Fibreglass sandwich construction, core?

[watchtherocks]

Originally Posted by tunnels

I can see i am wasting my time with this so for get what i have said and forget i was here !

No, you're not. Just because i disagree with you doesnt mean I havent taken on board what youve said. I'm the newbie here, and Im learning all I can.
Cheers waikikin I'll try them.

[tunnels]

Originally Posted by watchtherocks

No, you're not. Just because i disagree with you doesnt mean I havent taken on board what youve said. I'm the newbie here, and Im learning all I can.
Cheers waikikin I'll try them.

Ok last try . Core matt is a glass cloth impregnated with q cells , Now why has it got glass in it ?? CAN YOU WORK THAT OUT BY YOURSELF !!
Q cells mixed with resin is brittle and breaks real easy !!SO DONT USE IT AS A CORE !! . Its the dumbest thing i have ever heard ! OZ That makes sense !

[waikikin]

Watchtherocks, when you get your coremat or upica mat make sure you pre wet it with resin before placing it(especially on the back) in the laminate otherwise it scavenges resin from the layup beneath & you might get some dry spots, also it is pretty resin hungry & can get hot & "cook up" so watch your catalyst levels & overall layup. Have fun & regards from Jeff.

[watchtherocks]

I know it isnt ideal, but being able to shape the filler is too tempting. Ive got to give it at least one go.

[Steve Clark]

The way I have seen this done:
Lay up outside skin and let it sit for a while to gel but not cure 100%.
Add Q-cell / Cabosil mix ( try 2:1 ratio of Q cells to Cabosil) and trowel in place with a notched squeegee or trowel.
Once it is in place, immediately put in inside skin. It should wet out with resin "blotted" from the Q Cell mix.
Inside skin holds the putty in place.
I don't know how too describe what the best viscosity of the Q Cell/ Cabosil mix should be, you have to test it out.
Guys that do this well make really nifty parts very easily.
If you are trying to build a clear carbon fiber housing, you need to add some lamp black to the Q ells to make it darker.
SHC

[tunnels]

Originally Posted by Steve Clark

The way I have seen this done:
Lay up outside skin and let it sit for a while to gel but not cure 100%.
Add Q-cell / Cabosil mix ( try 2:1 ratio of Q cells to Cabosil) and trowel in place with a notched squeegee or trowel.
Once it is in place, immediately put in inside skin. It should wet out with resin "blotted" from the Q Cell mix.
Inside skin holds the putty in place.
I don't know how too describe what the best viscosity of the Q Cell/ Cabosil mix should be, you have to test it out.
Guys that do this well make really nifty parts very easily.
If you are trying to build a clear carbon fiber housing, you need to add some lamp black to the Q ells to make it darker.
SHC

Ok lets get a few things straight , NEVER USE Qcells as a filler when you want to STICK something Q cell makes a brittle mix that has little flexual strength !!!
Its used to make a lite weight filler to Fair with thats easy to sand and shape !! end of story !!so dont use it for anything else

Carbo sill is used to thicken resin with so it does not run and go everywhere !
and should be used in moderation !!.

[Steve Clark]

Geeze.
I guess I've been told.
Don't do it then.
SHC

[tunnels]

Originally Posted by Steve Clark

Geeze.
I guess I've been told.
Don't do it then.
SHC

50%flexable resin and 50%std resin + carbo sill + talc + milled fibre makes a really good mix to stick anything down with !!
milled fibre is very small strands of glass , the carbo sill and the talc are used as thickening agents , A small % of cobalt to promote the flexable resin , the flexable resin make the mix more flexable and less prone to being brittle and along with the milled fibre is really holds together . .
Have use this for more that 30 years and works 110% on everything ! wood , balsa , and any of the foams .

Never use Q cells for a adhesive type resin mix !!

[dinoa]

To keep resin/filler mixes from drooping add fumed silica (carbo sil?) such as HDK or Aerosil. Its heavier and harder to sand than microballoons but not much is required. If used as a core, filler mix strength is adequate but it should never contaminate resin used for laminating if you are applying it wet on wet.


dino

[Steve Clark]

Oh now I understand.
You are glueing things together with polyester.
I thought he was making a syntactic foam core.
Further, I was assuming this guy was laminating with epoxy.
Distinctly different.
SHC

[Herman]

If it is for a camera casing, I would design it in such a way that I would not need any core. It is way to fiddly to apply any core material. A larger, flat bit of the structure could be cored with some foam or balsa (which typically are available from 3 resp 5 mm) or Lantor Coremat or anything similar.

Coremat, by the way, is a polyester veil, impregnated with dissolved expancel. Running this veil through a steam oven, it expands. After that it is force-dried, then rolled. Pretty impressive machinery for that.