I purchased the 1700 plan set, and hope to source as much material locally as possible. I'm using hoop pine that i can source locally, I've been ripping the wood to size from larger stock.
Started in January and gradually climbing the learning curve.
So far I completed one rib and a fin and rudder. I think this fin and rudder is the one that I built to throw away, it looks ok but on closer inspection I need to do better.
I am sure that I will have many questions to ask the forum, here is one; Has any one built a Max completely from Douglas Fir or similar ? what was the final weight ?
Welcome! You have begun a journey that is full of highs and lows and great satisfaction. I hope that you enjoy your experience. Nothing built by man (or woman) is ever perfect. Lots of knowledgeable people on the website. Hope to hear from you on your progress. Work safe and have fun.
Good to see you are still progressing with your build. I think there's a lot more douglas fir in the kit wood supplied than fair dinkum spruce, so I doubt your weight penalty will be much. Hoop pine is a tad heavier than spruce, but also a bit stronger, so if you were really concerned you could reduce the dimensions of your material by a tiny amount to get the weight back. But i wouldn't recommend it, unless you have a good knowledge of the properties of the materials & the ability to calculate effect of dimension reduction.
The trick is to be conscious of tiny weight savings in everything you do. Collectively they all add up. Engine and paint choice can be big factors in final weight. And, of course, don't forget your own body mass! See Brian 'Bigbrix's thread for how he was inspired by his Max to lose a lot of weight. He even inspired me to lose the best part of 10kg!
I've been away from the forum for a while but the build is continuing.
Thanks All for the encouraging words.
mullacharjak ; according to my records I have spend 23 hours on the fin and rudder, that is not counting the time spent on pieces that did not end up in the final product. (I had to build the leading edge twice)
Also as I'm ripping my own wood to size so I'm spending a lot of time doing that but will not count that towards 'build time'
Bruce ; I dont know enough to play around with the wood sizes, I'm building 'to the plans'
The tail looks ok in these photographs but really is not up to standard, I would be reluctant to put this on a craft that I will fly. I will have to build another one. I'm not disappointed, as this was the first component of any size that I built and will consider it a training exercise.
I have moved on to building Ribs, four done so far.
Also I am taking my first flying lesson on Monday!
I finished off the first set of ribs and am ready for the next batch, spent a weekend ripping wood and then cut all the pieces in the weekday evenings. Ready to build the rest of the ribs.
Glad to see your back at it. The build is a journey of discovery with the pay off comes an airplane that you can get into and fly. I hope your journey is a smooth one but do'nt be discouraged cause there will be a few bumps along the way. Best wishes .
I am enjoying the journey and looking forward to the destination.
I'm continuing building the ribs.
Today was the first day that I built in really hot weather (37C) and the speed at which the epoxy cured caught me off guard. It was almost a gel like consistency when gluing on the last gussets. I hope the glue joints are good. I guess I'll have to work quicker in the summer.
I have a question for anyone who used/uses West System Epoxy, how much filler did you add to the epoxy ? I seem to need at least 1.5 to 2 times the hardener volume (eg 15ml resin , 3 ml hardener and 5 ml of filler )
I've been using West 105, and 206. West calls the 206 hardener a Slow hardener. I mix cabosil in for the filler, and I use different amounts of filler depending on the application. Don't worry too much about how thick the epoxy gets when gluing wood. As long as it hasn't turned lumpy, it should be fine. The times that you want to worry about how thick, or runny the epoxy is is when you are concerned about penetration, or wetting out glass cloth. Mix your glue in small batches, because the glue itself generates heat, and in large quantities accelerates the curing process. There are other fillers like chopped glass fibers, ground glass, cotton fiber, micro-balloons and even carbon for different applications. I use mostly cabosil, and I just repaired my wife's cane this morning with West epoxy, and cabosil.
I've just finished the ribs for a new design using west system and the 206 hardener, I had cut all my pieces with a compound miter saw using stop blocks and guides clamped to the fence to get identical perfect fitting joints so when it came to glueing they fit together in my jig perfectly. I found that if I laid all the pieces and gussets for two ribs out on the table, then used a bristle brush to paint the epoxy on all the pieces first to get good penetration while it was still very liquid I could get two ribs together before it started to gel (and was about perfectly one pump each of epoxy/hardener with just enough left over to test as a confirmation of full set up strength). I also painted more on each piece as it went into the jig, but didn't have to worry about it not soaking into the wood if it started thickening.
Korale, you should always brush the cut ends of any joint with unthickened WEST before you make the joint with thickened epoxy. This ensures a good bond to the wood fibres, so that the adhesive is "in" the wood, not "on" the wood. WEST epoxy has diluents specifically made to thin the adhesive, allowing it to penetrate. Then use thickened epoxy on assembly.
As regards how much filler to use, you will get a feel for this after a bit of time. Basically, just use enough to stop the mixed epoxy slumping out of the joint. But do remember to paint the raw wood with unthickened epoxy first.
Remember, you can buy both fast and slow hardener for WEST. This time of year in Victoria, you defo need the slow hardener (temp today is forecast 45 ºC or 113ºF)!
Of course, this does not apply if you are using T88 epoxy.
I have no experience with "west" system epoxies, but it sounds like the old slow and fast cure epoxies that model builders are used to. T88 takes 24-36 hours to fully cure at 77 degress. I would sticky with t88 .just saying!
I've been using West 105, and 206. West calls the 206 hardener a Slow hardener. I mix cabosil in for the filler, and I use different amounts of filler depending on the application. Don't worry too much about how thick the epoxy gets when gluing wood. As long as it hasn't turned lumpy, it should be fine. The times that you want to worry about how thick, or runny the epoxy is is when you are concerned about penetration, or wetting out glass cloth. Mix your glue in small batches, because the glue itself generates heat, and in large quantities accelerates the curing process. There are other fillers like chopped glass fibers, ground glass, cotton fiber, micro-balloons and even carbon for different applications. I use mostly cabosil, and I just repaired my wife's cane this morning with West epoxy, and cabosil.
That sounds good Greg and I'm sure it will work fine for you.but for the average builder I would still say stick with t88 for ease of mixing for beginners.
T88 is five times more expensive here than it is in the US which is why I'm using West System.
It's probably a little more fiddly to use that T88 with three parts and a two step gluing process.
I built and destroyed several small fixtures to learn how to use it but this was the first time i used it in such hot conditions.
I tested the glue samples from the hot day and it broke in the wood so I'm happy that the rib is OK. I've had a few things to do around the house so have not built another rib yet.
I'll qualify this by saying it is my opinion. I've been using epoxies for 40 years, and in it's day T88 was the standard, but I believe West is not only superior, but FAR superior, and there are better epoxies then West (105/206) but West more then meets our requirements. The slight drawback to West is that you need the pumps, or mixing scales because of the 5to1 mix ratio. I just partially disassembled my elevator to do some repairs. The T88 joints separated far easier (with heat) then the West joints.
FWIW I used West Systems for large areas like spar caps as its lower viscosity helps with spreading it on. T-88 is thicker but on small glue jobs not a problem and easy to mix a small batch. Never used or needed any fillers. Cant go wrong with either product. I'd want to get it on and the parts together before its jell like.
I'm not recommending this without further information (perhaps some other members have info?), but years ago when I switched to west epoxy,as a "training exercise" I built a small boat out of laminated radiata pine bows and formers with mahogany ply skins covered in 6oz glass. Working outside in 90+F temps and not being well prepared caused me to waste a lot as it would set up before I could use it (it thickened enough I didn't trust it to penetrate the wood fibers). I had then started mixing a batch and pouring it into a few styrofoam bowls (approximately 1/4" deep) and putting the bowls in the kitchen freezer. I'd use one, grab the next, a few seconds of stirring in the hot air and when it hit the hot wood it would thin back out almost immediately. All the Samples I made failed in the wood grain, but without further corroboration I can't in clear conscious recommend it for structural bonds in an aircraft. Another plus of west system is once you have it and the metering pumps, a few different fillers etc it is amazing how many uses you can find for it. I can't begin to list the things I've fixed around my farm with it, have two gallons in reserve at all times in addition to the jugs with the pumps in them, and have professed for the last three years that I'll never not have epoxy on hand, it's that useful and convenient.
Stilson, Plus 1 to everything you said. If I want to slow my epoxy's rate of cure, I place it in water with ice cubes. Keeping it cool to slow the cure rate doesn't hurt the final integrity of the epoxy. The history of West epoxy is centered around boat building, so it was designed to be used in different environments. I try to avoid cold weather, but this past Thursday I glued some parts on my Max in the garage (probably in the mid 50 deg's). I put a 200 watt light bulb on it for a couple of hours. Post curing at an elevated temperature improves the durability of the glue, but it's still stronger then the wood when cured at room temperature.
I like you Greg but you are stubborn old man stuck in his stubborn ways. When it comes to glue joints in airplanes, this is no time to be experimenting with glue when folks.lives are relying on your voice which is a good voice I might add.
Thanks for the idea of keeping the epoxy 'on ice' on a hot day I was thinking of doing something like that, good to know that will work.
Hi Arthur,
The lessons are going great, I'm flying with TVSA out of Bacchus Marsh and really enjoying it.
I drove down to Marine Timbers on Friday as I was running low on wood, Warren (great guy) was also low on Hoop Pine but I got a couple of pieces, and some plywood. have spent a couple of hours rough cutting nose ribs and the other bits of ply needed for the ribs.
Jeffro, I suppose I'm stubborn, in that I'm convinced that West is superior to T88. Using West epoxy on wood airplanes is not experimenting. West has been approved, and proven by many builders, and companies. T88 is old technology. By virtue of it's 1 to 1 mixing ratio it already has a filler in the hardener. The filler is in a liquid form. Sometimes in cold conditions the the filler solidifies in the hardener. The solution to reconstitute the hardener is to place it in boiling water. The filler doesn't contribute to the chemical reaction that makes the glue harden. The sole purpose of the filler is for the convenience of a product that is mixed in a 1 to 1 ratio. West is mixed in a 5 to 1 ratio because that is the optimum. West solved the mixing ratio dilemma with the pumps. If T88 came to the market today, it would be a "pump ratio product". Like many things in aviation, old technology, that was the standard years ago, and FAA approved, is hard to beat, but that doesn't mean that there aren't better products available today. 70 year old wood airplanes were built with resorcinol glue. It's glue made from horse blood. If you are repairing a 70 year old certified airplane you cannot use T88, you have to use the same or similar glue that the airplane was certified with. So in no way am I saying that T88 is not a great adhesive. What I'm saying is that West is better.
Greg +1. I'm not saying old ways are bad, I still stand by "Indian head gasket shellac" as my go to fitting and gasket sealant, but in my opinion it is foolish to not use the wealth of advances that have occurred in epoxy development.
Greg +1. I'm not saying old ways are bad, I still stand by "Indian head gasket shellac" as my go to fitting and gasket sealant, but in my opinion it is foolish to not use the wealth of advances that have occurred in epoxy development.
The same can be said for coatings. We have turned the page on latex house paint.
There is an excellent, brief article in the latest issue of Sport Aviation (the EAA publication, page 110) on laminating wing tip bows for a Hatz biplane. The author used West 105/206 epoxy. Interestingly, even though I'm a fan of West epoxy, I personally would use aliphatic wood glue (like Titebond) for wing bows, because I could steam, or soak the wood strips in water, before gluing. An old saying goes; "There is more then one way to skin a cat".
You can steam bend wood intended to be epoxy glued. While heat with high humidity does soften the fibers enough temporarily to allow bending there really isn't much absorption of water into the wood. You have to leave the bent wood to "set" anyway and once it is dry it will glue with epoxy just like it always does. Of course you can always eliminate steaming simply by using more but thinner layers. Conversely you can usually steam bend the full thickness of wood and not laminate it at all. The only caution about steaming thicker pieces to a tight radius is that it does weaken the wood some as you bend to increasingly tight radii in relation to its thickness. There is a "rule of thumb" formula for this. If anybody is really interested in it private message me.
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