Does fibreglass need an etch base?

[molten]

the primer was mixed with thinners then added the liquid resin and styrene 3 quareter primer to quarter resin . mix a small amout up and do a test piece 1st

Hello
I opted to try this approach first as I had the materials. However I the 1st coat seems to take ages to dry off. Overcoated with normal celly primer.

Question.
If I added too much resin, would it still eventually dry/cure (seems to be drying but not sure if just celly primer overcoat) or will it never dry?

Thanks

 

[brightspark]

Hello
I opted to try this approach first as I had the materials. However I the 1st coat seems to take ages to dry off. Overcoated with normal celly primer.

Question.
If I added too much resin, would it still eventually dry/cure (seems to be drying but not sure if just celly primer overcoat) or will it never dry?

Thanks

i just mixed the resin with the amount of styrene recomended to cure it then added it to the thinned celly primer .do a test piece 1st . dont want u to c.//./..k it up

 

[langy]

Did you add the hardener ???

Hello
I opted to try this approach first as I had the materials. However I the 1st coat seems to take ages to dry off. Overcoated with normal celly primer.

Question.
If I added too much resin, would it still eventually dry/cure (seems to be drying but not sure if just celly primer overcoat) or will it never dry?

Thanks

 

[Engineer]

i just mixed the resin with the amount of styrene recomended to cure it then added it to the thinned celly primer .do a test piece 1st . dont want u to c.//./..k it up

Seems strange that styrene was suggested as a hardener for resin? Did it work ok?

 

[rtbcomp]

Dragging this up.........

http://shop.oval.co.uk/epages/62071729.sf/en_GB/?ObjectPath=/Shops/62071729/Products/106.001/SubProducts/106.001.1

is etching primer is suitable for

"Washfiller etch is recommended to be applied over ;
- Bare steel
- Aluminium
- Galvanised metal
- G R P (Glass reinforced plastic)
- Rigid Plastic bumpers
- T P A Thermoplastic acrylic : * Please take note!
- Polyester fillers and stoppers after flatting cellulose"

 

[langy]

I do a lot of glass and i find Epoxy the best first coat, etch can also be used, although hi build 2K primer doesn't adhere as well as either.

 

[marc.w]

+1 for epoxy as a 1st layer on GRP

 

[Keith 66]

I have spent many years working on boats most of them GRP, in the boat game nobody would use an etch primer unless it was on metal.
A cured polyester (grp) surface if sanded & prepped will take any 2k primer or topcoat direct. Where most problems occurr is with traces of release agent from the mould that the hull or part came from or polishes (wax or silicone) used afterwards. Cleaning any surface contamination off is of paramount importance. Epoxy primers are excellent but not always necessary.

 

[lexi]

For GRP, as stated the 2k epoxy is good for primer. Also Polyurethane paint has a natural adhesion to GRP , used mainly on boats.

The Styrene is present in the resin of lay up, or gel coat. When you add extra it is mainly as a thinner. The hardener is actually MEKP. It is not correct to use Acetone to thin resin .

 

[Keith 66]

As above, Styrene is the solvent used in Polyester resin it is not a hardener, The peroxide Catalyst (hardener) is what kicks the reaction of & makes the resin cure. The peroxide is nasty stuff that can get a fire started like you would not believe. Never wipe spillages up with rags or paper & leave them lying around.

 

[langy]

As above, Styrene is the solvent used in Polyester resin it is not a hardener, The peroxide Catalyst (hardener) is what kicks the reaction of & makes the resin cure. The peroxide is nasty stuff that can get a fire started like you would not believe. Never wipe spillages up with rags or paper & leave them lying around.

I was adding some hardener to some resin a few years ago and someone nudged me and i tipped in way to much and it ignited within a few seconds