I just glassed a board using poly laminating resin and put 1/2 the recommended sanding agent in the resin that you would use for the hotcoat.I’m doing a cutlap on the deck,after about 20 minutes I went to pull tape and do the cutlap and noticed the cloth pulls away from the board easily.Will the sanding agent cause bonding issues?
yes, its not good but it's too late. wait another 2-3 hours
The board is cedar,should I just peel the lam off or let it ride?
only seen it happen on foam, not sure about the cedar.
Thanks,I guess I’ll let it ride,I wont use sanding agent on the deck,so if the bottom delams and not the top I’ll know why.
The bond with the wood is suprisingly poor, even with epoxy. With poly it will be even worse.
But, its actually good enough - most foam delams occur from the foam failing, and wood is stronger than foam, so it should be adequate.
I’ve done many basic peel tests on wood, and noticed the same as what you are seeing.
The wax won’t affect the bond to the wood, unless it didn’t rise to the surface properly, which I guess could maybe happen if the cloth stops it some how.
I wouldn’t use wax in a lam anyway, it doesn’t serve any purpose.
It should be alright though, just give it a light scuff with 400 grit before hotcoating.
Thanks for the advice,I’ll give it a go.It was difficult to get a good cut on the lap with the laminate trying to peel up as I went,and to top it off the resin attacked my tape all the way around the board,the best way I could find to remove the sticky shit was with my fingertips.I just finished glassing the deck though and it’s really starting too come alive,I love how cedar gets dark and all the little grains jump out when resin hits it.If I don’t ruin the thing I’ll post pics.
Post some pics anyway please.
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I just glassed a board using poly laminating resin and put 1/2 the recommended sanding agent in the resin that you would use for the hotcoat.I'm doing a cutlap on the deck,after about 20 minutes I went to pull tape and do the cutlap and noticed the cloth pulls away from the board easily.Will the sanding agent cause bonding issues?
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Sorry stuffed up on my response.Am i missing something here or did you say your using filler resin to laminate your board.Bad move if you are.Waxed resin on waxed resin wont produce a satisfactory bond. Waxed resin is used in a sanding coat or a gloss coat.The bond needs to be tacky on tacky,normally.I suppose if you sand the first layup then apply the second layup you will get away with a reasonable laminate but then you need to fill the weave after,and that involves another application of a filler resin.Back to square 1.Not only making more work for yourself but risking the main bond between top and bottom laminates.IMHO
Just curious, why did you put sanding agent in a fiberglass lamination? Did you hear somewhere that it was the thing to do?
I normally work with epoxy and additive f and didn’t think it would affect the bond to have some sanding agent in the lam,figured it would thin the resin and make sanding the lap easier.
I have a few pics in the “what are you working on thread”,it’s the cedar board.
You understand that the sanding agent, more appropriately called “surfacing agent”, is a wax that rises to the surface during cure so that the polyester resin will cure hard and not tacky. Any bonding you need to do with it after you use surfacing agent and the wax should be removed. Which means sanding. But in the fiberglass lamination coat you will not have a smooth surface to get all the wax where it is in the dimples of the glass weave because you don’t want to sand into the glass fibers. As you know now, never use surfacing agent in a polyester resin lamination.
I would guess that the hot coat will fisheye profusly
Tip for removing tape residue from wood, use an eraser. Press hard and rub and the residue will stick to the eraser.
before the hot coat lightly scuff up lam with 120 and give it a rub with styrene on a lint free cloth to cut the wax and make the lam slight tacky.
poly does not like to stick to oily/resious woods (like ceadar), poly realy doesn't like to stick to anything other then poly, epoxy woul dhave been a better bet, but it should still be ok.