Couple o' questions..

[briankk]

I'm in the process of "gearing up" to build a plane with 4130 space frame and wood wing. I've bought a reasonable mitre saw for the wood, and abrasive cutoff wheel for the tubing. Since then, I've found a 77 tooth carbide tipped blade that will fit the saw,, says it's only for mild steel. Any body know why this could be a problem with 4130 tubing .035 - .049 wall thickness?

As to the wood wing, anybody know where/how to buy Aerolite? It's for sale all over the UK, and none of the stores there will ship it to the US for some reason. Canada, maybe?

TIA

bk

[Jeff Point]

4130 is a hard steel and will dull that blade pretty quickly. The abrasive cutoff wheel in the saw will work well to cut steel, although it's noisy and throws a lot of sparks.

Since you will likely need to cut out a lot of flat stock as well as tubing, I recommend a metal cutting band saw. It cuts tubing and thicker angle as a horizontal saw but can also be used as a vertical saw for cutting flat stock for fittings, gussets and the like. Harbor Freight has an inexpensive model that I've had for years and has held up well. Buy a couple of spare blades when you buy the saw, as a fuselage project will go through several.

http://www.harborfreight.com/horizon...saw-93762.html

Can't help with the Aerolite, but I wonder why you want to use it? There are plenty of other commonly available glues for wood construction.

[Aaron Novak]

I'm in the process of "gearing up" to build a plane with 4130 space frame and wood wing. I've bought a reasonable mitre saw for the wood, and abrasive cutoff wheel for the tubing. Since then, I've found a 77 tooth carbide tipped blade that will fit the saw,, says it's only for mild steel. Any body know why this could be a problem with 4130 tubing .035 - .049 wall thickness?As to the wood wing, anybody know where/how to buy Aerolite? It's for sale all over the UK, and none of the stores there will ship it to the US for some reason. Canada, maybe?TIAbk

Ditto on the above post on the saw suggestion. The little bandsaws with a good bi-metal blade will be your best friend. As for the aerolite, if you are talking about the acid cat type I would avoid it. Instead might I suggest a plastic resin type adhesive such as DAP weldwood plastic resin. It has all the good traits of the acid cat type aerolite, but none of the issues. It has much better creep resistance than epoxy as well.

[briankk]

Bandsaw and belt sanders both on my list. Probably need a router too, and maybe a table for it.

Trying to think incrementally, I don't have room to build the fuse here and now, but wings I could do. Naturally, I'm well equipped to build the fuse I have no room for, but lack a lot of woodshop equipment I need for the wings I have room for, unless, of course I set up a wood shop to build them.

Got the Weldwood on the shelf here now, wanted to do some comparison bits with Aerolite to see which I prefer, and start building ribs. I'm told that the Falco is done with Aerolite, but that they have to import the stuff in bulk to buy it at all. Perhaps I should go talk to those guys and see how they do it. I don't understand how such a common component could become rare and difficult to get, but there it is..

bk

[Aaron Novak]

Bandsaw and belt sanders both on my list. Probably need a router too, and maybe a table for it.Trying to think incrementally, I don't have room to build the fuse here and now, but wings I could do. Naturally, I'm well equipped to build the fuse I have no room for, but lack a lot of woodshop equipment I need for the wings I have room for, unless, of course I set up a wood shop to build them.Got the Weldwood on the shelf here now, wanted to do some comparison bits with Aerolite to see which I prefer, and start building ribs. I'm told that the Falco is done with Aerolite, but that they have to import the stuff in bulk to buy it at all. Perhaps I should go talk to those guys and see how they do it. I don't understand how such a common component could become rare and difficult to get, but there it is..bk

The acid cat aerolite type adhesive was/is popular for plywood sandwich type construction due to the long open time needed for that type of construction. Unfortunately it also has had issues with longevity under some conditions that lead it being banned in Australia. Note that the "weldwood" type was not banned and is still approved for certified aircraft in australlia. If you are doing a standard type "open" construction I think you will find the weldwood type just as nice if not nicer to use since you dont need the long open time, and there is only one component to deal with.

[amv8vol]

For an adhesive I would recommend T-88 epoxy, probably the most popular adhesive for homebuilts.
Here is my Harbor Frieght band saw set up for vertical sawing

[Aaron Novak]

For an adhesive I would recommend T-88 epoxy, probably the most popular adhesive for homebuilts.
Here is my Harbor Frieght band saw set up for vertical sawing

Unfortunately popularity is not always a good indicator of performance. In some cases yes, and in some cases its a me-too attitude that builds something's popularity. When you look at the "great glue debate" with an objective mindset, it becomes very clear that there is really one big tradeoff. Simply put if you group the room temperature resin glues (weldwood) and resorcinol together, and compare them to an epoxy, what you are trading off is performance for the need of precision joinery. You will never exceed the mechanical and thermal properties of a properly done resorcinol joint with any readily available material, period. Theres hard data for that so its not a debate. Epoxys are less fussy about joint fitment and are good for gaps. Is that a good thing? Im not sure as I hope it does not permit sloppy work. Unfortunately epoxys don't like heat, and even creep at room temperatures ( ever notice wind turbine blades that have taken a permanent bow due to the force against them?). So there you have it, trading easier joinery for adhesive performance. Don't get me wrong, I use both West and T-88, but I know their limitations, and I know its not the best performing structural adhesive.

[briankk]

Ah. The "glue wars". I won't bother you with the extensive research I've done online about this, but the upshot is that I won't be having any epoxy in my plane.

I have a little Tab book by a woman named Ruth Spencer, spent 20-30 years building, restoring and repairing wooden aircraft, never used anything but Weldwood, never had a failed joint..

The Mosquito bomber, built with Aerolite, was used widely for several decades there after with no documentable complaints I could find until the guy in OZ started on about it.

I've concluded that a lot of the "information" concerning the problems with the Urea glues is likely FUD from epoxy blenders, and though I've no evidence of that, I'm aware of enough problems with epoxy to avoid it if I have a choice..

[Aaron Novak]

Ah. The "glue wars". I won't bother you with the extensive research I've done online about this, but the upshot is that I won't be having any epoxy in my plane. I have a little Tab book by a woman named Ruth Spencer, spent 20-30 years building, restoring and repairing wooden aircraft, never used anything but Weldwood, never had a failed joint..The Mosquito bomber, built with Aerolite, was used widely for several decades there after with no documentable complaints I could find until the guy in OZ started on about it.I've concluded that a lot of the "information" concerning the problems with the Urea glues is likely FUD from epoxy blenders, and though I've no evidence of that, I'm aware of enough problems with epoxy to avoid it if I have a choice..

Glad to hear it. Fads come and go. Usually they come into popularity when they are "new and exciting", then time proves them good or not, determining their future. The Australlian CAA banned all UF glues, then later reversed that decision a few years later as the failures were all with one manufacturer with one type of UF glue in the 1940's plus their own testing. Unfortunately the same fellow that got Australlia to ban all UF glues, got the FAA to listen to him as well. Hopefully with some pressure the "weldwood" type adhesives will be put back in 43.13 following Australlias lead. In all honesty I dont know why T-88 is still around in homebuilding. The lap sheer is no better than modern PVA glues, its bond to woods like oak just stinks and it cant handle heat. Oh well......luckily most designs people build are designed around casein glue and its properties.

[briankk]

Somebody said: "Laminate your spars with resourcenal and do everything else with Aerolite". I intend to adhere closely to this advice, but that my spars aren’t laminated and I can't get any Aerolite ;-)