capping stringers

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Sangster21

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Is there some special technique for this? I have 3/4 ply stringers, I have tabbed them in place with 3 layers of 1708 and I need to cap or encapsulate them now. I have a hard time with the 1-1/2 oz csm. I can't always get it to lay flat on the radius on the top. The guru at the plastics store suggested to tear the pieces of csm. What size chunks work out best for this fiddly job? I have experimented with the tearing bit, but you sure end up with a bit of a fuzzy mess on your hands. Could some one help a bro out?
Alan
 
tpenfield

tpenfield

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Re: capping stringers

Tearing CSM . . . now that would be a neat trick. Cutting it perhaps.

Here is my idea and you may not find this in a text book or anything like that. . .

if you can stretch some 1 mil (+/-) plastic sheeting over the top of the stringer after you wet out the CSM and tape it down tight to the lower portion of the stringer, it will hold the CSM tight against the stringer top giving you a decent square top shape.

When I do this sort of thing, I usually get one side of the plastic taped in place, so I can quickly drape the plastic over the top of the piece after wetting out and secure the other side. - - - another one of my million uses for duct tape.
 
Scott Danforth

Scott Danforth

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Re: capping stringers

tear it into about 5" wide strips.

after wetting it, let it set for just a bit, then go back over with the brush to get the stray hairs and bubbles out.
 
S

Sangster21

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Re: capping stringers

Georgesalmon said:
you did put a radius on the edges of the plywood?
Click to expand...

Yes I did put a radius on the top edge. Just looking to find out "best practice" for this task. I haven't got a lot of air bubbles, but I do have a couple of spots I need to grind and re do.
I wet out the stringer, place CSM, dab on more resin and let the binder dissolve a bit. As has been noted go back and smooth out wrinkles and bubbles. The front third of my stringers I wrapped a layer of woven roving over the top. I quite like the roving as it seems to wrap over the top quite nicely. It seems that you need to be carefull with the amount of resin, too much and the csm seems to float a bit.
Thoughts?

Alan
 
Last edited:
Woodonglass

Woodonglass

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Re: capping stringers

Check the first link in my signature below. Theres a drawing and instructions showing and telling you exactly what you are describing. You are absolutely correct about "Tearing" the CSM. Cut it into 3" strips and use your hands to tug it and pull it to loosen the strands and tear it. The Loosened fibers will lay over the top much easier and you should use a Chip brush to DAB the resin on NOT brush or roll it. A little practice and you'll be a pro in no time.
 
Yacht Dr.

Yacht Dr.

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Re: capping stringers

If the tops of your ply stringers are not fully prepped with resin first you will always have a hard time keeping bubbles out of it. Make sure you resin coat the crap outa them edges before trying to lam over it ( that goes for the faces of ply too ). Its all about prep brother..

Think of glass and resin like your suction cup.. can your surface hold a suction cup to it.

Another Trick of the Trade is to mix some cabosil and resin up to mayo putty and use a spreader to work that putty into your end grain wood. Then lightly resin coat and start your Mat cappin glassin :) .. shhh. its a secret :D .

YD.
 
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