Fin Can Testing-Wood Glue Smokes Epoxy
Mark Simpson
Epoxy Vs wood glue, check out:
http://home.sprynet.com/~monel/fintest.htm
Both Jon Demar and I smoked System 3 Epoxy with our wood glue. ;-)
My fincan also had basswood fillets which most likely accounted for its
increased performance over the other wood glued samples.
Thnaks Drake for the interesting work.
Mark Simpson
NAR 71503 Level II
BTW, where are the other two epoxy fin cans. We want to smoke them too.
>;-)
Mr. Bill . . . Kennedy
I see Mark you are a vastly superior builder of these particular fin cans.
As mentioned before I build mine per the Docs instructions. More so as a
'minimum standard' build.
Give me another set and I'll match 'ya, yeh baby.
I do like your basswood reinforcements!!!
Later Tater,
Mr. Bill
"Mark Simpson" <mark.s...@comcast.net> wrote in message
news:3C8CBE0A...@comcast.net...
Jerry Irvine
Mark Simpson <mark.s...@comcast.net> wrote:
> For all of those that haven't seen Drake's results on fincan testing
> Epoxy Vs wood glue, check out:
>
> http://home.sprynet.com/~monel/fintest.htm
>
> Both Jon Demar and I smoked System 3 Epoxy with our wood glue. ;-)
Very intersting and consistent with what I have been saying for years.
Jerry
--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to:01ro...@gte.net>
Please bring common sense back to rocketry administration.
Produce then publish.
Mark Simpson
I'm the first to admit that wood glue isn't worth a darn for fillets.
That's why I use balsa, or in this case, basswood for fillets. It's
stronger and lighter than epoxy fillets, too.
Next time, make sure that you put glue on the fins before you slide them
through the body tube like John and I did, and you'll get better
results. >;-)
Mark Simpson
NAR 71503 Level II
John Gordon
I wonder, how do you get the angle right? I imagine it's about a 120 degree
angle? Lots of sanding maybe? I could imagine doing it with a table
saw...
Have you written an article on your basswood fillets yet?
Thanks,
John Gordon
"Mark Simpson" <mark.s...@comcast.net> wrote in message
news:3C8D09A6...@comcast.net...
Mark Simpson
my Bruiser EXP Clone "Woody". As for getting the angle right, with
larger rockets, I've filled the gap with Wood putty or spackling.
Recently, I've found that dollhouse "cortise" (I think that's it.
Someone e-mailed me the proper name, but I'm too lazy to look it up
right now). It has two angled sides and doesn't come to a sharp edge
which helps with fitting BT to fin.
Mark Simpson
NAR 71503 Level II
If you want some photos, I can e-mail them to you.
Dave
> Both Jon Demar and I smoked System 3 Epoxy with our wood glue. ;-)
Smokin weed is one thing but smoking epoxy with wood glue?!?!
David Weinshenker
Eeeww!!! The smoke would taste awful!
-dave w
Mr. Bill . . . Kennedy
One other note. I chose the 'side load' test (#1) as I thought it would
represent 'fin flutter' better. Maybe thats were my low number came from.
I'm sure as the Doc has time he'll fill us in with the sample details.
Bring on the second round, baby.
Mr. Bill
"Mark Simpson" <mark.s...@comcast.net> wrote in message
news:3C8D09A6...@comcast.net...
Drake
been scarce. Sorry for that. I have dozens of strips of material from balsa
to carbon fiber laminated G-10. I will be doing the 3-point bend test on
these. I just need machine time.
I will be putting pictures of the tested fin cans on the web site. Mark's
cornice molding fillet assembly was the only one to actually break the
centering rings and "oval out" the tube. His fins never actually broke free
from the assembly. I think the major contributor was the ID cornices. They
acted like structural braces, distributing the load over a greater area. The
others just broke the glue or delaminated the paper.
There are still more fin cans out there. (No names) If I can get more parts,
I will send out more kits and do the lateral bending "side load" test on
these. No voting this time.
--
Drake "Doc" Damerau
Remove "my shorts" to e-mail me
HPR Strength of Materials Site:
http://home.sprynet.com/~monel/rmr.htm
"Mr. Bill . . . Kennedy" <sillybil...@worldnet.att.net> wrote in
message news:qvhj8.6530$Ex5.6...@bgtnsc04-news.ops.worldnet.att.net...
Jerry Irvine
"Drake" <mo...@sprynet.myshorts.com> wrote:
> I've been busy with some R&D for some new weapon systems, so the testing has
> been scarce. Sorry for that. I have dozens of strips of material from balsa
> to carbon fiber laminated G-10. I will be doing the 3-point bend test on
> these. I just need machine time.
>
> I will be putting pictures of the tested fin cans on the web site. Mark's
You really need to put in the notes section the materials types, vendors
and thicknesses. Tubes vary from source to source alot.
Let me know if you need more parts and what kinds.
Mark Simpson
I believe that they were all tested identically by "pulling the wings
off". Correct me if I'm wrong, Drake.
Bring on round 2. We'll take on the fiberglass crowd next. >;-)
Mark Simpson
NAR 71503 Level II
"Mr. Bill . . . Kennedy" <sillybil...@worldnet.att.net> wrote in message news:<qvhj8.6530$Ex5.6...@bgtnsc04-news.ops.worldnet.att.net>...
John DeMar
Titebond II. But, I used no extra parts... just the wood glue!
All mating surfaces were double-glued and well-sanded.
Another interesting test would be a vibration stress test. My guess is
that the flexible wood glue would out-last the stiff epoxies. This would
simulate "fin buzzing" when flight dynamics cause the fins to vibrate at
their natural frequency. It's not the static force that delaminates fins
and fillets!
-John "real men use wood glue" DeMar
Mr. Bill . . . Kennedy
It believe you are correct.
The undisputed "Cornice King"
Give me a fin can to assemble upon my return.
Mr. Bill
"Mark Simpson" <mark.s...@home.com> wrote in message
news:2ada0da.02031...@posting.google.com...
Mark Simpson
sure that the fins were glued to the centering rings, including the
square basswood (not cornices)that I used on the inside of the fin
root/BT intersection. I've seen others use dowels and epoxy to get
the same effect. I debated using some additional cornice to anchor
the fin root to the motor tube, but though that would be overkill.
Mark Simpson
NAR 71503 Level II
"Drake" <mo...@sprynet.myshorts.com> wrote in message news:<a6km0d$ge5$1...@slb3.atl.mindspring.net>...
some deleted
> I will be putting pictures of the tested fin cans on the web site. Mark's
> cornice molding fillet assembly was the only one to actually break the
> centering rings and "oval out" the tube. His fins never actually broke free
> from the assembly. I think the major contributor was the ID cornices. They
> acted like structural braces, distributing the load over a greater area. The
> others just broke the glue or delaminated the paper.
NStich
I would love the chance to build a two or three more fin cans, the way I want
this time.
I have more System 3, AeroPoxy (I haven't tried this yet) and some 2 part foam
from System 3.
Send out the Fin Cans.
Nick in Kansas
Drake
Sorry guys. I'm fixing that now and I'm putting the "before and after test"
pictures there too. I'll have it done and uploaded by 8 or 9:00 pm Eastern.
Jerry,
I would like to do more testing on these. I know you have sent me allot of
stuff already, but we could use more of the materials. Just the fin can kit
materials. I do have some 2.6 glassine body tubes and 29mm MMT tubes but I
need more fins and CR's.
--
Drake "Doc" Damerau
Remove "my shorts" to e-mail me
HPR Strength of Materials Site:
http://home.sprynet.com/~monel/rmr.htm
"Jerry Irvine" <01ro...@gte.net> wrote in message
news:01rocket-D2F05B...@news.bellatlantic.net...
Lew Garrow
>From: "Drake" mo...@sprynet.myshorts.com
>Date: 3/13/2002 5:18 AM Eastern Standard Time
>Message-id: <a6n8vr$2id$1...@slb3.atl.mindspring.net>
Drake,
If the epoxy joins weren't done using additional structural material, as used
in the wood glue fincans, aren't the test results invalid? In effect the wood
glue joint has been made to a larger surface area....apples to oranges for the
test base. This is now not two different adhesives, it is two different
adhesives and 2 different joining methods. Were other wood glue examples tested
not using wood fillets as well as glue? This is really an interesting test and
supports the wood glue proponents' strength claims fairly well, as is.
Lew
Lew Garrow
TRA 7181 L3
NAR 77928 L3
METRA VP
Maryland Delaware Assn
****remove the plex from my email to reply****
Jerry Irvine
"Drake" <mo...@sprynet.myshorts.com> wrote:
> Yeah, I kind of just threw the results up and didn't get a chance to finish.
> Sorry guys. I'm fixing that now and I'm putting the "before and after test"
> pictures there too. I'll have it done and uploaded by 8 or 9:00 pm Eastern.
>
> Jerry,
> I would like to do more testing on these. I know you have sent me allot of
> stuff already, but we could use more of the materials. Just the fin can kit
> materials. I do have some 2.6 glassine body tubes and 29mm MMT tubes but I
> need more fins and CR's.
Okay the next time I go to the USR shop I will fill another box. That
would be alot of fins so email me with a more complete list including
some tubes.
Oh, and I wonder how Gassaway, Dodger, and the other perpetual Jerry
bashers will spin this? Jerry forces rmr public to break hundreds of
rocket parts. ban him. News at eleven.
Jerry
Drake
> If the epoxy joins weren't done using additional structural material, as
used
> in the wood glue fincans, aren't the test results invalid? In effect the
wood
> glue joint has been made to a larger surface area....apples to oranges for
the
> test base. This is now not two different adhesives, it is two different
> adhesives and 2 different joining methods. Were other wood glue examples
tested
> not using wood fillets as well as glue? This is really an interesting test
and
> supports the wood glue proponents' strength claims fairly well, as is.
> Lew
> Lew Garrow
> TRA 7181 L3
> NAR 77928 L3
> METRA VP
> Maryland Delaware Assn
> ****remove the plex from my email to reply****
Agreed, apples and oranges. The pictures I am uploading tonight will qualify
the results of the tests. I have views of the external failures and then a
cut away of the internal failure and construction methods. This then shows
the resultant data as well as the glue and construction technique. You can
then judge for yourself.
Drake
--
Drake "Doc" Damerau
Remove "my shorts" to e-mail me
HPR Strength of Materials Site:
http://home.sprynet.com/~monel/rmr.htm
"Jerry Irvine" <01ro...@gte.net> wrote in message
news:01rocket-C29A26...@news.bellatlantic.net...
Drake
There are still two more of you that have not finished the fin cans. Come on
guys, how much longer?
--
Drake "Doc" Damerau
Remove "my shorts" to e-mail me
HPR Strength of Materials Site:
http://home.sprynet.com/~monel/rmr.htm
"Drake" <mo...@sprynet.myshorts.com> wrote in message
news:a6n8vr$2id$1...@slb3.atl.mindspring.net...
Mark Simpson
I used wood fillets because that's something that can't be duplicated
with wood glue. The instructions stated that fillets should be used. I
made my fillets out of wood. I suppose that I could have ground up some
sawdust and mixed it with the wood glue and approximated the same
performance.
I've always said that good designs were an important part of the rocket
building process. Building techniques that play to epoxy's strengths
don't necessarily translate to other adhesives' strengths.
Try laminating strips of wood veneer with epoxy and then fly the fins at
supersonic speed. You'll quickly discover one of epoxy's main weaknesses
as the fin delaminates and breaks up before your eyes.
If you'd like, build a wood/wood butt joint without fillets using epoxy
and I'll do
the same with wood glue so that we can compare apples and apples. I've
done that already. Wood glue wins when the materials of construction
favor them, ie, are made of wood and loses miserably when the materials
are phenolic and G-10.
Mark Simpson
NAR 71503 Level II
John DeMar
>
> Drake,
> If the epoxy joins weren't done using additional structural material, as used
> in the wood glue fincans, aren't the test results invalid? In effect the wood
> glue joint has been made to a larger surface area....apples to oranges for the
> test base. This is now not two different adhesives, it is two different
> adhesives and 2 different joining methods. Were other wood glue examples tested
> not using wood fillets as well as glue? This is really an interesting test and
> supports the wood glue proponents' strength claims fairly well, as is.
My fin can was done without any additional structural materials. Just
Titebond II.
-John DeMar
NAR 52094
Jerry Irvine
wrote:
> My fin can was done without any additional structural materials. Just
> Titebond II.
>
> -John DeMar
> NAR 52094
You effectively used USR parts in the intended way and got 2nd place
over someone who added alot of reinforcing materials.
Lew Garrow
>Date: 3/13/2002 11:26 PM Eastern Standard Time
>Message-id: <3C902685...@syr.edu>
That answers the question. Its kind of interesting to note that when good
construction techniques are used the bond itself is usually stronger than the
materials joined. Most of the time you will see an airframe break or tear, or a
fin break rather than the joint failing.
Bill Westfield
construction techniques are used the bond itself is usually stronger than
the materials joined. Most of the time you will see an airframe break or
tear, or a fin break rather than the joint failing.
Is that necesarilly a good thing? I mean, it's easier to fix if only the
glue joint fails - just replace the glue...
BillW
Doc
the lowest result was the only fin can to not have a filet on the ID surface
of the fin. For this load mechanism, the ID filet serves as a mechanical
support against the body tube and other two fillets are just bonds between
the fin and the paper tube. With this, one may then surmise that the
critical filet is an ID fillet.
--
Drake "Doc" Damerau
I.M. Name: eutectoid
Remove "my shorts" to e-mail me
HPR Strength of Materials Site:
http://home.sprynet.com/~monel/rmr.htm
"Bill Westfield" <bi...@cypher.cisco.com> wrote in message
news:54lmcrl...@cypher.cisco.com...
Mark Simpson
the fins, the external fillets would have more importance.
Mark Simpson
NAR 71503 Level II
Doc
--
Drake "Doc" Damerau
I.M. Name: eutectoid
Remove "my shorts" to e-mail me
HPR Strength of Materials Site:
http://home.sprynet.com/~monel/rmr.htm
"Mark Simpson" <mark.s...@comcast.net> wrote in message
news:3C950CD3...@comcast.net...
Mark Simpson
I looked at the pictures that you posted and made a few notations.
From the cutaway, it looks like I didn't get much glue along the fin
root/motor tube contact area. Is that an accurate statement? Also,
would it be possible to have the assembly sent back to me to look at
more closely if you are planning to conduct another wood glue vs epoxy
test? I'll pay your shipping costs as I did previously.
Thanks for the interesting work. You should consider compiling all of
it into an article for a magazine (pick one that actually publishes
issues) or a NAR research project.
Mark Simpson
NAR 71503 Level II
"Doc" <mo...@sprynet.myshorts.com> wrote in message news:<a733o8$vdi$1...@slb4.atl.mindspring.net>...
John DeMar
Also, I second Mark's motion: publish your results. It would make a
great NARAM R&D report, and NARTS could offer reprints.
-John DeMar
NAR 52094 L1.98
Doc
didn't get thrown out. :-) When I first started, I promised to write a
paper, and I will. I don't know if it will be published.
You mean to say that there are publications such as a magazine, that don't
get published on a regular basis? That can't be! That would be IMMORAL and
UNETHICAL to charge for something and not deliver.
--
Drake "Doc" Damerau
I.M. Name: eutectoid
Remove "my shorts" to e-mail me
HPR Strength of Materials Site:
http://home.sprynet.com/~monel/rmr.htm
"Mark Simpson" <mark.s...@home.com> wrote in message
news:2ada0da.02031...@posting.google.com...
Doc
test that have not come yet and I still need more parts. When I get more
parts, I'll send them out to you and Mark for "round two".
As for publishing, like I told Mark, I'll write the paper but so far I don't
have anyone offering to publish it other than an outfit in the Netherlands.
I'm not looking for money. If any were offered, I'd give it to the NAR war
chest for legal fees.
BTW, It looks promising for the lateral flex test of the fin materials
tomorrow.
--
Drake "Doc" Damerau
I.M. Name: eutectoid
Remove "my shorts" to e-mail me
HPR Strength of Materials Site:
http://home.sprynet.com/~monel/rmr.htm
"John DeMar" <jsd...@syr.edu> wrote in message
news:3C960946...@syr.edu...
Bill Nelson
> John,
> That answers the question. Its kind of interesting to note that when good
> construction techniques are used the bond itself is usually stronger than the
> materials joined. Most of the time you will see an airframe break or tear, or a
> fin break rather than the joint failing.
Ask anyone who as seen me fly my Lil' Nuke on H238 motors. The fins are
surface mounted using yellow glue - no "pinholes" or other methods of
strengthening the bases. The fillets are minimal in size and also made
out of yellow glue. All they do is fill in a tiny area on each joint.
They have survived fine for over 20 launches - no cracking or other
signs of failure. And I use the stock streamer for recovery.
--
Bill Nelson (bi...@peak.org)
Lew Garrow
a good wood glue and surface mount fins are reasonable for that rocket/motor
combo.
>Subject: Re: Fin Can Testing-Wood Glue Smokes Epoxy
>From: Bill Nelson bi...@spock.peak.org
>Date: 3/21/2002 5:46 AM Eastern Standard Time
>Message-id: <a7cdla$h95$1...@quark.scn.rain.com>
Mark Simpson
its chute failed to unfurl and snapped off a fin 3" away from the
root. I cut the fin off at the base, sanded the TTW stub flat and
surface mounted a new fin and balsa fillet assembly with Titebond II.
The rocket has since flown a half dozen times without any damage to
any of the fins, surface-mounted or otherwise.
Too many rockets are so overbuilt that they become as bad as building
with metal airframe components.
Mark Simpson
NAR 71503 Level II
lgarr...@aol.complex (Lew Garrow) wrote in message news:<20020321074432...@mb-cg.aol.com>...