Thickening polyester resin

[Ardenfour]

I'm aware of the various thickening agents for use with epoxy resin, can I use the same products with polyester to make a thick paste? I'm planning to modify the mast rake by altering the existing wedge below the tabernacle, so has to be fairly strong and resist cracking/compression.

 

[thinwater]

I'm aware of the various thickening agents for use with epoxy resin, can I use the same products with polyester to make a thick paste? I'm planning to modify the mast rake by altering the existing wedge below the tabernacle, so has to be fairly strong and resist cracking/compression.

Yes. I have used Cabosil/colloidal silica many times.

 

[StefanSG]

Chopped up strands add strength, dont add too much silica or it tends to get brittle (IMHE)

SSG

 

[William_H]

I did the same using chopped strand mat in multiple layers tapering in area to provide wedge shape. Very strong. But yes any thickener for epoxy will be good for polyester. (even talcum powder. ) ol'will

 

[PaulRainbow]

Chopped strands in polyester = Isopon P40

P.40 - U-Pol

 

[Ardenfour]

Thanks for all replies

 

[Keith 66]

Bear in mind that Colloidal silica sold by West is considerably more expensive than Cabosil & is effectively the same stuff, as said brittle on its own so add choppies first.

 

[WindyWindyWindy]

One of the GRP companies do 3mm strands that you can use like silica, it gives a rougher finish but is much stronger.
Chopped Strands - 3 mm
Silica alone will be as brittle as gel coat.

 

[hurley]

I have used flour in the past with good results, tip passed to by by a Chemical Engineer 30 years ago.

 

[Rappey]

Cheapest has to be car body filler. It's virtualy uncrushable, easy to mould and sand and very durable with a coat of paint, and grp sticks very nicely to it.

 

[DownWest]

Cheapest has to be car body filler. It's virtualy uncrushable, easy to mould and sand and very durable with a coat of paint, and grp sticks very nicely to it.

Yes, but it is porous. As I found many years ago, when usig it to seal a test piece for a pressure test.

 

[PaulRainbow]

Yes, but it is porous. As I found many years ago, when usig it to seal a test piece for a pressure test.

The P40 i mentioned in post #5 isn't porous, it's chopped strand and polyester resin, cheap as chips and very strong.

 

[Ardenfour]

I have used flour in the past with good results, tip passed to by by a Chemical Engineer 30 years ago.

Tried mixing up a test batch with flour, I'm going to whack it with a hammer tomorrow, see how brittle it is.