JonC Posted January 25, 2021 Share Posted January 25, 2021 Here’s one for the boat restoration fibre glass enthusiasts, This is my boats propeller tube. When I was rubbing the old anti foul down I noticed wet water weeping out of the join, not from the inside where I’ve removed the cutlass. I understand that when the boats are taken out of the mould there is just a hole there and the tube is added afterwards. It appears to have sealant of some sort, maybe sikaflex around it. Ive been told that some are done with sikaflex at the factory and others are glassed in and gel coated over. The latter sounds better to me, how hard is it for a mere mortal to do? I can always dig out the old sealant and replace but fibreglass is going to be a better job I think. Quote Link to comment Share on other sites More sharing options...
Saintly Fish Posted January 25, 2021 Share Posted January 25, 2021 I had a similar thing with mine Jon. No water ingress, but the outside edge of the sealant was starting to peel. So I cut it all out, sanded it clean and then washed. Allowed it to dry properly and then re sikaflexed it. Hence my thread on sikaflex a couple of weeks ago. Quote Link to comment Share on other sites More sharing options...
JonC Posted January 25, 2021 Author Share Posted January 25, 2021 12 minutes ago, Saintly Fish said: I had a similar thing with mine Jon. No water ingress, but the outside edge of the sealant was starting to peel. So I cut it all out, sanded it clean and then washed. Allowed it to dry properly and then re sikaflexed it. Hence my thread on sikaflex a couple of weeks ago. Thanks for reply. I didn’t realise that you was using it for a similar application. The big difference is for my boat is that my boat’s propeller tube is fibreglass, so I will be able to bond it fully hopefully as opposed to your boat’s bronze or brass tunnel where sikaflex is clearly the way to go. Quote Link to comment Share on other sites More sharing options...
suzook12 Posted January 25, 2021 Share Posted January 25, 2021 You would have to be careful that the heat generated doesn't distort the tube or cause misalignment. Maybe thats why they sikaflex them in? Quote Link to comment Share on other sites More sharing options...
JonC Posted January 25, 2021 Author Share Posted January 25, 2021 23 minutes ago, suzook12 said: You would have to be careful that the heat generated doesn't distort the tube or cause misalignment. Maybe thats why they sikaflex them in? I hadn’t considered that. I don’t know if there is a lot of heat, it’s cooled by the boats raw water system I believe Quote Link to comment Share on other sites More sharing options...
suzook12 Posted January 25, 2021 Share Posted January 25, 2021 (edited) 7 minutes ago, JonC said: I hadn’t considered that. I don’t know if there is a lot of heat, it’s cooled by the boats raw water system I believe No, I mean while glassing, the exothermic reaction (big word for the day) of the resin going off Edited January 25, 2021 by suzook12 Quote Link to comment Share on other sites More sharing options...
JonC Posted January 25, 2021 Author Share Posted January 25, 2021 10 minutes ago, suzook12 said: No, I mean while glassing, the exothermic reaction (big word for the day) of the resin going off Right, I didn’t know that was a thing. How hot does it get? Quote Link to comment Share on other sites More sharing options...
suzook12 Posted January 25, 2021 Share Posted January 25, 2021 5 minutes ago, JonC said: Right, I didn’t know that was a thing. How hot does it get? The chemical reaction from the resin and activator. The more glassing you do in one go, the more heat generated. Likewise, done outside currently, it's highly possible not enough heat would be generated for a small amount of glasswork to cure properly. To do your tube looks like quite a bit of glassing would be required, though I will defer that to Geoff who has vastly more experience than me in glassing Quote Link to comment Share on other sites More sharing options...
JonC Posted January 25, 2021 Author Share Posted January 25, 2021 The tube is secure, I only need to make good the seal around where the old sealant was, maybe a 50mm band, I was thinking of cutting a few doughnut shaped rings to wrap around it. Quote Link to comment Share on other sites More sharing options...
suzook12 Posted January 25, 2021 Share Posted January 25, 2021 1 hour ago, JonC said: The tube is secure, I only need to make good the seal around where the old sealant was, maybe a 50mm band, I was thinking of cutting a few doughnut shaped rings to wrap around it. Then guess the only thing you need to worry about it being warm enough to glass it and flow coat it Geoff 1 Quote Link to comment Share on other sites More sharing options...
captin slows old outlaw Posted January 25, 2021 Share Posted January 25, 2021 if i rember jeff said to heat it a bit, i belive it likes 20 c to woork maybe put tarps hanging from the side of the boat to form a certin then a hot air heater ??? on small jobs i youse a paint striper on low heat Quote Link to comment Share on other sites More sharing options...
JonC Posted January 26, 2021 Author Share Posted January 26, 2021 16 hours ago, captin slows old outlaw said: if i rember jeff said to heat it a bit, i belive it likes 20 c to woork maybe put tarps hanging from the side of the boat to form a certin then a hot air heater ??? on small jobs i youse a paint striper on low heat Thanks, yes I can always wrap a sheet around the boat and run a space heater inside, get the temperature up a bit . captin slows old outlaw 1 Quote Link to comment Share on other sites More sharing options...
Geoff Posted January 26, 2021 Share Posted January 26, 2021 Jon, if you do decide to glass it in (a more permanent job in my opinion) I would think it would be better in a couple of months time and not in a freezing Jan/Feb. The area all around both surfaces must be clean and very dry and properly abraded to ensure good adhesion . Dig out any old sealant and make sure that there is a nice "vee" in the joint to allow the FG and resin to fill (we often use resin with a few chopped strands when filling in gaps etc. If glassing your tube in I think it would be best to form a small fillet radius around the tube to form a nice solid area for the mat. When "glassing in" the tube try to make each layer slightly bigger than the previous. I would not think that you will have any serious problems with distortion, but try to avoid using too much hardener. Applying a little heat will assist the curing, but it is quite easy to over do it. The best way to apply external local heat is with an electric hot air gun (or even a hair dryer). If you allow the FG to dry between layers the cured resin must be roughed up before the next layer. Good luck with your repair. Geoff. Quote Link to comment Share on other sites More sharing options...
JonC Posted January 26, 2021 Author Share Posted January 26, 2021 23 minutes ago, Geoff said: Jon, if you do decide to glass it in (a more permanent job in my opinion) I would think it would be better in a couple of months time and not in a freezing Jan/Feb. The area all around both surfaces must be clean and very dry and properly abraded to ensure good adhesion . Dig out any old sealant and make sure that there is a nice "vee" in the joint to allow the FG and resin to fill (we often use resin with a few chopped strands when filling in gaps etc. If glassing your tube in I think it would be best to form a small fillet radius around the tube to form a nice solid area for the mat. When "glassing in" the tube try to make each layer slightly bigger than the previous. I would not think that you will have any serious problems with distortion, but try to avoid using too much hardener. Applying a little heat will assist the curing, but it is quite easy to over do it. The best way to apply external local heat is with an electric hot air gun (or even a hair dryer). If you allow the FG to dry between layers the cured resin must be roughed up before the next layer. Good luck with your repair. Geoff. Thanks Geoff, I’m questioning the merits of it now, I certainly don’t want the boat out of the water much more than a month, so I may just settle for redoing the sikaflex! Quote Link to comment Share on other sites More sharing options...
Geoff Posted January 26, 2021 Share Posted January 26, 2021 23 minutes ago, JonC said: Thanks Geoff, I’m questioning the merits of it now, I certainly don’t want the boat out of the water much more than a month, so I may just settle for redoing the sikaflex! Oh Jon - if only you knew how long the verbiage took to write with my two sausage index fingers. Geoff. Quote Link to comment Share on other sites More sharing options...
JonC Posted January 26, 2021 Author Share Posted January 26, 2021 32 minutes ago, Geoff said: Oh Jon - if only you knew how long the verbiage took to write with my two sausage index fingers. Geoff. Pearls before swine someone used to say! Quote Link to comment Share on other sites More sharing options...
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