Brodhead Pietenpol Association

Original Posted By: McNarry, John
------- Forwarded Message Follows -------________________________________________________________________________________John:I would be the last person to say 'Never deviate from the plans'. I suspectthat even Bernie Peitenpol never built his airplanes directly to the plans.Things have changed since Bernie's day, I think it is in the true spirit ofMr. Pietenpol to experiment with new, inexpensive materials and techniques.I suspect that if He were to build an airplane today he would pick whicheverengine he thought would do the job and be inexpensive. He would probablyalso substitute fiberglass and aluminum for wood where it solves problemsand doesn't cost much.In the overall picture of building the airplane the glue being used is asmall issue money wise and a larger issue from a quality perspective. SinceI don't know a lot about glues, I decided to just use one of the standards.My woodworking skills are not perfect and T-88 does a better job of gapfilling than resourcinol. I think the issues with epoxies losing strengthin hot weather is not significant to those of us who don't live in hotclimates and who don't put a lot of G's on the airframe.Enjoyed your e-mailRandy Stockberger-----Original Message-----

Original Posted By: "McNarry, John"
I am really concrened about the glue issue...I, like everyone else,want a plane I can trust other peoples lives in...T-88 may be okay inin colder climates, but what should I be using in NC-where summertemps(read mid-april-late sept) are routinely 95+ degrees...I hadpretty much decided on resourcinol, but would like something withbetter gap filling properties-still easy enough for a novice to use(is there such a thing?) Any Suggestions??Thanks again All! Paris> > > > In the overall picture of building the airplane the glue being usedis a> small issue money wise and a larger issue from a qualityperspective. Since> I don't know a lot about glues, I decided to just use one of thestandards.> My woodworking skills are not perfect and T-88 does a better job ofgap> filling than resourcinol. I think the issues with epoxies losingstrength> in hot weather is not significant to those of us who don't live in hot> climates and who don't put a lot of G's on the airframe.> > Enjoyed your e-mail> > ________________________________________________________________________________

Original Posted By: Paris Wilcox
John, Any particular one of the west system epoxies- I am looking at awicks catalog now- there's quit a few....Which would be best- and whatare the real differences-Paris________________________________________________________________________________

Original Posted By: Ken Beanlands
---Paris Wilcox wrote:>> > John,> Any particular one of the west system epoxies- I am looking at a> wicks catalog now- there's quit a few....Which would be best- and what> are the real differences-Paris> Also- what kindof filler- the cab-o-sil looks interesting-claims notto change the properties of the epoxy.....paris> > > > > > ________________________________________________________________________________

Original Posted By: Paris Wilcox
Hi ParisThat is part of the reason I asked the question about others experiences with West System epoxies. The Boat builders( Some very high class stuff) use it alot. T-88 was originally developed for boat use. I found that the milled fiberglass filler could be added to the mix to make almost any consistency fromjust epoxy to almost like thick peanut butter. I couldn't break the bond betweenthe epoxy and wood (sitka spruce scraps) on any of the samples I tried. In every case the wood pulled apart first. I think the best thing we can do is toensure that the gaps in our joinery don't require much filler. On a slightly different note: Has anyone in the group tried lighteningthe fuselage by milling the braces? Routing off corners or milling the pieces to Xshapes? J Mc________________________________________________________________________________

Original Posted By: "Warren D. Shoun"
On Mon, 1 Jun 1998, Paris Wilcox wrote:> > John,> Any particular one of the west system epoxies- I am looking at a> wicks catalog now- there's quit a few....Which would be best- and what> are the real differences-Paris> I was using the Safety-Poxy product on the fuel tanks of my Christavia andhad good results. However, this spring I started building a 16' Cedarstrip canoe that's covered inside and out with West System Epoxy. Thisstuff is a treat to work with. Before, I spent over half of my timemeasuring out quantities. Now I just use the pumps; one of each. Greatsystem.Basically, from what I've seen, the resign is all the same: 105. There are5 different hardeners that Ive seen. Here's the basic differences:205 1:5 ratio quick cure (9-12 min working life)206 1:5 ratio slower cure (20-25 min working life)207 1:3 ratio slower cure (22-27 min working life). Special coatingepoxy with some UV protection.209 1:3 ratio slowest cure (40-50 min working life)I've been using the 207 product on the canoe and I've used the fast cureproduct on the plane for the instrument panel and other smaller parts. Theone thing I did learn was to leave 3-5 days cure time before attempting tosand. As for strength, UV resistance, etc, I'm not sure which one isbetter. If you have anymore questions, let me know. West Systems does havea web page at: http://www.concentric.net/~Westsys/I've actually heard the West System products described as the Cadillac ofepoxies and I tend to agree.Ken________________________________________________________________________________

Original Posted By: "McNarry, John"
A comment about T-88 quality. I built a mock cockpit from the firewall tobehind the rear seat. Sides were built of pine, but according to plans.Bracing on top and bottom was minimal. T-88 epoxy used throughout. When Iwas done with it, I tied it up in the roof of the garage. Well, it fellfrom about 10 feet. None of the side bracing broke, and the top and bottompieces that did let loose broke the wood, never on a glue line. Says a lotabout the strength of the design of the side bracing, and about the strengthof T-88.Al S.> I am really concrened about the glue issue...I, like everyone else,>want a plane I can trust other peoples lives in...T-88 may be okay in>in colder climates, but what should I be using in NC-where summer>temps(read mid-april-late sept) are routinely 95+ degrees...I had>pretty much decided on resourcinol, but would like something with>better gap filling properties-still easy enough for a novice to use(>is there such a thing?) Any Suggestions??>Thanks again All! Paris>> >> >> >> In the overall picture of building the airplane the glue being used>is a>> small issue money wise and a larger issue from a quality>perspective. Since>> I don't know a lot about glues, I decided to just use one of the>standards.>> My woodworking skills are not perfect and T-88 does a better job of>gap>> filling than resourcinol. I think the issues with epoxies losing>strength>> in hot weather is not significant to those of us who don't live in hot>> climates and who don't put a lot of G's on the airframe.>> >> Enjoyed your e-mail>> >> >>________________________________________________________________________________

Original Posted By: oil can
Paris:I used a milled fibre glass product that I purchased from the local West Systemsupplier. I haven't experimented with other fillers but I tend to agree with KenBeanlands that this stuff is GOOD. I know it is more expensive but it is very strong. I get around the wastage problem by metering the small mix batches with syringes a 60cc and a 12cc that I got from the Vet. I mix in the same proportions as the pumps deliver but in much smaller quantities and that way Iknow the mix is right.John Mc________________________________________________________________________________

Original Posted By: steve(at)byu.edu
very good commentary. Just a couple of questions, though. Were youmaking a fibreglass tank using the west system epoxy? If so, what wereyour experiences with making the gas tank? Any limitations? Any benefitsover using the metal? Have you found any that will stand a limitedamount of alcohol in the gas?thanks,-=Ian=-Ken Beanlands wrote:> > On Mon, 1 Jun 1998, Paris Wilcox wrote:> > >> > John,> > Any particular one of the west system epoxies- I am looking at a> > wicks catalog now- there's quit a few....Which would be best- and what> > are the real differences-Paris> >> > I was using the Safety-Poxy product on the fuel tanks of my Christavia and> had good results. However, this spring I started building a 16' Cedar> strip canoe that's covered inside and out with West System Epoxy. This> stuff is a treat to work with. Before, I spent over half of my time> measuring out quantities. Now I just use the pumps; one of each. Great> system.> > Basically, from what I've seen, the resign is all the same: 105. There are> 5 different hardeners that Ive seen. Here's the basic differences:> > 205 1:5 ratio quick cure (9-12 min working life)> 206 1:5 ratio slower cure (20-25 min working life)> 207 1:3 ratio slower cure (22-27 min working life). Special coating> epoxy with some UV protection.> 209 1:3 ratio slowest cure (40-50 min working life)> > I've been using the 207 product on the canoe and I've used the fast cure> product on the plane for the instrument panel and other smaller parts. The> one thing I did learn was to leave 3-5 days cure time before attempting to> sand. As for strength, UV resistance, etc, I'm not sure which one is> better. If you have anymore questions, let me know. West Systems does have> a web page at: http://www.concentric.net/~Westsys/> > I've actually heard the West System products described as the Cadillac of> epoxies and I tend to agree.> > Ken> ________________________________________________________________________________

Original Posted By: Paris Wilcox
On Fri, 5 Jun 1998, Ian Holland wrote:> very good commentary. Just a couple of questions, though. Were you> making a fibreglass tank using the west system epoxy? If so, what were> your experiences with making the gas tank? Any limitations? Any benefits> over using the metal? Have you found any that will stand a limited> amount of alcohol in the gas?> > thanks,> -=Ian=-Actually, I've been using the West System epoxy to cover my cedar stripcanoe. However, I did build my tanks from fiberglass. I used theSafety-Poxy products from Hexel. The end results were no different that ifI had used the West System stuff. I just hadn't heard of West System whenI started the tanks.The tanks were built using instructions from Alexander Aeroplane (now AS&SEast). I built 2 tanks, one nose tank of 25 gals and one 10 gals tank thatsits on the roof of the cabin between the root wing mounts (simular to thecenter section in the Piet's wing). The way that the nose tank is designedis such that a baffle is not required, but one was added to the reservetank. Basically, the tank is a sandwich of foam between two layers offiberglass. There are two glass laminates on each side of the foam. Theconstruction starts by glassing enouth 1/4" foam sheet to do all the flatsides of the tank. I did this by completely laminating 2.5 sheets. Theprocess is simple. the board is "primed with an epoxy/microbaloon paste.once the paste is tacky, the 2 layers of cloth are added and the resign isapplied. Squegees work well to remove the excess. Then, laminate in alayer of peel ply. This allows for a rough surface once the resign drys. Once all the boards are done, cut out the various parts of the tank(sides, front, rear, baffles) on a bandsaw. Glue all the parts togetherexcept the top sheet to form the tank using 5 min epoxy. round theexterior edges with sandpaper and the interior edges with a cottonflox/resign paste. Laminate a 2" tape and a 4" tape along each seam bothinside and out. Coat any exposed foam edges on the baffles with resign. Next, make your "hardpoints" for the filler and cap, vents, drains etc.The best way to do this is to remove one layer of fiberglass and the foamsuch that only one layer of glass exsists in the area for the hardpoint.Fill the hole in with 10 layers of glass/resign making the cloth patchesprogressively larger with the last 2 patches being 2 and 4 inches largerthan the area.Finally, add the top. Obviously, you can only glass the outside edgeunless you have gery small hands or a very larve filler neck . However,the top edges are subject to the least amount of fuel pressure.The advantages of this type of tank are:1. double wall construction minimizing the possibility of leaking2. insulating quality of the foam helps prevent condensation3. can be built with common tools (no aluminum welding or rivitingrequired)4. easy to make compound curves.5. easy to make (arguable obviously)6. easy to fix; drain the tank and slap on some resign and possibly aglass patch.7. using the same method as making the hardpoint, a simple site guage canbe made in the side of the tank.8. no worries about weaping rivits or fatigue cracking in welded joints.Disadvantage:1. foam/fiberglass combo is NOT a conductor so the tank needs to beproperly bonded (filler neck) to prevent static discharge.Hope this helps. If you have any more questions, let me know.Ken________________________________________________________________________________

Original Posted By: Ian Holland
After an excellent discussion of making a fiberglass fuel tank,Ken Beanlands noted:> Disadvantage:> 1. foam/fiberglass combo is NOT a conductor so the tank needs to be> properly bonded (filler neck) to prevent static discharge.Note also that a fiberglass fuel tank is likely to come out a good dealheavier than the equivalent tank in aluminum. That resin is dense.Owen Davies________________________________________________________________________________

Original Posted By: Paris Wilcox
Sorry Stevee-didn't mean to sound critical-I guess I let a littlepessimism slip in there...such an easy solution to this problem didnot seem possible- Many thanks! Paris---steve(at)byu.edu wrote:>> Paris,> > Don't know why this would be a bad idea... I did it with all fourlongerons> on my ship. I did choose to locate the joints behind the plywood upfront> and near a cross brace. Worked just fine. In fact I'm rather proudof> those joints because although they are in plain site you can't tellyour> looking at them unless it is pointed out.> > Stevee> > sounds like you had the same source of wood I did. 12' lengths.> > > > -----Original Message-----> Paris Wilcox> Sent: Monday, June 08, 1998 2:35 PM> To: Pietenpol Discussion> Subject:> > > > I know this sounds like a bad idea, but has anyone ever scarfed> longerons together- my next big problem is getting the length stock I> need to make my longerons with-all my material is in th 10-12 ftrange.> Paris> > > > > > ________________________________________________________________________________

Original Posted By: Ian Holland
My 24 gallon fiberglass tank is the same weight as the riveted aliminum18 gallon tank built by a fellow Christavia builder. If you properlysqueegee off all the excess and use peel ply (excess resign soaks upthrough the peel ply), the tank can be built quite light. Excessive resignonly adds weight without structural integrity.My tank weigh 8 lbs including filler and cap, vent, drain, strainer andfuel probe.KenOn Mon, 8 Jun 1998, Owen Davies wrote:> After an excellent discussion of making a fiberglass fuel tank,> Ken Beanlands noted:> > > Disadvantage:> > > 1. foam/fiberglass combo is NOT a conductor so the tank needs to be> > properly bonded (filler neck) to prevent static discharge.> > Note also that a fiberglass fuel tank is likely to come out a good deal> heavier than the equivalent tank in aluminum. That resin is dense.> > Owen Davies> ________________________________________________________________________________

Original Posted By: baileys(at)ktis.net (Robert M. Bailey)
Ve are Vatching you...!Actually, I sent the response after reading Owen's comments, before yousent your question ;-)KenOn Tue, 9 Jun 1998, Ian Holland wrote:> Wow! That is the fastest response I have ever gotten to any question. 30> seconds! thanks again.> ________________________________________________________________________________

Original Posted By: Dick Nelsen
steve(at)byu.edu wrote:> > Paris,> > Don't know why this would be a bad idea... I did it with all four longerons> on my ship. I did choose to locate the joints behind the plywood up front> and near a cross brace. Worked just fine. In fact I'm rather proud of> those joints because although they are in plain site you can't tell your> looking at them unless it is pointed out.> > Stevee> > sounds like you had the same source of wood I did. 12' lengths.> > -----Original Message-----> Paris Wilcox> Sent: Monday, June 08, 1998 2:35 PM> To: Pietenpol Discussion> Subject:>I did the same thing, but put the scarfs staggered near the tail.> I know this sounds like a bad idea, but has anyone ever scarfed> longerons together- my next big problem is getting the length stock I> need to make my longerons with-all my material is in th 10-12 ft range.> Paris> > ________________________________________________________________________________

Original Posted By: Ian Holland
Ken, thank you very much for your commentary on fiberglass tanks. Anyidea how much heavier it would be over aluminum. Owen, I appreciatedyour comment on grounding!________________________________________________________________________________

Original Posted By: Ken Beanlands
Wow! That is the fastest response I have ever gotten to any question. 30seconds! thanks again.________________________________________________________________________________