Model Boat Mayhem

Technical, Techniques, Hints, and Tips => GRP & Epoxy => Topic started by: wicker on June 27, 2014, 08:09:46 pm

Title: grp preparation
Post by: wicker on June 27, 2014, 08:09:46 pm

Is it advisable to use etching primer on a grp hull before painting -  thank

Title: Re: grp preparation
Post by: Subculture on June 27, 2014, 08:24:29 pm

No, that's for metal. Rub it down with 400 grit and hit it with normal primer.

Title: Re: grp preparation
Post by: wicker on June 27, 2014, 08:28:26 pm

Thanks for the advice - cheers

Title: Re: grp preparation
Post by: Stavros on June 27, 2014, 08:59:56 pm

Rub it down with 180grit..........trust me I am a paintsprayer
 
Dave

Title: Re: grp preparation
Post by: wicker on June 27, 2014, 09:21:45 pm

Yes I knew that - seen post in the past -  thank you -  and looking forward to Blackpool

Title: Re: grp preparation
Post by: Neil on July 03, 2014, 12:38:13 pm

Charlie.......I have used etching primer on grp many times................and it saves the paint flaking off when I use masking tape to waterline it.....not  paint sprayer..................or even a good painter....but never had any probs using it. neil.

Title: Re: grp preparation
Post by: wicker on July 03, 2014, 08:09:10 pm

Thanks for that Neil---soon be time for  meeting up again

Title: Re: grp preparation
Post by: Neil on July 03, 2014, 11:28:20 pm

aye Charlie....blackpool not to far away now..........mind you I suppose you'll be heading for the games in Glasgow in 3 weeks or so.............pop down to largs for the day...........I'll buy you a pint. neil.

Title: Re: grp preparation
Post by: wicker on July 04, 2014, 05:17:14 am

No not going to Glasgow but heading to Stornoway for 3 weeks and as for Largs I went to there lake and nobody spoke

Title: Re: grp preparation
Post by: cdsc123 on July 04, 2014, 04:24:17 pm

GRP etch primer is horrible  >:-o 
It will make the gelcoat more brittle and prone to cracking. It will help promote osmosis (on a real boat that is!). The softening/etching effect is lost after a while so after several layers of paint over the years you will lose whole patches several layers deep when you peel off masking tape. You will need to apply your paint within a specified time. There is no guarantee there is no mould release wax on the surface and etch primer will not work over wax.


Much better to use 180-240g wet and dry sandpaper with warm soapy water after acetone washing the whole thing inside and out, don't trust that the hull maker has done this for you  :-))

Title: Re: grp preparation
Post by: Neil on July 04, 2014, 06:42:42 pm

sorry but beg to disagree.........been using it on my own manufactured grp hulls for 20 years and never had a problem...............and can only speak from my own experience.. O0

Title: Re: grp preparation
Post by: wicker on July 04, 2014, 06:48:21 pm

I will try one with and one without just sanding