best epoxy for composite intake manifold repair

[garym]

I have a 2 piece sb chevy intake manifold that Brandywine cylinder heads made during the eighties , I think around that time period.The base/valley cover is aluminum, but the plenium is a composite type material.I need to repair the intake runner on the single 4 bbl intake, it is a tunnel ram type plenium single 4 bbl top.Hopefully someone will know about these intakes.I know Larry Woodward was an excellent cylinder head porter and he did 3 sets of cylinder heads and intake manifolds for me.I was told that he passed away , so hopefully I can get some info,I was thinking J B Weld or the Manley 2 part epoxy might work.Hope to get some info on what to use.THANKS garym

[Ron E]

The manley stuff will work fine. Any type will seal better if you cover from both sides of the crack. Even though its said to not be an issue with gas, consider getting some 2 part automotive clear coat to cover any that will be exposed to fuel to prevent the fuel from causing problems. Its insurance with gas, and a necessity with alcohol.

[pcnsd]

"Composite" covers a very wide territory. Is it injection molded or laid up glass? It is cracked or just in need of filler? A picture will help a bunch.

Paul

[Ron E]

Brandywine made some with a black plastic. i don't remember them being layered. Similar to ABS, but a little harder.

[garym]

the manifolds that I have are a white composite of some type.The material seem to sand fairly easy.Still looking for more info.THANKS garym

[Ron E]

Best results with Splash Zone. If you can pack it from the other side it's all you need along with the clear-coat. If not get JB Weld, heat the tubes to about 150°. That thins it out a lot. Work the heated JB into the crack after removing the stress (hole in ends of crack) When the crack is full, let it set until dry. Afterwards, rough up the exposed JB along with the manifold in the area. Cover with Splash Zone. After its completely cured. Coat with clear-coat. It's about as good as you can get. You can substitute the splash zone with Devcon if you like. No need to coat Devcon...I'm told.

[Walter R. Malik]

EVERCOTE epoxy liquid, 2-part fiberglass repair kit from the marine store.

The product is called EVERFIX; The other "super strength", I believe

[pcnsd]

the manifolds that I have are a white composite of some type.The material seem to sand fairly easy.Still looking for more info.THANKS garym

Is it 3D printed? If so most likely it is a nylon of some type. Before attempting repair or recommending a solution, I would want to nail down the base material. Is it cracked? This question was not answered.

[Walter R. Malik]

the manifolds that I have are a white composite of some type.The material seem to sand fairly easy.Still looking for more info.THANKS garym

Is it 3D printed? If so most likely it is a nylon of some type. Before attempting repair or recommending a solution, I would want to nail down the base material. Is it cracked? This question was not answered.

I am pretty sure no one had 3D printing in the 80's.

[pcnsd]

the manifolds that I have are a white composite of some type.The material seem to sand fairly easy.Still looking for more info.THANKS garym

Is it 3D printed? If so most likely it is a nylon of some type. Before attempting repair or recommending a solution, I would want to nail down the base material. Is it cracked? This question was not answered.

I am pretty sure no one had 3D printing in the 80's.

Ya think?

[garym]

Thank you all for the replies.Yes there are some small cracks in the runner along with a section that was very thin to begin with that will need to be repaired.The manifolds are in good condition and I want to try and use them if possible. Thanks garym

[pamotorman]

if you want epoxy to stick to a smooth surface lightly bead blast the area first. a good sealer is fuel proof model air plane dope and it will stand up ethanol. I used it to seal up the passage plugs in holley carbs that after time start to leak

[pcnsd]

The majority of plastics suitable for use with gasoline are by their nature not suitable for bonding. These include all the PE's, PP's and Acetals. Nylons are a bit more suited to bonding due to their surface structure. Glass filled will also make for a better chance of a repair bond. Trying to divine what you are faced with is just a WAG on my end. However given the capabilities and practices available in the US in the 80's, my WAG is a injection molded glass filled Acetal or Nylon.

To repair either; First degrease and then abrasive blast the exterior surface and two inches+ around. Clean this and the surrounding surface twice with acetone before bonding. Bond using either Walter Malik's suggested marine repair patch kit or a similar product used to repair industrial piping. (Epoxy all in one kit including glass reinforcement) Apply the patch to cover the repair location and two inches+ beyond. Put the whole mess in a heavy duty trash bag and pump/maintain a vacuum on it until the product is cured. You will likely need to perform some minor dress up afterward. The vacuum should outgas the cracks and drive the epoxy into that volume. The glass reinforcement will help to spread localized stresses. The large attachment area will promote bond strength.