the tube. Then I put the fillets over
the tape, and up onto the fin.

Both rockets survived the flight just fine, though I lost them both...

I haven't tried this over the whole body tube, since it'd be a pain to
fill in all the gaps in the weave. It might look cool to leave them in.
--

 
 
 

Light fiberglass

Post by Willia » Wed, 31 Jul 1996 04:00:00


In most "hardware" stores you can buy self-adhesive fiberglass "drywall tape",
which has a very open and lighweight weave (sort of like window screen.)
Is this of use in reinforcing rockets?  The self-adhesive properties seem
like a big win...

BillW

 
 
 

Light fiberglass

Post by Jack » Wed, 31 Jul 1996 04:00:00


Quote:

>Date:       30 Jul 1996 08:44:01 GMT

>Newsgroups: rec.models.rockets
>Subject:    Light fiberglass

>In most "hardware" stores you can buy self-adhesive fiberglass "drywall tap
>e",
>which has a very open and lighweight weave (sort of like window screen.)
>Is this of use in reinforcing rockets?  The self-adhesive properties seem
>like a big win...

>BillW

        Slick idea!...I'm gonna folowup on this one, and let you know!
Jack Wiker
 
 
 

Light fiberglass

Post by Matthew S Greenl » Wed, 31 Jul 1996 04:00:00


Quote:

>In most "hardware" stores you can buy self-adhesive fiberglass "drywall tape",
>which has a very open and lighweight weave (sort of like window screen.)
>Is this of use in reinforcing rockets?  The self-adhesive properties seem
>like a big win...
>BillW

   I used this reinforcement method on my Laser LOC 1.5.  I have not
flown it with any butt-kicker motors (G40 is the largest), but it has
held up just fine.  I do not think you gain much by using this method. If
you are going to go to the trouble of adding reinforcement in the fin
fillets, I think you would be better off with some light fiberglass cloth
sprayed with 3M spray adhesive.  This would offer the same convenience of
the drywall tape with a HUGE increase in strength.  I would reccommend
(depending on the rocket size) 2-6 Oz/yd^2.  The lighter cloth for
smaller rockets and the heavier cloth (possibly multiple layers) for the
larger rockets.  Best of luck.

--
Matthew Greenlaw                         Mechanical Engineering

http://hubcap.clemson.edu/~mgreenl      

 
 
 

Light fiberglass

Post by Bob Kapl » Fri, 02 Aug 1996 04:00:00



Quote:

>>In most "hardware" stores you can buy self-adhesive fiberglass "drywall tape",
>>which has a very open and lighweight weave (sort of like window screen.)
>>Is this of use in reinforcing rockets?  The self-adhesive properties seem
>>like a big win...

Drywall tape is a bit heavy and coarse for models. It would take a ton of
primer or filler to make it look good.

Quote:
>    I used this reinforcement method on my Laser LOC 1.5.  I have not
> flown it with any butt-kicker motors (G40 is the largest), but it has
> held up just fine.  I do not think you gain much by using this method. If
> you are going to go to the trouble of adding reinforcement in the fin
> fillets, I think you would be better off with some light fiberglass cloth
> sprayed with 3M spray adhesive.  This would offer the same convenience of
> the drywall tape with a HUGE increase in strength.  I would reccommend

Absolutely NOT! First, you will need more than 3M spray to hold it on. Second,
that spray will prevent epoxy resin or whatever from bonding to the glass. If
you must spray, use a clear dope which is compatable with the epoxy resin.

Quote:
> (depending on the rocket size) 2-6 Oz/yd^2.  The lighter cloth for
> smaller rockets and the heavier cloth (possibly multiple layers) for the
> larger rockets.  Best of luck.

6oz would be for awful big rockets. Rutan foam composite aircraft use 5oz
cloth. For models, I'd use 3/4oz to 1.5oz cloth unless you are talking
supersonic cloudbusters.

        Bob Kaplow      NAR # 18L       TRA # "Abort, Retry, Fail?"

 
 
 

Light fiberglass

Post by Matthew S Greenl » Sat, 03 Aug 1996 04:00:00


Quote:


Greenlaw) writes:
>Drywall tape is a bit heavy and coarse for models. It would take a ton of
>primer or filler to make it look good.
>>    I used this reinforcement method on my Laser LOC 1.5.  I have not
>> flown it with any butt-kicker motors (G40 is the largest), but it has
>> held up just fine.  I do not think you gain much by using this method. If
>> you are going to go to the trouble of adding reinforcement in the fin
>> fillets, I think you would be better off with some light fiberglass cloth
>> sprayed with 3M spray adhesive.  This would offer the same convenience of
>> the drywall tape with a HUGE increase in strength.  I would reccommend
>Absolutely NOT! First, you will need more than 3M spray to hold it on. Second,
>that spray will prevent epoxy resin or whatever from bonding to the glass. If
>you must spray, use a clear dope which is compatable with the epoxy resin.

   Let me clarify.  A LIGHT COAT of 3M spray adhesive will in NO WAY interfere
with the bonding of the glass and the epoxy.  You are only putting enough on to
help hold the cloth in place while you wet it out. Personally, I do not use it at
all, but if you like to position things ahead of time, it can help.  Unless you
have a very sharp concave radius (or sharp corner) that you are laying up, you should
not have any  problems with properly wet-out cloth sticking where you put it.  In
RC airplanes, we use 3M spray adhesive all the time to completely cover wings and
fuselages with NO PROBLEMS.  If it really bothers you, don't use it at all--I
don't unless it is a tricky lay-up.

Quote:
>> (depending on the rocket size) 2-6 Oz/yd^2.  The lighter cloth for
>> smaller rockets and the heavier cloth (possibly multiple layers) for the
>> larger rockets.  Best of luck.
>6oz would be for awful big rockets. Rutan foam composite aircraft use 5oz
>cloth. For models, I'd use 3/4oz to 1.5oz cloth unless you are talking
>supersonic cloudbusters.

^^^^^^^^^^^^^^^^^^^^^^^^

   I believe the Laser LOC 1.5 qualifies! :)  Remember, that althought Rutan uses
5 OZ cloth, he uses MULTIPLE layers of cloth.  We are usually limited by how thick we
can make our fillets.  So, a single layer of 6 OZ is really not too heavy.  I
would not use it for every rocket, but for medium to large high power rockets
that will see some high impulse motors, it works great.  If I am going to go to
the trouble of laying FG in the fillets and having to bother with smoothing the
fillets, filling the weave, etc, etc, I am going to make it worth my while.  Of
course, any additional reinforcement is better than none at all, but 3/4 oz.
cloth does not provide much increase in strength. (I didn't say NO increase)

Quote:
>    Bob Kaplow      NAR # 18L       TRA # "Abort, Retry, Fail?"

--
Matthew Greenlaw                         Mechanical Engineering

http://hubcap.clemson.edu/~mgreenl      
 
 
 

Light fiberglass

Post by Steven C. Smit » Thu, 08 Aug 1996 04:00:00


Quote:

> In most "hardware" stores you can buy self-adhesive fiberglass "drywall tape",
> which has a very open and lighweight weave (sort of like window screen.)
> Is this of use in reinforcing rockets?  The self-adhesive properties seem
> like a big win...

> BillW

Bill,

I built Rick Gaff's pyramid rocket from the May/June edition of Sport
Rocketry magazine.  It uses a rear ejection system whereby the motor
mount tube and rings get ejected from the rear of the rocket.  The only
problem that I had with this rocket was the fact that the motor mount
tumbled back to the earth with a spent D12-3 engine still inside.  This
caused the motor mount to buckle after only a few flights.

I have since built a new one, this time perching a small Marvin the
Martian figurine on top of it and painting it like a volcano and naming
it Mount Saint Marvin.  I brought it to the last NIRA meeting, where Bob
Wiersbe chastised me for putting Marvin, such a revered figure in NIRA,
in such peril.  I reassured Bob that Marvin would be all right.

Anyways, back to the fiberglass.  This time I wrapped the fiberglass
around the motor mount tube between the centering rings (see picture
below) and anchored it into place with 5 minute epoxy.  Mount Saint
Marvin made its madain flight this past weekend.  It flew like a charm
with NO damage to the motor mount tube, wither from the fall or the heat
of the D12-3 motor.

                        ---------
                        |       | <== motor mount tube
                        |       |
                     ---|-------|--- <== centering ring
                        |       | <==
                        |       |   |
                        |       |   |  
                        |       |   |  
                        |       | <== fiberglass wrap anchored with
                        |       |   | 5 minute epoxy in between the
                        |       |   | centering rings.  
                        |       |   |
                        |       | <==
                     ---|-------|--- <== centering ring
                        |       |
                        |       |
                        ---------
                            ^
                            |_________ load D12-3 motor here

If it worked so well in this application I can not see why it would not
work in others.

Hoped this helped....

Steve

 
 
 

Light fiberglass

Post by -Wiersbe,R. » Thu, 08 Aug 1996 04:00:00




Quote:

>> In most "hardware" stores you can buy self-adhesive fiberglass "drywall
>> tape", which has a very open and lighweight weave (sort of like window
>> screen.) Is this of use in reinforcing rockets?  

>> BillW
>Bill,
>I built Rick Gaff's pyramid rocket from the May/June edition of Sport
>Rocketry magazine.  It uses a rear ejection system whereby the motor
>mount tube and rings get ejected from the rear of the rocket.  The only
>problem that I had with this rocket was the fact that the motor mount
>tumbled back to the earth with a spent D12-3 engine still inside.  This
>caused the motor mount to buckle after only a few flights.
>I have since built a new one, this time perching a small Marvin the
>Martian figurine on top of it and painting it like a volcano and naming
>it Mount Saint Marvin.  I brought it to the last NIRA meeting, where Bob
>Wiersbe chastised me for putting Marvin, such a revered figure in NIRA,
>in such peril.  I reassured Bob that Marvin would be all right.

Steve was flying this model a lot at ECOF, on one flight it landed
back at the pad it was launched from! Small rocks do *** things to
pointy pyramids, which is why I think Marvin ended up on the top. I
believe Marvin has also shown up as the alien in the Venus Probe.

Quote:
>This time I wrapped the fiberglass around the motor mount tube between
>the centering rings and anchored it into place with 5 minute epoxy. Mount
>Saint Marvin made its madain flight this past weekend. It flew like a charm
>with NO damage to the motor mount tube, wither from the fall or the heat
>of the D12-3 motor.

[good picture deleted]

Nice application! This could be a good idea for any kit that needs
some extra reinforcement either for wimpy motor mount tubes (Estes), or
for models that are flown on "iffy" motors (Estes C5-3, E15-x, FSI xxxx,
etc) to keep the rocket from getting blown apart.

Now for the important question, did Marvin survive?

--

 
 
 

Light fiberglass

Post by Lee Re » Fri, 16 Aug 1996 04:00:00


: >
: > In most "hardware" stores you can buy self-adhesive fiberglass "drywall tape",
: > which has a very open and lighweight weave (sort of like window screen.)
: > Is this of use in reinforcing rockets?  The self-adhesive properties seem
: > like a big win...
: >
: > BillW

I've used pieces of this open weave, self adhesive "tape" to hold a shock
cord in place inside smaller rockets, and then epoxied over it.  It certainly
does not substitute for fiberglass cloth when areas are large, since it is only a few inches wide, but is does have some good uses where you need a little
reinforcement in a small area.
--
Lee Reep  

 
 
 

Light fiberglass

Post by Steven C. Smit » Sat, 17 Aug 1996 04:00:00


Quote:

> Now for the important question, did Marvin survive?

> --


Bob,

Do you really think that I would let Marvin be hurt in any way, shape or
form.  Besides he does wear a helmet with a nice soft plume of
feathers(?) on it (reminiscence of the Spartans), so no I don't believe
that Marvin was hurt.

Actually, were his legs meet his foot, you know his ankles, need to be
reinforced with some epoxy.  You can kind of think of it as preventative
medicine.

The guardian of Marvin,
Steve