mark IX

My Feedback: (9)

I am having a hard time finding a spray contact cement to use to glue the balsa sheeting to the foam wing core. At one time I used a 3M product but so I have not had any luck finding it. Any ideas will be appreciated.

Thanx, Mark

sensei

Hello Mark,

3M 30-NF is the best you can use, you can spray it on, or roll it on, it is water based so it has no bad odor, cleans up with water until dry that is, and only gets stronger with heat. Or second choice would be Super 77 spray adhesive.

Bob

mark IX

My Feedback: (9)

Bob, thx for the response. I have heard of the 3M 30-NF, where do you buy it? I tried the 3M-77 and Weldwood, but both dissolved the foam......... Another product I am currently experimenting with is LocTite Power Grab. White paste, good to 140F, drys in less than 30 min. Prefer a spray though.

Mark

sensei

Hello Mark,

You can get it at Grainger’s Walmart, Amazon, many places really. Once you use it, you won’t use anything else unless you goto an epoxy laminating system.

Bob

Pylonracr

Bob kind of eluded to it, I am going to come out with it. The very best and lightest method is epoxy laminating resin and vacuum bagging. That being said, in the past I have sheeted many wings using resin and weights. While not quite as good as using vacuum, the results are still superior to spray on contact cement and hope for the best when you stick the sheeting on. The time afforded by using resin allowing you to press the sheeting to the cores within the shucks and weight down over a perfectly flat surface before the resin cures will ensure a dead flat wing. Using a contact type cement is more of a stick the sheeting on and hope for the best - one shot deal type of operation. Not my idea of how to make a flat wing.

Scott

aspeed

In the old days?... There was a Sorghum contact cement that was popular. It would go on with a credit card. We had a water based one here that worked well. After many years it would stop sticking and need to be reglued. Epoxies are good. I have a feeling that the foaming type of polyurethane would be the lightest, and maybe even stronger because it expands a bit to fill up the small gaps. It is put on with a credit card so the amount would be the same as epoxy. I have heard that it can slip when clamping or bagging. I was going to use a plywood top piece, and about 2" foam rubber sandwich with weights. Some of my cores have no bucks. Can't really say that I tried it, have enough wings for a few years, and my Gorilla glue dried up on me.. Lots of guys swear by it though.

rcman58

I like using titebond polyurethane glue and vacuum bagging the glue will force its way through the pores in the balsa makes a vary strong wing

Randy

mark IX

My Feedback: (9)

Is the "titebond polyurethane glue" foam safe though..... have a picture of it?

aspeed

Probably this stuff. https://www.tegstools.com/Titebond-P...20group%20%231 it doesn't say that it foams up, but it likely does. That is a good thing IMHO, especially for sheeting and fixing ribs that are buried under covering. I used Elmers Nano and liked it because of the shelf life of a few years. It seems to have changed formula and name. Hard to get here now. Gorilla PU only lasted me a few months after opening. Maybe check the MSDS for whatever you intend to use.

rcman58

Yes it is foam safe .Randy

sensei

Hello Scott,

I agree with you my friend, it doesn’t get any better or lighter than using a laminating resin and a vacuum bag. He didn’t ask if epoxy was better than contact adhesive he asked about contact adhesive, you and I are sold on placing our skins on the core with epoxy and vacuum bagging and have gone to the expense to setup for doing things this way. There are those out there that will never do that, so when he asked for an opinion on what is the best contact adhesive to use, well I know for a fact through destructive and flight testing over a decade ago that 3M 30-NF is the best if you are going to use contact adhesive, when rolled on it soakes in at least one bead deep and because it is water based it is not destructive to the foam, as it dries the moisture leaves along with some of the weight, and it is not effected by heat like many other contact adhesives, so I gave him the information he requested.

Bob