Hi, i recently purchased a 1000x700mm fibreglass garden pot cheap at Bunnings as there were cracks. I youtubed how to repair fibreglass and after slightly grinding out the cracks I decided to use Protite fibreglass resin to fill them.Things got messy & I need to sand it back and apply more coats and last night i attacked it with liquid nails in an effort to smooth the surface ....the problem is that i’m really struggling to sand back the fibreglass. Killed my Ozito Orbital Sander in the process, attacked the pot again with my Makita grinder & now have even more to more to fill and sand eek! Any help would be appreciated, including power tool ideas. I was considering buying a belt sander but not sure? I’m a newbie female attempting quite a few projects. Pics attached
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Welcome to the Bunnings Workshop community @jaimew. It's fabulous to have you join us and many thanks for your question.
Can I ask what grit sandpaper you are using to try and sand the fibreglass resin? From what you have mentioned so far it sounds like you need to go down some grits. I'd start with 80 grit to knock the majority off and then step up to a 120 grit which will give you a reasonable finish.
Are you planning to paint these pots? What sort of attachment to you have on your angle grinder?
Hi Mitchell, thanks for your reply yes and i going to paint it. have 2 other matching pots which are much smaller and one i repaired with liquid nails then sanded and painted. However, i’ve been playing around with the idea of using this large one as a pond or water feature. The sandpaper was a 40 grit lol. But being my first time using Protite I started to go off quicker than i expected and i ended up with some raised blobs (shaking my head). I tried manually sanding and i’ve got extremely sore shoulders today then moved on the the small orbital but the velcro is worn in a few places now from me pushing.
Was the sandpaper filling/gumming up very quickly? When did you apply the resin? I'd like you to try something for me and doubly so if the sandpaper is filling up quickly. Take a litre of water and put 3 big squeezes of dishwashing detergent in it. You want a decent amount in there and you can't really put too much. Wet the area you are going to sand down with a liberal amount of the soapy mixture and try sanding again. You should also now be able to wash the build-up in the sanding pads out and continue using them.
I've had an issue before with this type of Polyester resin where the top layers exposed to oxygen didn't cure properly and it was a nightmare to sand. I had tried just about everything, my sandpaper was filling /gumming up almost instantly and I was getting nowhere. I was just about to give up on the project until I found this trick with the soapy water. It would have been great if you could've tried this whist the orbital sander was still functioning correctly.
In fact, now that I'm thinking about it, it was my crayon inlay coffee table which is here on Workshop.
that is exactly what was happening to the sandpaper gumming i’m guessing. i applied the resin weeks ago so i didn’t think it would be an issue
ill definitely try the dishwashing detergent. i’m finding many uses for it lately. thank you!
Mitchell, you are a genius the dishwashing liquid and water idea worked like a treat! it’s working perfectly, haven’t even gone through one sanding pad yet my arms gave out though. thank you so much for your help. Jaime
Fantastic, thanks so much for letting us know @jaimew.
Looking forward to seeing the end result.