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SikaFlex taping issue

Jwputnam

Well Known Member
I have taped my canopy and frame with black electric tape (lots) as many have suggested, but as I prepare to prime and glue, it occurs to me that pulling the tape for a nice even edge is a problem since a complete bead is not present until the hose spacers are pulled and filled about 12 hours later.

My inclination is to use a razor to cut the edge before pulling, but i am afraid of scratching the canopy or creating a stress line. I also thought about pulling the tape within a few minutes of the primary gluing and then re-taping the line prior to filling in the spacer gaps.

What did you guys do?
 
Leave the tape on until all Sikaflex is applied. Try to only spread it to the edge of the tape. I found that I wasn't using the right bead shape. Once I did a triangle cross section to the edge of the tape all was good.
 
A friend suggested doubling up the tape so that I can pull twice. Makes great sense.

How did you make a triangular bead? Did you cut the tip at an angle? Did you make a rather large bead?
 
Sikaflex has a pictorial on how to cut the nozzle, just tried to find it and couldn't. It is a vee shaped cut. I used disposible spoon handles and the actual spoon leading part to shape the bead. Double taping is a good idea,however, will leave a raised edge but that shouldn't be a problem. Try not to go too far over the edge of the tape. It works well to fair it to the tape. This stuff is pretty messy, you need lots of masking, gloves and old clothes.
 
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And don't use spacers.......:D

Cutting the tip to create a triangular bead is relatively easy. Sight down the end of the tip and imagine what shape you want to pipe, then use a new X-acto or similar. Practise on a cheap tube of Alex before hand with spare tips, that is what we did.

Spacers - your Safelite guy doesn't use them, he is using a similar product to glue your windshield in on your car. The triangular fillet is what is needed, the broad base gives a good fix onto the substrate and the 'peak' spreads out on contact with the canopy. What Sika say is they want an even 1/16 - 1/8" bed under the organic glass (perspex). Don't forget, they design 1 system for many applications. Spacers are a suggestion to create an even bed, but really only work on large flat areas.

We have done a 7 and an 8. I have sent snaps to a few guys on the forum, I must get round to figuring posting snaps one day as I could put a sticky (pun intended) thread somewhere.

Don't forget also, you really only mask the primer initially. The un primered area will release cured Sika like a booger coming off a kids nose :eek:

The second application of Sika to form a pleasing fillet must still land on the primer area and should not require further masking. Here, the trick is to use a tongue depressor stick (big popsicle) with a nice smooth sanded end to your desired profile. A deeeeep breath, a smooth and elegant swipe and the LEAVE ALONE.

A great product which gives a superb and resilient, professional finish. Yep, takes more time than drilling but a load less stressful and potentially expensive.
 
I am a few hours from gluing and NOW you tell me not to use spacers.

Well, I get your argument and you are probably correct, but I am already set up for spacers and I think that I will feel more secure with a larger bead. I DID notice that the sides do not come in flush with the rails to allow the side skirts to mount properly, so I eliminated the spacers at the edges of the bows to take care of this "problem".

I also removed the suggested black electrical tape in favor of 3M edge tape as I am told that the primer is very runny and needs a good edge. I will put two strips down on the canopy so as to peel the first back after initial application.

Off to the hardware store for foam brushes and tape. Thanks for all of the very good advice.
 
Be careful with the foam brushes and the primer. It is very runny and the foam brush can release too much as you brush it on. Been there, done that and had to clean up the mess.

I also recommend using the spacers. Try in the first pass just to get the canopy firmly secured in place. Wait 8 hours or so, pull the spacers and go back for the final pass and this is where you want to make the nice smooth fillets and quickly pull the tape before it tacks up.
 
Bruce,

I glued it at 4 PM today. I used a whole tube!

I intend to pull the spacers tomorrow AM and then go back and add Sika 295 to the gaps and add to the current fillets so that I can smooth them out and make them more presentable. I am hoping that the added Sika 295 cures over the top of the fillets. If not, I will just leave them as is. Your opinion?

I also have not pulled the electrical tape that protects the frame yet. I really can't do that until I let the whole mess sit for a week or so. I did pull the painters tape on the canopy, which went nicely.....and I put a new tape mask down for the added fillet work tomorrow.

How long before it is safe to release all the clamps? The stuff is still very flexible and spongy after 3 hours.
 
Sikaflex photos

Here is the link to my web log and the process I went through with Sikaflex. You can also look up Bruce Swayze and Bruce Hill as I referred to their websites when I was getting ready to adhere my canopy.

Mine
http://www.mykitlog.com/users/category.php?user=sdahrens&project=248&category=9962

Bruce Hill's EDIT if I had read more carefully I would have noticed he already replied to this thread
http://www.overthehills.com/RV-9A-Project/Finish-Kit/Canopy/i-x24r8Rn

Bruce Swayze
http://www.europa.com/~swayze/RV-7A/Finishing.html
 
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Thanks Scott. I checked it this am and the canopy is as solid as a rock. I am very pleased with it. The seams are not quite as sloppy as I thought, buy I am going to smooth them a little with fresh 295 as I fill the gaps later this morning.

I was worried about how I could remove the spacers and still keep the canopy clamped for a week or so, but that appears not to be an issue. The Sika does not move at all with the clamps on or off. It is set! No worry that the clamps will compress the seams with the spacers removed.

Now I am researching painting the seams. It is said that the 295 is able to be painted, so I may paint them white to match the canopy frame.....which I left white, but then I will probably wait until I paint the plane years from now to paint the canopy frame to match. Who knows?

At any rate, the process is so very simple really. I have plenty left to do though. Side skirts, rear skirts, blocks, latches, windshield, etc., etc.
 
Bruce,
I intend to pull the spacers tomorrow AM and then go back and add Sika 295 to the gaps and add to the current fillets so that I can smooth them out and make them more presentable. I am hoping that the added Sika 295 cures over the top of the fillets. If not, I will just leave them as is. Your opinion?

Yes, you can easily layer on the Sikaflex over itself. I would try to do so within 24 hours. I think I read that somewhere in the product documentation back in the day...

I would smooth out the fillets and get the tape on the edges pulled off right away before the Sikaflex starts to form a skin on it. If it starts to skin up and then you pull the tape, it will mess up the nice smooth edge from the tape. Either that or wait until it is fully cured to pull the tape.
 
NO electric

I DO NOT recommend using electrical tape. I know many have successfully but electrical tape is not designed for this purpose. Use 3M Fine Line tape. It is designed to cope with the various chemicals and solvents. Sure it is more money but the canopy is so critical.
 
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