Will polyester stick to aluminium

G DANE

Commander
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Nov 24, 2001
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2,476
I just inherited a lower unit for one of my parts motors, 35 Hp Evin, which were too good to trash. Unfortunately some unknown person tried to remove a stuck propeller by breaking with two screwdrivers and broke two chuncks off lower unit housing from edge around propeller. Instead of welding I thought of sandblasting edges of alloy, sanding thickness a bit down on outher and inner and fixing the missing pieces with poly resin mixed with cut glass and a very thin layer of cloth inside and outside. Sanded and painted at last. Will this work ?? I think welding there will heat bearing carrier, and motors isnt worth a lot. Gear works fine and seals are tight.
 

jim dozier

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Jan 8, 2003
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Re: Will polyester stick to aluminium

If you attempt such a repair use an epoxy based resin not polyester, much better adhesion, and a stronger matrix to add glass to. It may not be strong enough for your task but it will be better than polyester resin.
 

walleyehed

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Jun 29, 2003
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Re: Will polyester stick to aluminium

Marinetex is a fantastic repair product when worked thru glass cloth insted of resin.<br />Resin is not a true adhesive, marinetex due to it's chemical make-up, is.<br />As always, the alum. should be clean and pre-etched with acid for best adhesion.
 

WillyBWright

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Re: Will polyester stick to aluminium

Then again I've seen hunks out of this area on some motors without any ill effects. I like Marine Tex. Awesome stuff! I just wish it set up quicker. Quicker than JB Weld, though. Stays formed better too. JB would work, but I think it's too runny to work with. JB Weld is kinda like runny Marine Tex. Main advantage to JB would be availability. You can get that stuff anywhere. Marine Tex is more of a challenge. At least here in the States. In Denmark? I dunno.
 

G DANE

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Nov 24, 2001
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2,476
Re: Will polyester stick to aluminium

Thanks<br /><br />We dont have Marine Tex here. What we do have is of coarse poly and epoxy, and we have an aluminium repair paste made by a company called Plastic Padding. I might use that, and the reinforcement method. I'v got some af the priming acid from repair of a tank once.
 

jim dozier

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Re: Will polyester stick to aluminium

Both MarineTex and JBWeld are epoxy based resins with reinforcing materials added. If you can't find one of these American brands I am sure there are European equivalents. If not you can add finely chopped glass to any epoxy glue resin. If your resin is too runny you can add cabosil which is a thixotropic thickener.
 
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