cdtraver

was wondering if anybody could tell me what kind of adheasive to use to cover a foam core wing with balsa.

CGRetired

My Feedback: (1)

Well, a thin coat of 30 minute epoxy spread evenly and smoothly.

If you don't know this, use the cheeks and a LOT of weight to press the final product together and let it set for at least a day.

CGr.

DMcQuinn

My Feedback: (13)

I like polyurethane wood glue. Gorilla glue is a brand name. Other manufacturers also sell this type of glue. It looks like maple syrup. Use plenty of weight. I like to get 3 or more pounds per square inch.

speedracerntrixie

My Feedback: (29)

OK so on a 500 sq in wing you are stacking on 750 lbs per panel? The problem with using weight is that there is no way to get the weight evenly distributed. If you are going to build a few foam wings per year I would suggest building a vacuum bag system. In most cases you can find all the bits you need for under 100.00.


As for me. I use epoxy finishing resin. I find that Ican get a set of wings that are stronger, lighter, straiter then if I used poly glue. If you need to add glass or carbon cloth to key areas of the wing for added strength, epoxy is the only method.

DMcQuinn

My Feedback: (13)

I use a vacuum system for large wings (1000 square inches). But sometimes for small projects I just use weight.

goirish

Anyone have plans for the vacuum system suggested here?

MinnFlyer

My Feedback: (4)

I just lay a board over the whole thing and stack the weight (evenly) on top of it. The board will spread the weight evenly

Gray Beard

My Feedback: (-1)

Me too. I used to compete in shot gun events and hunt birds several times a week, hand loaded most of my own ammo. When I moved here I still had several hundred pounds of lead shot in 25 pound bags. I use wood glue over the foam then lay the sheeting over the foam, lay the shuck/shed over the top then add a sheet of ply over that and stack the lead. At one point I had a small vacuum system but I only see foam cores once every couple of years so it was just something I didn't use often. The wood sheeting can also slip out of place and not be noticed with a vacuum system so it's something that needs to be looked for if you use one. If you do a lot of foam cores then vacuum is the way to go, if not then weights are good for most people.

speedracerntrixie

My Feedback: (29)

You would be surprised how unevenly this distridutes the weight. I bag a ton of parts at work because we have found that no matter what kind of weight system we use we simply can't get uniform weight distibution.


To make a vacuum system you need:


Pump. Surplus stores have them cheap

Tank, I made one from 3" PVC and caps

Check Valve that goes between the pump and tank. Auto store item, emmissions part.

Vacuum switch, Aerospace Composites has these. It goes on the tank and switches off the pump when desired vacuum is reached.


Very simple to construct and once you get the hang of it, easier and faster then stacking weights.

MinnFlyer

My Feedback: (4)

Well, I've sheeted a few hundred wings using that method and never had one that wasn't straight, so I'm not going to recommend that someone buy a vacuum pump when they don't need one.

Gray Beard

My Feedback: (-1)

Well Mike, I only see maybe one foam core every couple of years so I don't have a lot of them under my belt as a builder. In my case I wouldn't bother with one either. I have used those cool vacuum storage bags to sheet smaller planes with and thought they worked pretty well. With the few foam cores I see these days I agree with you, it isn't cost effective and I have never gotten any loose sheeting using weights. If I was cutting my own foam cores for all my building then I would make a vacuum system, they are slick but for the normal kit builder it would be pretty silly to go to the trouble of making up a system. I may have a nice old Byron 60 size Sukhoi with the glass fuse and foam wings on the board this year? As nice as this plane is I still will be using bags of lead shot. I have seen a photo of Speeds system {I think} and it is great, Wish he lived in the area, it would be a great borrow!!

speedracerntrixie

My Feedback: (29)

Well Gray, you and Minn would be welcome in my workshop anytime. In fact the more I think about it, the more I realize that the odds are pretty good that I have crossed paths with one or both of you. In the early 90's I spent a couple years in the twin cities area. Flew at the 3M site, Alexandria and a place towards Shakopee. Used to buy from Maury at R/C City in St Paul and Hub Hobby Center in Little Canada. Up until about 4 years ago I was at every IMAC event at the North Vegas and Bennet fields.


Goirish asked for a pic of my vacuum system. Nothing fancy here but shows all the components and their location

Gray Beard

My Feedback: (-1)

I did go to Tom Cat field and flew the IMAA events and up until last year I did go to the IMACs at the north field. Once in a while I go to the IMAC at Bennet. I flew at a lot of the IMAAs in calif. And was the safety officer for the club that put on the Rally of Giants at Castle. There really isn't anything going on to speak of here in the Vegas area like there is in Calif.
Trust me, if I had someone close here with a good vac system I would be doing the borrow thing any time I came up with something with foam cores. I traded away all my lead shot this year too but it hasn't been loaded into shot shells yet so I can still borrow.

OzMo

My Feedback: (3)

Dave Brown's Southern sorgum? Or am I just showing my age here (its a water based contact glue)
I set up a vacuum system recently,haven't used it much yet. All the above will work.
Do what ever but do it on a FLAT surface that will stay flat with the weight. Spread the glue well and thin.

FLYBOY

My Feedback: (11)

I either use 3M transfer tape, or titebond white glue mixed with water and paint on both surfaces, then after they dry, I iron the wood on like covering with the wing in its foam bed so it is straight. Works like a charm. There are many ways, thats just a couple more.