fiberglass to metal method?

[MikeP]

I am going to temporarily fix one of my exhaust collectors which is seeping a bit. I plan to essentially glass-in the end section of the surge tube; the joint there is where the seep is located.

So, I assume I am going to start wrapping the surge tube a few inches from the end and then continue around the end of the tube, later grinding/sanding to make the repair look better.

When I actually start wrapping the metal 8" dia metal tube, do I just use regular fg resin to attach the first layer of FG to the tube? I assume I should rough up the tube a bit with some sandpaper. Is that correct? Any other steps to be taken to ensure the FG to metal bond is secure and leakproof?

Thanks - I have NO meaningful experience with FG.

[34Hatt]

Epoxy is your only chance and RUFF it up big time and clean!!
Use some of the bi-axial glass tape like a 3-4" should work well.

[rrrestorer]

Your description of what your going to do is correct. Do sand the risers for a little bite, and to clean up the riser for a good bond. Use cloth and not mat, you will be able to pull it in closer to the riser and make the enf result nicer. Pay particular attention to the mixing ratio of resin to hardener, to much hardener makes the fiberglass brittle, it loses is strength. If the resin turns brownish as it cures you have used too much hardener.
Its a messy job so be carefull.If you can find a thick bodied resin , get it, it will make the job a lot cleaner. The thick bodied stuff was available for body shops, when we did vertical stuff , so that we could put more resin on without it running down.
Keeping it in place is going to be your biggest problem, you are going to have to compromise between thoroughly soaking your cloth and having it run all over the place. Getting the cloth wet enough is very important for strength.
Glassing , like what yor going to do isa down and dirty job, you really have no choice but using your hands for spreading the resin around the tube. I would start by spreading a thin coat of resin on the tube , followed by wraing one layer of cloth, more resin, more cloth, untill you get the build up you need. Make sure you spread some drop clth to catch the dripping and have plenty of wiping rags and I like lacquer thinner for cleanup.
Keeping your work area cool will give you more working time, as will making sure your ratio of hardener is correct.
you might plan on doing it in more than one step if the build up you need is significant. That is do as much as you can and , as the resin starts to harden, quickly smooth your work down by hand and clean up , let it harden, come back with a second coat as soon as possible, etc.
Good luck, fiberglass work in a confined space especially is very messy.

[MikeP]

Thanks - GREAT INFO!

Yep...it's a confined area and I expect it to be a real mess - but maybe the resin fumes will help and I won't need to drink today!

[sgharford]

Maybe you could use a thickner like West System 406? I used thickner for blister job over winter as was really impressed with how much easier it was to work with.

[Brian Degulis]

West System has info on epoxy to metal repair. They talk about roughing it up then putting on epoxy and working it in with sandpaper while it's wet. Here is part of it

Repairingmetal and fiberglass auto bodies
You can repair badly corroded or damaged body panels with WEST
SYSTEM epoxy and fairing filler. Epoxy is stronger, more waterproof
and it bonds to metal better than polyester body fillers.
Where the metal is missing completely, you can rebuild the area
by saturating fiberglass cloth with epoxy and using it to bridge the
holes. When the epoxy hardens, you will have a rigid backer that
will anchor the remainder of the repair.
Remove all rust and loose material. Grind or sandblast down to
bright metal. Apply a thin coat of epoxy to the prepared surface
and while the coating is still wet, abrade the surface with a wire
brush or sandpaper. Work the wet epoxy into the steel. When the
coating gels and while it is still tacky, either apply the wet fiberglass
cloth or fill the dents or pits with thick epoxy/fairing filler.
Allow the epoxy to cure hard and sand it smooth. Re-coat sanded
fairing filler to seal it. Allow the final epoxy coat to cure and wet
sand it. Paint the repair area with standard automotive paints.

Here is the link http://www.westsystem.com/ss/assets/.../OtherUses.pdf

Brian

[rwetherington]

make sure your fiberglass is rated for the heat of the of the exhaust.

[smoothmove]

A buddy of mine showed me a pretty slick trick for applying fiberglass matt to a difficult area which sounds like your situation. When you have wetted out the fabric, lay it on a piece of waxed paper. Then you can pick up the paper and apply it wherever you need to without a lot of dripping and cursing. you can even press it down and work it around to create a void free corner. It has the added advantage of holding the resin in contact with the fabric long enough to set. After things have stiffened up a bit you can remove the wax paper and you're good to go. Makes for a much cleaner process.

Eric

[doc g]

I would check with Marine Exhaust , there is some special resin and cloth for just what you are doing . The link , http://www.mesamarine.com/index2.html .....................Pat

[MikeP]

Those dang Indians were pretty clever! Good tip.

I am not trying to make a permanent repair. I'm leaving here on Sat and will be back in late August. I'll undertake getting new collectors made at that time...or maybe just wait and have it done over the winter which probably makes more sense.

For now I just want to be sure it's not going to start leaking in my absence.