Stewart Systems covering process discussion

[N96337]

Re: Stewart Systems covering process discussion

Ok..just ran across this again, and I'd planned on putting it in this thread. I'll also put it in the "tape shrinking" thread if I can find it.
Here's a graph that Dupont put out, showing the effect of color on temperature.

[mhorowit]

Re: Stewart Systems covering process discussion

I've been covering tailfeathers using Stewart in accordance with their instructions, but would feel better if I understood more about what the physics were. The problem is it seems there are two different ways to attach fabric. There is "gluing over a dry glue bed" where you allow a glue bed to dry, tack fabric in place over that dry bed (using an iron), then force wet glue thru the fabric and wipe dry.We see this in the video where the blanket method is described. Then there is the "gluing over a wet bed". We see that with the reinforcing tapes (perimeter and wing).

I can see glue being forced thru the fabric and becoming part of the wet bed when gluing over a wet bed (encapsulating the fabric). It's gluing over a dry bed that makes me scratch my head. It seems that the two glue applications of glue (the dry bed and the wet over glue) would not become one.

Can someone give me their own interpretation of what is happening?

[Theuns]

Re: Stewart Systems covering process discussion

Hi.
The idea behind the dry bed is that the solvents in the wet glue applied over the fabric will soften the dry gluebed and "weld" the two together.
I personally as a fabric tec do not like to do this, maybe I an just to old school but I like the idea of putting the fabric into wet glue and letting it wet the fabric to attatch it to the frame.
If you work neatly and take care very beautiful results can be obtained.

Hope it helps

Theuns

[Theuns]

Re: Stewart Systems covering process discussion

Hi.
The idea behind the dry bed is that the solvents in the wet glue applied over the fabric will soften the dry gluebed and "weld" the two together.
I personally as a fabric tec do not like to do this, maybe I an just to old school but I like the idea of putting the fabric into wet glue and letting it wet the fabric to attatch it to the frame.
If you work neatly and take care very beautiful results can be obtained.

Hope it helps

Theuns

[N96337]

Re: Stewart Systems covering process discussion

That's right...the glue is forced down through the fabric and "reactivates" to the already dried glue under it as is stated above. The old MEK based glues didn't do this well, so Theuns is correct in saying he didn't like to do that with the old glues....this cement is more like a contact cement, and works wonderfully the way they say to use it. If you follow directions, you'll have a much stronger glue seam than ever possible with the older glues.
John

[taylorcraftbc65]

Re: Stewart Systems covering process discussion

Absolutelly you can have a "satin" finish!!! You can get anything from a gloss finish to a total flat finish and anything in between. That's not a problem at all...just ask for that finish in your paint.

I am getting ready to cover a full scale, ultralight legal replica of the Aeronca C2, and they assured me that they can make it's finish look 1930's correct.

[taylorcraftbc65]

Re: Stewart Systems covering process discussion

Do the chemicals, (Glue, Dope, etc,) have to be trucked as hazardous materials, or can they be legally sent to a "UPS store / mailbox place ? UPS, and FEDex have NO idea where we are out here in ranch country. I offered to cive them our GPS numbers, but they both said that they can not use that.

[N96337]

Re: Stewart Systems covering process discussion

Non hazardous all the way, so you should be fine!

[asq]

Re: Stewart Systems covering process discussion

Stewart's materials have no "solvents" in them. You can mail them. I often do. Also this is an adhesion process, not fusion.
As far a wet or dry bed, try lapping a couple of pieces of scrap both way and when dry seal them w/ an iron and pull test. I think you will be quite impressed. Larry

[Mark Julicher]

Re: Stewart Systems covering process discussion

Larry,
I could use some advice regarding Ekoprime. I get a rather rough finish when shooting cowlings and fiberglass, but if I add much water it runs and sags. Any suggestions? Is the mixture that critical? Is there a temperature that Ekoprime happens to like?

Thanks.

[cvavon]

Re: Stewart Systems covering process discussion

Mark I just sprayed it on the stinson and it flowed out great light sand with 320 and sprayed top coat did not thin at all sprayed right out of the can

[Mark Julicher]

Re: Stewart Systems covering process discussion

Looking good Charles! I can see a nice gloss in your photos and not my sandpaper finish.
I 'm thinking that maybe I need to shoot Stewarts when it is less that 80 degrees in the shop.
I have sprayed Stitts, AirTech and Randolph, epoxy, urethane and dope and always had good finishes, but Ekoprime is kicking my tail. South Texas summer makes the liquid flash off sort of fast.

[Guest]

Re: Stewart Systems covering process discussion

I just started using Stewarts Ekobond glue to install a ceconite headliner. Its a nice safe place to start as a first time user since there are no real negative repercussions to my mistakes.

I was wondering though about the results that I am getting compared to what you experienced folks have gotten.

Firstly I see that I am rushing the glue. The documentation says it becomes tacky in 5 minutes but I am experiencing a much longer time say 30 to 50 minutes at 65-67 degrees F room temp. I think that has been a problem for me and I will give it more time. Question is should I be having to wait longer at this temp. What has you guys seen in regard to this?

Secondly after 16 hours at 65-67 degrees F room temp the glue it still soft. If I peel a piece of fabric back at a glue joint the glue stretches and pulls and looks like a rubber cement joint that is pulling apart. It seems like a long time to get to that point. Does that seem normal? Is it a temperature related issue?

Looking for advice. Thanks, Dave.

[Helicopter D]

Re: Stewart Systems covering process discussion

I've noticed that it is very temp/humidity sensitive, and it does have that rubber cement like quality until you actually put the hot iron to it, after that it seems to really stick down.

[taylorcraftbc65]

Re: Stewart Systems covering process discussion

I've noticed that it is very temp/humidity sensitive, and it does have that rubber cement like quality until you actually put the hot iron to it, after that it seems to really stick down.

I kind of like that. You are not stuck with the way that you laid the cloth down, almost as soon as you place it, you can shift things around, and have not "bought" the positioning until you put heat to it.