KR> thinning micro
Thank you, Paul--I did appreciate your initial response below but was not sure from it whether you were specifically addressing my particular question about vinylester and isopropyl. I knew that I could use thinners with micro in the way you described but wanted to be aware if there were any bad reactions between the thinners we often use and vinylester in particular. Sorry for the misunderstandings and thank you for your feedback. -Seth On 9/24/2014 9:17 AM, Paul Visk via KRnet wrote: > Yes you can thin your resin/micro. The best stuff to use is MEK. MEK > substitute is ok to use also but it takes a little longer to evaporate out. > Something you can do is to mix a batch of micro up so thick it brakes the > stick then slowly put in some MEK to a consistency of a warm milk shake and > pour it out on your service and let it level out to a 1/8 to a 1/4" > thickness. This will fill your low spots. Let it harden then sand. It will > take a little longer to cure. > Back in my sheet metal days in the Air Force. We use to thin down fiberglass > resin with MEK enough to spray though a paint gun to give a glass finish. > > Paul Visk > Belleville Il > 618 406 4705 >
KR> thinning micro/Vinyl Ester
Thank you very much, Jeff and Jon-- I'm sorry for the earlier unnecessarily general reaction. Only one response surprised me and I'm embarrassed that I let it bother me. This group has been nothing but helpful and encouraging to me for the past three years. Jeff, thank you for all that you shared, and especially for your comment about using regular epoxies for finishing OVER vinylester. Knowing now that it is OK to do that, I will definitely take that route. That certainly simplifies things--thank you! -Seth On 9/25/2014 10:06 AM, jon kimmel wrote: > > You are probably finding out the hard way that nobody has an answer > because nobody has tried it. As a rule of thumb I wouldn't put a > thinner in resin for a structural application because it will likely > leave voids in the resin as it evaporates...but I love using it with > epoxy and micro as a replacement for foam or as a smoother on top of > the glass. > > https://sites.google.com/site/mykr2stretch/ > https://sites.google.com/site/mykr2stretch/parts-for-sale >
KR> thinning micro
Yes, thanks, there are many warnings--it is evil stuff. I use 1-2 CCs of it for each 8 oz. of Vinyl Ester resin and the reaction actually raises the temperature of my garage while it sets. I've started doing my layups early in the morning so I can leave it all outside in the sun and open air. It's kind of a catch-22--the more MEKP you use the faster things get tacky and hard to work with, the less you use the longer you have to deal with the stink while it takes longer to set, and the difference between a lot and a little can be like .2 mls. Plus I'm finding it extremely sensitive to external temperature changes. I never know quite what to expect when I start working with a new batch. On 9/24/2014 7:14 PM, Chris Kinnaman via KRnet wrote: > Be very, very careful with anything containing MEKP. It destroys eye > tissue and there isn't much you can do once you get it in your eye. > > Chris >
KR> thinning micro
Thanks--just wanted to know if MEK or Isopropyl alcohol (or any such thinners) can be used specifically with Vinyl Ester which uses MEKP as the catalyst. I know the thinners can be used with Aeropoxy but this Vinyl Ester stuff is definitely different to work with so I wondered if there were chemical incompatibilities I should be aware of. On 9/24/2014 10:58 AM, jon kimmel via KRnet wrote: > And now mek is outlawed in the air force...yet you can buy it by the gallon > at Lowes. > > https://sites.google.com/site/mykr2stretch/ > https://sites.google.com/site/mykr2stretch/parts-for-sale > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options
KR> Isopropyl Alcohol with Micro Balloons and Vinyl Ester...good or bad idea?
Hi All, I've read about the trick of mixing a little isopropyl alcohol with dry micro in order to make application easier. Will I be able to mix isopropyl with Vinyl Ester based dry micro as I smooth my front deck out or is this a bad combo? Thanks for any suggestions... -Seth
KR> Worktable/bench
I based mine on this EAA chapter's plans: http://www.eaa1000.av.org/technicl/worktabl/tablefig.htm Very sturdy and served me well. I used 3/4" thick fiberboard for the work surfaces--I think medium grade. I started with two tables--one 8' by 4' and the other about 4' by 4'. Your longerons will hang off one end of a 12 foot table a little but it's not a problem. -Seth On 8/30/2014 9:41 PM, Gary via KRnet wrote: > What size and construction have people used for their KR2S work table or > bench? Thought I'd start working on this while waiting for the plans > >
KR> Epoxy Question
Dan, I don't know where you are in your build, but I'm just about finished with all my structural wood components and will end up using close to a gallon of T-88 (half resin, half hardener). For fiberglass, I've only just completed my horizontal tail surfaces and have gone through about a quart of Aeropoxy resin (which mixes with hardener at 100 to 27). I suspect I'm liberal with the epoxy compared to many, which means some extra weight. -Seth On 11/25/2013 10:08 PM, Mark Langford wrote: > Dan Prichard wrote: > >> How much epoxy (ie gallons) is typically used on a KR2S. I know >> there will >> a lot of swing in the numbers. Just looking for an average. >
KR> Price quote.
Adam, I got all my wood from AS two years ago and it came to just above $2000. On 8/15/2013 7:35 PM, Adam Tippin wrote: > Does this look fair. > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options
KR> Aluminum Angle for control brackets
> Hi All, Today Aircraft Spruce notified me that they no longer carry their 1/8" thick 4" by 2.5" 6061-T6 aluminum angle, and Wicks has nothing in those width/length dimensions thinner than 1/4". I've made several calls to metal suppliers and also local machine shops and they told me I probably won't find extruded angle in those dimensions. I have plenty of 1/8" thick 6061 plate but as per plans I would of course prefer to use extruded angle for the controls. Has anyone used a brake to bend their control brackets? Any suggestions or leads on where I can find extruded angle? Thanks, Seth
KR> Re:Aluminum Protection
Thank you all for your responses. I'll look at that video and research further into alodine for the aluminum. -Seth On 12/26/2011 8:45 PM, smwood wrote: > For aluminum protection: Watch the EAA Hints for Homebuilders video and do > what Brian Carpenter says. It works! > http://www.eaavideo.org/channel.aspx?ch=ch_hints > > Anodize is the best (and pricey) aluminum treatment, but next best is > alodine and doable by anyone right on your work bench at home. > Zinc chromate is a good primer for a finish coat of a spray paint, but next > to worthless for aluminum metal protection. Powder coat is a great looking > finish and will provide excellent protection as long as the surface does not > crack or get scratched to the bare metal. Corrosion can then happily eat > away under the best looking part and you will not know it until the paint > can no longer support the load that the metal used to carry. > > Sid Wood > Tri-gear KR-2 N6242 > Mechanicsville, MD, USA > smw...@md.metrocast.net >
KR> steel and aluminum protection--suggestions?
Thank you all, for your replies. The home-made powder coating setup is intriguing, but I think I'll keep it simple and go as follows: Aluminum: Alumiprep treatment. Dry well. Followed promptly by zinc chromate. Steel: Clean well with acetone, then soap and water, then flush with lots of water, then dry, followed promptly by zinc chromate. It also appears I can use paint directly on zinc chromate if I wanted to. If this approach sounds problematic, please let me know. Again, thanks for your help! -Seth On 12/26/2011 1:32 PM, Dave_A wrote: > Alodyne works for aluminum > > epoxy primer or zinc-chromate will work for both. > > On 12/26/2011 10:38 PM, Dave McCauley wrote:
KR> steel and aluminum protection--suggestions?
> Hello all, and Merry Christmas-- I just received my wing attach fittings from the shop and am wondering if any of you have specific recommendations for protecting 4130 steel--specific types of paint or protective coatings that you particularly like and trust. I'd also appreciate any specific suggestions for aluminum protection. From Sonex builders' sites I seem to remember there's a zinc chromate (?) spray that people use. What do you think is best? Thanks for any suggestions... Seth
KR> 5/8 blocks around spar on outside skin
Sorry for asking a question before thinking longer about it. Don't worry, I will install the blocks. -Seth On 10/30/2011 12:00 PM, Seth and Karen Jersild wrote: > Hi All, > > I'm getting close to inserting the spars into the fuselage. > > In the manual, page 28, it says "Check that the spars properly fit > within the wing rib outlines previously drawn onto each fuselage side. > When all checks are satisfactory, epoxy in position. Fit, glue and > install the 5/8" sq. glue blocks (8 each) to fuselage outer side skin > and spar. See drawing no. 1." > > Drawing no. 1 refers to the KR-2 layout plans (not "S") and does indeed > show blocks on the outside of the fuselage around the spars. However, > on the KR-2S plans (Drawing A) it does not show these blocks. > > I'm building an "S." Do I have to install these blocks? > > Any clarification would be appreciated! > > -Seth Jersild > jersi...@gmail.com > > ___ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html
KR> 5/8 blocks around spar on outside skin
Hi All, I'm getting close to inserting the spars into the fuselage. In the manual, page 28, it says "Check that the spars properly fit within the wing rib outlines previously drawn onto each fuselage side. When all checks are satisfactory, epoxy in position. Fit, glue and install the 5/8" sq. glue blocks (8 each) to fuselage outer side skin and spar. See drawing no. 1." Drawing no. 1 refers to the KR-2 layout plans (not "S") and does indeed show blocks on the outside of the fuselage around the spars. However, on the KR-2S plans (Drawing A) it does not show these blocks. I'm building an "S." Do I have to install these blocks? Any clarification would be appreciated! -Seth Jersild jersi...@gmail.com
KR> Planning my build
Tim and Tony, I'm just a few months ahead of you two. I added the extra 14" bay behind the rear spar and 1" total to the front two bays. I'll add 1" of width to the firewall. The boat will be widened to 42" (outside edge of longerons) at the shoulders which will necessitate adding some width to all dimensions forward and aft of that point. I'm also considering using width dimensions proposed by Gunnar Olson here: http:/go-design.no/images2.html (scroll to bottom of the page) which would mean the longerons would run in a straight line from the "K" station back to the tail instead of from the "I" station. Not sure of that yet and would appreciate any input. This would obviously diffuse stress from around that tricky area just aft of the rear spar while bending the boat. His computer drawings sure make it look good. Sean Duggan, who started about a month before I did, had to make the frustrating decision to start all over again recently because of cracked longerons at that point and it's spooked me a little. I've made all my spars to the 5048-45 dimensions and am scarfing plywood to cover them. I eliminated the foam-and-glass extensions from the tips of the spars by extending the wood portion of the spars. At first I was concerned that doing this might make the spar caps too thin to work with at the tips, but it turned out to be a non-issue. The final product is very solid. If you go with the 5048-45 airfoil, where all the outboard spar verticals have to be different lengths, I found it helpful to do a full-scale drawing on my work table of the outboard spars, fore and aft, so I could get the exact angle of incline for both, and exact measurements for the length of all the verticals. The drawings also served as very useful templates while gluing the verticals and planing the caps down to size. An extremely helpful tip I got from Jodel and Falconar builders' websites was to use PVC clamps for the gussets and some of the diagonals on my fuselage trusses. Cut a 4" PVC pipe into narrow rings on your miter saw and then slice the ring at one point. This gives you a lot of very CHEAP, versatile clamps. Thicker rings make clamps with more pressure and rigidity, while thinner rings make clamps with less force and more flexibility. They've worked great for me so far and I hope to use as many of them as I can while completing the boat. Best wishes, Seth Jersild jersi...@gmail.com
KR> Longer Wings - please tell me if this is right
Hello All, I'm going to use the 5048-45 airfoil and want to confirm whether the following would be the right approach if I wanted to lengthen the wings one foot on each side... 1) Lengthen the forward outboard spars one foot, but still taper them to the dimensions given for the rib at the end of the wooden spar (just spreading the same transition from 5048 to 5045 over a longer distance) 2) Add the one foot foam spars as suggested in the plans and taper them to the foam tip rib dimensions given on the 5048-45 template. I'd use the foam extensions because if I take this approach, I won't have enough wood to extend the timber all the way to the "foam extension" tip rib. Am I correct in understanding that this will decrease the forward sweep of the rear spar a little bit? It also just occurred to me that if I used the foam tip rib template as given, the one foot piece at the end of the wing (over the foam spars) would taper at a slightly steeper vertical angle than the rest of the wing, since the vertical taper of the wood spar will become a tiny bit more shallow. Would I have to also lengthen the foam extensions proportionately to continue the same taper? Would any of this (decreased forward sweep and shallower taper) be something to be concerned about? Sorry if these are non-issues but the spars are the first thing I'm going to build. I'm no engineer and I want to be sure not to make a BIG mistake and screw up the airfoil dynamics. Thanks for any input! -Seth Jersild
KR> KR2 Plans
Is a KR2 / KR2S built by buying the KR1 plans and applying all the mods people have made over time ? Is there no way to buy an actual set of KR2 plans ? --- Hello Kieran, I was surprised to follow your link and not find the KR2/KR2S plans on that page, because that's where I ordered them from just two months ago. I suspect it's a temporary thing on the website. The KR2 and KR2S have their own plans (the "S" modifications come with the original KR2 plans as a supplement). You could try contacting NVAero directly or maybe someone here will be able to explain why they don't seem to be available at the moment... -Seth Jersild
KR> Re: KRnet Digest, Vol 353, Issue 23
Thank you very much for putting things in perspective, Mark. If the cumulative weight of all the materials adds up to just a few ounces more with the 5048-45, then I'm sure not going to worry about going with a stronger spar. Please forgive my ignorance--in a couple of weeks my garage will be full of spruce and I'll start getting a much better sense of things. -Seth Jersild On 1/22/2011 11:00 PM, krnet-requ...@mylist.net wrote: > Send KRnet mailing list submissions to > kr...@mylist.net > > To subscribe or unsubscribe via the World Wide Web, visit > http://mylist.net/listinfo/krnet > or, via email, send a message with subject or body 'help' to > krnet-requ...@mylist.net > > You can reach the person managing the list at > krnet-ow...@mylist.net > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of KRnet digest..." > > > Today's Topics: > > 1. Weight of 5048 wing vs. 5046 Noob questions >(Seth and Karen Jersild) > 2. Re: Weight of 5048 wing vs. 5046 Noob questions (Mark Langford) > > > ------ > > Message: 1 > Date: Sat, 22 Jan 2011 12:27:27 -0600 > From: Seth and Karen Jersild<jersi...@gmail.com> > Subject: KR> Weight of 5048 wing vs. 5046 Noob questions > To: kr...@mylist.net > Message-ID:<4d3b218f.5080...@gmail.com> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hello All, > > Next month I'll start cutting wing spars for a KR2S, and now I'm doing > my usual last-minute dithering between different options when I have to > make important decisions. I'll have enough wood to construct 5048-15 > airfoil spars. > > Since I might ultimately go with a smaller engine, I'm going to be hyper > weight-conscious in every decision I make. I think I understand the > advantages of the 5048 airfoil (strength, efficiency, more gas in the > wings if you want it), but I'm wondering whether the total weight of the > thicker wing (more wood, more glass, more glue etc.) is something worth > thinking about for someone who wants things light. I have no experience > regarding the weights of the materials I'll be using. I know the 5046 > is generally used by people who have already built stock RAF48 wings, > but would the 5046 wings also be lighter than the 5048 in any > significant way? > > I know it's difficult if not impossible to compare since so many other > factors are involved in performance, but I'd also be very interested if > someone who has flown planes with both 5046 and 5048 airfoils could give > me their subjective "general feel" impressions of any differences > between the two (takeoff, climb, cruise, approach, stall etc.) if any > were noticeable and could reasonably be attributed to the different > airfoils. > > Any feedback would be greatly appreciated! > > -Seth Jersild in Illinois > > > > -- > > Message: 2 > Date: Sat, 22 Jan 2011 13:02:42 -0600 > From: "Mark Langford"<m...@n56ml.com> > Subject: Re: KR> Weight of 5048 wing vs. 5046 Noob questions > To: "KRnet"<kr...@mylist.net> > Message-ID:<03083975E804468785776FA8051FBEFB@base> > Content-Type: text/plain; format=flowed; charset="iso-8859-1"; > reply-type=original > > Seth Jersild wrote: > > >>I'm wondering whether the total weight of the > thicker wing (more wood, more glass, more glue etc.) is something worth > thinking about for someone who wants things light.<< > > The main difference between the AS5046 and the AS5048 is 1.7 inch or so of > thickness (I'm too lazy to go look for the exact number). The spar caps are > the same thickness, so the only structural weight difference is in the > vertical spacers between spar caps and the thin plywood on both faces. It's > literally a few ounces. Easy enough to calculate if you really want to > know. The difference in fiberglass is going to be immeasurable. And given > that you're going to be tapering from AS5048 to AS 5045 on the outer wings > (I hope), you can cut the tiny weight gain in half. And if you're as serious > as seem about weight reduction, you can make your spar caps thinner and > reduce weight further over the AS5046 and still have the same strength, > since the taller AS5048 would be something like 18% stronger due to the > increased spar cap distance. You'll have to do a little homework on how > much thinner you can make them, but the airfoil website at > http://www.krnet.org/as504x/as5046inst.html mentions the exact number on it > somewhere, or back at http://www.krnet.org/as504x/ . Checking th
KR> Weight of 5048 wing vs. 5046 Noob questions
Hello All, Next month I'll start cutting wing spars for a KR2S, and now I'm doing my usual last-minute dithering between different options when I have to make important decisions. I'll have enough wood to construct 5048-15 airfoil spars. Since I might ultimately go with a smaller engine, I'm going to be hyper weight-conscious in every decision I make. I think I understand the advantages of the 5048 airfoil (strength, efficiency, more gas in the wings if you want it), but I'm wondering whether the total weight of the thicker wing (more wood, more glass, more glue etc.) is something worth thinking about for someone who wants things light. I have no experience regarding the weights of the materials I'll be using. I know the 5046 is generally used by people who have already built stock RAF48 wings, but would the 5046 wings also be lighter than the 5048 in any significant way? I know it's difficult if not impossible to compare since so many other factors are involved in performance, but I'd also be very interested if someone who has flown planes with both 5046 and 5048 airfoils could give me their subjective "general feel" impressions of any differences between the two (takeoff, climb, cruise, approach, stall etc.) if any were noticeable and could reasonably be attributed to the different airfoils. Any feedback would be greatly appreciated! -Seth Jersild in Illinois
