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-   S.P.A.D. Aircraft - Coroplast design (https://www.rcuniverse.com/forum/s-p-d-aircraft-coroplast-design-178/)
-   -   glue problems (https://www.rcuniverse.com/forum/s-p-d-aircraft-coroplast-design-178/8647760-glue-problems.html)

RuninWideOpen 04-04-2009 10:13 AM

glue problems
 
Well Im not haviing much luck with my spad, I cant seem to get the glu to stick with a dang Ive tried jet CA, elmers, and the last atemp was gorilla glu glued it last night and it just pulls right apart prepped the surface by sanding it lightly and cleaning with minreal spirits then clamped but no success any ideas

DavidAgar 04-04-2009 10:34 AM

RE: glue problems
 
Not sure what your problem is, but I usually use a torch to melt of the wax on the surface and then use CA to glue it all together. It works great. Good Luck, Dave

BillBabe 04-04-2009 10:54 AM

RE: glue problems
 
I concur with dave. I don't know what the problem is. I prepare my surface just like you then I use dots of medium CA throughout the glue area. Good luck!

Clarence


draftman1 04-04-2009 11:16 AM

RE: glue problems
 
I just flash is and wipe it off then glue it. make little dots, a full bead doesnt work. leave it clamped for a day. it does take some practice. old CA wont work either and make sure its medium. I had bad luck with zap but I think it was old. gorilla glue will work but you need to use a woodpecker tool to poke a bunch of holes in the coro and mix it with a very small amount of water, now that you have a bunch of different glues on the surface, just use GOOP, that works very well also. I use goop on edges and stuff were the CA wont work well Dont give up!!

huck1199 04-04-2009 12:46 PM

RE: glue problems
 
The mineral spirits may have left an oily residue. I use rubbing alcohol to wipe it down then scuff it up and put on some drops of CA.

TruBlu02 04-04-2009 06:37 PM

RE: glue problems
 
I have always used some white vinegar to clean all the oils off. I just wipe it down with a microfiber towel then let it air dry. Then use dots of CA to hold it together. I have used this method to glue down PVC control horns and it is all but impossible to get it back off once it sets. Good luck!

Villa 04-04-2009 06:47 PM

RE: glue problems
 
You say that you can rip the joint apart. Some joints are acceptable even when you can rip it apart. This, obviously, is a difficult thing to understand and worse, convey to others. I read that household rubbing alcohol has some oil in it so never use it. I only use Windex. When I tear apart some of my joints, sometimes small sections of the joint are "welded" together and will not come apart. The vast majority of the area of the joint, however, will pull apart, but you have to pull hard. The force that is required would probably pull a balsa plane apart also. If the glue joints can be kept in shear rather than in tension, the glue joint will be much stronger. This is true of the ailerons pulling on the wing. There is little tendency to pull the top wing surface apart from the lower wing surface. Plus the loads are not concentrated as they are if you grab a piece and pull it apart.

MrGreenSpeed 04-04-2009 07:52 PM

RE: glue problems
 
If You clean the coro with windex like Villa points out, then use a woodpecker tool to poke a bunch of holes in the coro and mix it,( the Gorilla glue), with a very small amount of water( one or 2 drops ). like draftman1 points out.
You will get a great glue joint. ( check the joint every so often to clean up any over foaming )

If You have to later, You'll be able to rip it apart to fix a broken spar or what ever You need to repair.

If You get the CA glue technique correct, it makes an incredibly good joint like the coro is welded together,( it is very important that once You put the coro together with the CA dot method that the coro doesn't move at all until the CA cures or the joint will be week. )

I've bin using poly glue on My Spads for 8 yrs and have hit a tree that removed 1/2 a wing (broke the spar at the center joint) and didn't pop the glue joints, I was able to rip the TE apart and replace the spar and have the Spad flying 2 days later.

Use test pieces of coro to test/practice Your gluing techniques.
Some coro (mostly used 4mil signs) I have, there is no way CA will work good with it, That's way I use poly glue for 90% of My Spads.

Good luck.
Jeff[8D]

hitster4 04-05-2009 12:47 PM

RE: glue problems
 
I drill 5-10 1/8 holes every 6"starting at the edge of both mating surfaces mix my poly glue and water in a dixie cup stir for 30 seconds then squeegee the glue over the areas that have been drilled really good then fill the areas in between the holes with a light coat after drying it can be taken apart with little or no damage to the coro. I was training a friend this weekend with my Deb and we ended up in the last years standing corn it looked like a combine went through the area. The deb had a broken prop a few dents in the leading edge and a cracked spar and I was able to pop the te apart and repair in no time. I use mostly free range coro so using ca is really not even an option as most of it has ink, paint or sign vinyl on it already and it is way to much work to try to get that stuff off. So this method is basically making glue rivets between your coro surfaces. I also use the poly water mix and a skewer to fill flutes for reinforcing.


Hitster4

RLR 04-09-2009 02:37 PM

RE: glue problems
 
Hi
I just sand the area I am going to clue with medium sandpaper, whipe it clean with acetone and apply drops of CA.
Never use to much. The idea is for the ca to melt the coro together.

Never had a problem.

Riaan

adrian222 04-09-2009 08:20 PM

RE: glue problems
 
All I ever use is contact adhesive no preparation just slap on both surfaces wait till touch dry push joint together no clamps Bobs your uncle and joint can be pulled apart later if need be.

Adrian

jaav 04-10-2009 06:42 AM

RE: glue problems
 
Ive used mineral spirits and glue would'nt hold.

CRC Electra clean is another one that I get perfect results all the time....Its also good for wiping down before painting, the whole surface has a flat sheen to it..

canardlover 04-24-2009 06:58 AM

RE: glue problems
 

I've bin using poly glue on My Spads for 8 yrs and have hit a tree that removed 1/2 a wing (broke the spar at the center joint) and didn't pop the glue joints, I was able to rip the TE apart and replace the spar and have the Spad flying 2 days later.
Jeff, do you refer to polyurethane glue here..??..can you please elaborate a bit on how you do it....THANKS..!

RuninWideopen, try double sided tape where applicable, it works nicely but you only get one try to mate the surfaces...;)....Cheers/Harald

millertym2000 04-24-2009 09:43 AM

RE: glue problems
 
I always just use a small torch or even a lighter will work if you dont have a torch just take s little longer. You can see it burning the oils off the coro. I'v been useing extra think ca ( thats what the LHS had) and its worked great. I glue the 2 pieces and put a 2x4 across it with anything I can find to add some weight. once it dries I cant pull it apart without ripping the coro to pieces. When I first started I used to glue it then put staples in it with a staple gun to make sure it held.

O2man 05-04-2009 06:48 PM

RE: glue problems
 
Guys, I have been using Handibond plastic friendly CA and get great joints without having to flame. As a matter of habit, I just wipe down the joint with denature alcohol and glue and clamp the joint. If you are in dry country you may need to allow an hour for it to set. I have to destroy the surrounding material to break the glue joints. All my SPADflyer production has done this way for the past four years.

PatrickCurry 09-28-2009 09:36 PM

RE: glue problems
 

ORIGINAL: draftman1

make little dots, a full bead doesnt work.
Why do little dots work and a full bead doesn't? Is there some kind of chemical breakdown that occurs or something? I've practiced on some scraps getting ready to make the wing for my Deb but I'm getting paranoid about how much glue to use. LOL Some places I've seen them say put a dot every 1/8".... Geez I'm going to have to buy a robot to get the glue right for my coro gluing! If you put a dot every 1/8" and squeeze it together, that becomes a bead!http://www.rcuniverse.com/forum/js/f...ular_smile.gifI'm thinking I'm gonna go with liquid nails. http://www.rcuniverse.com/forum/js/f...bout_smile.gifJ/K

Pat<br type="_moz" />

PatrickCurry 09-28-2009 09:48 PM

RE: glue problems
 
<span style="font-family: Arial, Verdana, sans-serif; ">

ORIGINAL: hitster4

I was training a friend this weekend with my Deb and we ended up in the last years standing corn it looked like a combine went through the area. 

I use mostly free range coro 

OMG that is so funny!  LOL  I just woke my girlfriend up laughing at this....  I've never heard the term "free range coro" but I hear ya...  LOL  A combine.....  LOL  I need oxygen!  http://www.rcuniverse.com/forum/js/f...eeth_smile.gif</span>

draftman1 09-28-2009 09:55 PM

RE: glue problems
 
Hey Patrick, dont be paronoid, I do a dot about every 1/4" apart and the dot is smaller than a pencil. for some reason, the bead will not cure and it will take alot longer for it to cure. thats what I have found out. wipe it down, flash it and then use the dots. you saw the video, it didnt take that long, they dont have to be placed in a pressision mannor. now for the deb wing, what really helps is if you really get that leading edge groove bent really good. I use a router to make a 3/8" groove. It really breaks the tension on the fold over. I have had then snap back if the glue wasnt cured and it was really hard to roll the wing. a groove will let it fold over nice and easy. if you want, I can do a demo of the deb wing tomorow.

PatrickCurry 09-29-2009 08:31 AM

RE: glue problems
 
No problem, I understand what you're saying.  And I was thinking about making a jig to hold the LE down some to maintain the flat bottom.  I was going to just trim off the corner of a 2x4 and clamp it to my workbench so the LE would fit under that notch.  Then when I clamp down the TE the LE won't rise up.  Hopefully I'll get to that wing tonight but....  :eek:

draftman1 09-29-2009 08:54 AM

RE: glue problems
 
yeap, I forgot, on the 4mil you will need a leading edge hold down jig

PatrickCurry 10-09-2009 09:30 AM

RE: glue problems
 

ORIGINAL: draftman1

I use a router to make a 3/8" groove. It really breaks the tension on the fold over.
Hey Andy, regarding that router option.... what kind of bit do you use? A regular square 3/8? Do you just make a regular rabbet right down to the outer skin? Thanks.

Pat

<br type="_moz" />

draftman1 10-09-2009 10:27 AM

RE: glue problems
 
Hey Patrick. actualy I use a 1/4" round nose bit. I make one full pass, then I make another pass that is half of the bit, so it becomes 3/8" wide. I make one pass for 90 deg bends. for a wing, its alot more than 90 deg so the groove has to be wider. I remove the outer skin and most of the flute material and just leave the skin on the opposite side

PatrickCurry 10-11-2009 06:56 PM

RE: glue problems
 
So far so good Andy.  I'm using the router attachment on my dremel instead of my router just cause my router is over at my shop.  Plus the dremel is smaller and *maybe* easier to control on the material.  Anyway, I knocked out 3/8" for the LE fold as you said and it's folding nice.  Then I used a 1/8" bit to knock out the other two fold lines (not all the way to the outer skin like the LE fold) and it's looking good.  I'm going really slow because I've never done it before. :-)  I've practiced on a scrap piece with my torch and when you hold it to the light, you can see where the oil was burned off because it's shiny there and dull where the torch was not.....  I'm keeping my fingers crossed!

draftman1 10-11-2009 07:19 PM

RE: glue problems
 
very cool! thats how its done! good luck!

PatrickCurry 10-11-2009 07:50 PM

RE: glue problems
 
Got the aileron and spacer glued on the left side..... the way I'm reading the instructions.... I just glue the spars on the bottom right?  I don't see where it says flash and glue the spars on the top.  I'm assuming the glue at the TE holds everything in place and you don't have to glue the top of the spars?


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